Diagnostic validity of electrocardiography compared with echocardiography for diagnosing left ventricular hypertrophy in patients with beta-thalassemia major

ABSTRACT

Left ventricular hypertrophy [LVH] is an important risk factor in determining cardiovascular disease prognosis. Echocardiography [ECHO] is a sensitive and specific tool for detection of LVH but cost and operational consideration tend to limit its utility; in contrast, the Electrocardiography [ECG] is widely available, expensive and less operator dependent. Since the comparison of diagnostic validity between ECG and ECHO for evaluating of LVH has not been well studied, this survey was carried out on a number of major beta-thalassemia patients. This descriptive-analytical study was performed on 135 patients [including male and female] with major beta- thalassemia over 8 years old. Patients with heart failure, valvular or structural heart disease, renal and endocrine disease and Hb<10g/dl were excluded. ECG and ECHO were performed 48 h after blood transfusion. ECG criteria of LVH and myocardial performance index [MPI] in ECHO were measured. Sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV] of ECG indexes were calculated separately for both sexes and compared with ECHO findings. The patients included 64 [47/4%] males and 71 [52/6%] females. ECG indexes were found as follows 70% sensitivity of the Sokolow-Lyon index, 14.3%; specificity, 90.3% PPV, 40% NPV and. Sensitivity of the Sokolow-Lyon-Rappaport, specificity, PPV, and NPV were 61.9%, 25/8%, 27/4%, 60%, respectively. Sensitivity of the Cornell index was66.6%. specificity 13.3%, PPV 86% and NPV 4.7%, Sensitivity of the White-Bock index was 0%, specificity 100%, PPV 0% and NPV was 68.9%. There was significant relationship between ECG indexes and some ECHO parameters. In this study there was a reverse and significant relationship between left acceleration time [AT] and the Sokolow-Lyon-Rappaport index statistically [r = 0.181, p = 0.035]. There was a significant direct relationship between left deceleration time [DT] and the Sokolow-Lyon-Rappaport index [r = 0.181, p = 0.036]. A reverse significant relationship between right AT and the Sokolow-Lyon index was seen [r = 0.173, p = 0.044]. A direct and significant relationship between diastolic inter ventricular septum diameter [IVSd] and the Sokolow-Lyon-Rappaport index was also observed [r = 0.186, p = 0.031]