The American journal of cardiology
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Nonsustained ventricular tachycardia (VT) in the late period (7 to 21 days) after myocardial infarction (MI) is reported to be a predictor of sudden death. Patients with 3-beat VT on Holter monitoring in the late infarction period would be suspected to demonstrate electrical instability on electrophysiologic studies. Forty-seven patients were identified as having at least 3-beat VT on Holter monitoring. ⋯ Two patients died, 1 of stroke and 1 of pump failure after a second MI. No sudden deaths were observed in this group. Two patients had breakthrough arrhythmias and were treated by alternative antiarrhythmic therapy that was also effective on initial electrophysiologic studies.(ABSTRACT TRUNCATED AT 250 WORDS)
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Dual-chamber cardiac pacing (DDD) offers obvious theoretical advantages over traditional ventricular demand (VVI) pacing. Nevertheless, no widely agreed upon criteria exist for the selection of patients for physiologic DDD pacemakers compared with the simpler VVI systems. Accordingly, a non-invasive method for measuring cardiac output (Doppler ultrasound) was used to identify candidates for pacing who would derive the greatest hemodynamic benefit from DDD vs VVI pacing. ⋯ In these patients, the mean improvement in cardiac output was 30.4 +/- 8.6% with DDD vs VVI pacing, as opposed to an average increase of only 14.4 +/- 3.4% in the remaining 20 patients (p = 0.02). Thus, Doppler ultrasound can be used to quantitate the change in cardiac output at rest that occurs with DDD vs VVI pacing. The change is independent of the level of left ventricular function but is substantially higher when there is evidence of ventriculoatrial conduction or the pacemaker syndrome.