Prognostic significance of beat-to-beat variability of spatial heterogeneity of repolarization analyzed from a 5-minute resting electrocardiogram in coronary artery disease

BACKGROUND

Data on the prognostic significance of temporal variability of spatial heterogeneity of electrocardiographic repolarization in coronary artery disease (CAD) are limited.

OBJECTIVE

The purpose of this study was to evaluate the prognostic value of temporal variability of T-wave morphology analyzed from a 5-minute resting electrocardiogram in CAD.

METHODS

The standard deviation (SD) of T-wave morphology dispersion (TMD-SD) and the SD of total cosine R-to-T were analyzed on a beat-to-beat basis from a 5-minute period of the standard resting 12-lead electrocardiogram obtained before the clinical stress test in 1702 patients with angiographically verified CAD and well-preserved left ventricular function.

RESULTS

During an average of 8.7 ± 2.2 years of follow-up, 60 patients experienced sudden cardiac death/arrest (SCD/SCA) (3.5%), 69 patients nonsudden cardiac death (NSCD) (4.1%), and 161 patients noncardiac death (9.5%). TMD-SD was significantly higher in patients who experienced SCD/SCA than in other patients (1.72 ± 2.00 vs 1.12 ± 1.75; P = .01) and higher in patients who succumbed to NSCD than in other patients (1.57 ± 1.74 vs 1.12 ± 1.76; P = .04), but it did not differ significantly between patients who experienced noncardiac death and those without such an event (1.16 ± 1.42 vs 1.14 ± 1.79; P = .86). In the Cox multivariable hazards model, TMD-SD retained its significant association with the risk of SCD/SCA (hazard ratio 1.119; 95% confidence interval 1.015-1.233; P = .024) but not with the risk of NSCD (hazard ratio 1.089; 95% confidence interval 0.983-1.206; P = .103).

CONCLUSION

TMD-SD is independently associated with the long-term risk of SCD/SCA in patients with CAD.

Day-of-the-week variation of sudden unexpected cardiac death

Background

There has been some controversy about the day-of-the-week (septadian) variation of unexpected sudden cardiac death (SCD).

Methods

We evaluated the incidence of unexpected SCD on different days of the week in a consecutive series of 5869 SCD victims from Northern Finland [the FINGESTURE study (Finnish Genetic Study of Arrhythmic Events)]. As it is mandatory in Finland, a medico-legal autopsy was performed on all unexpected sudden death victims. The autopsies were performed between the years 1998-2017.

Results

The mean incidence of unexpected SCD was higher at weekends (during the days from Friday to Sunday, peaking on Saturday) than during the days from Monday to Thursday (8.54 ± 0.72 vs. 7.22 ± 0.19 SCDs per day of the week per 100,000 inhabitants per year, p < 0.001). Regardless of sex or ischemic versus non-ischemic etiology of SCD, the distribution of the occurrence of SCD among the days of the week was similar compared with the whole SCD cohort.

Conclusion

The incidence of unexpected SCD was highest at weekends (during the days from Friday to Sunday, peaking on Saturday).

Lifestyle and Cardiac Structure and Function in Healthy Midlife Population

The association between lifestyle and cardiac structure and function measures, such as global longitudinal strain and diastolic function in a healthy midlife general population, is not well known. A subpopulation of the Northern Finland Birth Cohort 1966 took part in follow-up, including echocardiography (n = 1,155) at the age of 46. All antihypertensive medication users (n = 164), patients with diabetes (n = 70), subjects with any cardiac diseases (n = 24), and subjects with echocardiography abnormalities (n = 21) were excluded. Moderate to vigorous physical activity (MVPA) was recorded with a wrist-worn accelerometer over 14 days and categorized into high, moderate, and low MVPA groups. Similarly, alcohol consumption was categorized as low, moderate, and high-dose users of alcohol and smoking as nonsmokers, former, and current smokers. The total number of healthy subjects included in the study was 715 (44% males). Left ventricular mass index and left atrial end-systolic volume index were significantly higher in the high MVPA group compared with the low MVPA group (adjusted main effect p = 0.002 and p <0.001, respectively). Cardiac function did not differ among the physical activity groups. High alcohol consumption was associated with impaired global longitudinal strain and diastolic function (adjusted main effect p = 0.002 and p = 0.004, respectively) but not with any cardiac structure variables. Smoking was not associated with cardiac structure or function. In healthy middle-aged adults, MVPA was independently associated with structural changes in the heart but not with cardiac function. High alcohol consumption was associated with impaired modern cardiac function measures but not with cardiac structure.

Lower hemoglobin levels associate with higher baroreflex sensitivity and heart rate variability

The aim of this study was to cross-sectionally examine whether hemoglobin (Hb) levels within the normal variation associate with heart rate variability (HRV) measures and baroreflex sensitivity (BRS). The study population included 733 Finnish subjects of the OPERA cohort (aged 41-59 yr, 53% males, 51.7% treated for hypertension) of whom HRV was measured from a standardized 45-min period and whose Hb levels were within the Finnish reference intervals. The low Hb tertile (mean Hb, 135 g/L) had an overall healthier metabolic profile compared with the high Hb tertile (mean Hb, 152 g/L). BRS was higher in the low Hb tertile compared with the high Hb tertile (P < 0.05). R-R interval (RRi) and standard deviation (SD) of the RRi (SDNN)index were the longest in the low Hb tertile regardless of posture. Of the spectral components of HRV, HF power was the highest in the low Hb tertile regardless of posture (P < 0.05). In a stepwise logistic regression model, BRS associated negatively with Hb levels after adjusting for covariates (B = -0.160 [-0.285; -0.035]). Similar associations were observed for SDNNindex when lying down (B = -0.105 [-0.207; -0.003]) and walking (B = -0.154 [-0.224; -0.083]). For HF power negative associations with Hb levels were observed when lying down (B = -0.110 [-0.180; -0.040]), sitting (B = -0.150 [-0.221; -0.079]), and in total analysis (B = -0.124 [-0.196; -0.053]). Overall, lower Hb levels associated independently with healthier cardiac autonomic function.NEW & NOTEWORTHY Heart rate variability (HRV) and baroreflex sensitivity (BRS), which can be measured noninvasively, can predict cardiac and metabolic diseases. Our findings show that within normal variation subjects with lower hemoglobin (Hb) levels have an overall healthier HRV profile and increased cardiac parasympathetic activity in middle age, independent of age, sex, smoking status, and key metabolic covariates. These findings support our previous findings that Hb levels can be used in assessing long-term risks for cardiometabolic diseases.

Association of electrocardiographic spatial heterogeneity of repolarization and spatial heterogeneity of atrial depolarization with left ventricular fibrosis

AIMS

To evaluate the relationship between spatial heterogeneity of electrocardiographic repolarization and spatial heterogeneity of atrial depolarization with arrhythmic substrate represented by left ventricular fibrosis.

METHODS AND RESULTS

We assessed the associations of T- and P-wave morphology parameters analysed from the standard 12-lead electrocardiograms with left ventricular fibrosis in 378 victims of unexpected sudden cardiac death (SCD) who underwent medico-legal autopsy. Based on autopsy findings, the SCD victims were categorized into four different groups according to different stages of severity of left ventricular fibrosis (substantial fibrosis, moderate patchy fibrosis, scattered mild fibrosis, no fibrosis). T-wave and P-wave area dispersion (TWAd: 0.0841 ± 0.496, 0.170 ± 0.492, 0.302 ± 404, 0.296 ± 0.476, P = 0.008; PWAd: 0.574 ± 0.384, 0.561 ± 0.367, 0.654 ± 0.281, 0.717 ± 0.257, P = 0.011, respectively; low values abnormal), non-dipolar components of T-wave and P-wave morphology (T_NonDipolarABS: 0.0496 ± 0.0377, 0.0571 ± 0.0487, 0.0432 ± 0.0476, 0.0380 ± 0.0377, P = 0.027; P_NonDipolarABS: 0.0132 ± 0.0164, 0.0130 ± 0.0135, 0.0092 ± 0.0117, 0.0069 ± 0.00472, P = 0.005, respectively, high values abnormal), T-wave morphology dispersion (TMD: 45.9 ± 28.3, 40.5 ± 25.8, 35.5 ± 24.9, 33.0 ± 24.6, P = 0.030, respectively, high values abnormal), and P-wave heterogeneity (PWH: 20.0 ± 9.44, 19.7 ± 8.87, 17.9 ± 9.78, 15.4 ± 4.60, P = 0.019, respectively, high values abnormal) differed significantly between the groups with different stages of left ventricular fibrosis. After adjustment with heart weight, T_NonDipolarABS [standardized β (sβ) = 0.131, P = 0.014], PWAd (sβ = -0.161, P = 0.003), P_NonDipolarABS (sβ = 0.174, P = 0.001), and PWH (sβ = 0.128, P = 0.015) retained independent association, and TWAd (sβ = -0.091, P = 0.074) and TMD (sβ = 0.097, P = 0.063) tended to retain their association with the degree of myocardial fibrosis.

CONCLUSION

Our findings suggest that abnormal values of T- and P-wave morphology are associated with arrhythmic substrate represented by ventricular fibrosis partly explaining the mechanism behind their prognostic significance.

Use of psychotropic medication in victims of sudden cardiac death with nonischemic heart disease

BACKGROUND

Nonischemic heart disease (NIHD) is the underlying pathology in about 20% of sudden cardiac deaths (SCDs). Psychotropic medication has been reported as a risk factor for SCD among patients with coronary artery disease, but similar information concerning NIHD is scarce.

OBJECTIVES

We evaluated the use of psychotropic medication in victims of SCD due to NIHD and compared it to the general medication use in Finland.

