Christian Haarmark

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.

Reference values of electrocardiogram repolarization variables in a healthy population.

INTRODUCTION Reference values for T-wave morphology analysis and evaluation of the relationship with age, sex, and heart rate are lacking in the literature. In this study, we characterized T-wave morphology in a large sample of healthy individuals. METHOD A total of 1081 healthy subjects (83% men; range, 17-81 years) were included. T-wave morphology variables describing the duration, area, slopes, amplitude, and distribution were calculated using 10-second digital electrocardiogram recordings. Multivariate regression was used to test for dependence of T-wave variables with the subject age, sex, and heart rate. RESULTS Lead V5 (men vs women) T-wave variables were as follows: amplitude, 444 versus 317 muV; area, 48.4 versus 33.2 ms mV; Tpeak-Tend interval, 94 versus 92 milliseconds; maximal descending slope, -5.15 versus -3.69 muV/ms; skewness, -0.24 versus -0.22; and kurtosis, -0.36 versus -0.35. Tpeak-Tend interval, skewness, and kurtosis were independent of age, sex, and heart rate (r(2) < 0.05), whereas Bazett-corrected QT-interval was more dependent (r(2) = 0.40). CONCLUSION A selection of T-wave morphology variables is found to be clinically independent of age, sex, and heart rate, including Tpeak-Tend interval, skewness, and kurtosis.

Is it possible to predict hypotension during onset of spinal anesthesia in elderly patients

STUDY OBJECTIVE To evaluate the sensitivity and specificity of various predictors of hypotension during onset of spinal anesthesia in elderly patients. DESIGN Prospective study. SETTING 32 ASA physical status I, II, and III patients, aged >or=60 years, scheduled for elective lower limb surgery with spinal anesthesia. INTERVENTIONS Patients received spinal anesthesia with 10-17.5 mg of bupivacaine. No prophylactic ephedrine or fluid preloading was used. MEASUREMENTS A 5-minute baseline was recorded and during onset of spinal anesthesia, hemodynamic changes were measured every 10 seconds from the radial artery pressure curve. Data collection ended when patients were ready for surgery, or if ephedrine was given to increase mean arterial pressure. MAIN RESULTS 21 patients had hypotension. Baseline blood pressure variability low-frequency band power (BPV LF) >8 mmHg(2) and near-infrared spectroscopy (NIRS) reduction >or=5% had high sensitivity (0.73 and 0.90, respectively) and specificity (0.78 and 0.64, respectively), and were significantly associated with the development of hypotension. CONCLUSIONS Only NIRS and BPV LF could significantly predict hypotension among the elderly.

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.

Tilt-table testing of patients with pacemaker and recurrent syncope

The diagnosis of recurrent syncope in patients with pacemakers (PM) is quite challenging and the etiology of syncope is often multifactorial. To portray the mechanism of syncope in PM patients, we report the results of head-up tilt table testing (HUT) in a series of patients with PM, originally implanted for reasons other than neurally mediated syncope, referred due to syncope or pre-syncope (aborted syncope, vertigo, suspected orthostatic hypotension). Forty-one patients with PM undergoing a HUT in our syncope unit between January 1st, 2007 and December 31st 2011 were included. A standard HUT protocol with nitroglycerine provocation was used and the test results were classified according to current guidelines. Baseline data were retrieved from the medical records. Overall, 54% of patients had a positive response to HUT. Vasodepressor or orthostatic hypotensive response were the most prevalent responses accounting for 72% of patients with a positive test. There were no differences between groups with positive or negative test result regarding age, gender, resting blood pressure and heart rate, daily fluid intake, pacing mode, pacing indication or pacing rhythm at rest. HUT in patients with pacemakers has a high diagnostic yield. Although, the majority of patients had a vasodepressor or orthostatic hypotensive response, cardioinhibitory response leading to syncope was also seen.

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

T-wave morphology differences depending on genotype in long QT syndrome

Background Methadone is known to block hERG channels in vitro mimicking the molecular changes in patients with loss of function mutations in hERG. In patients methadone causes prolongation of the QT interval and Torsade de Pointes as known from Long QT syndrome type 2 (LQT2). This congruity between the molecular mechanism and clinical findings makes a population of methadone treated subjects ideal to investigate electrocardiogram (ECG) changes due to partial hERG blockade. The aim was to compare healthy controls with methadone induced T-wave morphology changes and patients with congenital LQT2. Methods The populations consisted of 1,081 self reported healthy subjects, 41 genotyped LQT2 patients and 374 heroin addicts enrolled from a methadone maintenance program. A 10 s digital ECGwas obtained from each individual. Dedicated software automated assigned fix-points correlating to essential ECG points of reference including T-wave start, peak and end. This led to computing variables describing T-wave morphologies in five categories: Duration, Area, Amplitude, Slope and Distribution. Results LQT2 and methadone treated patients clearly separates from healthy controls (Table). Furthermore methadone treated patients with T-wave morphologies that increasingly look more and more like LQTS patients as their QT-interval increases compared to methadone users with normal QT-interval e.g.: T amplitude 360 μV for QT< 440 ms and 261 μV for QT>440 ms, (P<0.0001) compared to 201 μV for LQTS2 and 422 μV for healthy subjects. Conclusions The T-wave morphology in subject with prolonged QT interval during methadone treatment resembles the T-wave morphology found in LQT2. T-wave morphology is a promising tool for future screening for drug induced LQTS.

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.