Assessment of Cardiac Performance

To the Editor. — The indirect measurement of left ventricular ejection time intervals for assessment of myocardial function was recently reviewed in an editorial (216: 2007, 1971). Many reports have verified the sensitivity of this technique and its good correlation with more elaborate cardiac function tests. A potential application not suggested heretofore is the employment of serial measurements of left ventricular ejection time (LVET) as a quantitative office or clinic test for changes in myocardial performance. The overlap between normal and abnormal values of LVET limits the value of a single determination for cardiac diagnostic screening. However, when patients with known heart disease are studied serially, the absolute value is relatively less than the changes of LVET which reflect alterations in myocardial function. Thus, the patient acts as his own control. Spodick et al have shown that with an inexpensive modification (less than 300) a standard single channel electrocardiograph can be