Value of cardiac MRI to evaluate ischemia-related ventricular arrhythmia substrates

Abstract

During the course of and after a myocardial ischemia-reperfusion insult, ventricular arrhythmia (VA) may have several single or overlapping potential substrates. Some of these may not be associated with morphological and functional changes, whereas others may have individual susceptibility. Nevertheless, cardiac magnetic resonance currently offers a comprehensive and highly effective toolset for the evaluation of a risk of VA on a patient basis after a myocardial infarction. Indeed, cardiac magnetic resonance has established itself as a reference for the evaluation of the myocardial function and properties, using respectively, cine and tissue characterization imaging to detect and evaluate the extent of acute myocardial injuries, scars and remodeling. This article describes and discusses imaging strategies used to evaluate the substrates for VA in the setting of a myocardial infarction.

Keywords:

• cardiac magnetic resonance
• ischemia
• myocardial infarction
• ventricular arrhythmia
• ventricular tachycardia

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Ventricular arrhythmia is the first cause of sudden death in the ischemic context.

• Several single or overlapping potential ischemic substrates can be responsible for malignant ventricular arrhythmia.

• Cardiac magnetic resonance (CMR) is established as the reference tool for the evaluation of myocardial injuries at all stages after myocardial infarction (MI).

• Using delayed-enhancement CMR imaging and tissue characterization sequences, distinct patterns of acute or chronic myocardial injury can be identified.

• After MI, CMR allows accurate evaluation of left ventricular function and size, the presence and extent of myocardial structural changes because of ischemic insult.

• CMR substrates of ventricular arrhythmia after MI include myocardial edema, hemorrhage, scar, fatty metaplasia and microvascular damage.

• On late gadolinium-enhanced CMR, total scar and grey zone seem to be the strongest predictors of ventricular tachycardia inductibility and outcome.

• Lipomatous metaplasia is a common finding after MI, easily detectable on CMR, for which the role in myocardial electrical instability has received only little attention so far.

Notes