Leading edge voltage of effective shocks was significantly lower when catheters with an 8-cm coil in right atrium were used compared with the alternative 5-cm coil catheters ( 301 + / - 80 volts vs 340 + / - 78 volts , P < .001 ) , and delivered energy ( 6.75 + / - 4.25 joules vs 7.86 + / - 4.29 joules , P = .043 ) and shock impedance ( 60 + / - 9 ohm vs 66 + / - 10 ohm , P < .001 ) were lower .
