Evaluation of ventricular ejection time in patients with atrial fibrillation
Pereira, M.S.; Bueno, M.S.; Celnik, D.; Sekeff, J.A.; Azevedo, A.d.C.
Arquivos Brasileiros de Cardiologia 44(5): 339-345
1985
ISSN/ISBN: 0066-782X PMID: 4091731 Document Number: 255034
In atrial fibrillation (AF) the stroke volume and the ventricular filling varies from beat to beat being a function of the length of the preceeding cycle. Since it is known that among the systolic time intervals, the left ventricular ejection time (LVET), obtained from external carotid pulse, is the one that correlates the best with the stroke volume and the diastolic ventricular filling. This variable is very useful in the ventricular filing study when the patient has atrial fibrillation. A phonocardiographic test was made in 59 persons did playing only AF or AF associated to other cardiopathies. LVET and RR intervals of the eletrocardiogram were measured. The correlation (r) and the regression (b) coefficients between these two parameters were calculated for each person. The correlation coefficient between the LVET and the preceeding RR was high for all patients with AF and it was higher among those exhibiting mitral stenosis (MS) (m = 0.74 .+-. 0.139) than among those who did not (m = 0.539 .+-. 0.226). The high correlation coefficient confirms that the variation of the duration of the cardiac cycle interfers with the LVET and ultimately with the stroke volume. As for regression coefficient (b) we got results significantly higher among patients exhibiting MS (specially those who had not operated upon) and those without mitral obstruction but with left ventricular failure (LVF). Among the persons exhibiting AF with MS it is the gradient across mitral valve which forces the filling of the ventricle. The higher the atrial pressure the longer the gradient in maintained and the higher is the dependency between the diastolic filling and the duration of the preceding cycle (RR) causing higher regression coefficient. The regression coefficient for patients for NS seems to indicate the seriousness of the mitral obstruction being higher for patients with more severe MS. This fact was suggested to us when we verified a significant statistic correlation between the regression coefficient and the gradient across mitral valve in patients submitted to cardiac catheterism and when we ascertained that 3 of the 6 patients submitted to a mitral surgery exhibited a reduction of the regression coefficient after the surgery. As for the patient with LVF it is possible that the high regression coefficient might be the result of an increased pressure during the diastolic filling which occurs with those who exhibit LVF.