Relative insesitivity of isovolumic phase indices in the assessment of left ventricular function.

1. The authors compared the sensitivity of the isovolumic phase indices (contractility indices) against LV function curves ("pump-function" indices) in assessing ventricular performance. 2. Certain modifications of the usual isovolumic phase indices, especially those introducing the concept of comparison of exercise with rest, seemed to us to be slightly more helpful in separating normal subjects from the patient with coronary artery disease or cardiomyopathies, but these differences were not striking when statistically evaluated, and could not be utilized in assessment of left ventricular function in individual patients. 3. The construction of left ventricular function curves, in our hands, yielded equally as satisfactory information and, in addition, was much simpler to perform. 4. It is concluded that contractility indices are relatively insensitive in the assessment of left ventricular function, and that they offer little advantage over "pump-function" indices for this purpose.