Potential link between atrial undersensing and calcium channel blockers

Potential link between atrial undersensing and calcium channel blockers

Potential link between atrial undersensing and calcium channel blockers: Single lead VDD pacemakers are convenient to implant and less expensive than DDD pacemakers. The advantage of single lead VDD system is that only a single lead need be implanted and thereby reducing procedure time, fluoroscopy time and the cost. There is also a chance for lower perioperative complications with single lead VDD systems compared to DDD systems. But there are a few concerns regarding the single lead VDD system. Though a single lead VDD system is a cheaper and simpler method to provide AV sequential pacing in those with high grade AV block and good sinus node function, there is a chance for loss of atrial sensing over time. This is due to the floating atrial lead which may become less reliable over a period of time. Another potential problem is the delayed onset of sinus node dysfunction which will lead to VVI pacing or need the implantation of an additional atrial lead. A recent study involving over one hundred and fifty patients [Europace (2010) 12(9): 1251-1255] evaluated the potential risk factors for loss of atrial sensing in the long term performance of single lead VDD systems. They found that the chance of inappropriate atrial sensing was higher in the elderly and in those with atrial potentials less than 3 millivolts. An interesting finding was the association with the concomitant use of non-dihydropyridine calcium channel blockers (P < 0.003). This finding needs to be confirmed in larger studies and by other researchers. Atrial fibrillation was another obvious reason for lack of sensing in this study (P < 0.001). Inappropriate atrial sensing in this study was defined as an AV synchrony ratio of less than 90% of the paced beats.