METHOD

Study population was derived from the Finnish Genetic Study of Arrhythmic Events (Fingesture) (n = 5,869, mean age 65±12, 79% males; 1,404 victims of SCD due to NIHD, mean age 57±13, 77% males). All deaths occurred in Northern Finland during 1998-2017. All victims underwent a medico-legal autopsy. Data on use of medication was defined using post-mortem toxicology results and patient records. Subjects with neither toxicological analysis nor information of medication use available were excluded. Information on general medication use was derived from Finnish Statistics on Medicines 2018 and presented as defined daily dose/1000 inhabitants/day.

RESULTS

Psychotropic medication was used by 579 (41%) subjects with NIHD, whereas in the general population only 12% were estimated to use psychotropics. The results were similar in subgroups of psychotropic medication: 27% vs 2.3% for benzodiazepines, 19% vs 7.5% for antidepressants and 18% vs 2.2% for antipsychotics.

CONCLUSIONS

Use of psychotropic medication is common in victims of SCD due to NIHD compared to the general population.

Prognostic value of P-wave morphology in general population

AIMS

To evaluate the prognostic significance of novel P-wave morphology descriptors in general population.

METHODS AND RESULTS

Novel P-wave morphology variables were analyzed from orthogonal X-, Y-, Z-leads of the digitized electrocardiogram using a custom-made software in 6906 middle-aged subjects of the Mini-Finland Health Survey. A total of 3747 (54.3%) participants died during the follow-up period of 24.3 ± 10.4 years; 379 (5.5%) of the study population succumbed to sudden cardiac death (SCD), 928 (13.4%) to non-SCD (NSCD) and 2440 (35.3%) patients to non-cardiac death (NCD). In univariate comparisons, most of the studied P-wave morphology parameters had a significant association with all modes of death (P from <0.05 to <0.001). After relevant adjustments in the Cox multivariate hazards model, P-wave morphology dispersion (PMD) still tended to predict SCD [hazard ratio (HR): 1.006, 95% confidence interval (CI): 1.000-1.012, P = 0.05) but not NSCD (HR: 0.999, 95% CI: 0.995-1.003, P = 0.68) or NCD (HR: 0.999, 95% CI: 0.997-1.001, P = 0.44). The P-wave maximum amplitude in the lead Z (P-MaxAmp-Z) predicted SCD even after multivariate adjustments (HR: 1.010, 95% CI: 1.005-1.015, P = 0.0002) but also NSCD (HR: 1.005, 95% CI: 1.002-1.009, P = 0.0005) and NCD (HR: 1.002, 95% CI: 1.000-1.005, P = 0.03).

CONCLUSION

Abnormalities of P-wave morphology are associated with the risk of all modes of death in general population. After relevant adjustments, PMD was still closely associated with the risk of SCD but not with NSCD or NCD. P-MaxAmp-Z predicted SCD even after adjustments, however, it also retained its association with NSCD and NCD.

Causes and characteristics of unexpected sudden cardiac death in octogenarians/nonagenarians

INTRODUCTION

The risk for sudden cardiac death (SCD) increases with ageing.

METHODS

We evaluated causes and characteristics of unexpected SCD in SCD victims aged ≥ 80 years in a consecutive series of 5,869 SCD victims in Northern Finland. All the victims underwent medico-legal autopsy as medico-legal autopsy is mandatory in cases of unexpected sudden death in Finland. All the non-cardiac deaths such as pulmonary embolism and cerebral hemorrhage were excluded from the study, as were unnatural deaths such as intoxications.

RESULTS

Among SCD victims ≥ 80 years, 91.0% of SCDs were due to ischemic heart disease (IHD) determined in autopsy and 9.0% due to non-ischemic heart disease (NIHD), whereas among those < 80 years, only 72.6% of SCDs were due to IHD and 27.4% due to NIHD (P < .001). Severe fibrosis in myocardium was more common whereas heart weight and liver weight, body mass index and abdominal fat thickness, were lower among SCD victims aged ≥ 80 years than among victims aged < 80 years. In those with IHD as etiology of SCD, at least 75% stenosis in one or more major coronary vessels was more common in SCD victims aged ≥ 80 years than among victims aged < 80 years (P = .001). SCD victims 80 years or older were less likely to die during physical activity than those under 80 years old (5.6% vs. 15.9%, P < .001). Dying in sauna was more common among those ≥ 80 years than among those < 80 years (5.5% vs. 2.6%, P < .001).

CONCLUSION

In victims of unexpected SCD aged ≥ 80 years, the autopsy-based etiology of SCD was more commonly IHD than in those aged < 80 years. In SCD victims aged ≥ 80 years, severe fibrosis in myocardium, representing arrhythmic substrate, was more common than in the younger ones.

Association of atrial depolarization variability and cardiac autonomic regulation with sudden cardiac death in coronary artery disease

AIMS

To evaluate the prognostic significance of the temporal variability of P-wave morphology, specifically in relation to cardiac autonomic regulation.

METHODS AND RESULTS

We analyzed the standard deviation of P-wave residuum (PWRSD) from five consecutive beats of the standard 12-lead ECG in 1236 patients with angiographically verified coronary artery disease (CAD). We evaluated the prognostic value of PWRSD, of PWRSD and PWR in relation to the 24 h standard deviation of normal-to-normal intervals (PWRSD/SDNN and PWR/SDNN). After 8.7 ± 2.2 years of follow-up on average, 43 patients (3.5%) experienced sudden cardiac death (SCD) or were resuscitated from sudden cardiac arrest (SCA), 34 (2.8%) succumbed to non-sudden cardiac death (NSCD) and 113 (9.1%) to non-cardiac death (NCD). In the Cox regression analysis, PWRSD (≥0.002727) had a significant univariate (uv) [hazard ratio (HR): 4.27, 95% confidence interval (CI): 2.26-8.08, P = 0.000008] and multivariate (mv) (HR: 2.58, 95% CI: 1.31-5.08, P = 0.006) association with SCD/SCA but not with NSCD (uv P = 0.76, mv P = 0.33) or NCD (uv P = 0.57, mv P = 0.66). All the studied P-morphology parameters retained a significant association with the risk of SCD/SCA after relevant adjustment (mv P-values from 0.00003 to <0.05) but not with NSCD or NCD. When dichotomized PWRSD, PWR, PWRSD/SDNN, and PWR/SDNN were added to the clinical risk model for SCD/SCD, the C-index increased from 0.799 to 0.834 and integrated discrimination index and net reclassification index improved significantly (P < 0.001).

CONCLUSION

Variability of P-morphology representing temporo-spatial heterogeneity of atrial depolarization, specifically when combined with cardiac autonomic regulation, independently predicts the risk of SCD in patients with CAD.

T-wave alternans poorly prognostic in primary prophylactic ICD patients: a prospective EU-CERT-ICD study

Background

New methods to identify patients who truly benefit from primary prophylactic implantable cardioverter defibrillation (ICD) are urgently needed. T-wave alternans (TWA) represents a beat-to-beat fluctuation in the morphology of the ST-segment and T-wave. It has been shown to associate with arrhythmogenesis of heart and sudden cardiac death [1]. We hypothised that TWA might associate with benefit from ICD implantation in primary prevention.

Methods

In EU-CERT-ICD study, we prospectively enrolled 2327 primary prophylactic ICD candidates from 15 European countries. A 24-hours Holter-monitoring was taken from all recruited patients at enrolment. TWA was assessed from Holter-monitoring using MMA method with Getemed Cardioday software. To assess the benefit from ICD treatment, we used outcomes all-cause mortality, appropriate shock and survival benefit. We conducted Cox regression model, competing risk regression model and propensity score adjusted Cox regression model. TWA was assessed both as contiguous variable and with cut-off points &lt;47 μV and &lt;60 μV.

Results

Final cohort included 1,734 valid T-wave alternans samples, 1,211 patients with ICD and 523 control patients with conservative treatment, with mean follow-up time 2.3 years. TWA &lt;60 μV predicted lower all-cause mortality in ICD patients in univariate cox regression model (HR 1.484, 95% CI 1.024–2.151, p=0.0374). In multivariate models, TWA did not predict death or appropriate shocks in ICD patients. In addition, TWA did not predict death in control patients. In propensity score adjusted Cox regression model, TWA did not predict ICD benefit.

Conclusion

T-wave alternans is poorly prognostic in primary prophylactic ICD patients. Altough it may predict life-threatening arrhythmias and sudden cardiac death in several patient populations, it cannot be used in assessing benefit from implantable cardioverter defibrillator in primary prevention among patients with ejection fraction ≤35%.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Community's 7th Framework Program FP7/2007-2013

Sex differences in prevalence of electrocardiographic and echocardiographic left ventricular hypertrophy among patients with coronary artery disease

Background

Both electrocardiographic left ventricular hypertrophy (ECG-LVH) and echocardiographic LVH (echo-LVH) are associated with higher risk of cardiovascular and sudden cardiac death. ECG-LVH seems to be partly distinct from echo-LVH as many subjects with echo-LVH do not have ECG-LVH and vice versa. The difference between sexes have not been studied earlier.

Purpose

The aim of this study was to determine sex differences in prevalence of ECG-LVH and echo-LVH among patients with coronary artery disease (CAD) and to study if ECG-LVH would have higher accuracy for echo-LVH in either of sexes.

Methods

Standard 12-lead electrocardiograms and echocardiographic measurements were studied from 1,894 subjects of ARTEMIS Study (31.8% women). Echo-LVH was determined as estimated left ventricular (LV) mass ≥201 g in men and ≥151 g in women and was categorized as mildly, moderately and severely abnormal. ECG-LVH was determined if either criteria of Sokolow-Lyon or Cornell were met.

