Abstract 10608: Cardiac MRI and Follow-Up of AICD and Pacemaker Events to Identify the Etiology and Natural History of Sudden Cardiac Arrest and Heart Blocks
Background: In patients with sudden cardiac arrest (SCA) and heart blocks, cardiac MRI (CMR) can be useful to evaluate ischemic, inflammatory, infiltrative and degenerative processes. Correlation of initial CMR findings with events recorded by automatic implantable cardiac defibrillator (AICD) or permanent pacemakers (PPM) can characterize the natural history of these life-threatening cardiac conditions.
Methods: We examined CMR studies of 161 patients with SCA, heart blocks or bundle-branch blocks with clinical symptoms (dyspnea, syncope or palpitations). In all patients, initial work-up was non-revealing for potential etiology, and CMR with late gadolinium enhancement (LGE) was performed. Most of these patients then underwent clinically indicated AICD or PPM placement. The interrogated AICD and PPM events were followed up for 1-4 years to monitor significant arrhythmias or long-term pacemaker dependence.
Results: Of the 83 patients resuscitated from SCA, CMR identified a possible substrate in 41%. In patients with heart blocks, CMR identified myocardial infiltrative processes in 44%. In patients with symptomatic LBBB/RBBB, CMR identified a plausible etiology in approximately 25%. Presence of myocardial LGE by CMR had 90% sensitivity and 80% NPV for long-term pacemaker dependence in patients with heart block; whereas presence of other major diagnostic findings in CMR in SCA patients had 67% sensitivity for significant AICD-events.
Conclusions: Beyond standard diagnostic algorithm, CMR can identify potential cause of SCA and heart blocks in over 40% of the patients. Presence of LGE or other major diagnostic findings on CMR can identify patients with long-term pacemaker dependence or significant AICD events.
- © 2013 by American Heart Association, Inc.