Intermittent ventricular bigeminy as an expression of modulated parasystole.

posterior chest diameter. Chest width and body weight correlate with transthoracic resistance and may explain the higher pacing thresholds in these patients.6 In general, we easily determined the appearance of pacing capture by simultaneous observation of the oscilloscope and palpation of the femoral pulse. Difficulty arose when the patient’s intrinsic heart rate was similar to the maximal pacing rate of the device. This problem could have been avoided if a pacing rate higher than 90 beats/min had been available. In summary, prophylactic external pacing may provide a safe, effective alternative to prophylactic transvenous pacing in patients who are considered to be at risk of bradycardia after cardioversion of atria1 tachyarrhythmias. Acknowledgment: We thank Maureen Adams and Belinda Anderson for assistance in the preparation of this manuscript. References