An evaluation of the utility of LVdP/dt, QA interval, LVdP/dt and Tau as indicators of drug-induced changes in contractility and lusitropy in dogs.

These findings indicate that this experimental model can accurately and consistently detect changes in cardiac contractility, across multiple sites and instrumentation systems. While LVdP/dt produced responses similar to LVdP/dt, the QA interval and lusitropic parameters LVdP/dt and Tau were not markedly changed at the dose of drugs tested. Further studies with drugs that affect early diastolic relaxation through calcium handling are needed to better evaluate drug-induced changes on lusitropic properties of the heart.