Results

Echo-LVH was found from 1,162 of the study subjects (women 34.3%, p=0.004) and ECG-LVH only from 222 of the subjects (women 55.9%, p&lt;0.001). Of those with ECG-LVH, 82.0% had increased LV mass (p&lt;0.001), and ECG-LVH seemed to correlate slightly better to echo-LVH in women than in men (82.3% vs. 81.6%, p&lt;0.001). Of those with ECG-LVH, 47.7% had severe echo-LVH (p&lt;0.001). The prevalence of ECG-LVH was the higher the greater the LV mass was. Among men with ECG-LVH, 46.9% had severe echo-LVH (p&lt;0.001). Among women with ECG-LVH, 16.1% had mild echo-LVH (p=0.029) and 48.4% severe echo-LVH (p&lt;0.001). In addition, 18% of those with ECG-LVH did not have echo-LVH (p&lt;0.001). This proportion was slightly smaller in women than in men (17.7% vs. 18.4%, p&lt;0.001).

Only 15.7% of the subjects with echo-LVH had ECG-LVH (p&lt;0.001). This proportion was significantly higher in women than in men (25.6% vs. 10.5%, p&lt;0.001). ECG-LVH was more common finding in subjects with severe echo-LVH as 20.9% of those CAD patients had ECG-LVH (p&lt;0.001). Among women with severe echo-LVH, ECG-LVH was found in 35.3% (p&lt;0.001) whereas only in 13.7% of men with severe echo-LVH (p&lt;0.001). The prevalence of ECG-LVH seemed to be considerably higher among female CAD patients with T2DM and without prior MI as ECG-LVH was seen in 33.0% of those subjects with at least midl echo-LVH (p&lt;0.001) and 43.8% of those subjects with severe echo-LVH (p&lt;0.001). In male patients from similar subgroup and some degree of echo-LVH, ECG-LVH was seen in 6.7% (p=0.042) and with severe echo-LVH in 12.2% (p&lt;0.001) of the subjects.

Conclusions

In patients with CAD echo-LVH was often seen without signs of ECG-LVH, especially in men. Majority of the CAD patients with ECG-LVH had also echo-LVH and the prevalence on ECG-LVH was the higher the greater the LV mass was. ECG-LVH seemed to correlate better to anatomic LVH in women with CAD than in men, and the sex difference was highlighted in CAD patients with T2DM and no prior MI.

Funding Acknowledgement

Type of funding sources: None.

The Risk of Sudden Cardiac Death Associated with QRS, QTc and JTc intervals in the General Population Revision #4

BACKGROUND

QRS duration and QTc interval have been associated with sudden cardiac death (SCD), but no data is available on the significance of repolarization component (JTc interval) of QTc as an independent risk marker in the general population.

OBJECTIVE

In this study, we sought to quantify the risk of SCD associated with QRS, QTc and JTc.

METHODS

This study was conducted using data from 3 population cohorts from different eras, comprising a total of 20,058 individuals. The follow-up was limited to 10 years and age at baseline to 30-61 years. QRS duration and QT interval (Bazett's) were measured from standard 12-lead electrocardiograms at baseline. JTc interval was defined as QTc - QRS duration. Cox proportional hazard models that controlled for confounding clinical factors identified at baseline were used to estimate the relative risk of SCD.

RESULTS

During a mean period of 9.7 years, 207 SCDs occurred (1.1 per 1000 person-years). QRS duration was associated with a significantly increased risk of SCD in each cohort (pooled hazard ratio 1.030 per 1 ms increase (95% confidence interval 1.017-1.043). The QTc interval had borderline to significant associations with SCD and varied among cohorts (pooled HR 1.007, 95%CI 1.001-1.012). JTc interval as a continuous variable was not associated with SCD (pooled HR 1.001, 95%CI 0.996-1.007).

CONCLUSIONS

Prolonged QRS durations and QTc intervals are associated with an increased risk of sudden cardiac death. However, when QTc is deconstructed into QRS and JTc intervals, the repolarization component (JTc) appears to have no independent prognostic value.

Genetic Variants Associated With Sudden Cardiac Death in Victims With Single Vessel Coronary Artery Disease and Left Ventricular Hypertrophy With or Without Fibrosis

Objective: Cardiac hypertrophy with varying degrees of myocardial fibrosis is commonly associated with coronary artery disease (CAD) related sudden cardiac death (SCD), especially in young victims among whom patterns of coronary artery lesions do not entirely appear to explain the cause of SCD. Our aim was to study the genetic background of hypertrophy, with or without fibrosis, among ischemic SCD victims with single vessel CAD.

Methods: The study population was derived from the Fingesture study, consisting of all autopsy-verified SCDs in Northern Finland between the years 1998 and 2017 (n = 5,869). We carried out targeted next-generation sequencing using a panel of 174 genes associated with myocardial structure and ion channel function in 95 ischemic-SCD victims (mean age 63.6 ± 10.3 years; 88.4% males) with single-vessel CAD in the absence of previously diagnosed CAD and cardiac hypertrophy with or without myocardial fibrosis at autopsy.

Results: A total of 42 rare variants were detected in 43 subjects (45.3% of the study subjects). Five variants in eight subjects (8.4%) were classified as pathogenic or likely pathogenic. We observed 37 variants of uncertain significance in 39 subjects (40.6%). Variants were detected in myocardial structure protein coding genes, associated with arrhythmogenic right ventricular, dilated, hypertrophic and left ventricular non-compaction cardiomyopathies. Also, variants were detected in ryanodine receptor 2 (RYR2), a gene associated with both cardiomyopathies and catecholaminergic polymorphic ventricular tachycardias.

Conclusions: Rare variants associated with cardiomyopathies, in the absence of anatomic evidence of the specific inherited cardiomyopathies, were common findings among CAD-related SCD victims with single vessel disease and myocardial hypertrophy found at autopsies, suggesting that these variants may modulate the risk for fatal arrhythmias and SCD in ischemic disease.

Blood alcohol levels in Finnish victims of non-ischaemic sudden cardiac death

INTRODUCTION

Non-ischaemic heart disease (NIHD) is the underlying pathology in∼20% of all sudden cardiac deaths (SCDs). Heavy drinking is known to be associated with SCD due to ischaemic heart disease, but studies on association of recent alcohol consumption and SCD in patients with NIHD are scarce. We evaluated the blood alcohol levels of autopsy verified non-ischaemic SCD victims.

METHODS

Study population was derived from the Finnish Genetic Study of Arrhythmic Events (Fingesture) (n = 5869, mean age 65 ± 12, 79% males). All deaths occurred in Northern Finland during 1998-2017. All victims underwent a medico-legal autopsy. Subjects of SCD due to ischaemic heart disease were excluded.

RESULTS

A total of 1301 (mean age 57 ± 12, 78% males) victims of SCD due to NIHD were included in the study. The blood ethanol level was elevated in 543 (42%) subjects, out of which the blood alcohol level was ≥0.10%in 339 (62%) subjects and ≥0.15%in 252 (46%) subjects. Male SCD victims had alcohol in blood more frequently compared to females (45% versus 31%, p < .001).

CONCLUSION

Elevated blood alcohol level is common in SCD victims due to NIHD, especially in males. Recent alcohol consumption might contribute to the subsequent SCD in many non-ischaemic SCD victims.KEY MESSAGESElevated blood alcohol level is common in victims of sudden cardiac death due to non-ischaemic heart disease, especially in males.Recent alcohol consumption may contribute to the subsequent death in many nonischemic sudden cardiac death victims.

Q waves are the strongest electrocardiographic variable associated with primary prophylactic implantable cardioverter-defibrillator benefit: a prospective multicentre study

AIM

The association of standard 12-lead electrocardiogram (ECG) markers with benefits of the primary prophylactic implantable cardioverter-defibrillator (ICD) has not been determined in the contemporary era. We analysed traditional and novel ECG variables in a large prospective, controlled primary prophylactic ICD population to assess the predictive value of ECG in terms of ICD benefit.

METHODS AND RESULTS

Electrocardiograms from 1477 ICD patients and 700 control patients (EU-CERT-ICD; non-randomized, controlled, prospective multicentre study; ClinicalTrials.gov Identifier: NCT02064192), who met ICD implantation criteria but did not receive the device, were analysed. The primary outcome was all-cause mortality. In ICD patients, the co-primary outcome of first appropriate shock was used. Mean follow-up time was 2.4 ± 1.1 years to death and 2.3 ± 1.2 years to the first appropriate shock. Pathological Q waves were associated with decreased mortality in ICD patients [hazard ratio (HR) 0.54, 95% confidence interval (CI) 0.35-0.84; P < 0.01] and patients with pathological Q waves had significantly more benefit from ICD (HR 0.44, 95% CI 0.21-0.93; P = 0.03). QTc interval increase taken as a continuous variable was associated with both mortality and appropriate shock incidence, but commonly used cut-off values, were not statistically significantly associated with either of the outcomes.

CONCLUSION

Pathological Q waves were a strong ECG predictor of ICD benefit in primary prophylactic ICD patients. Excess mortality among Q wave patients seems to be due to arrhythmic death which can be prevented by ICD.

Prognostic significance of flat T-waves in the lateral leads in general population

BACKGROUND

Negative T-waves are associated with sudden cardiac death (SCD) risk in the general population. Whether flat T-waves also predict SCD is not known. The aim of the study was to examine the clinical characteristics and risk of SCD in general population subjects with flat T-waves.

METHODS

We examined the electrocardiograms of 6750 Finnish general population adults aged ≥30 years and classified the subjects into 3 groups: 1) negative T-waves with an amplitude ≥0.1 mV in ≥2 of the leads I, II, aVL, V4-V6, 2) negative or positive low amplitude T-waves with an amplitude <0.1 mV and the ratio of T-wave and R-wave <10% in ≥2 of the leads I, II, aVL, V4-V6, and 3) normal positive T-waves (not meeting the aforesaid criteria). The association between T-wave classification and SCD was assessed during a 10-year follow-up.

RESULTS

A total of 215 (3.2%) subjects had negative T-waves, 856 (12.7%) flat T-waves, and 5679 (84.1%) normal T-waves. Flat T-wave subjects were older and had more often cardiovascular morbidities compared to normal T-wave subjects, while negative T-wave subjects were the oldest and had most often cardiovascular morbidities. After adjusting for multiple factors, both flat T-waves (hazard ratio [HR] 1.81; 95% confidence interval [CI] 1.13-2.91) and negative T-waves (HR 3.27; 95% CI 1.85-5.78) associated with SCD.

