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<0.001. After adjustment for age, gender and LA enlargement expressed as LA area >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 <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

Christmas holiday triggers of myocardial infarction

Background

Christmas holidays have been associated with the highest incidence of myocardial infarction (MI). We wanted to assess possible triggers of MI during Christmas.

Method

A nationwide, retrospective postal survey with case-control design. All individuals suffering a MI during the Christmas holidays 2018 and 2019 in Sweden were identified through the SWEDEHEART registry and a control group matched in age and gender with chronic coronary syndrome who did not seek medical attention during Christmas, were asked for participation. Subjects completed a questionnaire asking them to rate 27 potential MI-triggers as having occurred more or less than usual.

Results

A total of 189 patients suffering a MI on Christmas Eve, Christmas Day, or Boxing Day and 157 patients in control-group responded to the questionnaire, representing response rates of 66% and 62%, respectively. Patients with MI on Christmas experienced more stress (36.7% vs 20.9%, p=0.002), depression (20.9% vs 10.5%, p=0.024) and worry (25.9% vs 10.1%, p<0.001) compared to the control-group. The food and sweets-consumption were increased in both groups, but to a greater extent in the control-group (33.0% vs 49.7%, p=0.002 and 32.4% vs 43.3, p=0.031). There were no increases in quarrels, anger, economic worries or reduced compliance with medication.

Conclusions

Patients suffering MI on Christmas holiday experienced higher levels of stress and emotional distress compared to patients with chronic coronary syndrome, possibly explaining the phenomenon of holiday heart attack. Understanding what factors increase the number of MI on Christmas may help reduce the excess number of MIs and cardiovascular burden.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swedish Heart and Kund FoundationSwedish Scientific Research Council

Myocardial involvement in COVID-19: data from 102 unselected autopsies during the first wave of pandemic

Background

Myocardial involvement in COVID-19 has been described as either coronary artery related ischemic lesions, lymphocyte myocarditis or microangiopathy. Assessment of the link between COVID-19 and the cause of death has been hampered by the limited number of autopsies performed during the pandemics and risk factors associated with the type and extent of myocardial damage remain poorly described. In Russia, the mandatory autopsy approach has been advocated for the cases of suspected COVID-19 related deaths.

Purpose

To describe the prevalence, extent and risk factors associated with myocardial damage in an unselected cohort of patients deceased with COVID-19.

Methods

Consecutive patients with PCR-confirmed or suspected COVID-19 who died either in-hospital (clinical autopsy) or out-of-hospital (forensic autopsy) during COVID-19 pandemic underwent post-mortem PCR on pulmonary parenchymal tissue. Tissue PCR-positive cases were referred for histology study of pulmonary and extrapulmonary organ specimens through a central laboratory. Based on the extent of diffuse alveolar damage (DAD), COVID-19 was categorized as either being related to death or a concomitant condition not associated with death. Myocardial involvement was categorized as either (1) coronary artery related myocardial infarction, (2) microangiopathy with interstitial edema and erythrocyte aggregates occluding the capillaries with or without lymphomononuclear infiltration and (3) lymphocyte myocarditis. The presence of myocardial involvement was assessed with regard to age, gender and autopsy-verified significant coronary artery disease (CAD) and diabetes (information available only for the clinical autopsy cohort).

Results

102 autopsies were included, of whom 42 were clinical and 60 forensic (age 73±15 years, 50% men; 58% had CAD). Ten patients from the clinical autopsy cohort had diabetes (24%). Deaths were COVID-19 related in 80 patients (78%). Myocardial infarction was noted in 3 (2.9%) patients. Microangiopathy was seen in 45 (44%) and lymphocyte myocarditis in 2 (1.9%) patients, of whom it was the primary cause of death in one. The prevalence of microangiopathy did not differ between patients with and without significant DAD (46% vs 45%, p=0.848). Patients with diabetes were more likely to have microangiopathy with lymphomononuclear infiltration in the myocardium than patients without diabetes (40% vs 3.1%, p=0.008; OR=22, 95% CI 1.63–305, p=0.020 after adjustment for age, gender and CAD)

Conclusion

Systematically performed autopsies revealed causative association between SARS-CoV2 and death in the vast majority. Myocardial involvement was observed in nearly half of the patients and was not related to the extent of DAD. Myocarditis appears to be a rare finding, though it can be the primary cause of death. Microangiopathy with capillary occlusion and lymphomononuclear infiltration in the myocardium was associated with the history of diabetes.

Funding Acknowledgement

Type of funding sources: None.

First-in-world assessment of outcomes of catheter ablation for atrial arrhythmias in arrhythmogenic right ventricular cardiomyopathy

Introduction

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetically inherited disease characterized by fibro-fatty infiltrations (FFI). FFI in ARVC patients usually originates in the ventricles, but recent imaging studies showed FFI at the atrial level as well. Effectiveness of catheter ablation (CA) for atrial arrhythmias (AA) in this subset of patients is currently unknown.

Purpose

Aim of our study is to describe acute and long-term effectiveness of CA for AA in ARVC patients.

