Central and peripheral components of chronic heart failure: determinants of exercise tolerance.

This study sought to determine the relationship between myocardial dysfunction and peripheral haemodynamic disorders to exercise intolerance in patients with chronic heart failure (CHF). Seventeen patients with mild to moderate CHF (peak oxygen consumption (VO2) >16 ml/min/kg) and 13 with severe CHF (peak VO2 <16 ml/min/kg) underwent invasive (Swan-Ganz) cardiopulmonary exercise testing and forearm venous occlusion plethysmography at rest and during maximal dilatation in reactive hyperaemia. There was a shift from central to peripheral haemodynamic factors limiting exercise, suggesting an increasing importance of peripheral factors in parallel to the progression of CHF. In mild to moderate CHF peak VO2 was closely related to central haemodynamics (r = 0.57 for cardiac index at rest; r = 0.76 for cardiac index at maximal workload; r = -0.54 for right arterial pressure at maximal workload; all p<0.05) and poorly correlated with peripheral haemodynamics (blood flow, vascular resistance and venous tone). In contrast, in severe CHF peak VO2 was closely related to peripheral haemodynamic factors (r = 0.79 for forearm blood flow; r = -0.82 for vascular resistance; r = -0.77 for venous tone; all p<0.05) and less to central ones. Thus, exercise tolerance of patients with mild to moderate CHF is predominantly determined by central haemodynamic factors, notably by the cardiac index. In severe CHF peripheral factors assume ever greater importance in the determining of exercise capacity.

Left ventricular remodelling: common process in patients with different primary myocardial disorders.

Currently the problem of left ventricular remodelling in the early and late stages after myocardial infarction are under intense study. Studies of the role of remodelling of the left ventricle in patients with long-term arterial hypertension have been recently initiated. The purpose of this investigation was to study whether left ventricular remodelling is common for different primary myocardial disorders. The study population consisted of 212 patients with primary myocardial lesions (121 with dilated cardiomyopathy, 45 with chronic myocarditis and 46 with prolonged damage of the myocardium with alcohol; 196 male and 16 female, mean age 42.6+/-11.3 years) and 32 age matched normal subjects (24 male and eight female). Cardiac catheterization for ventriculography and coronary angiography was performed in all subjects for detection of left ventricular haemodynamics, including chamber volume and shape at end-systole and end-diastole. Worsening of heart failure was associated with a progressive enlargement of the left ventricle, with increases in end-systolic left ventricular wall stress, that lead to increases in left ventricular muscle mass, alteration of left ventricular geometry from a more ellipsoid to a more spherical shape and a progressive decrease of relative wall thickness index that reflects inadequate enlargement of the ventricular chamber in comparison with the increase in muscle mass. This process of left ventricular remodelling was common to all the primary myocardial disorders studied. Thus, regardless of the different etiological nature, most primary myocardial disorders show a similar left ventricular remodelling process suggesting common mechanisms for the development of chronic heart failure.