CONCLUSIONS

Cardiovascular risk factors and disease are common among subjects with flat T-waves, but these minor T-wave abnormalities are also independently associated with increased SCD risk.

Prognostic value of heart rate variability in patients with coronary artery disease in the current treatment era

Coronary artery disease (CAD) mortality has declined substantially over the past decades thanks to advancing medical and interventional/surgical treatments; therefore, the prognostic value of the heart rate variability in CAD in the current treatment era is not well established. We evaluated the prognostic significance of baseline heart rate variability in 1,757 ARTEMIS study patients with angiographically verified CAD. During an average follow-up time of 8.7 ± 2.2 years, a total of 285 (16.2%) patients died. Of the patients, 63 (3.6%) suffered sudden cardiac death or were resuscitated from sudden cardiac arrest (SCD/SCA), 60 (3.4%) experienced non-sudden cardiac death (NSCD), and death attributable to non-cardiac causes (NCD) occurred in 162 (9.2%) patients. For every 10 ms decrease in standard deviation of normal to normal intervals the risk for SCD/SCA, NSCD and NCD increased significantly: HR 1.153 (95% CI 1.075–1.236, p<0.001), HR 1.187 (95% CI 1.102–1.278, p<0.001) and HR 1.080 (95% CI 1.037–1.125, p<0.001), respectively. The natural logarithm of the low-frequency component of the power spectrum and the short-term scaling exponent of the detrended fluctuation analysis also had significant association with all modes of death (p<0.001). After relevant adjustment, standard deviation of normal-to-normal intervals retained its association with NSCD and NCD (p<0.01), the natural logarithm of the low-frequency component of the power spectrum with all modes of death (p from <0.05 to <0.01), and the short-term scaling exponent of the detrended fluctuation analysis with SCD/SCA (p<0.05) and NCD (p<0.001). In conclusion, impairment of many measures of heart rate variability predicts mortality but is not associated with any specific mode of death in patients with stable CAD during the current treatment era, limiting the clinical applicability of heart rate variability to targeting therapy.

Orthogonal P-wave morphology, conventional P-wave indices, and the risk of atrial fibrillation in the general population using data from the Finnish Hospital Discharge Register

AIMS

Identifying subjects at high and low risk of atrial fibrillation (AF) is of interest. This study aims to assess the risk of AF associated with electrocardiographic (ECG) markers linked to atrial fibrosis: P-wave prolongation, 3rd-degree interatrial block, P-terminal force in lead V1, and orthogonal P-wave morphology.

METHODS AND RESULTS

P-wave parameters were assessed in a representative Finnish population sample aged ≥30 years (n = 7217, 46.0% male, mean age 51.4 years). Subjects (n = 5489) with a readable ECG including the orthogonal leads, sinus rhythm, and a predefined orthogonal P-wave morphology type [positive in leads X and Y and either negative (Type 1) or ± biphasic (Type 2) in lead Z; Type 3 defined as positive in lead X and ± biphasic in lead Y], were followed 10 years from the baseline examinations (performed 1978-80). Subjects discharged with AF diagnosis after any-cause hospitalization (n = 124) were defined as having developed AF. Third-degree interatrial block was defined as P-wave ≥120 ms and the presence of ≥2 ± biphasic P waves in the inferior leads. Hazard ratios (HRs) and confidence intervals (CIs) were assessed with Cox models. Third-degree interatrial block (n = 103, HR 3.18, 95% CI 1.66-6.13; P = 0.001) and Type 3 morphology (n = 216, HR 3.01, 95% CI 1.66-5.45; P < 0.001) were independently associated with the risk of hospitalization with AF. Subjects with P-wave <110 ms and Type 1 morphology (n = 2074) were at low risk (HR 0.46, 95% CI 0.26-0.83; P = 0.006), compared to the rest of the subjects.

CONCLUSION

P-wave parameters associate with the risk of hospitalization with AF.

Electrocardiographic Risk Markers of Cardiac Death: Gender Differences in the General Population

Background

Cardiac death is one of the leading causes of death and sudden cardiac death (SCD) is estimated to cause approximately 50% of cardiac deaths. Men have a higher cardiac mortality than women. Consequently, the mechanisms and risk markers of cardiac mortality are not as well defined in women as they are in men.

Aim

The aim of the study was to assess the prognostic value and possible gender differences of SCD risk markers of standard 12-lead electrocardiogram in three large general population samples.

Methods

The standard 12-lead electrocardiographic (ECG) markers were analyzed from three different Finnish general population samples including total of 20,310 subjects (49.9% women, mean age 44.8 ± 8.7 years). The primary endpoint was cardiac death, and SCD and all-cause mortality were secondary endpoints. The interaction effect between women and men was assessed for each ECG variable.

Results

During the follow-up (7.7 ± 1.2 years), a total of 883 deaths occurred (24.5% women, p < 0.001). There were 296 cardiac deaths (13.9% women, p < 0.001) and 149 SCDs (14.8% women, p < 0.001). Among those who had died due to cardiac cause, women had more often a normal electrocardiogram compared to men (39.0 vs. 27.5%, p = 0.132). After adjustments with common cardiovascular risk factors and the population sample, the following ECG variables predicted the primary endpoint in men: left ventricular hypertrophy (LVH) with strain pattern (p < 0.001), QRS duration > 110 ms (p < 0.001), inferior or lateral T-wave inversion (p < 0.001) and inferolateral early repolarization (p = 0.033). In women none of the variables remained significant predictors of cardiac death in multivariable analysis, but LVH, QTc ≥ 490 ms and T-wave inversions predicted SCD (p < 0.047 and 0.033, respectively). In the interaction analysis, LVH (HR: 2.4; 95% CI: 1.2–4.9; p = 0.014) was stronger predictor of primary endpoint in women than in men.

Conclusion

Several standard ECG variables provide independent information on the risk of cardiac mortality in men but not in women. LVH and T-wave inversions predict SCD also in women.

Temporal variability of T-wave morphology and risk of sudden cardiac death in patients with coronary artery disease

Background

The possible relationship between temporal variability of electrocardiographic spatial heterogeneity of repolarization and the risk of sudden cardiac death (SCD) in patients with coronary artery disease (CAD) is not completely understood.

Methods

The standard deviation of T‐wave morphology dispersion (TMD‐SD), of QRST angle (QRSTA‐SD), and of T‐wave area dispersion (TW‐Ad‐SD) were analyzed on beat‐to‐beat basis from 10 min period of the baseline electrocardiographic recording in ARTEMIS study patients with angiographically verified CAD.

Results

After on average of 8.6 ± 2.3 years of follow‐up, a total of 66 of the 1,678 present study subjects (3.9%) had experienced SCD or were resuscitated from sudden cardiac arrest (SCA). TMD‐SD was most closely associated with the risk for SCD and was significantly higher in patients who had experienced SCD/SCA compared with those who remained alive (3.61 ± 2.83 vs. 2.64 ± 2.52, p = .008, respectively), but did not differ significantly between the patients who had experienced non‐SCD (n = 71, 4.2%) and those who remained alive (3.20 ± 2.73 vs. 2.65 ± 2.53, p = .077, respectively) or between the patients who succumbed to non‐cardiac death (n = 164, 9.8%) and those who stayed alive (2.64 ± 2.17 vs. 2.68 ± 2.58, p = .853). After adjustments with relevant clinical risk indicators of SCD/SCA, TMD‐SD still predicted SCD/SCA (HR 1.107, 95% CIs 1.035–1.185, p = .003).

Conclusions

Temporal variability of electrocardiographic spatial heterogeneity of repolarization represented by TMD‐SD independently predicts long‐term risk of SCD/SCA in patients with CAD.

Increased Beat-to-Beat Variability of T-Wave Heterogeneity Measured From Standard 12-Lead Electrocardiogram Is Associated With Sudden Cardiac Death: A Case-Control Study

Introduction

The prognostic significance of beat-to-beat variability of spatial heterogeneity of repolarization measured from standard 12-lead ECG is not well-understood.

Methods

We measured the short-term variability of repolarization parameters, such as T-wave heterogeneity in leads V4–V6 (TWH) and QT interval (QT), from five consecutive beats of previously recorded standard 12-lead ECG in 200 victims of unexpected sudden cardiac death (SCD) confirmed to be due to complicated atherosclerotic coronary artery disease (CAD) in medico-legal autopsy and 200 age- and sex-matched controls with angiographically confirmed CAD. The short-term variability of repolarization heterogeneity was defined as the standard deviation (SD) of the measured repolarization parameters. All ECGs were in sinus rhythm, and no premature ventricular contractions were included in the measured segment.

Results

TWH-SD and QT-SD were significantly higher in SCD victims than in subjects with CAD (6.9 ± 5.6 μV vs. 3.8 ± 2.6 μV, p = 1.8E-11; 8.3 ± 13.1 ms vs. 3.8 ± 7.1 ms, p = 0.00003, respectively). After adjusting in the multivariate clinical model with factors, such as diabetes, RR interval, and beta blocker medication, TWH-SD and QT-SD retained their significant power in discriminating between the victims of SCD and the patients with CAD (p = 0.00003, p = 0.006, respectively). TWH-SD outperformed QT-SD in identifying the SCD victims among the study subjects (area under the curve in the receiver operating characteristics curve 0.730 vs. 0.679, respectively).

Conclusion

Increased short-term variability of repolarization heterogeneity measured from standard 12-lead ECG is associated with SCD.

