© 2004 by European Society of Cardiology
Heart rate regularisation in patients with permanent atrial fibrillation implanted with a VVI(R) pacemaker*
aUnità Operativa Cardiovascolare, Ospedale di Cecina Azienda USL 6, Via Marrucci, 60, 57023 Cecina, (LI), Italy; bDivisione di Cardiologia, Ospedale Misericordia e Dolce di Prato Prato, Italy; cDivisione di Cardiologia, Ospedale Area Aretina Nord Arezzo, Italy; dDivisione di Cardiologia, Ospedali Riuniti Val di Chiana Montepulciano,(SI), Italy; eDivisione di Cardiologia, Ospedale Civile di La Spezia La Spezia, Italy; fVitatron Medical Italia Bologna, Italy
Irregularity of ventricular cycles is a cause of haemodynamic impairment and symptoms in patients with atrial fibrillation (AF).
AIM OF THE STUDY: Aim of the study was to determine the optimal pacing rate to stabilise ventricular cycle length at rest in patients with chronic AF, bradycardiac symptoms and VVI pacing.
METHODS: The compensatory pause (CP) in AF, as defined by Langendorf, was used as a reference value in pacing the heart. The spontaneous mean heart rate (MHR) was assessed with the PM OFF. The CP was then calculated with the pacing rate programmed at 40 bpm. Four pacing rates were tested: rate of the CP (RCP), RCP+5 bpm, RCP5 bpm and RCP10 bpm.
RESULTS: RCP provided a good estimate of the MHR (r=0.92). Pacing percentage (P%) was 24±15% at the pacing rate of RCP10 bpm, 39±19% at RCP5 bpm, 63±17% at RCP, and 79±19% at RCP+5 bpm (p<0.001). The corresponding HR modestly increased from 65±13 bpm to 66±13 bpm (p=NS), 68±13 bpm (p<0.001) and 71±13 bpm (p<0.001), respectively.
CONCLUSION: The RCP estimates, during pacing, what the spontaneous MHR would be. Ventricular stimulation at the RCP causes a high P%, stabilising cardiac cycles with a modest increase in HR.
Key Words: atrial fibrillation, ventricular pacing, compensatory pause, irregularity, stabilisation
*Corresponding author. Tel.: +39-0586-630143; fax: +39-0586-614268. E-mail address: gianfrancomz{at}tiscalinet.it (G. Mazzocca).