Assessment of Left Ventricular Contractility in Patients Receiving Doxorubicin

Abstract

The usual indices of left ventricular systolic performance have been incapable of accurately recognizing early myocardial impairment in many patients treated with doxorubicin. Recently, several new load-independent, highly sensitive indices of left ventricular contractility have been developed including the slope value of the endsystolic pressure (P_es)-dimension (D_es) relation and the position of the left ventricular end-systolic wall stress (σ _es)-percent fractional shortening (%ΔD) relation. We used these indices to study 46 patients receiving either low dose or high dose doxorubicin. Results were compared with data from 30 healthy subjects. Resting %ΔD failed to accurately recognize left ventricular dysfunction in 9 of 17 patients with low normal values. These patients had reduced afterload, as measured by σ_es, permitting normal extent of left ventricular fiber shortening despite impaired contractility as quantified by diminished P_es-D_es slope values. There was 98% concordance between the relative position of the σ_es%ΔD relation and the slope value of the P_es-D_es, relation. These indices offer an improved means of recognizing and quantitating impaired contractility in patients treated with doxorubicin.