Lower ST-elevation myocardial infarction incidence during COVID-19 epidemic in Northern Europe

We compared the ST elevation myocardial infarction (STEMI) incidence during COVID-19 pandemic (March 2020) to January-February 2020 and to same time period in earlier years 2017-2019 in five Nordic-Baltic tertiary centers. During 2017-2019, there were no marked differences in STEMI incidence between January, February and March. During 2020, there was an average drop of 32% in STEMI incidence in March. The isolation measures may decrease the risk for respiratory virus infection and contribute to the lower STEMI incidence and that we might benefit from firmer suggestions on hand hygiene and social distancing during flu season at least among high-risk individuals.

Electrocardiographic Risk Markers for Heart Failure in Women Versus Men

Heart failure (HF) is one of the leading causes of hospitalization in the Western world. Women have a lower HF hospitalization rate and mortality compared with men. The role of electrocardiography as a risk marker of future HF in women is not well known. We studied association of electrocardiographic (ECG) risk factors for HF hospitalization in women from a large middle-aged general population with a long-term follow-up and compared the risk profile to men. Standard 12-lead ECG markers were analyzed from 10,864 subjects (49% women), and their predictive value for HF hospitalization was analyzed. During the follow-up (30 ± 11 years), a total of 1,743 subjects had HF hospitalization; of these, 861 were women (49%). Several baseline characteristics, such as age, body mass index, blood pressure, and history of previous cardiac disease predicted the occurrence of HF both in women and men (p <0.001 for all). After adjusting for baseline variables, ECG sign of left ventricular hypertrophy (LVH) (p <0.001), and atrial fibrillation (p <0.001) were the only baseline ECG variables that predicted future HF in women. In men, HF was predicted by fast heart rate (p = 0.008), T wave inversions (p <0.001), abnormal Q-waves (p = 0.002), and atrial fibrillation (p <0.001). Statistically significant gender interactions in prediction of HF were observed in ECG sign of LVH, inferolateral T wave inversions, and heart rate. In conclusion, ECG sign of LVH predicts future HF in middle-aged women, and T wave inversions and elevated heart rate are associated with HF hospitalization in men.

Association of Silent Myocardial Infarction and Sudden Cardiac Death

Importance

Myocardial infarction in the absence of major or unrecognized symptoms are characterized as silent (SMI). The prevalence of SMI among individuals who experience sudden cardiac death (SCD), with or without concomitant electrocardiographic (ECG) changes, has not previously been described in detail from large studies to our knowledge.

Objective

To determine the prevalence of SMI in individuals who experience SCD without a prior diagnosis of coronary artery disease (CAD) and to detect ECG abnormalities associated with SMI-associated SCD.

Design, Setting, and Participants

This case-control study compared autopsy findings, clinical characteristics, and ECG markers associated with SMI in a consecutive cohort of individuals in the Finnish Genetic Study of Arrhythmic Events (Fingesture) study population who were verified to have had SCD. The Fingesture study consists of individuals who had autopsy-verified SCD in Northern Finland between 1998 and 2017. Individuals who had SCD with CAD and evidence of SMI were regarded as having had cases; those who had SCD with CAD without SMI were considered control participants. Analyses of ECG tests were carried out by investigators blinded to the SMI data. Data analysis was completed from October 2018 through November 2018.

Main Outcomes and Measures

Silent MI was defined as a scar detected by macroscopic and microscopic evaluation of myocardium without previously diagnosed CAD. Clinical history was obtained from medical records, previously recorded ECGs, and a standardized questionnaire provided to the next of kin. The hypothesis tested was that SMI would be prevalent in the population who had had SCD with CAD, and it might be detected or suspected from findings on ECGs prior to death in many individuals.

Results

A total of 5869 individuals were included (2459 males [78.8%]; mean [SD] age, 64.9 [12.4] years). The cause of SCD was CAD in 4392 individuals (74.8%), among whom 3122 had no history of previously diagnosed CAD. Two individuals were excluded owing to incomplete autopsy information. An ECG recorded prior to SCD was available in 438 individuals. Silent MI was detected in 1322 individuals (42.4%) who experienced SCD without a clinical history of CAD. The participants with SMI were older than participants without MI scarring (mean [SD] age, 66.9 [11.1] years; 65.5 [11.6] years; P < .001) and were more often men (1102 of 1322 [83.4%] vs 1357 of 1798 [75.5%]; P < .001). Heart weight was higher in participants with SMI (mean [SD] weight, 483 [109] g vs 438 [106] g; P < .001). In participants with SMI, SCD occurred more often during physical activity (241 of 1322 [18.2%] vs 223 of 1798 [12.4%]; P < .001). A prior ECG was abnormal in 125 of the 187 individuals (66.8%) who had SCD after SMI compared with 139 of 251 (55.4%) of those who had SCD without SMI (P = .02).

Conclusions and Relevance

Many individuals who experienced SCD associated with CAD had a previously undetected MI at autopsy. Previous SMI was associated with myocardial hypertrophy and SCD during physical activity. Premortem ECGs in a subset with available data were abnormal in 67% of the individuals who had had a SCD after an SMI.

Electrocardiogram as a predictor of survival without appropriate shocks in primary prophylactic ICD patients: A retrospective multi-center study

BACKGROUND

Abnormal 12-lead electrocardiogram (ECG) can predict cardiovascular events, including sudden cardiac death. We tested the hypothesis that ECG provides useful information on guiding implantable cardioverter defibrillator (ICD) therapy into individuals with impaired left ventricular ejection fraction (LVEF).

METHODS

Retrospective data of primary prevention ICD implantations from 14 European centers were gathered. The registry included 5111 subjects of whom 1687 patients had an interpretable pre-implantation ECG available (80.0% male, 63.3 ± 11.4 years). Primary outcome was survival without appropriate ICD shocks or heart transplantation. A low-risk ECG was defined as a combination of ECG variables that were associated with the primary outcome.

RESULTS

A total of 1224 (72.6%) patients survived the follow-up (2.9 ± 1.7 years) without an ICD shock, 224 (13.3%) received an appropriate shock and 260 (15.4%) died. Low-risk ECG defined as QRS duration <120 ms, QTc interval <450 ms for men and <470 ms for women, and sinus rhythm, were met by 515 patients (30.5%). Multivariable Cox regression showed that the hazard (HR) for death, heart transplantation or appropriate shock were reduced by 42.5% in the low-risk group (HR 0.575; 95% CI 0.45-0.74; p < 0.001), compared to the high-risk group. The HR for the first appropriate shock was 42.1% lower (HR 0.58; 95% CI 0.41-0.82; p = 0.002) and the HR for death was 48.0% lower (HR 0.52; 95% CI 0.386-0.72; p < 0.001) in the low-risk group.

CONCLUSION

Sinus rhythm, QRS <120 ms and normal QTc in standard 12-lead ECG provides information about survival without appropriate ICD shocks and might improve patient selection for primary prevention ICD therapy.

P481The genetic background of sudden cardiac deaths caused by single vessel coronary artery disease and myocardial hypertrophy with fibrosis

Funding Acknowledgements

Sigrid Juselius Foundation, Finnish Foundation for Cardiovascular Research, Aarne Koskelo Foundation, The Finnish Medical Foundation

Background

Coronary artery disease (CAD) is the most common underlying cause of sudden cardiac death (SCD). Cardiac hypertrophy with varying amount of myocardial fibrosis is a common risk factor for CAD related SCD especially in young SCD victims where severity of CAD seems not to entirely explain the cause of SCD.

Purpose

The aim was to study the genetic background of hypertrophy and fibrosis among young, ischemic SCD victims with single vessel CAD.

Methods

The study population was derived from the Fingesture study consisting of all autopsy-verified sudden cardiac deaths in Northern Finland between years 1998-2017 (n = 5,869). CAD was determined to be the cause of SCD in 4,392 victims (74.8%). We carried out targeted next-generation sequencing using a panel of 174 genes associated with myocardial structure and ion channel function in 95 ischemic-SCD victims (mean [standard error] age, 63.6 [1.06] years; 88.4% males) with single-vessel CAD and cardiac hypertrophy in the absence of previously diagnosed CAD, and whose DNA passed the quality control for further analysis. Assessment for pathogenicity of detected variants was based on American College of Medical Genetics consensus guidelines.

Results

A total of 43 variants were detected in 43 of the study subjects (45.3 %). Five variants in eight subjects (8.4%) were classified as pathogenic or likely pathogenic. We observed 38 variants of uncertain significance in 39 victims (40.6 %). Variants were detected in myocardial structure protein coding genes, associated with arrhythmogenic right ventricular cardiomyopathy (13 variants), dilated cardiomyopathy (16 variants), hypertrophic cardiomyopathy (6 variants) and left ventricular non-compaction cardiomyopathy (3 variants). Five variants were detected in RYR2 associated with both cardiomyopathies and catecholaminergic polymorphic ventricular tachycardias. Seven variants were detected in multiple unrelated subjects. None of the subjects presented characteristic autopsy findings related to cardiomyopathies.

Conclusions

Variants associated with cardiomyopathies were common findings among CAD related SCD victims with single vessel disease and myocardial hypertrophy found at autopsies, suggesting that these variants may modulate the risk for fatal arrhythmias and sudden death in ischemic disease.

Automated electrocardiographic quantification of myocardial scar in patients undergoing primary prevention implantable cardioverter-defibrillator implantation: Association with mortality and subsequent appropriate and inappropriate therapies

BACKGROUND

Myocardial scarring from infarction or nonischemic fibrosis forms an arrhythmogenic substrate. The Selvester QRS score has been developed to estimate myocardial scar from the 12-lead electrocardiogram.

OBJECTIVE

We aimed to assess the value of an automated version of the Selvester QRS score for the prediction of implantable cardioverter-defibrillator (ICD) therapy and death in patients undergoing primary prevention ICD implantation.

METHODS

Unselected patients undergoing primary prevention ICD implantation were included in this retrospective, observational, multicenter study. The QRS score was calculated automatically from a digital standard preimplantation 12-lead electrocardiogram and was correlated to the occurrence of death and appropriate and inappropriate shocks during follow-up. Analyses were performed in groups defined by QRS duration < 130 ms vs ≥ 130 ms.