Methods

Nine ARVC registries from Europe, US, and China were retrospectively searched for ARVC patients undergoing CA for AA (namely: atrial fibrillation (AF), atrial tachycardia (AT), and cavo-tricuspid dependent atrial flutter (CTI-FL)). Baseline, procedural, and long-term outcome data were collected.

Results

Thirty-five pts (86% male, median CHA2DS2-VASc 1 [1–2], HAS-BLED 1 [0–2], and EHRA scores 2 [2–3]) were enrolled, in which a total of 45 CA procedures for AA were performed (left atrial CA: n=19 AF, n=10 AT; right atrial CA: n=16 CTI). Mean age at AA CA was 48.2±14.8 y.o. At baseline, 63% of pts were on oral anticoagulants (OAC) (n=9 warfarin; n=13 NOAC). Catheter ablation was successful and sinus rhythm obtained at the end of the procedure in all patients, with 2 (6%) AF patients requiring electrical cardioversion. Over a median follow-up of 36 [14–74] months, 12 (27%) pts experienced arrhythmia recurrence (left atrial group: n=6 AF recurrences, n=3 AT recurrences; CTI-FL group: n=1 CTI-FL recurrence; n=1 new AF with previous CTI-dependent flutter ablation), with a 1-year follow-up resulting comparable to what has been reported in the literature for the general population. [Figure 1 and 2]. 61% pts were on OAC at last follow-up.

Conclusion

Age at the time of CA for AA is about 10 years younger in patients with ARVC as compared to the general population. CA for AA in ARVC pts is safe and effective; surprisingly, long-term CA outcomes for AF and left AT result comparable to those reported in the general population, whereas recurrence rates of CTI-dependent flutter seem to be higher.

Funding Acknowledgement

Type of funding source: None

P992Incidence, predictors, and success of ventricular tachycardia catheter ablation in arrhythmogenic right ventricular cardiomyopathy (ARVC): A long-term cohort study from the Nordic ARVC registry

Background

Catheter ablation may reduce ventricular tachycardia (VT) burden in arrhythmogenic right ventricular cardiomyopathy (ARVC) patients. However, little is known about factors predicting need for ablation and various outcomes have been reported.

Purpose

We sought to investigate predictors and use of VT ablation and to evaluate the post-procedural outcome in ARVC patients.

Methods

We studied 435 patients from the Nordic ARVC registry including 220 probands with definite ARVC according to the 2010 task force criteria and 215 mutation-carrying relatives identified through cascade screening. Patients were followed until first-time VT ablation, death, heart transplantation, or January 1st 2018. Additionally, patients undergoing VT ablation were further followed from the time of ablation for recurrent ventricular arrhythmias.

Results

Cumulative use of VT ablation was 4% (95% CI 3%-6%) and 11% (95% CI 8%-15%) after 1 and 10 years. All procedures were performed in probands in whom the cumulative use was 8% (95% CI 5%-12%) and 20% (95% CI 15%-26%). In adjusted analyses restricted to probands, only young age predicted need for ablation. In patients undergoing ablation, risk of recurrent arrhythmias was 59% (95% CI 44%-71%) and 74% (95% CI 59%-84%) 1 and 5 years after the procedure. Despite high recurrence rates, the burden of ventricular arrhythmias was reduced after ablation (p=0.0042). Young age, use of several antiarrhythmic drugs and inducibility to VT immediately after ablation were associated with an unfavorable outcome.

Conclusions

Twenty percent of ARVC probands developed a clinical indication for VT ablation within 10 years after diagnosis whereas mutation-carrying relatives were without such need. Although the burden of ventricular arrhythmias decreased after ablation, risk of recurrence was substantial.

Novel mutation in the KCNJ2 gene is associated with a malignant arrhythmic phenotype of Andersen-Tawil syndrome

BACKGROUND

Andersen-Tawil syndrome (ATS) is a rare inherited multisystem disorder associated with mutations in KCNJ2 and low prevalence of life-threatening ventricular arrhythmias. Our aim was to describe the clinical course of ATS in a family, in which the proband survived aborted cardiac arrest (ACA) and genetic screening revealed a previously unknown mutation (c.271_282del12[p.Ala91_Leu94del]) in the KCNJ2 gene.

METHODS

A cascade family screening was performed in a 5-generation family after identification of the KCNJ2 mutation in the proband. Subsequently, 10 of 21 screened individuals appeared to be mutation carriers (median age 38 [range 10-75] years, 3 female). Mutation carriers underwent clinical examination including biochemistry panel, cardiac ultrasound, Holter ECG, and exercise stress test.

RESULTS

(1) At baseline, 2 patients had survived ACA, 3 had syncope or presyncopal attacks, and 2 reported palpitations. Exercise-induced nonsustained bidirectional ventricular tachycardia was documented in 4 patients, 2 received implantable cardioverter-defibrillators (ICD) for primary prevention and 2 for secondary prevention. (2) During follow-up, 1 primary prevention and 1 secondary prevention patient received in total 4 adequate ICD shocks. Life-threatening ventricular arrhythmias were documented during childhood in 5 of 10 mutation carriers. (3) All mutation carriers presented with characteristic mild dysmorphic features. Only 1 patient suffered from periodic paralysis. All had normal serum potassium level at repeated assessments and none had any other extracardiac disease manifestation.

