Comparison of distinctive clinical and cardiac magnetic resonance features between ST elevation myocardial infarction patients with incomplete myocardial rupture and those with moderate to severe pericardial effusion.

Background: Whether patients with incomplete myocardial rupture (IMR) present distinctive clinical and cardiac magnetic resonance features from those with moderate-severe pericardial effusion (⩾10 mm (PE)) remains unknown.
Methods: We compared the clinical, angiographic and cardiac magnetic resonance characteristics of nine patients with IMR (diagnosed angiographically and/or by cardiac magnetic resonance) with 29 with PE, and also with 38 without IMR or PE with evidence of transmural necrosis (reference group) matched for age, gender and year of admission.
Results: Patients with IMR were younger than those with PE ( p <0.001) but the two groups shared a higher rate of admission delay (78% and 41%) than those without IMR/PE (5%, p <0.001) and lower frequency of reperfusion therapy (44%, 55% and 100%, respectively, p <0.001). Thirteen patients with PE (45%) but only one IMR (11%) presented recurrent chest pain. IMR patients tended to present smaller infarct size at cardiac magnetic resonance ( p =0.153 and 0.036) and number of segments with ⩾75% necrosis than PE patients and those without IMR/PE ( p =0.098 and 0.029, respectively). Ten PE patients presented cardiac tamponade (35%). A control 2D-echocardiogram performed within two years in 71 patients (93%) documented a pseudoaneurysm in one PE and in one IMR patient.
Conclusions: IMR is generally silent and occurs in younger patients with smaller infarct size than those with PE although both present late and are often untreated with reperfusion therapy. These findings may warrant imaging assessment in ST elevation myocardial infarction patients with delayed admission, particularly in absence of reperfusion, to rule out an IMR.