Esben Vedel-Larsen

The prognostic value of the Tpeak-Tend interval in patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

INTRODUCTION The Tpeak-Tend interval (TpTe) has been linked to increased arrhythmic risk. TpTe was investigated before and after primary percutaneous coronary intervention (pPCI) in patients with ST-segment elevation myocardial infarction (STEMI). METHOD Patients with first-time STEMI treated with pPCI were included (n = 101; mean age 62 years; range 39-89 years; 74% men). Digital electrocardiograms were taken pre- and post-PCI, respectively. Tpeak-Tend interval was measured in leads with limited ST-segment deviation. The primary end point was all-cause mortality during 22 +/- 7 months (mean +/- SD) of follow-up. RESULTS Pre- and post-PCI TpTe were 104 milliseconds [98-109 milliseconds] and 106 milliseconds [99-112 milliseconds], respectively (mean [95% confidence interval], P = .59). A prolonged pre-PCI TpTe was associated with increased mortality (hazard ratio, 10.5 [1.7-20.4] for a cutoff value of 100 milliseconds). Uncorrected QT and heart rate-corrected QT intervals (Fridericia-corrected QT) were prolonged after PCI (QT: 401 vs 410 milliseconds, P = .022, and Fridericia-corrected QT: 430 vs 448 milliseconds, P < .0001). CONCLUSION In patients with STEMI undergoing pPCI, pre-PCI TpTe predicted subsequent all-cause mortality, and the QT interval was increased after the procedure.

TpeakTend interval in long QT syndrome

BACKGROUND The T(peak)T(end) (T(p)T(e)) interval is believed to reflect the transmural dispersion of repolarization. Accordingly, it should be a risk factor in long QT syndrome (LQTS). The aim of the study was to determine the effect of genotype on T(p)T(e) interval and test whether it was related to the occurrence of syncope. METHODS Electrocardiograms were taken in 95 patients with LQTS drawn from the Danish long QT registry (44 patients with KvLQT1, 43 with HERG, and 8 with SCN5A mutations) and manually evaluated for the QT, QT(peak), and RR interval. RESULTS AND CONCLUSION (1) T(p)T(e) cannot be used to distinguish symptomatic from asymptomatic patients with LQTS; (2) HERG patients have longer T(p)T(e) than KvLQT1 patients; and (3) there is no need to heart rate-correct T(p)T(e) intervals in patients with LQTS.

Heritability of Tpeak-Tend Interval and T-wave Amplitude: A Twin Study

Background— Tpeak-Tend interval (TpTe) and T-wave amplitude (Tamp) carry diagnostic and prognostic information regarding cardiac morbidity and mortality. Heart rate and QT interval are known to be heritable traits. The heritability of T-wave morphology parameters such as TpTe and Tamp is unknown. TpTe and Tamp were evaluated in a large sample of twins. Methods and Results— Twins from the GEMINAKAR study (611 pairs, 246 monozygotic, 365 dizygotic; mean age, 38±11 years; 49% men) who had an ECG performed during 1997 to 2000 were included. Tamp was measured in leads V1 and V5. Duration variables (RR interval, QTpeak and QTend interval) were measured and averaged over 3 consecutive beats in lead V5. TpTe was calculated as the QTend- and QTpeak-interval difference. Heritability was assessed using structural equation models adjusting for age, sex, and body mass index. All models were reducible to a model of additive genetics and unique environment. All variables had considerable genetic components. Adjusted heritability estimates were as follows: TpTe, 46%; Tamp lead V1, 34%; Tamp lead V5, 47%; RR interval, 55%; QT interval, 67%; and Bazett-corrected QT interval, 42%. Conclusions— RR interval, QT interval, Tamp, and TpTe interval are heritable ECG parameters.

T-wave morphology analysis of competitive athletes.

BACKGROUND T-wave morphology has been shown to be more sensitive than QT and QTc interval to describe repolarization abnormalities. The electrocardiogram (ECG) performed in athletes may manifest abnormalities, including repolarization alterations. The aim of this study was to investigate the characteristics of T-wave morphology features in athletes. METHODS Eighty male elite athletes, consisting of 40 Tour de France cyclists (age 27±5years), 40 soccer players (age 26±6years) and 40 healthy men (age 27±5years) were included. RESULTS Sinus bradycardia, left ventricular (LV) hypertrophy, incomplete right bundle branch block and early repolarization were documented in 25 %, 20%, 13% and 14% of athletes, respectively. ECG criteria for LV hypertrophy in 12-lead ECG were more common in cyclists (35%) than in soccer players (5%), P<0.0001. Cyclists and soccer players had significantly longer RR interval, and repolarization features than the control group. CONCLUSIONS T-wave morphology of athletes is different from non-athletes, depending of the sport. Decreased potassium current in cardiomyocytes associated with LVH may contribute to these changes.

Major rapid weight loss induces changes in cardiac repolarization.

