Biomedical subjects

Gabriella Malfatto

Publications and source records attributed to Gabriella Malfatto.

7 recordsLinked to original sources

PubMed2006

Low-K+ dependent QT prolongation and risk for ventricular arrhythmia in anorexia nervosa.

BACKGROUND: QT prolongation and ventricular arrhythmia have been proposed as the mechanism for sudden death in anorexia nervosa. The prevalence and the cause of QT prolongation remain controversial. OBJECTIVES: 1) to evaluate ventricular repolarization in patients with anorexia; 2) to evaluate factors that may influence repolarization, with focus on electrolyte plasma levels and heart rate. METHODS: 29 patients with anorexia, age 22 +/- 5 years, BMI 13.8 +/- 1.5 were compared to 14 control female subjects, age 23 +/- 2 years, BMI 20.7 +/- 1.1. QT interval and QT dispersion were measured. Whenever a low potassium (<3.5 mEq/l) was found, ECG was repeated after normalization of serum levels. Heart rate and its variability in the frequency domain (LF/HF ratio) were evaluated. RESULTS: Three patients (10.3%) showed severe hypokalemia (K(+) levels <2.0 mEq/l). In 2 patients, QT was severely prolonged (QT(c) 600 and 670 msec) and in one case associated with ventricular arrhythmia. QT(c) after K(+) plasma levels normalization was 392 +/- 25 in anorexia vs. 407 +/- 19 msec in controls, p = 0.08. Heart rate was 55 +/- 11 in anorexia vs. 66 +/- 8 beats per minute (BPM) in controls, p = 0.002. The LF/HF ratio was 1.79 +/- 1.35 in anorexia and 3.66 +/- 2.64 in controls, p = 0.006. CONCLUSIONS: QT interval is usually normal in patients with anorexia. QT prolongation and ventricular arrhythmia may develop in the setting of severe hypokalemia, exposing patients to high risk of sudden cardiac event. Resting heart rate is lower in anorexia than in controls with the spectral indices of sympatho-vagal balance indicating a prevalence of vagal activity.

Adult↗

PubMed2005

[Favourable effects of cardiovascular rehabilitation on funcional capacity and autonomic balance in elderly patients with heart failure].

In 42 patients with chronic heart failure we evaluated left ventricular function, exercise capability and autonomic control before and 3 months after a program of cardiovascular rehabilitation. The results were analyzed separately for younger (Group 1, n=18, age 51 +/- 6 years) and older patients (Group 2, n=24, age 68 +/- 4 years), with comparable clinical characteristics and therapy. Before rehabilitation, compared to younger patients, Group 2 patients showed a lower exercise capability, a comparable left ventricular ejection fraction and similar high sympathetic activity at rest, with no response to regular breathing (= stimulation of cardiopulmonary receptors, i.e. parasympathetic challenge) and active standing (= sympathetic stimulation). After rehabilitation, in both groups a 20% improvement of exercise tolerance and aerobic performance was observed, as well as a slightly increase of left ventricular ejection fraction (about 10%), and a recovery in vagal and sympathetic responsiveness. Thus, in heart failure patients age does not hinder the favorable clinical and autonomic modulation induced by cardiovascular rehabilitation.

Adult↗

PubMed2005

Original articles primary coronary angioplasty and subsequent cardiovascular rehabilitation are linked to a favorable sympathovagal balance after a first anterior myocardial infarction.

