Background: Left ventricular diastolic abnormalities are associated with adverse outcome in myocardial infarction. Intra-aortic balloon pump (IABP) support is associated with improved diastolic filling. In the SHOCK trial and registry, average left ventricular ejection fraction (LVEF) was approximately 30%, higher than expected based on the classic paradigm. We hypothesized that restrictive physiology plays a role in cardiogenic shock (CS).
Methods: Echocardiograms obtained during the SHOCK trial within 24 hours of randomization were centrally interpreted. Patients with quantifiable mitral E-wave deceleration time were included (n = 64). The restrictive filling pattern was defined as deceleration time < 140 milliseconds.
Results: The restrictive pattern was seen in 60.9% of patients studied. Patients with this pattern had lower LVEF (31.1% vs 39.0%, P = .02) and higher wall motion score index (2.1 vs 1.8, P = .05). Patients with restriction were more likely to have IABP support during echocardiography (73.7% vs 43.5%, P = .03). There was no difference with and without restriction in demographic and hemodynamic variables or in mitral regurgitation degree or extent of coronary disease. The restrictive pattern had positive predictive value of 80% for pulmonary capillary wedge pressure > or = 20 mm Hg. Thirty-day survival was 53.9% with restriction versus 68.0% without restriction, P = .31. There was no difference in New York Heart Association class at 1 year between groups.
Conclusions: The restrictive filling pattern is common in patients with CS, which may suggest that diastolic dysfunction contributes to CS pathogenesis. Patients with the restrictive pattern had lower LVEF despite IABP support. An association between the restrictive pattern and mortality was not demonstrated; power was limited by sample size.