Wednesday, December 16, 2009


ABSTRACT: Background. Transcoronary pacing for the treatment of bradycardia duringpercutaneous coronary intervention (PCI) is not well established, but may be a useful technique ininterventional cardiology. We developed a porcine model to examine the feasibility and efficacy oftranscoronary pacing during PCI. Methods and Results. Eight pigs under general anesthesiaunderwent unipolar transcoronary pacing with a standard floppy guidewire in a coronary artery (asthe cathode) and a skin patch electrode (as the anode). We examined the effect of skin-patchposition (groin vs. anterior or posterior chest wall), the presence of an angioplasty balloon on theguidewire and also which coronary artery was “wired” on the efficacy of pacing as assessed bycapture and threshold data. Pacing with the bare guidewire and a maximum output of 10 V wassuccessful in 54% of the animals with a groin patch and the anterior chest-wall patch, but in 100%with a posterior chest-wall patch. The pacing thresholds were 8.3 ± 2.2 V, 7.6 ± 2.8 V and 3.4 ± 2.4V with the patch in these sites, respectively. With an angioplasty balloon over the guidewire, pacingefficacy increased to 100% (irrespective of the target vessel or patch location) and pacing thresholdswere significantly reduced (p < 0.05) to 2.7 ± 1.5 (with a groin patch) and 1.0 ± 0.7 V (with aposterior chest-wall patch). With optimal pacing set-up (posterior chest-wall patch and angioplastyballooninsulation), pacing thresholds were similar to those obtained with standard bipolartransvenous pacing at 1.2 ± 0.8 V. We did not observe any adverse effects of coronary pacing.Skeletal muscle contraction was only generated at high-output levels. Conclusions. This pig modelexamines the practicalities of transcoronary pacing and shows that this technique can produce 100%capture at thresholds comparable to the transvenous approach. This technique may have a roleduring PCI, particularly in an emergency situation.J INVASIVE CARDIOL 2009;21:634–638

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