Complete heart block. Studies of atrial and ventricular pacemaker site and function.

British Heart Journal
D H Dighton

Abstract

Atrial and ventricular pacemaker function was studied in 20 patients with idiopathic chronic complete heart block using the rate response to an intravenous bolus dose of isoprenaline (5 mug/70 kg bodyweight). Pacemaker responses were compared with those of 16 normal control subjects. None of the patients was having syncopal attacks at the time of admission and they were therefore selected in that none required immediate pacing. Ten of the patients had His bundle electrograms; all were shown to have a pre-His type of atrioventricular block. Two major groups emerge from the responses to isoprenaline. (a) High risk group: 11 of the 14 patients with reduced ventricular pacemaker responses had frequent syncopal attacks; 8 of the patients with Adams-Stokes syncope had a bundle-branch block pattern, while 3 had a narrow QRS. These patients require pacing. (b) Low risk group: a low risk asymptomatic group (5 patients) was identified with atrial and ventricular responses to isoprenaline within normal range. One of these patients had a bundle-branch block pattern, while 4 had a narrow QRS. These patients might be managed without pacing. The atrial response to isoprenaline was reduced in 12 of the 20 cases, 10 of whom also had reduced ven...Continue Reading

References

Mar 1, 1975·British Heart Journal·K S Smith
Aug 1, 1974·British Heart Journal·D H Dighton
Oct 1, 1974·British Heart Journal·J F Finucane, J Gialafos
Sep 1, 1966·American Heart Journal·C R AyersM S Spach
Jul 1, 1941·British Heart Journal·J ParkinsonW Evans

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