CONCLUSION

Our findings suggest that the novel KCNJ2 mutation is associated with a predominantly cardiac phenotype of Andersen-Tawil syndrome with high propensity to life-threatening ventricular arrhythmias presenting from childhood and young adulthood.

Clinical trials in Russia and Eastern Europe: recruitment and quality

OBJECTIVE

To review the current situation of clinical trials in Russia and Eastern Europe.

FINDINGS

The volume of clinical trials in these territories is increasing. The quality of the data obtained, ethical care and compliance with Good Clinical Practice guidelines is at least as good as anywhere else. United States Food and Drug Administration inspection data indicate that sites in these countries are often superior to those elsewhere. Large-scale clinical trials conducted in these territories have been subsequently published in mainstream journals. Territory-specific attention must be paid to communications' equipment and language. However, this is countered, for example, by the fact that most clinical research associates in Russia hold degrees in medicine, that patients with previously untreated disease are more easily found than in North America or Western Europe, and the participation of large, purpose-built, healthcare institutions.

CONCLUSION

Eastern Europe and Russia are well-established locales for clinical trials. These territories offer a solution to the competition for patients among clinical trials in North America or Western Europe.

Changes in tissue optical properties due to radio-frequency ablation of myocardium

The optical properties of pig heart tissue were measured after in vivo ablation therapy had been performed during open-heart surgery. In vitro samples of normal and ablated tissue were subjected to measurements with an optically integrating sphere set-up in the region 470-900 nm. Three independent measurements were made: total transmittance, total reflectance and collimated transmittance, which made it possible to extract the absorption and scattering coefficients and the scattering anisotropy factor g, using an inverse Monte Carlo model. Between 470 and 700 nm, only the reduced scattering coefficient and absorption could be evaluated. The absorption spectra were fitted to known tissue chromophore spectra, so that the concentrations of haemoglobin and myoglobin could be estimated. The reduced scattering coefficient was compared with Mie computations to provide Mie equivalent average radii. Most of the absorption was from myoglobin, whereas haemoglobin absorption was negligible. Metmyoglobin was formed in the ablated tissue, which could yield a spectral signature to distinguish the ablated tissue with a simple optical probe to monitor the ablation therapy. The reduced scattering coefficient increased by, on average, 50% in the ablated tissue, which corresponded to a slight decrease in the Mie equivalent radius.

Effects of MgSO4 and glucose, insulin and potassium (GIK) on atrial conduction during the first 12 hours after DC-conversion of chronic atrial fibrillation

OBJECTIVE

To investigate changes in atrial conduction induced by MgSO4 and glucose, insulin and potassium (GIK) during the first 12-h period of sinus rhythm after successful DC-conversion of chronic atrial fibrillation (CAF).

METHODS

Signal-averaged P-wave duration, QRS-duration and PQ-time were recorded in 20 patients who were randomly assigned to control or intervention. Ten patients received no infusates (control group) and 10 patients received MgSO4 and GIK infusions (intervention group). P-wave duration was determined from the X-, Y- and Z-leads, which were further combined to obtain a spatial magnitude. P-wave morphology was studied by analysing global activation patterns and discrete components from the calculated spatial magnitude signal.

RESULTS

No changes in the measured parameters were seen in the control group. The P-wave duration, QRS-duration and PQ-time increased from 139(13) [mean(SD)] to 149(15) (p < 0.01), 90(7) to 94(9) (p < 0.05) and 188(10) to 207(13) ms (p < 0.01). respectively, after bolus infusion of MgSO4. The time from the start of the P-wave to its 1st and 2nd max. locations increased by 6 ms (p < 0.01) in both cases after bolus infusion of MgSO4 and had reversed after 10 h of MgSO4 and GIK infusion. P-wave duration and PQ-time decreased after 10 h of MgSO4 and GIK infusion, from 149(34) (bolus) to 138(12) and from 207(13) to 195(27) ms (p < 0.05), respectively, in spite of an even higher serum Mg concentration at the end of this period.

CONCLUSION

Bolus infusion of MgSO4 2 h after DC-conversion of CAF produced an intra-atrial conduction delay that could be reversed by adding a GIK infusion, in spite of a concomitant increase in serum Mg concentration. No recovery of the intra-atrial conduction delay, seen after DC-conversion of CAF, was observed in either of the two groups during the 12-h study period.

[Atrial fibrillation--new knowledge yields new therapeutic possibilities]

Atrial fibrillation (AF) is the most common cardiac arrhythmia prompting treatment. Advances in our knowledge of the pathophysiology of AF provide the basis for new and improved treatment modalities. Thus, focal excitation and localised impulse conduction defects are possible trigger factors which can be counteracted by focal ablation and pacing synchronisation, respectively. Perpetuation of AF, caused by continuous multisite re-entry, is promoted by successive shortening of repolarisation. Internal defibrillation and anatomical limitation of re-entry are treatments that counteract perpetuation of the arrhythmia. Current knowledge of AF and the application of new treatments are discussed by the Lund AF research group.