CLINICAL PREDICTORS OF DEFIBRILLATION ENERGY-REQUIREMENTS IN PATIENTSTREATED WITH A NONTHORACOTOMY DEFIBRILLATOR SYSTEM

Many factors can influence defibrillation energy requirements (DER) in patients with a nonthoracotomy defibrillator. No large studies, howev er, have correlated clinical characteristics with the DER. In this stu dy, 124 patients underwent the same DER protocol with the identical bi phasic waveform, nonthoracotomy lead system, and lead configuration. T hese patients were 63 +/- 12 years old (mean +/- SD); 99 were men; the ejection fraction was 0.32 +/- 0.13, and 36 were taking an antiarrhyt hmic medication. New York Heart Association congestive heart failure c lass I was present in 28, class II in 70, and class III in 26 patients . Male sex (454 +/- 94 V vs 406 +/- 91 V for female sex) was associate d with a significantly higher DER (p = 0.02) and an increased risk of a DER >550 V (p = 0.047). No other clinical variable was associated wi th the DER or a DER >550 V. In conclusion, women tend to have lower DE Rs than men.