Follow-up of Corrected QT Interval in the Detection of Doxorubicin Cardiomyopathy: an Experimental Study

Coınprehensive ca rdiac eval uations are recoınınended for all doxorubicin-treated patients to detect subclinical cardiac failure. In this study we exaınined the prolongation of con-ected QT interval (QTc) in doxorubicin treated rabbits. Male New Zealand rabbits (n=24) were randomised into two groups. Group A (n=l2) was given doxorubicin (2ıng/kg once a week) and Group B (n=l2) was given saline during 10 weeks. QTc intervals were ıneas ured in every two weeks from ex tre ınity leads for each aniınaL At the end of the study cardiac saınples were examined histologically and each animal was given a histopathological score between O and 4 according to degree of cardiomyopathy. Histopathological scores were 3 for one rabbit and 4 for the remaining 1 1 rabbits in Group A and were O for all the rabbits in Group B. QTc intervals at the beginn ing and at the end of the study were 248.5± 17 .7 msec. and 298.8±13.7 msec. consecutively (p=0.012) in Group A, 243.8±17.6 msec. and 245.4±17.8 msec. consecutively (p>0.05) in Group B. Prolongation of QTc was statistically significant at the end of the 4th week (262.3±17.9 msec.) when compared with the basa! value in Group A (p<.05). As a result, prolongation of QTc, a measure of myocardial repolarization may reflect injury to myocardial cells and is an easy and inexpensive method that can be used in the detection of subclinical cardiomyopathy in doxorubicin treated patients.