The Evaluation of Doxorubicin Cardiomyopathy By Signal Averaged Electrocardiography

Purpose: Signal-averaged electrocardiography detects low-amplitude signals designated as late potentials which are strongly related to myocardial damage. We aimed to search for the possible relation between the myocardial effects of doxorubicin and signal-averaged electrocardiographic parameters. Material and Methods: Fortyeight patients who received doxorubicin included chemotherapy were enrolled. Signalaveraged electrocardiographic parameters were detected by using 3 parameters; filtered QRS (fQRS), the square root of the voltage obtained during the last 40 milliseconds of the duration of fQRS (RMS40), the duration starting from the last 40 miliseconds of fQRS till the decrease of voltage under 40 microvolts. (HFLA40). Ejection fractions of the patients were measured by echocardiographic evaluation. Results: Median age was 44 (27-70) years. Mean cumulative doxorubicin dosage was 475.56 +/- 98.45 mg. Mean values of the measured signal-averaged electrocardiographic parameters were as follows; fQRS: 78.27 +/- 10.74 miliseconds, RMS40: 115.10 +/- 50.23 and HFLA was 21.95 +/- 8.39 microvolts. The doses of doxorubicin showed a positive correlation with fQRS (r= 0.28, p= 0.02) and a negative correlation with RMS40 (r=-. 31, p= 0.03). There was no correlation between the doxorubicin dosage and the ejection fraction of the patients (r=. 18, p= 0.22). Conclusion: Our results suggested that significant correlations are present between fQRS and RMS40 and cumulative doxorubicin dosages. Therefore, signal-averaged electrocardiographic parameters may be of value for predicting the prognosis of the patients who have received doxorubicin included chemotherapy.