A routine ECG of a seventy-year-old man, who had been followed for five years because of complete right bundle branch block (CRBBB) with first-degree atrioventricular (AV) block, showed CRBBB and three different mean frontal plane QRS axes suggesting normal conduction, bradycardia-dependent left anterior hemiblock, and tachycardia-dependent left posterior hemiblock—all within the same tracing. Holter recording demonstrated transient advanced AV block, and a permanent pacemaker was implanted.
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References
1.
Rosenbaum MB , Elizari MV, Nau GJ, et al: Intraventricular trifascicular blocks. The syndrome of right bundle branch block with intermittent left anterior and posterior hemiblock. Am Heart J78:306-317, 1969.
2.
Rosenbaum MB , Elizari MV, Lazzari JO, et al: Intraventricular trifascicular blocks. Review of the literature and classification. Am Heart J78:450-459, 1969.
3.
Cannom SD, Goodman DJ, Harrison DC: Electrophysiological studies in patients with rate-related intermittent left bundle-branch block. Br Heart J36:653-659, 1974.
4.
Schullenburg RM, Durrer D.: Rate dependency of functional block in the human His bundle and bundle branch-Purkinje system. Circulation38:526-540, 1973.
Rosenbaum MB , Elizari MV, Lazzari JP, et al: The mechanism of intermittent bundle branch block: Relationship to prolonged recovery, hypopolarization and spontaneous diastole repolarization. Chest63:666-677, 1973.
8.
Cohen HC, D'Cruz I., Arbel ER, et al: Tachycardia- and bradycardia-dependent bundle branch block alternans. Clinical observations. Circulation55:242-246, 1977.
9.
Massumi RA: Bradycardia-dependent bundle-branch block. A critique and proposed criteria . Circulation38:1066-1073, 1968 .
