Relation of echocardiographic wall motion score index and response to dobutamine stress to defibrillation threshold at the time of implantation of a cardiac defibrillator

Predictors of defibrillation threshold (DFT) at implantation remain poorly defined. It was hypothesized that a greater wall motion score index (WMSI) at rest on echocardiography and an ischemic or biphasic response on dobutamine stress echocardiography (DSE) would predict a greater DFT. Consecutive patients who underwent implantable cardiac-defibrillator implantation underwent echocardiography and DSE. DFT at implantation was assessed using the step-down method. Thirteen men aged 68 ± 10 years with left ventricular ejection fractions of 28 ± 10% participated in the study. DFTs ranged from 5 to 25 J (mean 14 ± 8). A WMSI at rest of <2.5 had a 71% positive predictive value and an 83% negative predictive value for a DFT <15 J. An ischemic or biphasic response during DSE did not predict a greater DFT at implantation.