Placing pacing leads into the cavity of the left ventricle using a snare catheter: Innovating a tabooed procedure

Abstract

Every once in a while, a singleor dual-chamber pacemaker with only 1 ventricular lead placed into the right ventricle paces with a right bundle branch morphology in lead V1. Often, the patient may have a dilated heart and have the lead placed deeply into the apex on fluoroscopy. The implanter may wonder, “How could I have placed a lead in the right ventricle which is now pacing the left ventricle?” Although it is good practice to move a single-plane fluoroscope into a lateral position to ensure inadvertent placement of the lead into the coronary sinus, it may not always be done during implantation. If the lateral chest X-ray does not demonstrate posterior lead position into the coronary sinus, the implanter begins to worry about having traversed the septum via either a congenital defect or a lead perforation. The next step often involves echocardiography or another imaging modality to ensure that the lead does not require repositioning. Placing leads in the left side of the heart is a feared complication of device implantation. Years ago, there was even concern about inadvertently placing a lead in the coronary sinus. Of course, this was before the era of pacemaker therapy to improve symptomatic congestive heart failure in patients without bradyarrhythmias. In multiple large randomized clinical trials, cardiac resynchronization therapy has been consistently shown to decrease mitral regurgitation, improve left ventricular ejection fraction, reduce hospitalizations, improve quality of life, and reduce overall mortality in patients with systolic dysfunction, congestive heart failure, and prolonged QRS intervals. Leads must be meticulously placed into the coronary sinus to allow left ventricular pacing with excellent stability and thresholds to ensure consistent capture and permit adequate battery longevity. Despite advances in lead design and delivery systems, accessing the coronary sinus and finding an adequate position cannot be achieved in all patients sent for cardiac resynchronization. Patients who fail coronary sinus lead placement are often sent for epicardial lead insertion, requiring a thoracotomy or at very least a thoracoscopic procedure. Some patients are too sick to undergo these more invasive surgical procedures and may