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Rate Adaptive Atrial Pacing in the Bradycardia Tachycardia Syndrome
Author(s) -
SCHWAAB BERNHARD,
FRÖHLIG GERD,
SCHWERDT HOLGER,
LINDENBERGER IRENE,
SCHIEFFER HERMANN
Publication year - 1998
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1998.tb00033.x
Subject(s) - medicine , chronotropic , cardiology , heart rate , bradycardia , atrial fibrillation , supine position , tachycardia , sick sinus syndrome , anesthesia , sinus rhythm , atrioventricular block , blood pressure
In 42 patients (26 men, 16 women; mean age 69 ± 10 years), who were paced and medicated with antiarrhythmic drugs for the bradycardia tachycardia syndrome, chronotropic response and AV conduction with rapid atrial pacing during exercise were studied. Patients were included if they had no second‐ or third‐degree AV block, no complete bundle branch or bifascicular block, and a PQ interval ≤ 240 ms during sinus rhythm at rest. The interval between the atrial spike and the following Q wave (SQ) was measured in the supine position at rest with an AAI pacing rate of 5 beats/min above the sinus rate (SQ‐R+5), and at the end of exercise with 110 beats/min (SQ‐E110). Bicycle ergometry was performed using the Chronotropic Assessment Exercise Protocol with the pacemakers being programmed to AAI with a fixed rate of 60 beats/min. Chronotropic incompetence was defined as peak exercise heart rate: (1) < 100 beats/min; (2) < 75% of the maximum predicted heart rate; or (3) the heart rate at half the maximum workload < 60 + 2 beats/min per mL O 2 /kg per minute (calculated O 2 consumption). During exercise, one patient developed atrial fibrillation. Chronotropic incompetence was present in 71 % (29/41) of the patients according to definition 2, and in 76% (31/41) according to definition 1 or 3. Ten out of 41 patients (24%) exhibited a second‐degree AV block with atrial pacing at 110 beats/min at the end of exercise. Only 9 out of the remaining 31 patients (29%) showed a physiological adaptation of the SQ‐E110, and 21 patients (68%) exhibited a paradoxical increase of the SQ interval with rapid atrial pacing at the end of exercise as compared to the SQ‐R+5. These observations indicate that the pacing system to be used in most patients paced and medicated for the bradycardia tachycardia syndrome should be dual chamber, and the option of rate adaptation should be considered.