BACKGROUND: Modulation of the autonomic tone may contribute to the positive clinical effects of reperfusion of the ischemic zone after acute myocardial infarction (AMI). Little information exists about the effects on the sympathovagal balance of the early reopening of the vessel achieved by means of primary coronary angioplasty (PTCA). Even less is known on the autonomic effects of rehabilitation in patients undergoing PTCA. METHODS: We performed spectral analysis of the RR interval variability during 15 min of ECG in resting conditions in 51 patients (47 males, 4 females, mean age 55 +/- 6 years) 2-3 weeks after a first anterior AMI, and after 8 weeks of rehabilitation with physical training. The ratio between the low- and high-frequency (LF/HF) components of each autospectrum was used to describe the sympathovagal balance. Patients were divided into three groups: group 1 (n = 26, primary PTCA/stenting); group 2 (n = 11, recombinant tissue-type plasminogen activator); group 3 (n = 14, no reperfusion). Treatment was similar in the three groups and was maintained during the whole rehabilitation period. Results. Before rehabilitation, group 1 showed an adrenergic activation that was more blunted than that observed in groups 2 and 3. This activation was maximal in those patients with the shortest delay before the procedure. Cardiovascular rehabilitation modulated the LF/HF ratio in all groups. CONCLUSIONS: Early and effective reperfusion of the infarct-related artery is associated with a better sympathovagal tone shortly after AMI; this is followed by the known benefits of cardiovascular rehabilitation on autonomic tone.

Angioplasty, Balloon, Coronary↗

PubMed2005

Reverse ventricular remodeling and improved functional capacity after ventricular resynchronization in advanced heart failure.

BACKGROUND: Ventricular resynchronization is a non-pharmacological treatment for advanced heart failure refractory to drug therapy and with intraventricular conduction delay. We describe the time course of echocardiographic and functional recovery after resynchronization in 31 patients (mean age 67 +/- 8 years). METHODS: We evaluated NYHA class, echocardiogram, respiratory function, and cardiopulmonary test before pacemaker implantation (baseline), after 1-3 months (short-term evaluation), and 10-15 months afterwards (long-term evaluation, n = 21 patients). Mortality at 1 year was considered. RESULTS: Both at short and long-term, patients improved NYHA class, ventricular function, and ventricular volumes. Already at short-term, we observed an increase in oxygen consumption at peak exercise (12.6 +/- 0.6 vs 10.5 +/- 0.5 ml/kg/min), oxygen consumption at anaerobic threshold (9.8 +/- 0.6 vs 8.3 +/- 0.6 ml/kg/min) and oxygen pulse (8.3 +/- 0.5 vs 7.5 +/- 0.5 ml/beat). Ventilatory efficacy (VE/VCO2 slope) and alveolo-capillary diffusion (estimated by the measurement of lung diffusion capacity for carbon monoxide - DLCO) improved only at long-term (VE/VCO2: 40.7 +/- 1.6 vs 45.3 +/- 1.8; DLCO: 70.3 +/- 2.7 vs 59.4 +/- 5.9% of predicted, p = 0.05). The 1-year mortality was 9.7%. CONCLUSIONS: Ventricular resynchronization is linked to a fast and prolonged recovery of NYHA class, echocardiographic variables and stress tolerance. The improvement of indexes known to carry a prognostic value confirms that ventricular resynchronization can positively interfere with the evolution of the disease.

Aged↗

PubMed2003

Long-term treatment with the beta-blocker carvedilol restores autonomic tone and responsiveness in patients with moderate heart failure.

The authors performed two studies on the effects of carvedilol on autonomic tone and responsiveness in patients with heart failure. In study 1, the autonomic responses of 25 patients (age, 60 years+/-2; New York Heart Association [NYHA] class, 2.6+/-0.5; pVO2, 16.6 mL/Kg/min+/-1.1) treated with angiotensin-converting enzyme inhibitors, diuretics, and carvedilol (38.0 mg/d+/-2.5) were compared to those of 25 patients of similar age, therapy, NYHA class, and pVO2 in whom carvedilol was not yet administered. In study 2, autonomic tone and responsiveness were studied in 20 patients (age, 57 years+/-9; NYHA class, 2.5+/-0.2; pVO2, 15.6 mL/Kg/min+/-3.4), before and 6 months after additional carvedilol treatment (40.0 mg/d+/-12.5). Autonomic evaluation was performed with autoregressive power spectral analysis of RR variability during 10 minutes of supine rest (control), breathing 20 times per minute (vagal stimulus), and standing (sympathetic activation). The ratio between low-frequency (LF) and high-frequency (HF) components of the autospectra indicated the sympathovagal interaction. In study 1, spectral analysis in controls showed sympathetic hyperactivity which was blunted in patients receiving carvedilol (LF/HF ratio: 10.4+/-1.4 vs. 7.0+/-1.1; P<0.05) who responded to vagal and adrenergic stimuli (LF/HF, -35% with regular breathing and 72% standing). In study 2, left ventricular function, volumes, and exercise performance improved with carvedilol (EF, 31%; EDLV volume, -22%; pVO2, 11%; P<0.05). Sympathetic hyperactivity in control was reduced (LF/HF ratio, 4.9+/-0.8 from 7.9+/-1.3; P<0.05), whereas a response to vagal and adrenergic activation on breathing and standing reemerged (LF/HF ratio, -31% during regular breathing and 88% on standing). Therefore, combined autonomic and hemodynamic effects may determine the favorable effects of beta-blockers in heart failure.