INTRODUCTION Obesity is associated with increased all-cause mortality, but weight loss may not decrease cardiovascular events. In fact, very low calorie diets have been linked to arrhythmias and sudden death. The QT interval is the standard marker for cardiac repolarization, but T-wave morphology analysis has been suggested as a more sensitive method to identify changes in cardiac repolarization. We examined the effect of a major and rapid weight loss on T-wave morphology. METHODS AND RESULTS Twenty-six individuals had electrocardiograms (ECG) taken before and after eight weeks of weight loss intervention along with plasma measurements of fasting glucose, HbA1c, and potassium. For assessment of cardiac repolarization changes, T-wave Morphology Combination Score (MCS) and ECG intervals: RR, PR, QT, QTcF (Fridericia-corrected QT-interval), and QRS duration were derived. The participants lost on average 13.4% of their bodyweight. MCS, QRS, and RR intervals increased at week 8 (p<0.01), while QTcF and PR intervals were unaffected. Fasting plasma glucose (p<0.001) and HbA1c both decreased at week 8 (p<10(-5)), while plasma potassium was unchanged. MCS but not QTcF was negatively correlated with HbA1c (p<0.001) and fasting plasma glucose (p<0.01). CONCLUSION Rapid weight loss induces changes in cardiac repolarization. Monitoring of MCS during calorie restriction makes it possible to detect repolarization changes with higher discriminative power than the QT-interval during major rapid weight loss interventions. MCS was correlated with decreased HbA1c. Thus, sustained low blood glucose levels may contribute to repolarization changes.

Alterations in TPEAK-TEND interval, ST segment deviation, and QTC in patients with ST segment elevation myocardial infarction immediately after primary PCI

Introduction A 38 year old woman with arrhythmogenic right ventricular cardiomyopathy (ARVC) presented with signs and symptoms of right heart failure. Methods and Results ARVC was initially diagnosed in 1999 and treated with a dual chamber implantable cardioverter–defibrillator (ICD). Her clinical course was complicated by two episodes (2004 and 2006) of poor pacing and sensing function due to progressive RV disease. These required re-operation. In 2004, a new RV pace/sense lead was placed. In 2006, her endocardial RV leads were replaced by epicardial left ventricular leads. In addition to her lead complications, the patient experienced greater than ten appropriate ICD shocks over the decade since diagnosis. Physical exam on presentation was notable for abdominal distention and marked lower extremity edema. Electrocardiogram showed atrial tachycardia with an atrial rate of 160 bpm and 2:1 AV conduction. Echocardiogram revealed a large RV thrombus occupying more than 50% of the area of the RV. (Figure) Additional large thrombi were present in the right atrium and on the pacemaker wire. Treatment included anticoagulation and diuresis. Conclusion Right atrial and ventricular thrombosis is a rare complication of ARVC. Risk factors for thrombosis include atrial arrhythmias, marked atrial and ventricular dilation and hypokinesis, aneurysmal dilation and multiple pacing/ICD leads. Clinical surveillance in the presence of these risk factors is important to avoid thromboembolic complications. 18-2 Abstract 05-02 Low prevalence of arrhythmias in patients with pulmonary arterial hypertension

Heritability of Tpeak-Tend Interval and T-Wave AmplitudeClinical Perspective

Background— Tpeak-Tend interval (TpTe) and T-wave amplitude (Tamp) carry diagnostic and prognostic information regarding cardiac morbidity and mortality. Heart rate and QT interval are known to be heritable traits. The heritability of T-wave morphology parameters such as TpTe and Tamp is unknown. TpTe and Tamp were evaluated in a large sample of twins. Methods and Results— Twins from the GEMINAKAR study (611 pairs, 246 monozygotic, 365 dizygotic; mean age, 38±11 years; 49% men) who had an ECG performed during 1997 to 2000 were included. Tamp was measured in leads V1 and V5. Duration variables (RR interval, QTpeak and QTend interval) were measured and averaged over 3 consecutive beats in lead V5. TpTe was calculated as the QTend- and QTpeak-interval difference. Heritability was assessed using structural equation models adjusting for age, sex, and body mass index. All models were reducible to a model of additive genetics and unique environment. All variables had considerable genetic components. Adjusted heritability estimates were as follows: TpTe, 46%; Tamp lead V1, 34%; Tamp lead V5, 47%; RR interval, 55%; QT interval, 67%; and Bazett-corrected QT interval, 42%. Conclusions— RR interval, QT interval, Tamp, and TpTe interval are heritable ECG parameters.

Heritability of Tpeak-Tend Interval and T-Wave AmplitudeClinical Perspective: A Twin Study

Background— Tpeak-Tend interval (TpTe) and T-wave amplitude (Tamp) carry diagnostic and prognostic information regarding cardiac morbidity and mortality. Heart rate and QT interval are known to be heritable traits. The heritability of T-wave morphology parameters such as TpTe and Tamp is unknown. TpTe and Tamp were evaluated in a large sample of twins. Methods and Results— Twins from the GEMINAKAR study (611 pairs, 246 monozygotic, 365 dizygotic; mean age, 38±11 years; 49% men) who had an ECG performed during 1997 to 2000 were included. Tamp was measured in leads V1 and V5. Duration variables (RR interval, QTpeak and QTend interval) were measured and averaged over 3 consecutive beats in lead V5. TpTe was calculated as the QTend- and QTpeak-interval difference. Heritability was assessed using structural equation models adjusting for age, sex, and body mass index. All models were reducible to a model of additive genetics and unique environment. All variables had considerable genetic components. Adjusted heritability estimates were as follows: TpTe, 46%; Tamp lead V1, 34%; Tamp lead V5, 47%; RR interval, 55%; QT interval, 67%; and Bazett-corrected QT interval, 42%. Conclusions— RR interval, QT interval, Tamp, and TpTe interval are heritable ECG parameters.