1,720,983 research outputs found
Aritmie cardiache: diagnosi e trattamento
Full text linkIl capitolo tratta della diagnosi e terapia, sia farmacologica che interventistica, delle principali aritmie cardiache. Il testo è ad uso dei Corsi di Laurea Magistrali in Medicina e Chirurgi
Influence of aging and chronic heart failure on temporal dispersion of myocardial repolarization
No full textQT and Tpeak-Tend (Te) intervals are associated with sudden cardiac death in patients with chronic heart failure (CHF). We studied age-dependent influence on short-term temporal dispersion of these two variables in patients with postischemic CHF. Method: We grouped 75 CHF and 53 healthy control subjects into three age subsets: ≤50 years, >50 years and ≤65 years, and >65 years. We then calculated the following indices: QT and Te variability index (QTVI and TeVI), the ratio between the short-term variability (STV) of QT or Te, and the STV of resting rate (RR) (QT/RR STV and Te/RR STV). Results: In all different age subgroups, patients with CHF showed a higher level of QTVI than age-matched control subjects (≤50 years: P 50 years and ≤65 years: P 65 years: P 2: 0.178, P 2: 0.433, P < 0.001) were positively related to age in normal subjects, even if the first correlation was weaker than the second one. Conclusion: Our data showed that QTVI could be used in all ages to evaluate repolarization temporal liability, whereas the other indices are deeply influenced by age. Probably, the age-dependent increase in QTVI was more influenced by a reduction of RR variability reported in older normal subjects. © Piccirillo et al, publisher and licensee Dove Medical Press Ltd
Curative radiofrequency catheter ablation for permanent junctional reciprocating tachycardia.
No full text
Effect of Pacemaker rate-adaptation on 24h beat-to- beat heart rate and blood pressure profiles
No full textEFFECTS OF LONG-TERM BETA-BLOCKER (METOPROLOL OR CARVEDILOL) THERAPY ON QT VARIABILITY IN SUBJECTS WITH CHRONIC HEART FAILURE SECONDARY TO ISCHEMIC CARDIOMYOPATHY
No full textChronic heart failure (CHF) is a risk factor for sudden death. Temporal and spatial changes in repolarization are among the most studied mechanisms for inducing fatal ventricular arrhythmias. Beta blockers effectively reduce the risk of sudden death in CHF. Our aim in this study was to investigate changes induced by metoprolol and carvedilol on the QT variability index (QTVI), a new measure reflecting the temporal heterogeneity of cardiac repolarization. A total of 82 subjects, who were in New York Heart Association functional class II or III, underwent short-term spectral analysis of RR and QT variability before and after a 1-year course of high-dose metoprolol (40 subjects) or carvedilol (42 subjects) at baseline (rest) and after sympathetic stress (head-up tilt). At rest, both drug-treated groups had lower QTVI (p <0.001) than after placebo, but during tilt patients treated with carvedilol had a lower QTVI than those treated with metoprolol (p <0.05). Although both beta-blocker treatments helped to normalize the QTVI measured in normal subjects at rest, they each differentially altered the index after tilt. Carvedilol seemed to improve the QTVI more than metoprolol. (C) 2002 by Excerpta Medica, Inc
Autonomic function during closed loop stimulation and fixed rate pacing: heart rate variability analysis from 24-h Holter recordings”
No full textHeart rate and blood pressure variability in patients implanted with rate-responsive pacemaker.
No full textRate-responsive pacemakers (PMs) aim at having pacing rates as similar to physiological cardiac rhythms as possible. The pacemaker INOS2+-CLS (Biotronik, Germany) implements a closed loop strategy (CLS) based on indirect measures of right ventricle contractility using intracardiac impedance signal. The contractility is, in turn, related to the autonomic nervous system control to the heart. Aim of this study was to evaluate the 24h beat-to-beat heart rate and blood pressure profiles in patients implanted with CLS rate adaptive PM. 24h ECG and arterial pressure waveform acquisition were performed by a digital HOLTER system by the Portapres equipment, respectively. A proper-designed algorithm was developed to classify PM pacing modalities. For each beat we estimated the heart rate (HR), and the systolic and diastolic pressure values (SP, DP). So far, 6 patients have been studied: 4 patients have been analyzed both with and without rate responsive modalities (DDD-R and DDD, respectively); 2 patients have been studied only with rate-responsive modality. Results obtained in 6 patients show that this rate adaptive PM accurately preserve the heart rate and blood pressure variability throughout the 24h. In particular, the rate adaptation of PM based on impedance measurements succeeds in maintaining the spontaneous HR, SP and DP on a beat-to-beat basis
Effects of long-term beta-blocker (Metoprolol or Carvedilol) therapy on QT variability index in subjects with chronic heart failure
No full text- …
