Atrial sounds and endocardial electrograms recorded during coarse atrial fibrillation.

Hearing atrial sounds is unusual during atrial flutter and rare during atrial fibrillation. We report a patient with hypertrophic cardiomyopathy and coarse atrial fibrillation in whom atrial sounds were recorded phonocardiographically during endocardial atrial electrography. The atrial sounds were recorded phonocardiographically at the same periodicity as the atrial electrograms, and both had beat-to-beat variability in morphology, amplitude, and cycle length. These observations suggest that atrial sounds originate from the atrium and that organized electrical and mechanical activity occur in some types of atrial fibrillation.