Usefulness of T(peak) -T(end) interval to distinguish arrhythmogenic right ventricular cardiomyopathy from idiopathic right ventricular outflow tract tachycardia

Predictive value of Tpeak-Tend interval for ventricular arrhythmia and mortality in heart failure patients with an implantable cardioverter-defibrillator: A cohort study

BACKGROUND

Tpeak-Tend interval (TpTe), a measurement of transmural dispersion of repolarization (TDR), has been shown to predict ventricular tachyarrhythmia in cardiac resynchronization therapy with defibrillator (CRT-D) patients. However, the ability of TpTe to predict ventricular tachyarrhythmia and mortality for heart failure patients with a cardioverter-defibrillator (ICD) is not clear. The purpose of this study was to assess the predictive ability of TpTe in heart failure patients with ICD.

METHODS AND RESULTS

We enrolled 318 heart failure patients treated after ICD. Patients were divided into 3 groups according to their post-implantation TpTe values and were evaluated every 6 months. The primary endpoint was appropriate ICD therapy. The secondary endpoint was all-cause mortality. During long-term follow-up, the TpTe > 110 ms group (n = 111) experienced more VT/VF episodes (45%) and all-cause mortality (25.2%) than the TpTe 90-110 ms group (n = 109) (26.4%, 14.5%) and TpTe < 90 ms group (n = 98) (11.3%, 11.3%) (overall P < .05, respectively). In Cox regression, longer post-implantation TpTe was associated with an increased number of VT/VF episodes [HR: 1.017; 95% CI: 1.008-1.026; P < .001], all-cause mortality [HR: 1.015; 95% CI: 1.004-1.027; P = .010] and the combined endpoint [HR: 1.018; 95%CI: 1.010-1.026; P < .001].

CONCLUSIONS

Post-implantation TpTe was an independent predictor of both ventricular arrhythmias and all-cause mortality in heart failure patients with an implanted ICD.

Evaluation of Tp-e Interval, Tp-e/QT Ratio, and Tp-e/QTc Ratio in Patients with Asymptomatic Arrhythmogenic Right Ventricular Cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by progressive replacement of ventricular myocytes with variable amounts of fibrous and adipose tissue. Several studies have suggested that the interval from the peak to the end of the electrocardiographic T wave (Tp-e) may correspond to the transmural dispersion of repolarization and that increased Tp-e interval and Tp-e/QT ratio are associated with malignant ventricular arrhythmias. The aim of this study was to evaluate repolarization dispersion measured from the 12-lead surface electrocardiogram (including Tp-e interval, Tp-e/QT, and Tp-e/QTc ratio) in asymptomatic ARVD patients METHODS: We selected 27 patients with asymptomatic ARVD and 27 age- and gender-match young, healthy volunteers.

RESULTS

Tp-e interval, Tp-e/QT and Tp-e/QTc ratio were also significantly higher in ARVD group compared to the control group (all P < 0.001). There were negative correlation between S global and Tp-e, Tp-e/QT, Tp-e/QTc ration (r = -0.57, P = 0.02; r = -0.85, P = 0.02; r = -0.63, P < 0.01; respectively). There were also negative correlation between Sm global and Tp-e, Tp-e/QT, Tp-e/QTc ration (r = -0.61, P < 0.01; r = -0.67, P < 0.01; r = -0.68, P < 0.01; respectively). Moreover, Em global were negative correlation between Tp-e, Tp-e/QT, and Tp-e/QTc (r = - 0.64, P < 0.001, r = - 0.75, P < 0.01; r = -0,69, P < 0.01; respectively) CONCLUSION: In conclusion, we have presented strong evidence suggesting that Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were increased in asymptomatic ARVD patients.

Sympathetic nerve stimulation, not circulating norepinephrine, modulates T-peak to T-end interval by increasing global dispersion of repolarization

BACKGROUND

T-peak to T-end interval (Tp-e) is an independent marker of sudden cardiac death. Modulation of Tp-e by sympathetic nerve activation and circulating norepinephrine is not well understood. The purpose of this study was to characterize endocardial and epicardial dispersion of repolarization (DOR) and its effects on Tp-e with sympathetic activation.

METHODS AND RESULTS

In Yorkshire pigs (n=13), a sternotomy was performed and the heart and bilateral stellate ganglia were exposed. A 56-electrode sock and 64-electrode basket catheter were placed around the epicardium and in the left ventricle (LV), respectively. Activation recovery interval, DOR, defined as variance in repolarization time, and Tp-e were assessed before and after left, right, and bilateral stellate ganglia stimulation and norepinephrine infusion. LV endocardial and epicardial activation recovery intervals significantly decreased, and LV endocardial and epicardial DOR increased during sympathetic nerve stimulation. There were no LV epicardial versus endocardial differences in activation recovery interval during sympathetic stimulation, and regional endocardial activation recovery interval patterns were similar to the epicardium. Tp-e prolonged during left (from 40.4±2.2 ms to 92.4±12.4 ms; P<0.01), right (from 47.7±2.6 ms to 80.7±11.5 ms; P<0.01), and bilateral (from 47.5±2.8 ms to 78.1±9.8 ms; P<0.01) stellate stimulation and strongly correlated with whole heart DOR during stimulation (P<0.001, R=0.86). Of note, norepinephrine infusion did not increase DOR or Tp-e.

CONCLUSIONS

Regional patterns of LV endocardial sympathetic innervation are similar to that of LV epicardium. Tp-e correlated with whole heart DOR during sympathetic nerve activation. Circulating norepinephrine did not affect DOR or Tp-e.