RESULTS

Overall, 1047 patients (872 [83%] men; median age 64 years IQR [55-71]) with ischemic (648, 62%) or nonischemic (399, 38%) cardiomyopathy were included. The median QRS duration was 123 ms (interquartile range [IQR] 111-157 ms), and the median QRS score was 5 (IQR 2-8). The QRS duration was <130 ms in 59% and ≥130 ms in 41%. During a median follow-up of 45 months (IQR 24-72 months), a QRS score of ≥5 was independently associated with a significantly higher risk of mortality (hazard ratio [HR] 1.67; 95% confidence interval [CI] 1.05-2.66; P = .031) and appropriate (HR 1.83; 95% CI 1.07-3.14; P = .028) and inappropriate (HR 2.32; 95% CI 1.04-5.17; P = .039) shocks in patients with QRS duration ≥ 130 ms. No association of the QRS score and outcome was observed in patients with QRS duration < 130 ms (P > .05).

CONCLUSION

The automatically calculated Selvester QRS score, an indicator of myocardial scar burden, predicts mortality and appropriate and inappropriate shocks in patients undergoing primary prevention ICD implantation with a prolonged QRS duration.

Physical Activity and the Risk for Sudden Cardiac Death in Patients With Coronary Artery Disease

BACKGROUND

The association between leisure-time physical activity (LTPA) and the risk of sudden cardiac death (SCD) in coronary artery disease patients is not well known. We aim to assess whether there is an association between LTPA and the risk of SCD and non-SCD in patients with coronary artery disease.

METHODS

Patients with angiographically verified coronary artery disease (n=1946) underwent a clinical evaluation, including filling in an LTPA questionnaire and extensive risk profiling at the baseline. The patients were classified into 4 groups according to LTPA: (1) inactive; (2) irregularly active; (3) active, exercise regularly 2× to 3× weekly; (4) highly active, exercise regularly ≥4× weekly. Age, sex, body mass index, left ventricular ejection fraction, type 2 diabetes mellitus, history of myocardial infarction, Canadian Cardiovascular Society grading of angina pectoris class, and exercise capacity were used as covariates in the multivariate Cox regression analysis.

RESULTS

During follow-up (median 6.3 years), 52 SCDs and 49 non-SCDs occurred. Inactive patients had increased risk for SCD compared with active patients (hazard ratio, 2.45 [95% CI, 1.01-5.98]; P<0.05). A significant LTPA×Canadian Cardiovascular Society grading of angina pectoris class interaction was observed in SCD risk (P=0.019 in highly active patients). LTPA was not associated with SCD in patients with Canadian Cardiovascular Society grading of angina pectoris class 1 (n=1107, 18 events). Among patients with Canadian Cardiovascular Society grading of angina pectoris class 2 or higher (n=839, 34 events), increased risk for SCD was encountered in highly active patients (hazard ratio, 7.46 [95% CI, 2.32-23.9]; P<0.001) and inactive patients (hazard ratio, 3.64 [95% CI, 1.16-11.5]; P<0.05) as compared to active patients. A linear association was observed between LTPA and non-SCD; those with high LTPA had the lowest risk for non-SCD.

CONCLUSIONS

Inactive coronary artery disease patients had increased risk for SCD. In subgroup analysis among symptomatic patients, the risk of SCD was increased in highly active and inactive patients compared with active patients. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01426685.

Association of non-shockable initial rhythm and psychotropic medication in sudden cardiac arrest

Background

Asystole (ASY) and pulseless electrical activity (PEA) have a poor outcome during sudden cardiac arrest (SCA). Psychotropic medication has been associated with a risk for sudden cardiac death (SCD). Our aim was to study the association of psychotropic medication with ASY/PEA during SCA.

Methods and results

A total of 659 SCA subjects were derived from the emergency data of Oulu University Hospital (2007-2012). Subjects with non-cardiac origin of SCA and over 30-minute delay to rhythm recording were excluded. Population included 222 subjects after exclusions (mean age 64 ± 14 years, 78% males). Initial rhythm was ventricular fibrillation (VF) or ventricular tachycardia (VT) in 123 (55%), ASY in 67 (30%) and PEA in 32 (14%) subjects. The delay (collapse to rhythm recording) was similar in VF/VT and ASY/PEA subjects (median 8 min [1st-3rd quartile 3-12 min] versus 10 [0-14] minutes, p = 0.780). Among VF/VT subjects underlying cardiac disease was more often ischemic compared to ASY/PEA subjects (85% versus 68%, p = 0.003). Psychotropic medication was associated with ASY/PEA rhythm (OR 3.18, 95%CI 1.40-7.23, p = 0.006) after adjustment for gender, age and underlying cardiac disease. Subsequently, antipsychotics (OR 4.27, 95%CI 1.28-14.25, p = 0.018) were more common in the ASY/PEA group. Benzodiazepines and antidepressants were not associated with ASY/PEA.

Conclusion

Psychotropic medication and especially antipsychotics are associated with non-shockable rhythm during SCA and may lower the possibility of survival from the event. This might partly explain the risk of SCD related to psychotropic medication.

Appropriate Shocks and Mortality in Patients With Versus Without Diabetes With Prophylactic Implantable Cardioverter Defibrillators

OBJECTIVE

Diabetes increases the risk of all-cause mortality and sudden cardiac death (SCD). The exact mechanisms leading to sudden death in diabetes are not well known. We compared the incidence of appropriate shocks and mortality in patients with versus without diabetes with a prophylactic implantable cardioverter defibrillator (ICD) included in the retrospective EU-CERT-ICD registry.

RESEARCH DESIGN AND METHODS AND RESULTS

A total of 3,535 patients from 12 European EU-CERT-ICD centers with a mean age of 63.7 ± 11.2 years (82% males) at the time of ICD implantation were included in the analysis. A total of 995 patients (28%) had a history of diabetes. All patients had an ICD implanted for primary SCD prevention. End points were appropriate shock and all-cause mortality. Mean follow-up time was 3.2 ± 2.3 years. Diabetes was associated with a lower risk of appropriate shocks (adjusted hazard ratio [HR] 0.77 [95% CI 0.62-0.96], P = 0.02). However, patients with diabetes had significantly higher mortality (adjusted HR 1.30 [95% CI 1.11-1.53], P = 0.001).

CONCLUSIONS

All-cause mortality is higher in patients with diabetes than in patients without diabetes with primary prophylactic ICDs. Subsequently, patients with diabetes have a lower incidence of appropriate ICD shocks, indicating that the excess mortality might not be caused primarily by ventricular tachyarrhythmias. These findings suggest a limitation of the potential of prophylactic ICD therapy to improve survival in patients with diabetes with impaired left ventricular function.

Sudden Cardiac Death in Women

BACKGROUND

Despite recent progress in profiling of risk for sudden cardiac death (SCD) and prevention and intervention of cardiac diseases, SCD remains a major cause of death. Among women, the incidence of SCD is significant, but lower than in men, particularly in the premenopausal and early postmenopausal years. Possibly, as a consequence of the difference in population burden, the mechanisms and risk markers of SCD are not as well defined for women. The aim of this study was to determine the autopsy findings and causes of death among women in a large SCD population. Additionally, we sought to classify prior ECG characteristics in male and female subjects with SCD.

METHODS

The Fingesture study has systematically collected clinical and autopsy data from subjects with SCD in Northern Finland between 1998 and 2017. The cohort consists of 5869 subjects with SCD. Previously recorded ECGs were available and analyzed in 1101 subjects (18.8% of total population; and in 25.3% of women).

RESULTS

Female subjects with SCD were significantly older than men: 70.1±13.1 years versus 63.5±11.8 years (mean ± standard deviation, P<0.001). The most frequently identified cause of death was ischemic heart disease in both sexes: 71.7% among women versus 75.7% among men, P=0.005. In contrast, women were more likely to have nonischemic cause of SCD than men (28.3% versus 24.3%, P=0.005). The prevalence of primary myocardial fibrosis was higher among women (5.2%, n=64) than in men (2.6%, n=120; P<0.001). Female subjects with SCD were more likely to have normal prior ECG tracings (22.2% versus 15.3% in men, P<0.001). A normal ECG was even more common among nonischemic female subjects with SCD (27.8% versus 16.2% in men, P=0.009). However, ECG markers of left ventricular hypertrophy, with or without repolarization abnormalities, were more common among women (8.2%; 17.9%) than in men (4.9%; 10.6%, P=0.036; P<0.001, respectively).

CONCLUSIONS

Women were considerably older at the time of SCD and more commonly had nonischemic causes. Women were also more likely to have a prior normal ECG than men, but an increased marker for SCD risk based on ECG criteria for left ventricular hypertrophy with repolarization abnormalities was more commonly observed in women.

Three-year outcomes related to coronary stenting; a registry-based real-life population study

Objectives. Developments in medication and coronary interventions have improved coronary artery disease (CAD) treatment. We studied long-term outcomes in an observational, real-life population of CAD patients undergoing percutaneous coronary intervention (PCI) depending on the presentation and the stent type used. Design and results. Register included 789 consecutive patients undergoing PCI. Follow up period was three years with primary composite outcome (MACE) of all cause -mortality, myocardial infarction and target lesion revascularization. Mean age was 65 ± 11 and 69% were male. New-generation drug-eluting stents (DES-2) were associated with lower adjusted rates of MACE (HR 0.47; 95% CI 0.29-0.77) but not mortality (HR 0.50; 95% CI 0.22-1.14) in comparison to bare-metal stents. Patients with STEMI (14.4%) or NSTEMI (13.7%) had higher crude mortality rates than those with unstable (4.5%) or stable CAD (3.1%; p < .001). The association diminished after adjustments in NSTEMI (HR 2.01; 95% CI 0.88-4.58). Among smokers 45% quitted and 36% achieved recommended cholesterol levels. Conclusions. The overall prognosis was good. Irrespective of comorbidities, NSTEMI was not associated with worse outcome than stable CAD. DES-2 was associated with lower rates of MACE than BMS without affecting mortality rate. Patients succeeded better in smoking cessation than reaching recommended cholesterol levels.

