This study tested the hypothesis that combination ion channel blockers of the transient outward current (I(to)) and the rapid component of the delayed rectifying current (I(Kr)) would produce greater prolongation of the ventricular action potential duration (APD) and increased dispersion of the APD in hypertrophied hearts compared with control hearts. Isolated rabbit hearts were studied 48 +/- ...

AIM The aim of this study was to identify adaptations in muscle activity distribution to spinal tissue creep in presence of muscle fatigue. METHODS Twenty-three healthy participants performed a fatigue task before and after 30 minutes of passive spinal tissue deformation in flexion. Right and left erector spinae activity was recorded using large-arrays surface electromyography (EMG). To chara...

The effects of spironolactone or metoprolol added to a conventional treatment protocol on QT dispersion, which is accepted as a sudden cardiac death predictor, were evaluated in heart failure patients.? A total of 105 New York Heart Association class III patients were included in this study. The conventional treatment protocol was standardized by giving ramipril, furosemide, and digoxin to all ...

BACKGROUND Hypertension is an important risk factor for sudden cardiac death, of which the incidence increases with increases in blood pressure. Prolonged QT dispersion has been identified to indicate increased risk of life-threatening ventricular arrhythmia and sudden cardiac death. In this study, QT dispersion was investigated in hypertensive patients during the strain phase of the Valsalva m...

BACKGROUND Drug-induced increase in QT dispersion has been associated with potentially fatal ventricular arrhythmias. Little is known about the use of psychotropic substances, alone or in combination with other drugs on QT dispersion. OBJECTIVES To evaluate the impact of psychotropic drugs on QT interval dispersion in adults. METHODS An observational cohort study was designed involving 161 ...

AIMS Hypertrophic cardiomyopathy (HCM) patients are at risk of ventricular arrhythmias (VAs). We aimed to explore whether systolic function by strain echocardiography is related to VAs and to the extent of fibrosis by cardiac magnetic resonance imaging (CMR). METHODS AND RESULTS We included 150 HCM patients and 50 healthy individuals. VAs were defined as non-sustained and sustained ventricula...

AIMS Arrhythmogenic right ventricular dysplasia is a rarely diagnosed cardiomyopathy, but a frequent cause of ventricular arrhythmia and sudden cardiac death. QT interval dispersion, measured as an interlead variability of QT, is a marker of dispersion of ventricular repolarization and, hence, of electrical instability. The present study was conducted to assess the occurrence of QT dispersion a...

BACKGROUND The growing population with Fontan operation surviving into adulthood has significant morbidity and mortality rates from recurrent atrial tachyarrhythmias. We hypothesized that the structural characteristics and electrical behavior of atria may differ in these patients compared with those without arrhythmias. METHODS AND RESULTS We studied 33 consecutive patients (age, 25.4+/-9.5 y...

INTRODUCTION The induction of ventricular fibrillation (VF) by T-wave shocks has been related to dispersion of repolarisation, but only indirect evidence of this hypothesis exists. The effects of drugs prolonging repolarisation like d-sotalol on the vulnerability to T-wave shocks remain unknown. METHODS In 9 isolated rabbit heart, 7 monophasic action potentials (MAPs) and an ECG were recorded...