Correlation between left ventricular contractility and relaxation in patients with idiopathic dilated cardiomyopathy.

BACKGROUND AND HYPOTHESIS

It is not fully understood whether alterations in left ventricular (LV) relaxation in patients with idiopathic dilated cardiomyopathy (DCM) precede or follow alterations in LV systolic function. Accordingly, we investigated the relationship between LV systole and diastolic relaxation in patients with DCM using LV pressure-volume analysis.

METHODS

Hemodynamic data were collected for 38 consecutive patients with DCM in normal sinus rhythm and in the resting steady state (New York Heart Association functional class II to III). Continuous simultaneous pressure-volume relationships were obtained by conductance catheter. Left ventricular end-systolic elastance (Ees) was determined during transient occlusion of the inferior vena cava.

RESULTS

Left ventricular ejection fraction, peak negative dP/dt, and peak positive dP/dt were depressed (31 +/- 11%, -1242 +/- 351 mmHg/s, and 1118 +/- 253 mmHg/s, respectively). The LV end-diastolic volume index, the time constants of isovolumic LV pressure decay TL and TD were increased (141 +/- 38 ml/m2, 54 +/- 14 ms, and 69 +/- 17 ms, respectively). Ees was markedly depressed (0.9 +/- 0.5 mmHg/ml) and was not correlated with established systolic or diastolic indices except for peak positive dP/dt. Our results showed that abnormalities of relaxation were not correlated with contractile dysfunction in patients with DCM in the resting steady state; however, most patients (79%) had both prolonged relaxation and extremely depressed contractility. Abnormal relaxation may have been transient or compensated in some patients (21%) with DCM who had preserved relaxation despite severely depressed contractility.