Long-term haemodynamic and antiarrhythmic benefits of DDIR versus DDI pacing mode in sick sinus syndrome and chronotropic incompetence.
OBJECTIVE
The aim of this Italian multicentre study was to evaluate the haemodynamic and antiarrhythmic effects of DDIR versus DDI pacing mode in sick sinus syndrome with chronotropic incompetence.


METHODS
Seventy-nine patients were implanted with a dual chamber rate-responsive pacemaker (Medtronic 7075) and centrally randomised to DDI or DDIR pacing mode. After six months, the pacing modality was crossed over. Follow-up included clinical data, rest ECG, echocardiography, Holter monitoring and exercise testing in DDIR.


RESULTS
a) Haemodynamic effects. Comparing postimplant exercise testing in DDIR mode with preimplant tests, peak heart rate increased from 96 +/- 17 to 115 +/- 17 bpm (+20%, p < 0.0001), total work capacity from 7.0 +/- 3.5 to 8.8 +/- 4.3 minutes (+26%, p < 0.0001), peak oxygen uptake from 1238 +/- 406 to 1453 +/- 423 ml/min (+17%, p < 0.001) and oxygen uptake at anaerobic threshold from 977 +/- 343 to 1222 +/- 415 ml/min (+25%, p < 0.001). These benefits persisted unchanged during one-year follow-up. b) Antiarrhythmic effects. After six months, paroxysmal atrial fibrillation recurrence significantly decreased in the whole population: group I (DDI) 20.7 vs 48.3%, p < 0.02; group II (DDIR) 21.2 vs 36.4%, p < 0.05; group I + II (DDI + DDIR) 21.0 vs 41.9%, p < 0.001. After one year no significant differences were found between DDI and DDIR. Group I: DDI 23.8 vs DDIR 28.6%, ns; group II: DDI 22.7 vs DDIR 18.2%, ns.


CONCLUSIONS
DDIR vs DDI significantly improves short- and long-term haemodynamic performance. Dual chamber pacing shows a significant reduction of paroxysmal atrial fibrillation recurrence, regardless of rate responsiveness.
Santini
M
M
Ospedale S. Filippo Neri, Roma.
Ricci
R
R
Puglisi
A
A
Mangiameli
S
S
Proclemer
A
A
Menozzi
C
C
De Fabrizio
G
G
Leoni
G
G
Lisi
F
F
De Seta
F
F
D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000503:physiopathology / Q000628:therapy*; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000628:therapy; D018880:Atrial Premature Complexes / Q000503:physiopathology / Q000628:therapy; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006334:Heart Function Tests; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012008:Recurrence; D012129:Respiratory Function Tests; D012804:Sick Sinus Syndrome / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D018879:Ventricular Premature Complexes / Q000503:physiopathology / Q000628:therapy