[Left ventricular mechanics in Chagas' disease and primary dilated myocardiopathies. A hemodynamic study]. / Mecánica ventricular izquierda en la enfermedad de Chagas y las miocardiopatías dilatadas primarias. Estudio hemodinámico.

The evolution of several mechanical parameters of left ventricular function was studied in 32 control subjects, 171 chronic chagasic and 60 primary dilated cardiomyopathy patients, which were submitted to an extensive invasive and non-invasive protocol. Preload and afterload (end-diastolic and end-systolic stress), contractile status (ejection fraction), the magnitude (mass/index) and adequacy of hypertrophy (mass/volume ratio) and afterload (systolic stress/volume ratio) were derived from the invasive explorations. There was an increased afterload in 25% of chronic chagasic patients without other evidence of early myocardial damage, which was accompanied by signs of inadequate hypertrophy. Both findings increased further with the progression of the disease. Systolic performance was initially preserved, but showed a progressive depression paralleling the clinical evolution. Patients with dilated cardiomyopathy showed a mechanical profile similar to chagasic patients with advanced degree of myocardial damage. The hemodynamic determination of mass index, mass/volume ratio, end-systolic and end-diastolic stress seem to be the best parameters for detection of early abnormalities in loading conditions of the heart in chronic Chagas, disease, and for indication and evaluation of the results of vasodilator therapy in both groups of patients.

[Ventricular mechanics and cardiac arrhythmias in patients with chagasic and primary dilated cardiomyopathy. Echo-electrocardiographic follow-up]. / Mecánica ventricular y arritmias cardiacas en pacientes chagásicos y con miocardiopatías dilatadas primarias. Seguimiento eco-electrocardiográfico.

PURPOSE: To determine the prognostic significance of several parameters of left ventricular mechanics and of complex ventricular arrhythmias. PATIENTS AND METHODS: 184 chronic chagasic and 85 primary dilated cardiomyopathy patients were submitted to non-invasive and invasive studies, including Holter monitoring and "M" mode echocardiogram and followed for a maximum of 8 years. RESULTS: Finding of a depressed left ventricle (LV) systolic function (% AC) was the most important independent prognostic factor in both groups of patients. The presence of complex ventricular arrhythmias had an additional, but very limited, independent prognostic importance, observed only in chagasic patients with depressed LV systolic function. When patients with similar degrees of left ventricular systolic dysfunction, inadequate hypertrophy or increased afterload were compared, chagasic patients had significantly worse prognosis than those with primary dilated cardiomyopathy. This is partly attributed to higher prevalence of complex ventricular arrhythmias. CONCLUSION: The higher prevalence of complex ventricular arrhythmias in patients with chronic Chagas' disease may explain the prognostic differences between the groups.

Ventricular arrhythmias and left ventricular myocardial function in chronic chagasic patients.

To study the relationship of complex ventricular arrhythmias to the presence and extent of myocardial damage, 556 chronic chagasic patients were submitted to an extensive protocol, including left ventricular cineangiography and Holter monitoring, and properly classified according to clinical, electrocardiographic and hemodynamic findings. Stages of the clinical-hemodynamic classification corresponded to increasing degrees of myocardial damage, age, prevalence and complexity of ventricular arrhythmias. Myocardial damage (particularly left ventricular dilatation) was the most important clinical factor linked to the presence of complex ventricular arrhythmias. A clear difference in terms of ventricular function was found only when arrhythmias were grouped into simple (Lown grades I and II) and complex (grades III and IV) forms. It is recommended that any classification for chagasic patients must be based on signs of myocardial involvement, instead of clinical or electrocardiographic findings alone. Evaluation should include accurate determination of left ventricular myocardial function, along with the search for the presence of complex ventricular arrhythmias and abnormalities of conduction.

[Left ventricular mechanics in Chagas' disease and dilated cardiomyopathy: echocardiographic study]. / Mecánica ventricular izquierda en la enfermedad de Chagas y las miocardiopatias dilatadas: estudio ecocardiografico.

For purposes of studying left ventricular mechanics, 184 chronic chagasic and 85 primary cardiomyopathy patients were submitted to an extensive invasive (LV cine, right and left cardiac catheterization and coronarography) and non-invasive protocol. The afterload, (mean wall stress), the contractile status (ejection fraction and circumpherential shortening) and the degree of hypertrophy (mass index) were assessed by M mode echocardiography. There was a very early increase of afterload in 8% of chagasic patients without evidences of LV myocardial involvement in the left cineventriculogram (group I-A). This increased afterload was accompanied by signs of inadequate hypertrophy in 15% of patients with early segmental myocardial damage (group IB). In contrast, ejection fraction and % circumpherential shortening were depressed only in patients with clinical evidences of congestive heart failure. Dilated primary CM patients showed similar findings, except for a more evident depression of contractility in those cases without signs of congestive heart failure (group II) and more hypertrophy than equivalent group III chagasic patients. Measurements of mean systolic wall stress and mass index are valuable parameters for identification of those patients with early increased after-load and inadequate hypertrophy which could benefit from the administration of oral vasodilators.