Effect of Sex and Underlying Disease on the Genetic Association of QT Interval and Sudden Cardiac Death

Background Sudden cardiac death (SCD) accounts for ≈300 000 deaths annually in the United States. Men have a higher risk of SCD and are more likely to have underlying coronary artery disease, while women are more likely to have arrhythmic events in the setting of inherited or acquired QT prolongation. Moreover, there is evidence of sex differences in the genetics of QT interval duration. Using sex- and coronary artery disease-stratified analyses, we assess differences in genetic association between longer QT interval and SCD risk. Methods and Results We examined 2282 SCD subjects and 3561 Finnish controls. The SCD subjects were stratified by underlying disease (ischemic versus nonischemic) and by sex. We used logistic regression to test for association between the top QT interval-associated single-nucleotide polymorphism, rs12143842 (in the NOS1AP locus), and SCD risk. We also performed Mendelian randomization to test for causal association of QT interval in the various subgroups. No statistically significant differences were observed between the sexes for associations with rs12143842, despite the odds ratio being higher in females across all subgroup analyses. Consistent with our hypothesis, female non-ischemics had the highest odds ratio point estimate for association between rs12143842 and SCD risk and male ischemics the lowest odds ratio point estimate (P=0.036 for difference). Similar trends were observed for the Mendelian randomization analysis. Conclusions While individual subgroup comparisons did not achieve traditional criteria for statistical significance, this study is consistent with the hypothesis that the causal association of longer QT interval on SCD risk is stronger in women and nonischemic individuals.

Predicting sudden cardiac death in a general population using an electrocardiographic risk score

OBJECTIVE

We investigated whether combining several ECG abnormalities would identify general population subjects with a high sudden cardiac death (SCD) risk.

METHODS

In a sample of 6830 participants (mean age 51.2±13.9 years; 45.5% male) in the Mini-Finland Health Survey, a general population cohort representative of the Finnish adults aged ≥30 years conducted in 1978-1980, we examined their ECGs, following subjects for 24.3±10.4 years. We analysed the association between individual ECG abnormalities and 10-year SCD risk and developed a risk score using five ECG abnormalities independently associated with SCD risk: heart rate >80 beats per minute, PR duration >220 ms, QRS duration >110 ms, left ventricular hypertrophy and T-wave inversion. We validated the score using an external general population cohort of 10 617 subjects (mean age 44.0±8.5 years; 52.7% male).

RESULTS

No ECG abnormalities were present in 4563 subjects (66.8%), while 96 subjects (1.4%) had ≥3 ECG abnormalities. After adjusting for clinical factors, the SCD risk increased progressively with each additional ECG abnormality. Subjects with ≥3 ECG abnormalities had an HR of 10.23 (95% CI 5.29 to 19.80) for SCD compared with those without abnormalities. The risk score similarly predicted SCD risk in the validation cohort, in which subjects with ≥3 ECG abnormalities had HR 10.82 (95% CI 3.23 to 36.25) for SCD compared with those without abnormalities.

CONCLUSION

The ECG risk score successfully identified general population subjects with a high SCD risk. Combining ECG risk markers may improve the risk stratification for SCD.

P6588Impact of age and sex on the long-term prognosis associated with early repolarization in the general population

Background

Early repolarization (ER) in the electrocardiogram (ECG) has been associated with increased sudden cardiac death (SCD) risk in the general population. However, controversy remains about the risk associated with ER in different population subgroups.

Purpose

We evaluated whether age and sex affect the prognostic significance of ER in general population subjects.

Methods

The study population consisted of Finnish general population subjects aged over 30 years participating in the Mini-Finland Health Survey in 1978–80. Subjects underwent extensive baseline health examinations including a resting 12-lead ECG and were followed for 24±10 years. After excluding ECGs with QRS duration >110ms, the presence of ER (J-point elevation ≥0.1 mV in ≥2 inferior/lateral leads) was assessed from the remaining 6,631 subjects. The association between ER and SCD risk was analysed in subgroups according to age (<50 years or ≥50 years) and sex by using the Cox proportional hazards model. Effect modification of ER by age group and by sex was tested using the Wald test.

Results

ER was present in 250 (15.7%) of the 1,592 male subjects aged <50 years, 117 (6.8%) of the 1,713 female subjects aged <50 years, 182 (13.4%) of the 1,362 male subjects aged ≥50 years, and 244 (12.4%) of the 1,964 female subjects aged ≥50 years. There was a significant interaction between age group and ER (p=0.011). Among subjects aged <50 years, ER was associated with SCD risk after adjusting for age, sex, blood pressure, body mass index, serum cholesterol, coronary artery disease, diabetes, and active smoking (hazard ratio [HR] 1.79; 95% confidence interval [CI] 1.09–2.92; p=0.021), whereas in subjects aged ≥50 years ER was not associated with increased risk of SCD. Particularly female subjects aged <50 years with ER had a high risk of SCD (HR 4.85; 95% CI 1.65–14.29; p=0.004) in the multivariate analysis, whereas among <50-year-old male subjects ER was not associated with SCD (p=0.024 for interaction between sex and ER).

Conclusion

Our results suggest that among adults <50 years old, and especially among <50-year-old women, ER is associated with increased SCD risk, whereas among older subjects ER is not associated with SCD. Future research should focus on identifying the factors accounting for the difference between the age groups and to improve the risk stratification in the younger female patient populations with ER.

Acknowledgement/Funding

Aarne Koskelo foundation and Paavo Ilmari Ahvenainen Foundation

P4168Ischemic sudden cardiac deaths among victims under 50 years - Characteristics and autopsy findings

Background

Sudden cardiac death (SCD) is one of the most prevalent cause of death in Western countries representing nearly 20% of total mortality. About 70–80% of SCDs are due to coronary artery disease (CAD). Especially among young victims, whose first cardiac event is often SCD, decent risk prediction and prevention strategies are sadly lacking.

Purpose

The aim of this study was to determine the characteristics and autopsy findings of ischemic sudden cardiac deaths among young victims under the age of 50 years.

Methods

The study population is derived from Fingesture study, consisting of prospectively collected consecutive victims of SCD in Northern Finland among whom post-mortem examinations were performed between years 1998–2017 (n=5,869). According to Finnish law, all unexpected deaths undergo medico-legal autopsy. All post-mortem examinations included histological examinations, as well as a toxicology investigation was carried out if needed. Information about the victims was collected from autopsy data, death certificates, medical records, standardized questionnaire to the closest family members of the victims and police reports about the conditions of the death. 10% off all SCDs occurred among victims aged under 50 years (607 victims).

Results

CAD was the most common underlying cause of SCD among young victims (265 victims, 44%), followed by obesity related (102 victims, 17%) and alcoholic cardiomyopathy (67 victims, 11%). The mean age of ischemic SCD victims was 44±4 years and they were mostly men (89%). 90% of victims had no history of CAD prior to death and 34% of these had a myocardial scar at autopsy indicating previously unrecognized MI. 26% of SCDs occurred during physical activity. Hypertrophied hearts (59%) and myocardial fibrosis (83%) were common findings among young ischemic SCD victims. 27% of victims had a history of heavy drinking and alcohol was found in toxicology investigations in 35% of victims. At least one cardiovascular risk factor (diabetes mellitus, hypertension, dyslipidemia, obesity) was present in 51% of cases.

Conclusions

CAD was the most common cause of SCD among victims under 50 years. Most ischemic SCDs among young occurred without previously diagnosed CAD, and yet severe findings were seen at autopsy.

Acknowledgement/Funding

Sigrid Juselius Foundation, Finnish Foundation for Cardiovascular Research, Aarne Koskelo Foundation

P3511Gender differences in electrocardiographic risk markers of heart failure

Background

Heart failure (HF) is one the leading causes of hospitalization in the Western world. Women have a lower rate of HF hospitalization and mortality compared to men. Role of 12-lead electrocardiography (ECG) as a risk marker of future HF in women is not well known.

Purpose

We studied the association of standard 12-lead ECG and clinical risk factors to HF hospitalization in women and in men separately from a large middle aged general population sample with a long-term follow-up.

Methods

Standard 12-lead ECG markers were analyzed from 10,864 subjects (48.8% women, N=5,215) of the prospective Mobile Clinic Study, and their predictive value for HF hospitalization was analyzed.

Results

During the follow-up (29.6±11.2 yrs.), a total of 1,743 subjects had HF hospitalization; out of these, 861 were women (49.4%). Several baseline characteristics, such as age, body mass index, blood pressure, and history of prior cardiac disease predicted the occurrence of HF both in women and men (P<0.001 for all). After adjusting for baseline variables, ECG sign of left ventricular hypertrophy (LVH) (P<0.001), and atrial fibrillation (P<0.001) were the only baseline ECG variables that predicted the future HF in women. In men, HF was predicted by fast heart rate (P=0.008), T wave inversions (P<0.001), abnormal Q waves (P=0.002), and atrial fibrillation (P<0.001). Statistically significant gender interactions in prediction of HF were observed in ECG sign of LVH (P<0.001), inferolateral T wave inversions (P=0.005), and heart rate (P=0.012).

Conclusions

ECG sign of LVH predicts future HF in middle-aged women independently, and T wave inversions and elevated heart rate are associated with HF hospitalization in men in.

Acknowledgement/Funding

Finnish Cultural Foundation, The University of Oulu Scholarship Foundation, Juho Vainio Foundation

3254Manifestations of myocardial fibrosis in the standard 12-lead electrocardiogram

Background

Myocardial fibrosis has substantial role in sudden cardiac deaths (SCD). Major challenge in preventing SCDs is early recognition of vulnerable patients with fibrotic cardiomyopathy. Our aim was to find manifestations of myocardial fibrosis in 12-lead electrocardiogram (ECG).

