Background Non-traumatic out of hospital cardiac arrest (OHCA) is the leading cause of death in Europe and USA. Acute coronary syndromes represent the most common aetiology and in 2/3 of patients a culprit lesion can be identified on angiogram. Among patients with unobstructed coronaries, the differential diagnosis remains unclear. Cardiovascular Magnetic Resonance (CMR), with its superior tissue characterisation, can establish differential diagnosis over and above echocardiography.
Methods This retrospective observational study was performed in two tertiary centres on consecutive patients surviving OHCA referred for CMR (October 2009–January 2015). Coronary angiography and echocardiography were performed as part of the diagnostic work-up. A comprehensive CMR protocol (cine, late gadolinium enhancement, T2 weighted STIR imaging or adenosine perfusion) was performed within 6 weeks from index event.
Results We identified 140 patients (109 male, age 56.1 ± 15.7 years) surviving OHCA. 134 patients underwent coronary angiography, with evidence of coronary artery disease (CAD) in 71 (53%). Sixty-three (47%) showed unobstructed coronaries. Among patients with CAD, sixty (85%) had ischaemic cardiomyopathy on CMR. Among patients with unobstructed coronaries, CMR identified a normal scan in 17 (27%), ischaemic cardiomyopathy in 9 (14%), non-ischaemic cardiomyopathy in 27 (43%) (Figure 1), and non-specific findings in 10 (16%). Different underlying cardiomyopathies have been identified by CMR among patients with non-ischaemic cardiomyopathy, as shown in Table 1. Overall, the diagnostic pick-up rate of CMR was 91%.
Conclusion Cardiac MRI identified the underlying diagnosis in the large majority of patients, particularly in those with unobstructed coronaries (pick-up rate 84%), leading to a change in management in all. CMR has therefore a promising role in the clinical work-up of patients surviving OHCA.