Cardiac rupture in acute myocardial infarction: a cardiac magnetic resonance study

Aims: We assessed the feasibility of cardiac magnetic resonance (CMR) and the role of myocardial strain in the diagnostic work-up of patients with acute myocardial infarction (AMI) and a clinical suspicion of cardiac rupture (CR).

Methods and results: Consecutive patients with AMI complicated by CR who underwent CMR were enrolled. Traditional and strain CMR findings were evaluated; new parameters indicating the relative wall stress between AMI and adjacent segments, named wall stress index (WSI) and WSI ratio, were analysed. A group of patients admitted for AMI without CR served as control. 19 patients (63% male, median age 73 years) met the inclusion criteria. Microvascular obstruction (MVO, P = 0.001) and pericardial enhancement (P < 0.001) were strongly associated with CR. Patients with clinical CR confirmed by CMR exhibited more frequently an intramyocardial haemorrhage than controls (P = 0.003). Patients with CR had lower 2D and 3D global radial strain (GRS) and global circumferential strain (in 2D mode P < 0.001; in 3D mode P = 0.001), as well as 3D global longitudinal strain (P < 0.001), than controls. The 2D circumferential WSI (P = 0.010), as well as the 2D and 3D circumferential (respectively, P < 0.001 and P = 0.042) and radial WSI ratio (respectively, P < 0.001 and P: 0.007), were higher in CR patients than controls.

Conclusion: CMR is a safe and useful imaging tool to achieve the definite diagnosis of CR and an accurate visualization of tissue abnormalities associated with CR. Strain analysis parameters can give insights into the pathophysiology of CR and may help to identify those patients with sub-acute CR.