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Abstract It is usually considered difficult or impossible to make the electrocardiographic diagnosis of left ventricular hypertrophy in the face of left bundle branch block. The distinction between the two situations, however, may be crucial, as left ventricular hypertrophy is an independent risk factor for increased cardiovascular morbidity and mortality. The aim of this work is to find, if any, an electrocardiographic clue(s) to the diagnosis of left ventricular hypertrophy in presence of left bundle branch block. Two groups of patients were included in this study, 50 patients each. The first group (group1) included patients with left bundle branch block and no left ventricular hypertrophy by M-Mode echocardiography. The second group (group II) included patients with left bundle branch block and left ventricular hypertrophy. All patients were subjected to thorough history taking, clinical examination, resting 12-leads electrocardiography and M-mode echocardiography. Summary 08 Comparing groups I and II, a significant increase of voltage in group II was occured in most leads more than in group I. In addition, significant more incidence of left axis deviation and left atrial changes were occured in group II. Remembering that both groups shared a common feature which is left bundle branch block, this difference must be attributed to the presence of left ventricular hypertrophy (Table 3 and 4). Sensitivities of these features for electrocardiographic diagnosis of left ventricular hypertrophy in the presence of left bundle branch block were calculated, and the results were values range from 26 %to 68% The four criteria (SV3 > 25mm , SV3 + RaVL > 30mm , R + S in any precordial lead > 45mm and QRS duration ≥ 0.16 msec) were the most sensitive ( 55% - 68% ) (Table 5). All the selected ECG parameters had very high specificity ranging from 75 % to 100% except for QRS duration > 0.16 msec which had very low specificity (35%) (Table 5). In the present study the following ECG criteria had reasonable sensitivities and specificities and hey might be suggested to be used in the diagnosis of of LVH in the presence of LBBB. - SV3 > 25mm (sensitivity 68 % and specificity 78%) Summary 08 - SV3 + RaVL > 30 mm (sensitivity 62 % and specificity 100%) - R + S in any precordial lead > 45 mm (sensitivity 55% and specificity 100%) - Left atrial abnormality (sensitivity 40 % and specificity 82%) - RaVL > 11mm (sensitivity 28 % and specificity 100%) - SV3 > 25 mm and SV2 > 30 mm (sensitivity 46 % and pecificity 100%). The results were tabulated and statistically analyzed. |