Clinical research in cardiology : official journal of the German Cardiac Society
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To maximize the hemodynamic benefit of cardiac resynchronization therapy (CRT), echocardiographic AV interval optimization is routinely performed, complemented by VV interval optimization especially in non-responders. Programming of the basic pacing rate, however, is largely empirical in these patients. Therefore, the present study aimed to systematically evaluate the impact of basic pacing rate on hemodynamic parameters in CRT patients with sinus bradycardia. ⋯ In the range between 40 and 70 bpm, an increase in basic pacing rate enhances CO without reducing SV. According to this pilot study, a basic pacing rate between 60 and 70 bpm would appear reasonable.
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The present study aimed to investigate the causative medications and underlying risk factors that predispose to drug-induced QT interval prolongation. Twenty-one patients with drug-induced long QT (90% females, mean age 64.3 +/- 14.1 years) were included in the study. Transthoracic echocardiography as well as continuous or ambulatory 48-h electrocardiographic monitoring was carried out in all patients during their hospitalization. ⋯ TdP and cardiac arrest events were both associated with a QTc interval >510 ms (P < 0.05). Advanced age (>60 years), female gender, hypertension and paroxysmal atrial tachyarrhytmias were the most common identifiable pre-existing factors for drug-induced long QT in our patient cohort. Marked QTc interval prolongation should be considered of prognostic significance for TdP and cardiac arrest events.
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Intensive endurance training is able to cause a distinct pattern of functional and structural changes of the cardiovascular system. In an unknown proportion of athletes a so called "athlete's heart" develops. There is an overlap between this type of physiologic cardiac hypertrophy and mild forms of hypertrophic cardiomyopathy (HCM), the most common genetic disorder of the cardiovascular system with a prevalence of 0.2%. ⋯ A correct diagnosis may on the one hand prevent some athletes from sudden cardiac death. On the other hand sportsmen with an athlete's heart are reassured and able to continue as competitors. New insights into electrophysiological changes during physiological hypertrophy could probably change this view.