Hai, JoJo

Introduction: The T peak - T end interval (Tpe) is a measure of transmural dispersion of repolarisation with prolongation of this interval linked to an increased risk of ventricular arrhythmias and sudden death. Patients with cardiac amyloid experience a high rate of sudden cardiac death. Objective: To determine the prognostic utility of the Tpeak-Tend interval in patients with transthyretin (TTR) cardiac amyloidosis. Methods: Of the 240 patients who underwent evaluation for TTR amyloidosis at our tertiary referral center from 1966 to 2010, 39 met inclusion criteria (65 excluded for AF, 66 BBB/Paced Rhythm, 25 CAD, 21 other). Inclusion criteria were presence of histological diagnosis of TTR amyloid and confirmed cardiac involvement by echocardiogram or biopsy and absence of atrial fibrillation (AF) or bundle branch block/paced rhythm on the index surface ECG, or history of coronary heart disease (CAD). Tpe was measured in leads V3 and V5. Cox proportional hazards model were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). Kaplan-Meier curves were used to estimate overall survival and differences between curves were estimated using log rank. Primary endpoints were death or heart transplantation. Results: Of the 39 patients, 85% were male, and 69% were mTTR. Mean age 66.4 ± 13.9 years. Mean follow up period of 4.2 ± 3.2 years, 25 died and 5 received heart transplants. Median survival was 3.8 years, with 5 year survival 34%. On univariate analysis, Tpe in lead V3 was predictive of adverse outcome, HR per 10msec, 1.195 (1.051-1.370). Further multivariate analysis, in a model accounting for age, gender, Lead V3 Tpe was independently associated with survival, HR per 10msec, 1.207, (1.094-1.411, p=0.009). Conclusions: The Tpe interval in Lead V3 at diagnosis is a novel, noninvasive independent predictor of survival in transthyretin cardiac amyloidosis patients in sinus rhythm.

Objective Sudden cardiac arrest (SCA) is the most devastating outcome in hypertrophic cardiomyopathy (HCM). We evaluated repolarisation features on the surface electrocardiogram (ECG) to identify the potential risk factors for SCA. Methods Data was collected from 52 patients with HCM who underwent implantable cardioverter defibrillator (ICD) implantation. Leads V2 and V5 from the ECG closest to the time of ICD implant were utilised for measuring the Tpeak-Tend interval (Tpe), QTc, Tpe/QTc, T-wave duration and T-wave amplitude. The presence of the five traditional SCA-associated risk factors was assessed, as well as the HCM risk-SCD score. Results 16 (30%) patients experienced aborted cardiac arrest over 8.5±4.1 years, with 9 receiving an ICD shock and 7 receiving ATP. On univariate analysis, T-wave amplitude was associated with appropriate ICD therapy (HR per 0.1 mV 0.79, 95% CI 0.56 to 0.96, p=0.02). Aborted SCA was not associated with a greater mean QTc duration, Tpeak-Tend interval, T-wave duration, or Tpe/QT ratio. Multivariate analysis (adjusting for cardinal HCM SCA-risk factors) showed T-wave amplitude in Lead V2 was an independent predictor of risk (adjusted HR per 0.1 mV 0.74, 95% CI 0.57 to 0.97, p=0.03). Addition of T-wave amplitude in Lead V2 to the traditional risk factors resulted in significant improvement in risk stratification (C-statistic from 0.65 to 0.75) but did not improve the performance of the HCM SCD-risk score. Conclusions T-wave amplitude is a novel marker of SCA in this high risk HCM population and may provide incremental predictive value to established risk factors. Further work is needed to define the role of repolarisation abnormalities in predicting SCA in HCM.