Transvenous biventricular defibrillation

The recent success of biventricular pacing with transvenously implantable l eft ventricular leads suggests that left ventricular leads may be useful fo r other modes of therapy, Animal studies showed small leads inserted into a left ventricular vein dramatically reduced defibrillation strength require ments, This article describes a human investigation of the feasibility of b iventricular defibrillation. Fifty-one patients undergoing implantable card ioverter defibrillator (ICD) implantation were enrolled. After insertion of a standard ICD lead, a prototype over-the-wire left ventricular defibrilla tion lead was inserted through the coronary sinus and into a vein on the le ft ventricle, Lead insertion was guided by retrograde venography, The left ventricular lead's location was randomized to the anterior or posterior vei n, Randomized, paired defibrillation threshold (DFT) testing was performed to compare a standard ICD shock configuration (Control: right ventricle(-) --> superior vena cava(+) + CAN(+)) to 1 of 3 biventricular shock configura tions. In the anterior vein, the left ventricular lead was tested with eith er a single biphasic shock from right ventricle + left ventricle- --> super ior vena cava+ + CAN(+) or a dual biphasic shock, In the posterior vein, th e left ventricular lead was tested with a dual biphasic shock. Dual shocks consisted of a 40% tilt biphasic shock from right ventricle- --> superior v ena cava(+) + CAN(+) followed by another 40% tilt biphasic shock from left ventricle(-) --> superior vena cava(+) + CAN(+), delivered from a single 22 5 muF capacitance, Left ventricular lead positioning was successful in 41 o f 46 patients (89%), Mean left ventricular lead insertion time was 17 +/- 1 7 minutes and 13 +/- 15 minutes for anterior and posterior locations, respe ctively. Mean DFTs were not statistically lower for the left ventricular sh ock configurations, but retrospective analysis showed a well-defined region of the posterolateral left ventricle where consistent DFT reduction was ac hieved with dual shocks (14.0 +/- 2.7 J vs 7.8 +/- 0.9 J; n = 5; p = 0.04). There were no adverse events requiring intervention doe to the use of the left ventricular lead. Biventricular defibrillation is feasible and safe un der the conditions used in this study, Additional studies are needed to ver ify whether dual shocks with posterolateral left ventricular lead positions consistently reduce DFTs. (C) 2000 by Excerpta Medica, Inc.