Methods

Study population is based on the Fingesture study, which has gathered data from 5,869 consecutive autopsied SCD victims between 1998 and 2017 in Finland. The degree of fibrosis was determined based on the histological samples taken from the heart during autopsy and was categorized into four groups; 1) no fibrosis, 2) scattered mild fibrosis, 3) moderate patchy fibrosis and 4) substantial fibrosis. We were able to collect pre-mortem 12-lead ECGs from 1,100 SCD victims. Ischemic cardiomyopathy was the cause of death in 689 cases and 411 had nonischemic cardiomyopathy at autopsy in the group where ECG was available.

Results

Mean age of the study subjects was 66±13 years and 75% were male. At least some amount of myocardial fibrosis was present in 92% of the victims. QRS duration in ECG correlated with the degree of fibrosis in autopsy as follows; 96±21ms in group 1 (n=93), 97±20ms in group 2 (n=357), 103±26ms in group 3 (n=506) and 108±27ms in group 4 (n=144; p<0.001, β=0.153). Prevalence of fragmented QRS complex was higher among victims with severe fibrosis (40% in group 1, 43% in group 2, 60% in group 3 and 65% in group 4; p<0.001). Additionally, inferolateral T-wave inversions were more common in groups with increasing amount of myocardial fibrosis (5.4% in group 1, 13.2% in group 2, 20.4% in group 3 and 31.9% in group 4; p<0.001). Associations were visible in both ischemic and nonischemic SCDs but reached statistical significance only among ischemic SCD victims. Heart rate corrected JT interval and Sokolow-Lyon index had no linear correlation with the degree of fibrosis.

Conclusions

Myocardial fibrosis was associated with QRS prolongation, T-wave inversions and QRS fragmentation among SCD victims. Fibrosis did not manifest as clearly in ECG among patients with nonischemic cardiomyopathies as among ischemic SCD victims. The results may explain the increased risk for SCD in patients with abnormal QRS complex or inverted T waves providing means for recognizing patients with underlying fibrotic cardiomyopathy.

Acknowledgement/Funding

Sigrid Juselius Foundation, Foundation of Cardiac Research, Paavo Nurmi Foundation and Paulo foundation, Finland

3056Orthogonal P wave morphology, traditional P wave indices, and the risk of atrial fibrillation in the general population

Background

A substantial portion of the risk of atrial fibrillation (AF) remains unexplained by the established risk markers. However, accurate assessment of AF risk would be beneficial, especially among stroke patients and subjects with symptoms attributable to arrhythmia.

Purpose

To study the associations of P-wave indices with AF risk in the general population.

Methods

Electrocardiograms, including orthogonal leads, of 7217 Finnish subjects aged over 30 years who took part in the baseline examinations of the Mini-Finland Health Survey in 1978–80, were digitized. P-wave duration, third-degree interatrial block (IAB), and P terminal force (PTF) were assessed manually. PTF was considered abnormal when the amplitude of the negative terminal part of the P wave in lead V1 was ≥0.1mV and duration ≥40ms. Third-degree IAB was defined as P-wave duration ≥120ms and the presence of ≥2 +/− biphasic P-waves in the inferior leads. Orthogonal P-wave morphology, which is related to left atrial breakthrough site and affected by atrial fibrosis (1 being considered benign, 2 borderline, and 3 shown to be associated with adverse events), was assessed with an automated algorithm, and ascertained manually. Subjects were followed 10 years for AF hospitalization and mortality. The risk of AF associated with P wave parameters was assessed using Cox proportional hazards models. Model discrimination improvement was quantified by the change in C index, integrated discrimination improvement (IDI), and continuous net reclassification improvement (cNRI).

Results

There were 5489 subjects (47.8% male, mean age 50.5 years) with a readable ECG, sinus rhythm, no missing data, and a predefined orthogonal P-wave morphology. Type 3 orthogonal P morphology (n=216, multivariate adjusted HR [maHR] 3.01, 95% confidence interval [CI] 1.66–5.45, p<0.001), P-wave duration ≥120ms (n=752, maHR 1.67, 95% CI 1.06–2.64, p=0.027), and third-degree IAB (n=103, maHR 3.18, 95% CI 1.66–6.13, p=0.001) were independently associated with the risk of AF in separate models. PTF did not independently predict AF. Subjects presenting with both Type 1 orthogonal P-wave morphology and P-wave duration <110ms (n=2074) were at low risk of AF (maHR 0.46, 95% CI 0.26–0.83, p=0.006) when compared to the rest of the subjects. The inclusion of variables combining orthogonal P-wave morphology and P-wave duration to a multivariate model including conventional AF risk factors improved C index from 0.815 to 0.832 (change 0.017, 95% CI 0.001–0.033), IDI was 0.012 (95% CI 0.006–0.051), and cNRI was 0.220 (95% CI 0.048–0.357).

Conclusions

P-wave indices and orthogonal P-wave morphology can be used to identify subjects at high and low risk for AF and possibly direct extensive AF screening protocols towards high-risk subjects in the general population in order to decrease the risk of cardioembolic stroke. However, more research is needed in this topic.

Acknowledgement/Funding

Finnish Medical Foundation, Onni and Hilja Tuovinen's Foundation, Orion Research Foundation, Paavo Nurmi's Foundation, Veritas Foundation

P5647Temporal variability of T-wave morphology and risk of sudden cardiac death in patients with coronary artery disease

Background

The possible relationship between temporal variability of electrocardiographic spatial heterogeneity of repolarisation and the risk of sudden cardiac death (SCD) in patients with coronary artery disease (CAD) is not completely understood.

Purpose

To investigate the prognostic value of temporal variability of T-wave spatial heterogeneity in SCD in patients with CAD.

Methods

The Innovation to reduce Cardiovascular Complications of Diabetes at the Intersection (ARTEMIS) study population consisted of 1,946 patients with angiographically verified CAD. T-wave morphology dispersion (TMD), which estimates the average angle between all reconstruction vector pairs in T-wave loop based on leads I-II and V2-V6, was analysed on beat-to-beat basis from 10 minutes period of the baseline electrocardiographic recording in 1,678 study subjects. The temporal variability of TMD was evaluated by standard deviation of TMD (TMD-SD).

Results

After on average of 7.4±2.0 years of follow-up, a total of 47 of the 1,678 study subjects (2.8%) had experienced SCD or were resuscitated from sudden cardiac arrest (SCA). TMD-SD was significantly higher in patients who had experienced SCD/SCA compared with those who remained alive (3.64±2.57 vs. 2.65±2.54, p<0.01, respectively), but did not differ significantly between the patients who had experienced non-sudden cardiac death (n=40, 2.4%) and those who remained alive (2.98±2.43 vs. 2.67±2.55, p=0.45, respectively) or between the patients who succumbed to non-cardiac death (n=88, 5,2%) and those who stayed alive (2.74±2.44 vs. 2.67±2.55, p=0.81). After adjustments with relevant clinical risk indicators of SCD/SCA, such as left ventricular ejection fraction, diabetes, left bundle branch block and Canadian Cardiac Society class, TMD-SD still predicted SCD/SCA (HR 1.113, 95% CIs 1.028–1.206, p<0.01). The discrimination and reclassification accuracy increased significantly (p=0.02, p=0.033) and the C-index increased from 0.733 to 0.741 when TMD-SD was added to the clinical risk model of SCD/SCA. The Kaplan-Meier survival curves show proportional probabilities of event-free survival for different modes of death for patients classified according to the optimised TMD-SD cut-off point (Figure).

Figure 1

Conclusions

Temporal variability of electrocardiographic spatial heterogeneity of repolarisation represented by TMD-SD independently predicts long-term risk of SCD/SCA in patients with CAD.

Acknowledgement/Funding

Sigrid Juselius Foundation and Finnish Foundation for Cardiovascular Research

P5642A clinical risk score for estimating sudden cardiac death risk in the general population

Background

Sudden cardiac death (SCD) remains a major cause of premature mortality worldwide, so there has been an ongoing pursuit for tools for SCD risk stratification. Coronary artery disease is the major cause for SCD in adults, but the level of risk associated with multiple cardiovascular risk factors is not well established.

Purpose

To create a clinical risk score for estimating SCD risk in the general population.

Methods

Using data from a Finnish general population cohort of 7200 adults (mean age 51y, 46% male) with a mean follow-up of 24±11 years, we assessed the incremental SCD risk associated with the presence of several cardiovascular risk factors. SCD events were adjudicated based on death certificates according to the established criteria (autopsy was performed on 48% of SCD cases). Hazard ratios (HR) for SCD and all-cause mortality were calculated using the Cox proportional hazards model. Of the multiple parameters analysed, male sex, increasing age, diabetes, hypertension, smoking and previously diagnosed cardiac disease were independently associated with SCD in a multivariable model. Based on the magnitude of risk, a SCD risk score was created (2 points: age >70y; 1 point: male sex, age 60–70y, diabetes, hypertension, smoking, cardiac disease).

Results

75.2% of the study subjects had 0–2 risk points, 12.8% 3 risk points, and 12.0% >3 risk points. During the follow-up, 400 SCDs occurred. Increasing risk score was associated with a progressively greater risk for SCD (Figure). Compared with subjects without risk factors, those with a risk score of 3 had a HR of 21.2 (95% CI 12.7–35.4, p<0.001) and those with a risk score of >3 had a HR of 52.6 (95% CI 31.3–88.3, p<0.001) for SCD. Clinical risk score predicted significantly also all-cause mortality (HR 31.5 with risk score >3 [95% CI 27.6–35.9, p<0.001]).

Risk of SCD according to the risk score

Conclusions

Accumulation of multiple cardiovascular risk factors is associated with a markedly elevated risk for SCD in the general population. This highlights the need for SCD prevention efforts with lifestyle interventions and medical therapy in the high-risk subjects. Studies on focused SCD risk stratification may be warranted in the subjects at highest risk.