Mitral valve prolapse with ventricular arrhythmias: does it carries a worse prognosis?

The association of mitral valve prolapse (MVP) with ventricular arrhythmias has long been known and has generally been considered a benign condition. In recent years, however, a small but not negligible risk of malignant ventricular arrhythmias and sudden cardiac death has been documented in the large population of subjects with MVP. The main predictors of major arrhythmic risk identified so far include history of syncope, ventricular repolarization abnormalities in the inferior-lateral electrocardiogram leads, right bundle branch block morphology of ventricular ectopic beats, finding of areas of myocardial fibrosis on cardiac magnetic resonance, and mitral annular disjunction (MAD) on echocardiogram, as well as a possible pro-arrhythmic genetic substrate. The stratification of arrhythmic risk, with the active search for red flags and in particular of MAD, is important to identify patients with the malignant arrhythmic variant of MVP in whom to implement closer surveillance and possible therapeutic interventions.

Electrocardiographic Imaging of Repolarization Abnormalities

Background Dispersion and gradients in repolarization have been associated with life‐threatening arrhythmias, but are difficult to quantify precisely from surface electrocardiography. The objective of this study was to evaluate electrocardiographic imaging (ECGI) to noninvasively detect repolarization‐based abnormalities. Methods and Results Ex vivo data were obtained from Langendorff‐perfused pig hearts (n=8) and a human donor heart. Unipolar electrograms were recorded simultaneously during sinus rhythm from an epicardial sock and the torso‐shaped tank within which the heart was suspended. Regional repolarization heterogeneities were introduced through perfusion of dofetilide and pinacidil into separate perfusion beds. In vivo data included torso and epicardial potentials recorded simultaneously in anesthetized, closed‐chest pigs (n=5), during sinus rhythm, and ventricular pacing. For both data sets, ECGI accurately reconstructed T‐wave electrogram morphologies when compared with those recorded by the sock (ex vivo: correlation coefficient, 0.85 [0.52–0.96], in vivo: correlation coefficient, 0.86 [0.52–0.96]) and repolarization time maps (ex‐vivo: correlation coefficient, 0.73 [0.63–0.83], in vivo: correlation coefficient, 0.76 [0.67–0.82]). ECGI‐reconstructed repolarization time distributions were strongly correlated to those measured by the sock (both data sets, R 2 ≥0.92). Although the position of the gradient was slightly shifted by 8.3 (0–13.9) mm, the mean, max, and SD between ECGI and recorded gradient values were highly correlated ( R 2 =0.87, 0.75, and 0.86 respectively). There was no significant difference in ECGI accuracy between ex vivo and in vivo data. Conclusions ECGI reliably and accurately maps potentially critical repolarization abnormalities. This noninvasive approach allows imaging and quantifying individual parameters of abnormal repolarization‐based substrates in patients with arrhythmogenesis, to improve diagnosis and risk stratification.

Repolarization abnormalities at admission predict 30-day outcome in COVID-19

Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): BV is supported by a research grant of the Frans Van de Werf Fund for Clinical Cardiovascular Research. Introduction COVID-19 can be related with a poor clinical outcome. ECG abnormalities in COVID-19 have been widely described, but literature on the predictive value of a 12-lead ECG at hospital admission and normalization of these abnormalities after infection is limited. Purpose To describe the predictive value of ECG abnormalities on admission and after recovery of COVID-19. Methods After informed consent patients older than 18 years admitted with COVID-19 between March and July 2020 were included in a prospective registry. Diagnosis was confirmed by PCR-assay or based on suggestive clinical and radiological presentation. Demographic and clinical data were collected by review of the electronic medical record. All ECGs from admission until last follow-up were assessed lead by kead for repolarization abnormalities. The index ECG was defined as first ECG available after admission, a post-COVID ECG was obtained after hospital discharge in the absence of acute pathology. Minor abnormalities included iso-electric T-waves and ST-depression ≤2 mm. Major abnormalities were ST-depression >2 mm, ST-elevation, biphasic T-waves and T-wave inversion. Myocardial regions were defined as anterior (V1-V4), lateral (I, aVL, V5, V6) and inferior (II, III, aVF). Patients with a ventricular pacemaker were excluded. Results A total of 283 patients were included, median age 65 years and 64.7% were male. The 30-day mortality rate was 20.5%. In 96.8% of patients an ECG was available within 48 hours after admission. Repolarization abnormalities were observed in 48.8% of patients. In 27.2% this was limited to minor abnormalities. Abnormal repolarization was related to age, cardiovascular medical history, renal function, high-sensitive troponin-T and NT-proBNP levels. There were no significant differences in clinical presentation, ICU admission, need for ventilation or ECMO. On Kaplan-Meier analysis (figure) the presence (p < 0.001) and the extent of repolarization abnormalities (p < 0.001) were associated with 30-day mortality. Forward Cox regression modelling identiefied age (per year, HR 1.07, 95% CI 1.05-1.09), history of heart failure (HR 2.12, 95% CI 1.08-4.52), neurological disorders (HR 2.47, 95% CI 1.36-4.51), active oncological disease (HR 2.13, 95% CI 1.01-4.50) and the extent of repolarization abnormalities (per region, HR 1.37, 95% CI 1.05-1.79) as independent predictors. A post-COVID ECG was available in 172 patients (60.8%), the median time between index and post-COVID ECG was 63.3 days. There was 1 new first-degree AV-block and 1 new RBBB. Repolarization abnormalities were present in 32 patients (11.3%); however, only 3 patients (1.7%) had new abnormalities, 2 of whom died during further follow-up. Conclusions The extent of repolarization abnormalities on an ECG at admission for COVID-19 is an independent predictor of 30-day mortality. New ECG abnormalities after COVID-19 infection are uncommon but may be associated with adverse outcome. Abstract Figure.