Case Report: A Recently Released Implantable Biventricular Defibrillator

Case Report

A 67-year-old man with a history of coronary artery bypass surgery, prior myocardial infarction, near-syncope, and New York Heart Association Class III congestive heart failure on optimal medical drug therapy had a left ventricular ejection fraction of 33 percent, first-degree AV block and a right bundle branch block pattern with a QRS of 160 milliseconds. The patient was referred for an electrophysiology study which demonstrated inducible sustained monomorphic ventricular tachycardia. The patient was subsequently referred for a biventricular ICD (InSync Maximo Model #7303, Medtronic Inc., Minneapolis, Minnesota). Informed consent was obtained from the patient. The patient was prepped and draped in the usual sterile manner. A 5 cm incision was made two fingerbreadths below the left clavicle (in the midclavicular line). A device pocket was made using blunt and sharp dissection at the level of the prepectoral fascia. The patient subsequently underwent a left prepectoral implant with venous access obtained via the left cephalic venous approach. The right ventricular lead was positioned via fluoroscopy in the right heart and secured by passive fixture. The atrial lead was fluoroscopically placed in the right atrium and secured by active fixture (lead sensing and capture threshold were determined and impedance was recorded at 5 volts). All three pacing leads were placed through a single cephalic vein. By utilizing a steerable guide catheter, we were able to access the coronary sinus vein. A coronary sinus venogram was performed which assisted in defining a left lateral vein (Figure 1). After using the guide catheter, the Medtronic Attain OTW (Model #4193, Medtronic Inc.) was positioned in the vessel with excellent biventricular pacing and sensing. Figures II, III, and IV show AP, right anterior oblique, and left anterior oblique projections of the pacing wire, respectively. The patient underwent defibrillation threshold testing and had a defibrillation threshold of less than or equal to 20 joules. There were no complications incurred during the EP study or the implantation of the InSync Maximo Model #7303 biventricular implantable cardioverter-defibrillator.

Discussion

This patient was a candidate for cardiac resynchronization therapy as per the American College of Cardiology/American Heart Association Guidelines. The patient received the latest and most advanced biventricular ICD. Our EP team was one of the first in the country to utilize this novel implantable biventricular device. The InSync Maximo offers a rapid charge time, increased longevity and high-voltage output. In time, with FDA approval, it may be upgradable to V to V timing programmability. These added features make the InSync Maximo #7303 a new and superior alternative for cardiac resynchronization therapy.

Conclusion 

In closing, one should consider the newer devices for cardiac resynchronization therapy. The InSync Maximo is certainly a welcome addition.