title: Is DDD pacing superior to VVI,R? A study on cardiac sympathetic nerve activity and myocardial oxygen consumption at rest and during exercise.
abstract: Rate responsive ventricular pacing (VVI,R) has been demonstrated to equal atrial synchronous ventricular pacing (DDD) with regard to hemodynamics and exercise tolerance. Whether the two modes are also comparable, with regard to cardiac metabolic effects, is not yet clear. We assessed central hemodynamics, cardiac sympathetic nerve activity (cardiac norepinephrine overflow), and myocardial oxygen consumption in 16 patients treated with rate responsive atrial synchronous ventricular pacemakers (DDD,R) due to high degree AV block. The study was performed at rest and during supine exercise at two workloads (30 +/- 12 and 68 +/- 24 watts, respectively) during VDD and rate matched VVI pacing (VVIm). Ventricular rates at rest and during both workloads were almost identical. Cardiac output at rest tended to be higher in the VDD mode, due to a slightly higher stroke volume. Central pressures including right atrial pressure and pulmonary capillary wedge pressure were similar in the pacing modes. The coronary sinus blood flow, the coronary sinus arteriovenous oxygen difference, and the myocardial oxygen consumption did not differ between the two pacing modes. Cardiac norepinephrine overflow was similar in the two pacing modes, at rest or during exercise. Thus, we found no significant differences between VDD and VVIm pacing with regard to central hemodynamics, cardiac sympathetic nerve activity (cardiac norepinephrine overflow), or myocardial oxygen consumption either at rest or during moderate exercise.
authors.affiliation: Department of Cardiology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Linde-Edelstam
authors.forename: P
authors.initials: P
authors.lastname: Hjemdahl
authors.forename: S K
authors.initials: SK
authors.lastname: Pehrsson
authors.forename: H
authors.initials: H
authors.lastname: Aström
authors.forename: R
authors.initials: R
authors.lastname: Nordlander
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002302:Cardiac Output; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002306:Cardiac Volume; D002395:Catecholamines / Q000378:metabolism; D003326:Coronary Circulation; D005260:Female; D006321:Heart / Q000294:innervation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D005082:Physical Exertion; D013318:Stroke Volume; D013564:Sympathetic Nervous System / Q000503:physiopathology*
chemical_list: D002395:Catecholamines