The 500 microF, long duration waveform reduced peak voltage 41% (374 +/- 18 V [STD] vs 219 +/- 14 V [LD], P < 0.001) and reduced peak current 38% (11.0 +/- 1.1 A [STD] vs 6.8 +/- 0.6 A [LD], P < 0.001) but did not significantly change the delivered energy (12.4 +/- 1.3 J [STD] vs 13.4 +/- 1.0 J [LD]). Durations increased from 10.0 +/- 0.2 to 17.6 +/- 0.5 msec (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)