P-wave characteristics as electrocardiographic markers of atrial abnormality in prediction of incident atrial fibrillation - The Malmö Preventive Project

BACKGROUND

P-wave indices reflect atrial abnormalities contributing to atrial fibrillation (AF). We aimed to assess a comprehensive set of P-wave characteristics for prediction of incident AF in a population-based setting.

METHODS

Malmö Preventative Project (MPP) participants were reexamined in 2002-2006 with electrocardiographic (ECG) and echocardiographic examinations and followed for 5 years. AF-free subjects (n = 983, age 70 ± 5 years, 38% females) with sinus rhythm ECGs were included in the study. ECGs were digitally processed using the Glasgow algorithm. P-wave duration, axis, dispersion, P-terminal force in lead V1 and interatrial block (IAB) were evaluated. ECG risk score combining the morphology, voltage and length of P-wave (MVP score) was calculated. New-onset diagnoses of AF were obtained from nation-wide registers.

RESULTS

During follow up, 66 patients (7%) developed AF. After adjustment for age and gender, the independent predictors of AF were abnormal P-wave axis > 75° (HR 1.63 CI95% 1.95-11.03) and MVP score 4 (HR 6.17 CI 95% 1.76-21.64), both correlated with LA area: Person r - 0.146, p < 0.001 and 0.192, p < 0.001 respectively. Advanced IAB (aIAB) with biphasic P-wave morphology in leads III and aVF was the most prevalent variant of aIAB and predicted AF in a univariate model (HR 2.59 CI 95% 1.02-6.58).

CONCLUSION

P-wave frontal axis and MVP score are ECG-based AF predictors in the population-based cohort. Our study provides estimates for prevalence and prognostic importance of different variants of aIAB, providing a support to use biphasic P-wave morphology in lead aVF as the basis for aIAB definition.

Morphology-Voltage-P-wave duration (MVP) score in prediction of incident atrial fibrillation in an elderly epidemiologic cohort

Background

Interatrial block (IAB) on electrocardiography (ECG) and reduced P wave voltage reflect atrial abnormalities which may contribute to development of atrial fibrillation (AF).

Purpose

We aimed to assess the value of a recently proposed ECG risk score that combines the morphology, voltage and length of the P wave (MVP score) for prediction of incident AF in a prospective population-based setting.

Material and methods

The study population is based on the large, prospective Malmö Preventative Project (MPP) cohort. We included subjects without a history of AF, with a readable ECG in sinus rhythm and an echocardiography performed in 2002–2006 (n=983, mean age 70±5 years, 38% females). Median follow-up was 4.2 (IQR 3.7–4.8) years. ECGs were digitally processed using the Glasgow algorithm. Advanced IAB (aIAB) was defined as a P-wave ≥120 ms and biphasic morphology (+/−) in inferior leads, partial IAB (pIAB) as P-wave ≥120 ms and a monophasic positive morphoology in inferior leads. MVP score was calculated based on the P-wave morphology in inferior leads, voltage in lead 1, and P-wave duration (Table 1).Incident AF events (n=66, 7%) were obtained from the Swedish Hospital Discharge Register and Cause of Death Register. Cox regression analysis and Kaplan Meier curve analysis were used to study the association of echocardiographic and P-wave characteristics with the risk of new onset AF.

Results

At baseline the mean MVP score was 1±1, none of the subjects had MVP score above 4. MVP score correlated with left atrial (LA) area: Pearson r=0.192, p&lt;0.001. After adjustment for age, gender and LA enlargement expressed as LA area &gt;20 cm2, new onset AF was associated with MVP score 4 (HR 6.17, 95% CI 1.76–21.64 compared to those with MVP score &lt;4, Figure 1). Neither aIAB (univariate HR 1.93 CI 95% 0.82–4.56), nor pIAB (univariate HR 1.16 CI 95% 0.52–2.55) predicted incident AF.

Conclusion

In a population-based elderly epidemiological cohort, the ECG-based MVP score was significantly associated with incident AF, independently of LA enlargement.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The Swedish Heart-Lung Foundation

Evolution of P-wave indices during long-term follow-up as markers of atrial substrate progression in arrhythmogenic right ventricular cardiomyopathy

AIMS

Patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) have increased prevalence of atrial arrhythmias indicating atrial involvement in the disease. We aimed to assess the long-term evolution of P-wave indices as electrocardiographic (ECG) markers of atrial substrate during ARVC progression.

