Abstract
Background
The occurrence of in-hospital heart failure in the acute phase of myocardial infarction carries an ominous prognosis and is often preceded by abrupt loss of functioning myocardium. However ,In hospital heart failure may occur in patients with apparently only minor myocardial injury and preserved or only moderately reduced left ventricular ejection fraction and still carries a significantly increased risk of adverse outcome. In patients with clinical symptoms of heart failure despite preserved left ventricular ejection fraction(heart failure with preserved ejection fraction), abnormalities in longitudinal myocardial mechanics have been reported suggesting that the discrepancy between near normal left ventricular ejection fraction and clinical symptoms may be partially explained by theses indices.
Purpose
Evaluation of the role of global longitudinal strain in prediction of the occurrence of in hospital heart failure in patients presenting with acute myocardial infarction particularly in patients with normal ,or moderately impaired ejection fraction.
Methods
forty patients with first attack of acute myocardial infarction were ranked according to killip class during their hospital admission and course. The patients were divided into two groups: Group 1: patients having in-hospital heart failure (killip class > 1).Group2: Patients not having in–hospital heart failure (killip class = 1). Echocardiogaraphic examination was done for them including global longitudinal strain within 72 hours after successful reperfusion .Comparison of different echocardiographic parameters between the two groups was done. Patients with mildly impaired ejection fraction (Ejection fraction > 40%) were studied for echocardiographic parameters correlated significantly with the occurrence of in-hospital heart failure .
Results
Patients with in-hospital heart failure had significantly impaired global longitudinal strain(-8.63%+1.57% vs -12.41%+1.31%, p = 0.000), lower left ventricular ejection fraction (34.17%+8.17% vs 42.92 %+7.98%,p < 0.001) and higher wall motion score index (1.57 + 0.32 vs 1.31 +0.24 ,p < 0.006). In patients with left ventricular ejection fraction >40% experienced in-hospital heart failure also exhibited significantly impaired global longitudinal strain p= 0.035 .
Conclusion
Global longitudinal strain can offer accurate, feasible, and non invasive predictor of hemodynamic deterioration in patients with myocardial infarction. Global longitudinal strain was superior to left ventricular ejection fraction , wall motion score index in evaluation of myocardial dysfunction specially in those with preserved left ventricular ejection fraction(EF > 40%).Global longitudinal strain was also superior to left ventricular ejection fraction , wall motion score index in detection of patients with Killip class II ( those without overt heart failure ,and who can be easily missed).
The utility of global longitudinal strain in the identification of prior myocardial infarction in patients with preserved left ventricular ejection fraction
