Anterior lead ST-segment depression in inferior wall infarction. Early angiographic study. Effect on the results of intracoronary thrombolysis

Of 32 patients with inferior myocardial infarction undergoing coronary angiography in the first 6 hours for intracoronary streptokinase thrombolysis, 19 (Group I) had ST depression of more than 1 mm in the anterior chest wall leads (VI-V4) whilst 13 (Group II) had no ST changes in these leads. Quantitative analysis of left ventricular angiograph showed a significantly lower ejection fraction in Group I (52 +/- 8.5%) compared to Group II (59 +/- 8%, p less than 0.05) and that this difference was due to a greater zone of inferior wall hypokinesia, irrespective of whether this was assessed by measuring its surface area (HKS cm2: Gr I: 11 +/- 6, Gr II: 4 +/- 3, p less than 0.01) or percentage ventricular perimeter (HK%: Group I 45 +/- 15, Group II 26 +/- 12, p less than 0.001). On the other hand, anterior wall motion was normal in both groups. Coronary angiography showed proximal obstruction of the right coronary artery in 84% of patients in Group I. In Group II, the coronary obstruction tended to be distal or incomplete. The prevalence and average severity of associated stenosis of the left anterior descending artery were the same in both populations. The success rate of thrombolysis was not significantly different between the two groups. In successful procedures with a patent artery on the 14th day, improved regional contractility was only observed in Group I (HKS cm2: 11.5 +/- 6 vs 8 less than 4.4, p less than 0.05; HK%: 47 +/- 14 vs 38 +/- 9, p less than 0.05): the hypokinetic zone was unchanged in Group II.(ABSTRACT TRUNCATED AT 250 WORDS)