Key result
Hemiblocks rarely occur in healthy persons and are commonly associated with coronary or hypertensive disease, cardiomyopathies, and calcified aortic disease.
Provides a reappraisal of the diagnostic criteria and clinical associations of left anterior and left posterior hemiblocks.
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Warrants evaluation for underlying cardiac disease when hemiblocks are detected; leaves open prospective validation of reappraised criteria.
The left bundle branch separates into the left anterior and the left posterior divisions. The impulse travels to the left ventricle via both divisions when they are intact. When one division is blocked, the diagnosis is hemiblock. Diagnostic criteria for left anterior hemiblock are marked left axis deviation, small Q wave in lead I and small R wave in lead III, little or no prolongation of the QRS interval, and no evidence of other causes of left axis deviation. Criteria for left posterior hemiblock are marked right axis deviation, small R wave in lead I and small Q wave in lead III, little or no prolongation of the QRS interval, and no evidence of other causes of right axis deviation. A pure form of hemiblock is not uncommon, especially during acute anterior myocardial infarction, but right bundle-branch block often coexists with hemiblock. Like left bundle-branch block, hemiblocks rarely occur in healthy persons. They are commonly associated with coronary or hypertensive disease or both and are less commonly associated with cardiomyopathies and calcified aortic disease.
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Edward K. Chung (1975) conducted a review in Hemiblock. Hemiblock was evaluated. Hemiblocks rarely occur in healthy persons and are commonly associated with coronary or hypertensive disease, cardiomyopathies, and calcified aortic disease.
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