[Clinical and prognostic significance of echocardiographic parameters in dilated cardiomyopathy: a prospective study on 225 patients. The Italian Multicenter Study of Cardiomyopathies Group]. / Significato clinico e prognostico dei parametri ecocardiografici nella cardiomiopatia dilatativa: studio prospettico su 225 pazienti. Gruppo SPIC.

To assess the prognostic role of echocardiographic indexes and their relation to clinical conditions, 225 patients with dilated cardiomyopathy were studied prospectively. All cases had a normal coronary angiogram and non specific endomyocardial biopsy findings. 163 men (72.4%) and 62 women (27.6%), mean age 41.5 +/- 12.3 (range 8-61), were studied. Clinical, electrocardiographic and echocardiographic parameters, normalized for body surface area, were tested according to NYHA class and presence of segmental or diffuse wall motion abnormalities. One hundred-four patients were in NYHA class I-IIa, 94 were in class IIb-III and 27 were in class IV. Left ventricular end systolic diameter index, right ventricular end diastolic diameter index, left atrial diameter index, left ventricular fractional shortening and ejection fraction, and radius to wall thickness ratio were significantly more impaired in patients with more severe symptoms. Twenty-eight patients (13%) showed segmental wall motion abnormalities and had smaller left ventricular end systolic and left atrial diameter index and higher left ventricular fractional shortening and ejection fraction. During a mean follow up of 23 +/- 15 months (range 1-67 months), 25 patients (11.1%) died from cardiac causes and 16 (7.1%) underwent heart transplant because of refractory heart failure. Prognostic evaluation was performed separately for cardiovascular mortality alone and for cardiac events (cardiovascular mortality and heart transplantation). At Cox multivariate analysis only right ventricular end diastolic diameter index (p < 0.005) predicted cardiovascular mortality, while left atrial diameter index (p < 0.001), right ventricular end diastolic diameter index (p < 0.01) and left ventricular ejection fraction (p < 0.05) were significant independent predictors of cardiac events.

Reflex cardiovascular control in congestive heart failure.

This article reviews evidence that the reflex control of the cardiovascular system provided by negative feedback mechanisms is impaired in congestive heart failure (CHF). The impairment involves vagal and sympathetic modulation of the heart exerted by arterial baroreceptors. It also affects baroreceptor control of blood pressure and peripheral vascular resistance, as well as the cardiopulmonary receptor's ability to modulate sympathetic activity. The degree of such impairment is most marked in severe CHF but is also apparent, to a minor degree, in mild heart failure. Reflex impairment is due to a reduction in the receptor signal, but other factor under investigation are probably also involved. Digoxin and other pharmacologic treatments of CHF improve reflex function, thereby facilitating a reduction in the elevated sympathetic activity and a stepping up of the reduced vagal activity typical of CHF. This may be relevant to a patient's prognosis.

Digitalis and baroreceptor reflexes in man.

Data in animals indicate that large amounts of digitalis potentiate arterial baroreflexes and that this factor may be important for the cardiovascular effects of the drug. To determine if arterial baroreflex potentiation also exists after administration of therapeutic doses of digitalis in man, we studied how stimulation and deactivation of arterial baroreceptors by phenylephrine and nitroglycerin injection affect heart rate and how stimulation and deactivation of carotid baroreceptors by neck suction and pressure affects blood pressure and heart rate. The study was performed in 29 normotensive or hypertensive subjects before and after injection of Lanatoside C (0.8 mg i.v.). Baroreceptor stimulation reduced heart rate and blood pressure, while baroreceptor deactivation increased both of these variables. The bradycardic and hypotensive effect of baroreceptor stimulation increased significantly after digitalis both in normotensive and hypertensive subjects. However, the tachycardic and hypertensive responses to baroreceptor deactivation were not affected by digitalis. Thus, therapeutic doses of digitalis in man enhance baroreceptor reflexes, and both the heart rate and the blood pressure reflex effects are involved. However, the enhancement occurs to a marked degree only with baroreceptor stimulation and is not evident with baroreceptor deactivation.