Abnormalities of endocardial activation pattern in patients with previous healed myocardial infarction and ventricular tachycardia.

Endocardial catheter mapping was performed in 27 patients with anterior wall acute myocardial infarction (AMI) and in 10 patients with inferior wall AMI. All patients had a history of ventricular tachycardia. Left ventricular breakthrough occurred at 10 +/- 4 ms after the QRS complex in inferior AMI and 11 +/- 7 ms after the QRS complex in anterior AMI. Total electrical activity recorded during sinus rhythm was 164 +/- 46 ms in inferior and 144 +/- 28 ms in anterior AMI (p = 0.05). Nine of the 10 patients with inferior AMI had complete activation of the anterior wall within the initial one-half of the QRS complex, compared with only 15 of the 27 patients with anterior AMI (p = 0.05). All 10 patients with inferior AMI had activation of the ventricular septum within the initial half of the QRS complex compared with only 13 of 27 with anterior AMI (p less than 0.005). None of the patients with inferior AMI had activation of the inferoposterior base within the initial one-half of the QRS complex, compared with 21 of 27 patients with anterior AMI (p less than 0.001). Complete activation of the anterior wall occurred at 33 +/- 15 ms in inferior and 58 +/- 30 ms in anterior AMI (p less than 0.005). Complete activation of the septum occurred at 38 +/- 12 ms in inferior and 63 +/- 28 ms in anterior AMI (p less than 0.005). Complete activation of the inferoposterior base occurred at 100 +/- 38 ms in inferior and 50 +/- 21 ms in anterior AMI (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)