Sublingual nitroglycerin significantly improved central chord shortening in the infarcted zone within 24 hours (from 13.1% to 27.2%, p<0.001) and at 5-7 days, but had no effect at 4-6 weeks.
Observational (n=16)
Does sublingual nitroglycerin improve contractile abnormalities in patients with acute myocardial infarction at different time points after onset?
The asynergic ischemic area after acute myocardial infarction improves considerably in response to nitroglycerin within the first week, but fails to improve after 4-6 weeks, suggesting a time-dependent loss of reversible ischemia.
Absolute Event Rate: 27.2% vs 13.1%
p-value: p=<0.001
The natural history of contraction abnormalities and their response after acute myocardial infarction in man were studied using radionuclide angiography. Sixteen patients were studied before and after sublingual nitroglycerin within 24 hours, 5-7 days and 4-6 weeks after the onset of chest pain. Within 24 hours, central chord shortening in the zone of infarction was reduced to 13.1 +/- 9.8%, but improved 27.2 +/- 18.4% (p less than 0.001) after nitroglycerin. After 5-7 days, central chord shortening improved similarly, but less markedly, from 12.9 +/- 9.2% to 24.4 +/- 13.2% (p less than 0.001). After nitroglycerin 4--6 weeks after the acute myocardial infarction, the central chord showed no response to nitroglycerin; it was 13.9 +/- 10.9% before and 13.4 +/- 2.5% after nitroglycerin. Changes in the lateral chords paralleled changes in the central chords in the three studies. Nonischemic zone improvement after nitroglycerin in all three studies. Global ejection fraction improved and end-diastolic and end-systolic volumes decreased in all three studies after nitroglycerin. These data indicate that after acute myocardial infarction, there is a significant reduction in hemiaxis shortening in the central and lateral chords that remains essentially unchanged over 4-6 weeks. However, the asynergic ischemic area improves considerably after nitroglycerin within 24 hours and 5-7 days, but fails to improve after 6 weeks.
Ramanathan et al. (Wed,) conducted a observational in acute myocardial infarction (n=16). sublingual nitroglycerin vs. baseline (before nitroglycerin) was evaluated on central chord shortening in the zone of infarction at 24 hours (p=<0.001). Sublingual nitroglycerin significantly improved central chord shortening in the infarcted zone within 24 hours (from 13.1% to 27.2%, p<0.001) and at 5-7 days, but had no effect at 4-6 weeks.