title: Effect of intravenous and oral acebutolol in patients with bundle branch block.
abstract: We studied the effect of intravenous (1 mg/kg) and oral (400 mg) acebutolol on atrioventricular conduction in 22 patients with idiopathic bundle branch block and 1 to 1 atrioventricular conduction. Seven patients had previously symptomatic complete heart block (Group 1) and 15 were asymptomatic with bundle branch block only (Group 2). Following intravenous acebutolol heart rate decreased 82 +/- 16 to 63 +/- 16/min (P less than 0.01), A-H interval lengthened 98 +/- 22 to 121 +/- 30 msec (P less than 0.005) and H-V time was prolonged 60 +/- 13 to 70 +/- 17 msec (P less than 0.02) in those with previous heart block. The corresponding changes in the patients with no previous block were 74 +/- 14 to 61 +/- 8/min (P less than 0.01), 90 +/- 17 to 109 +/- 22 msec (P less than 0.05) and 48 +/- 15 to 56 +/- 14 msec (P less than 0.01). There was no difference between the basal or induced changes between these two groups. After intravenous acebutolol infusion 2 of 6 patients with previous spontaneous heart block and none of those without previous heart block developed atrioventricular block distal to His. The induced block was temporary (less than 10 min) and corresponded to the time of peak plasma acebutolol levels. Temporary atrioventricular block followed oral acebutolol administration in 4/7 patients with previous spontaneous heart block and 0/14 in those without block. In patients with bundle branch block intravenous acebutolol prolonged H-V conduction times in 19/20 patients and intravenous and oral acebutolol induced A-V block in 4/7 patients with previous spontaneous block.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000070:Acebutolol / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D000284:Administration, Oral; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D002036:Bundle of His / Q000187:drug effects / Q000503:physiopathology; D002037:Bundle-Branch Block / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007263:Infusions, Parenteral; D008297:Male; D008875:Middle Aged; D011690:Purkinje Fibers / Q000187:drug effects / Q000503:physiopathology
chemical_list: D000070:Acebutolol