METHODS AND RESULTS

We included 100 patients with a definite ARVC diagnosis according to 2010 Task Force criteria [34% females, median age 41 (inter-quartile range 30-55) years]. All available sinus rhythm ECGs (n = 1504) were extracted from the regional electronic ECG databases and automatically processed using Glasgow algorithm. P-wave duration, P-wave area, P-wave frontal axis, and prevalence of abnormal P terminal force in lead V1 (aPTF-V1) were assessed and compared at ARVC diagnosis, 10 years before and up to 15 years after diagnosis.Prior to ARVC diagnosis, none of the P-wave indices differed significantly from the data at ARVC diagnosis. After ascertainment of ARVC diagnosis, P-wave area in lead V1 decreased from -1 to -30 µV ms at 5 years (P = 0.002). P-wave area in lead V2 decreased from 82 µV ms at ARVC diagnosis to 42 µV ms 10 years after ARVC diagnosis (P = 0.006). The prevalence of aPTF-V1 increased from 5% at ARVC diagnosis to 18% by the 15th year of follow-up (P = 0.004). P-wave duration and frontal axis did not change during disease progression.

CONCLUSION

Initial ARVC progression was associated with P-wave flattening in right precordial leads and in later disease stages an increased prevalence of aPTF-V1 was seen.

Reduction of left atrial strain and strain rate during conduit phase as the earliest marker of left ventricular diastolic disfunction

Funding Acknowledgements

Type of funding sources: None.

Left atrial (LA) functional abnormalities, including LA strain (LAS) and strain rate (LASR) reduction, are observed in patients with left ventricular diastolic disfunction (LVDD). However, the degree of reduction at different stages of LVDD is not fully clarified.

We aimed to assess the interdependence between LAS and LASR parameters and LVDD grades in subjects of advanced age with preserved ejection fraction (EF).

Material and methods

Consecutive patients, who underwent echocardiography within 12 months, were screened and included into the study in case of age older than 65 years, preserved EF, sinus rhythm at the time of study and preserved dataset of sufficient quality for speckle tracking analysis. LAS and LASR parameters, including LAS and peak LASR during reservoir, conduit, and contractile phases were calulated with single plane apical 4-chamber view assessment. One-way ANOVA analysis with Bonferroni correction was used to assess the difference between groups.

Results

Among 153 patients (mean age 74 ± 7 years; 105 female, mean EF 64 ± 5%) included in the study there were 38 patients with no evidence of LVDD, 67 with LVDD grade 1, 40 with LVDD grade 2, and 5 with LVDD grade 3. The values of LAS and LASR parameters for these groups are summarized in Table. All parameters were significantly reduced in grade 2 and 3 LVDD patients comparing to the patients with no LVDD. Contractile phase LAS and LASR were slightly higher in grade 1 than in no LVDD patients. Reservoir and conduit phase LAS and LASR were lower in grade 1 LVDD comparing to no LVDD, but only for conduit phase parameters the difference was significant. In ROC analysis for conduit phase LAS and LASR to be associated with the presence of LVDD of any grade the  area under the curve was 0,707 (p &lt; 0.001) and 0,742 (p &lt; 0.001) respectively.

Conclusion

Impaired LA function is seen in patients with LVDD. Whereas measurements characterizing LA reservoir and contractile functions demonstrate significant decrease at advanced stages of LVDD, conduit function is significantly reduced at grade 1 LVDD, providing the possibility for early detection of LVDD.

Group LAS (%) LASR (1/sec) reservoir conduit contractile reservoir conduit contractile No LVDD, n = 38 29,7 ± 9,3 †‡ 15,1 ± 6,6 §†‡ 14,6 ± 5,4 †‡ 1,28 ± 0,37 †‡ 1,18 ± 0,44 §† 1,68 ± 0,60 †‡ Grade 1, n = 69 28,6 ± 8,9 †‡ 11,6 ± 6,2 ƒ 17,0 ± 5,7 †‡ 1,23 ± 0,43 ‡ 0,90 ± 0,38 ƒ 1,99 ± 0,71 †‡ Grade 2, n = 40 19,1 ± 7,1 ƒ§ 9,2 ± 4,5 ƒ 9,9 ± 4,4 ƒ§ 0,87 ± 0,26 ƒ§ 0,72 ± 0,27 ƒ 1,07 ± 0,44 ƒ§ Garde 3, n = 5 13,8 ± 3,6 ƒ§ 7,7 ± 2,5 ƒ 6,1 ± 2,2 ƒ§ 0,8 ± 0,29 ƒ 0,75 ± 0,28 0,67 ± 0,27 ƒ§ Significant difference (p &lt; 0,05): ƒ – with No LVDD, § – with Grade 1 LVDD, † – with Grade 2 LVDD, ‡ – with Grade 3 LVDD

