A SIMPLE METHOD FOR PREOPERATIVE ASSESSMENT OF THE BEST FITTING ELECTRODE LENGTH IN SINGLE-LEAD VDD PACING

For single lead VDD pacing, electrodes with various distances between the lead tip and the floating atrial dipole (AV distance) are availabl e. Using different AV distances allows positioning of the atrial dipol e in the mid- to high right atrium, regardless of the size of the righ t heart. In this position, reliable atrial sensing and rejection of ve ntricular far-field potentials can be expected. A simple test for the preoperative assessment of the best fitting AV distance in the individ ual patient was tested. We studied 24 consecutive patients prior to im plantation of a VDD pacemaker. With the patient in supine position, a test electrode with an AV distance of 13 cm was taped onto the thorax. Under fluoroscopic control, it was moved until its course and project ion onto the heart was equal to that of a ventricular lead. If fluoros copy then showed a projection of the atrial dipole onto the mid- to hi gh right atrium, a lead with a similar AV distance of 13 or 13.5 cm wa s used for implantation. If the atrial dipole projected itself too hig h or too low, a shorter or longer lead had to be implanted. The maximu m time for the test was 2 minutes, and the maximum fluoroscopy time wa s 15 seconds. According to the test, a lead with an AV distance of 13 or 13.5 cm was implanted in 18 of 24 patients, and a lead with an AV d istance of 15.5 or 16 cm was implanted in 6 of 24 patients. The atrial dipole could easily be positioned in the mid- to high right atrium in all patients, demonstrating a correct preoperative assessment of the best fitting AV distance. Intraoperatively, a P wave amplitude of 3.5 +/- 3.0 mV was measured. The described test allows a fast and reliable assessment of the best fitting electrode length in single lead VDD pa cing.