Significance of left anterior hemiblock.

Abstract

SUMMARY To determine the relation between left anterior hemiblock and cardiovascular abnormalities in an ambulatory population, the clinical records and electrocardiograms of 16 600 male applicants for life insurance between 1966 and 1974 were reviewed. There were 413 applicants with left anterior hemiblock; they were compared with an age-matched control group. The subjects with left anterior hemiblock were divided into 2 subgroups based on the direction of the mean frontal place QRS axis: (a) greater than -30°but less than -60°, and (b) between -60°and -90°. The prevalence of left anterior hemiblock increased with age for each decade after the third. Left anterior hemiblock was not associated with cardiovascular abnormalities in 53-4 per cent of subjects age 30 and over and thus occurred as an isolated finding. There was no significant difference in the prevalence of isolated left anterior hemiblock when subjects with a mean QRS axis greater than -30°but less than -60°were compared with those with a mean QRS axis between -60°and -90°.When men of 30 and over with left anterior hemiblock were compared with an age and sex matched control group, there was a significant relation between electrocardiographic abnormalities, hypertension, and cardiac disease. There were no intergroup differences when subjects with a mean QRS axis greater than -30°but less than -600 were compared with subjects with a mean QRS axis between -600 and -90°. However, left anterior hemiblock was not a sensitive marker of clinical cardiac disease in these subjects since this diagnosis was absent in 86 per cent of subjects with left anterior hemiblock. In subjects under 30 a significant relation was present between clinical cardiac disease and left anterior hemiblock because of the high incidence of congenital heart disease in the left anterior hemiblock group.The significance of left anterior hemiblock in the general population remains controversial. Grant (1956) stressed the value of deviation of the mean manifest QRS axis in the frontal plane to the left beyond -30°as a sign of cardiac abnormality and postulated that left axis deviation signifies a conduction disturbance in the anterolateral wall of the left ventricle. On the basis of experimental evidence

Prognostic Significance of Left Anterior Hemiblock in Patients With Suspected Coronary Artery Disease

“…Previous studies. Previous data on the correlation between LAHB and cardiac disease in the general population are scarce (2)(3)(4). Corne et al (2) found a relation with systemic hypertension and cardiac disease in 390 men ages 30 years and over with LAHB compared with an age-and gender-matched control group.…”

“…Previous data on the correlation between LAHB and cardiac disease in the general population are scarce (2)(3)(4). Corne et al (2) found a relation with systemic hypertension and cardiac disease in 390 men ages 30 years and over with LAHB compared with an age-and gender-matched control group. Studies of the prognostic significance of isolated LAHB in the general population or in subjects without clinical evidence of cardiac disease are limited, but have reported no effect of LAHB on mortality (3,4).…”

“…In subjects with no evidence of cardiac disease, some investigators found a marginally increased incidence of coronary artery disease (CAD) in patients with LAHB (2). No association has been found between the presence of LAHB and an increased risk of cardiac death (3)(4)(5).…”

The epidemiological and prognostic significance of the R/S Ratio in DII derivation in patients with or without ST-segment elevation

“…The study by Corne et al 48 , conducted on 390 males older than 30 years, reported an increased incidence of CAD in patients with LAHB when compared to the sex-matched controls. Similar studies reported an association between LAHB and the increased risk of cardiac death [49][50][51] .…”

Examining Left Axis Deviation

“…Left axis deviation may also occur in the absence of apparent cardiac disease and it is not necessarily a sign of significant underlying heart disease [5]. Left axis deviation is relatively common with advancing age even in the absence of clinically overt heart disease and rare during early adult years [17,[28][29][30][31][32][33][34][35][36][37][38][39][40]. In a population-based study of the people 20 years and above, almost half of the people with left axis deviation had isolated left axis deviation without evidence of heart diseases [28].…”