摘要
The defibrillation threshold(DFT) and upper limit of vulnerability(ULV) were d etermined using step-down protocols in 50 patients who underwent implantable ca rdioverter-defibrillator placement or testing. The sensitivity and specificity of each ULV energy level was assessed for detecting an increased DFT, correlatio n of the DFT and ULV, and optimal shock timing for ULV determination. A ULV < 10 or 11 J(failure to induce ventricular fibrillation with 10-to 11-J shocks) wa s 100%predictive of an acceptable DFT and may be sufficient to exclude unaccept able DFTs in 60%of implantable cardioverter-defi-brillator recipients. All 4 shocks used to scan the peak of the T wave during ULV testing were necessary for accurate ULV determination.
The defibrillation threshold(DFT) and upper limit of vulnerability(ULV) were d etermined using step-down protocols in 50 patients who underwent implantable ca rdioverter-defibrillator placement or testing. The sensitivity and specificity of each ULV energy level was assessed for detecting an increased DFT, correlatio n of the DFT and ULV, and optimal shock timing for ULV determination. A ULV < 10 or 11 J(failure to induce ventricular fibrillation with 10-to 11-J shocks) wa s 100%predictive of an acceptable DFT and may be sufficient to exclude unaccept able DFTs in 60%of implantable cardioverter-defi-brillator recipients. All 4 shocks used to scan the peak of the T wave during ULV testing were necessary for accurate ULV determination.