P5653Atrial fibrillation in arrhythmogenic right ventricular cardiomyopathy and its association with left atrial volume index

Background

Recent studies in arrhythmogenic right ventricular cardiomyopathy (ARVC) support atrial involvement in the disease progression and consider atrial fibrillation (AF) as one of the primary manifestations of ARVC. We aimed to assess clinical factors, components of 2010 Task Force criteria (TFC2010) and echocardiographic characteristics of atria associated with AF in the Scandinavian cohort of ARVC patients.

Methods

Study sample comprised of 106 definite ARVC patients by TFC2010 from three tertiary care centers participating in the Nordic ARVC Registry (33% females, median age at ARVC diagnosis 41 years [IQR 30–54 years]). No concomitant diseases were observed in 90 patients (85%) while 16 patients had one or more comorbidities: hypertension (n=6), diabetes mellitus (n=5), coronary artery disease (n=5) or congestive heart failure (n=9). AF was included in the registry protocol as a pre-specified clinical event and verified by processing of the electronic ECG databases which contains all ECG recordings from the involved hospitals catchment areas (earliest ECG from 1988). Left (LA) and right atrial (RA) dimensions were obtained by revisiting cardiac ultrasound examinations performed at the time of ARVC diagnosis. Association between AF and clinical characteristics was assessed using multivariable logistic regression analysis adjusted for age and gender.

Results

AF was diagnosed in 29 patients (27%) at a median age of 53 (IQR 38–63) years, 7 females (24%). Median time from ARVC diagnosis to AF onset was 8 (IQR 2–12) years. AF was univariately associated with right ventricular structural abnormalities meeting the definition of major imaging criterion by 2010TFC, ventricular tachycardia (VT) with superior axis (major criterion) and LA volume index. Significantly associated variables were included in a multivariate model, in which LA volume index (OR=1.07, 95% CI 1.01–1.14, p=0.021) and superior axis VT (OR=7.45, 95% CI 1.82–30.55, p=0.005) remained independently associated with AF. In receiver operating characteristic (ROC) curve analysis, LA volume index was significantly associated with AF (AUC=0.703, p=0.005) and with superior axis VT (AUC=0.703, p=0.021). AF was not associated with either RA volume index (univariate OR=1.03, 95% CI 0.99–1.06, p=0.203) or left ventricular ejection fraction (OR=0.97, 95% CI 0.92–1.03, p=0.299).

Conclusion

In patients with ARVC,AF is primarily associated with LA structural abnormalities without indication of RA involvement and is strongly associated with ventricular arrhythmias thus indicating parallel development of atrial and ventricular arrhythmic substrate.

Interatrial block in prediction of all-cause mortality after first-ever ischemic stroke

Background

Interatrial block (IAB) is an ECG indicator of atrial fibrosis related to atrial remodeling and thrombus formation thus leading to embolic stroke and increasing mortality. We aimed to assess weather IAB predicted all-cause mortality during 10 years after ischemic stroke.

Methods

The study sample comprised 235 patients (median age 74 (interquartile range 25–75% 65–81) years, 95 female) included in the Lund Stroke Register in 2001–2002, who had sinus rhythm ECGs at stroke admission. IAB was defined as a P-wave duration ≥120 ms without = partial IAB (n = 56) or with = advanced IAB (n = 41) biphasic morphology (±) in the inferior ECG leads. All-cause mortality was assessed via linkage with the Swedish Causes of Death Register.

Results

During follow-up 126 patients died (54%). Advanced IAB, but not partial, was associated with all-cause mortality in univariate Cox regression analysis (hazard ratio (HR) 1.98, 95% CI 1.27–3.09, p = 0.003). After adjustment for age, gender, severity of stroke measured by NIHSS scale and smoking status in patients without additional comorbidities advanced IAB independently predicted all-cause mortality (HR 7.89, 95% CI 2.01–30.98, p = 0.003), while in patients with comorbidities it did not (HR 1.01 95% CI 0.59–1.72, p = 0.966).

