[Correlation between isovolumic and auxotonic indexes of left ventricular contractility at rest and during exercise...

The validity of isovolumic parameters of left ventricular contractility in assessing ventricular function at rest has been questioned repeatedly, and with some justification. By contrast, auxotonic parameters such as left ventricular ejection fraction provide a clinically useful index of functional impairment even under resting conditions. The correlation between isovolumic and auxotonic parameters during exercise remains unclear, however. To evaluate this relation, isovolumic m (max dP/dt, Vpm) and auxotonic (EF, Vcf) parameters of contractility were determined simultaneously at rest and after both leg raising and exercise using a manometer-equipped angiography catheter in 45 patients. Under resting conditions, there was no significant correlation between the parameters (Vpm: Vcf,r = 0,226). After leg raising (r = 0.543) and exercise (r = 0.801), the correlation became markedly closer. The presence of hypo- or akinetic regions did not affect the correlation. In patients with cardiomyopathy and uniform functional impairment, the correlation did not improve in comparison with the group of patients characterized by asynergy. The specificity of the various parameters was evaluated in patients with and without significant coronary-artery stenosis. The Vcf values during exercise yielded virtually optimal separation of the two groups, whereas isovolumic parameters were far less specific.