Adrenergic beta-Antagonists↗

PubMed2003

[Does the etiology of heart failure affect tone response and autonomic reactivity to cardiovascular rehabilitation?].

We examined if the aetiology of heart failure could influence the favourable autonomic response to cardiovascular rehabilitation. We used the autoregressive spectral analysis of RR intervals variability, obtained from 10 minutes of ECG recording: within each autospectrum, we calculated the power of the low (LH) and high frequency (HF) oscillations: their ratio LF/HF is a useful, well accepted index of the sympathovagal balance. In 43 patients with heart failure we evaluated the autonomic tone at rest, during regular breathing (= stimulation of cardiopulmonary receptors, i.e. a parasympathetic challenge) and during active standing (= sympathetic stimulation). The shift in such autonomic response to 3 months of cardiovascular rehabilitation was analyzed separately for patients with ischemic (n = 19) and non-ischemic (n = 24) cardiomyopathy. Before rehabilitation, patients with ischemic cardiomyopathy had a higher sympathetic activity at rest, and a preserved response to parasympathetic stimulation. After rehabilitation, both groups of patients showed an improvement in exercise tolerance and performance, no deterioration in ventricular pump function, and a change in the autonomic profile. Thus, the aetiology of heart failure, despite a different baseline sympathovagal balance, does not influence the favourable clinical and autonomic modulation induced by rehabilitation. Independently from the underlying disease, all clinically stable patients with heart failure can benefit from rehabilitation.

Female↗

PubMed2002

Recovery of cardiac autonomic responsiveness with low-intensity physical training in patients with chronic heart failure.

BACKGROUND: A gradual worsening of autonomic control of cardiovascular function accompanies the progression of heart failure. Exercise training modulates autonomic balance, and may affect the prognosis of the disease. AIMS: The sympathovagal balance was studied after 3 months of low-intensity rehabilitation compared with conventional therapy in 45 patients with heart failure (52% ischemic, 48% idiopathic), of whom 30 underwent rehabilitation and 15 did not. In 11 rehabilitated patients we also studied the effects on autonomic profile of 6 additional months of home-based training. Rehabilitated and non-rehabilitated patients had similar NYHA class, ejection fraction, exercise pVO2; 50% assumed carvedilol (39+/-5 mg/day). METHODS AND RESULTS: Autoregressive power spectral density of RR intervals variability were assessed during 10 min of: (1) supine rest and free breathing; (2) supine rest and breathing at 20 acts/min (=vagal stimulus); (3) standing (=sympathetic stimulus). During each period, the ratio LF/HF of the individual autospectrum indicated the sympathovagal balance. After 3 months of rehabilitation, pVO2 increased (20%); LF/HF at rest was unchanged (8.7+/-1.2 vs. 9.2+/-1.2); it decreased with controlled breathing (-18%) and increased during standing (+79%) (P<0.05). These changes were more evident after 6 months of home-based training, when pVO2 was still high: LF/HF at rest was reduced (5.4+/-0.9 vs. 8.5+/-2.1), decreased during controlled breathing (-17%) and increased during standing (87%) (P<0.05). No changes in any variable were seen in non-rehabilitated patients. CONCLUSIONS: A low intensity rehabilitation program restores autonomic tone and reactivity to vagal and sympathetic stimuli. Some of these effects are already evident after the initial hospital-based phase.

Aged↗