DDIR Versus VVIR Pacing in Patients with Paroxysmal Atrial Tachyarrhythmias GABRIEL VANERIO, JAMES D. MALONEY, SERGIO L, PINSKI, TONY W. SIMMONS, LON W. CASTLE, RICHARD G. TROHMAN, and BRUGE L. WILKOFF From the Pacemaker and Electrophysiology Section, Department of Cardiology, The Cleveland Clinic Foundation, Cleveland, Ohio VANERIO, G., ETAL.: DDIR Versus VVIR Pacing in Patients with Paroxysmal Atrial Tachyarrhythmias. Patients with sinus node dys/uncfion (SND) in particular (hose with tachycardia-bradycardia syndrome and patients undergoing atrioventricular nodaJ ahlation procedures for refractory paroxysmai atrial tachyarrhythmias (PAT), are candidates for single chamber fVVffl mode) or dual chamber rate responsive (DDIH mode) systems. To evaluate the benefits and disadvantages of each pacing mode we retrospectively analyzed 33 patients with a history of frequent PAT who received a VVIR [22 patients); or a DDDfl pacemaker (n patients) programmed to the DDIR mode. The mean/ollow-up time was 25 and 18 months, respectiveiy, PreimpJant left atrial diameter was signi/icantiy smaller in the DDIfi group. Chronic atrial fibrillation developed in 54% of the VVIfi patients and 27% of the DDIR group, but this dij^ference was not significant. Complications of patients with VVIR pacemakers included new mitral and tricuspid insufficiency, stroke, pacemaker intolerance and aggravated congestive heart failure. Patients with DDIR pacemakers had a iower incidence of symptoms and complications. However, this group received more antiarrhythmic medication, required a closer follow-up, and their pacemakers needed frequent repro- gramming. Ourfindings suggest that VVIR is a poor choice for patients with SND, congestive heart failure, and PAT, and that DDIR may be an acceptable alternative. (PACE, Vol. 14, November, Part I 1991) paroxysmal atrial tachyarrhythmias, sinus node dysfunction, atrial fibrillation Introduction Patients with sinus node dysfunction (SND] and frequent paroxysmal atrial tachyarrhythmias (PAT) with or without atrioventricular (AV) con- duction abnormalities constitute a therapeutic challenge,^"'' This population can be treated with single chamber or dual chamber rate responsive pacemakers, since a nonatrial sensor can drive the pacing rate during these nonphysiological rhythms. The increasing number of patients with refractory PAT who undergo catheter ablation of the AV junction enlarges the target population and Address for reprints: Bruce L. Wilkoff, M.D., Cardioiogy, desk F-15, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, Ohio 44195. Fax; (216) 444-0456. Received March 9, 1991; revision |une 24, 1991: accepted July 16, 1991. emphasizes the need to evaluate the most appropri- ate pacing modality. The high incidence of chronic atrial fibrillation in patients with frequent PAT and permanent pacemakers has been well documented and must be considered during pacemaker and mode selection.^•^•^•''"^^ Ghronic atrial fibrillation is associated with systemic embolization, conges- tive heart failure, and increased mortality. Standard DDD pacing is not recommended be- cause it carries the possibility of rapid ventricular pacing during atrial tachyarrhythmias. Various pacing modes have been designed to prevent rapid ventricular tracking of atrial tachyarrhythmias, Atrial pacing [with or without rate modulation) is superior to VVI in patients with SND,^^ ""* but is not useful for patients with impaired AV conduc- tion, DDI pacing is useful for patients with im- paired AV conduction,^^'^^^ but since the upper and lower rates are identical, rate modulation is 1630 November 1991, Part I PACE, Vol. 14