Conclusion

Advanced IAB predicted all-cause mortality after ischemic stroke, but mostly in patients without additional cardiovascular comorbidities.

Electrocardiographic and Echocardiographic predictors of paroxysmal atrial fibrillation detected after ischemic stroke

BACKGROUND

Detection of atrial fibrillation after ischemic stroke is challenging due to its paroxysmal nature. We aimed to assess predictors of paroxysmal atrial fibrillation using non-invasive surface ECG and transthoracic echocardiography to select candidates for atrial fibrillation screening.

METHODS

Ischemic stroke patients without documented atrial fibrillation (n = 110, 67 ± 10 years, 40 female) and a control group of age- and gender-matched patients with history of paroxysmal atrial fibrillation prior to stroke (n = 55, 67 ± 10 years, 19 female) comprised the study sample. Using non-invasive ECG monitoring for three weeks, short episodes of paroxysmal atrial fibrillation were detected in 24 of 110 patients (22 %). The standard 12-lead ECG with sinus rhythm at stroke onset was digitally processed and analyzed. Transthoracic echocardiography data were reviewed for these patients.

RESULTS

Atrial fibrillation history was independently associated with P terminal force in lead V 1 > 40 mm*ms (OR 4.04 95 % CI 1.34-12.14, p = 0.013) and left atrial volume index (OR 1.08 95 % CI 1.03-1.13, p = 0.002; for LAVI > 40 mL/m² OR 6.40 95 % CL 1.47-27.91, p = 0.013). Among patients without atrial fibrillation history, no ECG characteristics were predictive of atrial fibrillation detected after stroke. Left atrial volume index remained an independent predictor of atrial fibrillation detected after stroke (OR 1.09 95 % CI 1.02-1.16, p = 0.017). A cutoff of <40 mL/m² had an 84 % negative predictive value for ruling out atrial fibrillation on ambulatory monitoring with a sensitivity of 50 % and a specificity of 86 %.

CONCLUSION

In a post hoc analysis, left atrial dilatation assessed by left atrial volume index independently predicted atrial fibrillation after stroke in patients without prior atrial fibrillation history, while the other clinical or ECG markers were not predictive of atrial fibrillation detected early after ischemic stroke.

TRIAL REGISTRATION

This study is a post hoc analysis from the prospective case-control study registered in December 2011, ClinicalTrials.gov ID: NCT01325545 .

Predictors of new onset atrial fibrillation during 10-year follow-up after first-ever ischemic stroke

BACKGROUND

Paroxysmal atrial fibrillation (AF) may be underdiagnosed in ischemic stroke patients but may be pivotal for initiation of oral anticoagulation therapy. We assessed clinical and ECG predictors of new-onset AF during 10-year follow-up (FU) in ischemic stroke patients.

METHODS

The study sample comprised of 227 first-ever ischemic stroke patients without AF (median age 73, interquartile range 25%-75% 63-80years, 92 female) and 1:1 age- and gender-matched controls without stroke and AF enrolled in the Lund Stroke Register from March 2001 to February 2002. New-onset AF during FU was assessed by screening through regional ECG database and by record linkage with Swedish National Patient Register. The standard 12-lead sinus rhythm ECGs at stroke admission were retrieved from electronic database and digitally processed. Clinical baseline characteristics were studied using medical records.

RESULTS

During FU, AF was found in 39 stroke patients and 30 controls, p=0.296. In stroke patients in multivariate Cox regression analysis AF was associated with hypertension (HR 3.45 CI 95% 1.40-3.49, p=0.007) and QRS duration (HR 1.02 CI 95% 1.00-1.03, p=0.049). High cardiovascular risk was predictive for AF development: for CHADS2≥4 HR 2.46 CI 95% 1.45-4.18, p=0.001 and for CHA2DS2-VASc≥5 HR 2.29 CI 95% 1.43-3.68, p=0.001. New onset AF was not associated with baseline ischemic stroke: HR 1.46 95% CI 0.90-2.35, p=0.121.

CONCLUSION

High CHADS2 and CHA2DS2-VASc scores, but not baseline ischemic stroke, predict new onset AF in FU. QRS duration might be considered a potential risk marker for prediction of AF after ischemic stroke.