Noninvasive early detection of anthracycline‐induced cardiotoxicity in patients with hematologic malignancies using the phased tracking method

Anthracyclines are among the most effective and widely used anticancer drugs; however, their use is limited by serious cardiotoxicity. Early detection is necessary to prevent the high mortality rate associated with heart failure (HF). We evaluated cardiac function in 142 patients using conventional echocardiography and the phased tracking method (PTM), which was measured using the minute vibration and the rapid motion components, neither of which is recognized in standard M‐mode nor in tissue Doppler imaging. For systolic function comparison, we compared left ventricular ejection fraction (LVEF) in conventional echocardiography with the average velocity of ventricular septum myocytes (V(ave)) in the PTM. The V(ave) of 12 healthy volunteers was 1.5 (m/s)/m or more. At baseline of 99 patients, there was a positive correlation between LVEF and V(ave) in all patients. There were no significant differences in baseline cardiac function between patients with and without HF. There was a negative correlation between the cumulative anthracycline dose and LVEF or V(ave) among all patients. We determined that V(ave) 1.5 (m/s)/m was equivalent to LVEF 60%, 1.25 (m/s)/m to 55%, and 1.0 (m/s)/m to 50%. During the follow‐up period, there was a pathological decrease in LVEF (<55%) and V(ave) (<1.25 m/s/m) in patients with HF; decreases in V(ave) were detected significantly earlier than those in LVEF (P < 0.001). When V(ave) declined to 1.5 (m/s)/m or less, careful continuous observation and cardiac examination was required. When V(ave) further declined to 1.0 (m/s)/m or lower, chemotherapy was postponed or discontinued; thus, serious drug‐induced cardiomyopathy was avoided in patients who did not relapse. The PTM was superior to echocardiography for early, noninvasive detection and intermediate‐term monitoring of left ventricle systolic function associated with anthracycline chemotherapy, among patients with hematologic malignancies. The PTM was an effective laboratory procedure to avoid the progression to serious cardiomyopathy.