Diagnostic Accuracy of Electrocardiography in Diagnosis of Left Ventricular Hypertrophy
Keywords:Hypertension, left ventricular hypertrophy, Electrocardiography, Echocardiography, Sokolow Lyon product index, Cornell product index.
Objective: To determine diagnostic accuracy (in terms of sensitivity, specificity, positive predictive value and negative predictive value) of electrocardiography for left ventricular hypertrophy (LVH).
Study Design: Cross sectional validation type.
Place and Duration of Study: Pakistan Institute of Medical Sciences (PIMS) from 1 January 2013 to 30 June 2013.
Materials and Methods: A cross-sectional study was conducted at department of cardiology. Two hundred and fifty hypertensive patients, both male and female were included in the study. The data was collected by non-probability,purposive sampling. A performa was filled indicating their bio-data, history and clinical examination. All the patients were then subjected to 12 lead electrocardiogram (ECG) and echocardiography to detect LVH. Sokolow Lyon product index and Cornell product index was calculated on ECG to detect LVH. Data was analysed using SPSS 11.
Results: Out of 250 hypertensive patients, a total of 110 (44%) patients had LVH by echocardiography Out of these 110 patients, 60 (54.5%) patients had both positive Sokolow Lyon and Cornell product indices and 50 (45.5% ) had negative both Sokolow Lyon and Cornell product indices. The calculated sensitivity, specificity, positive predictive value, negative predictive value and overall diagnostic accuracy of combined Sokolow Lyon and Cornell product indices were 54.5%, 97.9%, 95.2%, 73.3% and 78.8% respectively.
Conclusion: The ECG criteria of combined Sokolow Lyon and Cornell product indices had a high specificity and PPV for the
detection of left ventricular hypertrophy using echocardiography as a gold standard. However ECG has low sensitivity and
NPV for LVH and hence is not a reliable screening tool for detection of LVH.