Associations between scar characteristics by cardiac magnetic resonance and changes in left ventricular ejection fraction in primary prevention defibrillator recipients

Abstract

BACKGROUND Left ventricular ejection fraction (LVEF) improves over time in 25%–40% of cardiomyopathy patients with primary prevention implantable cardioverter-defibrillators (ICD). The determinants of LVEF improvement, however, are not well characterized. OBJECTIVES We sought to examine the associations of clinical risk factors and cardiac imaging markers with changes in LVEF following ICD implantation. METHODS We conducted a retrospective analysis of cardiac magnetic resonance (CMR) images in 202 patients who underwent primary prevention ICD implantation to quantify the amount of heterogeneous myocardial tissue (gray zone [GZ]), dense core and total scar. LVEF was reassessed at least once after ICD implantation. RESULTS Over a mean follow-up of 3 years, LVEF decreased in 21.3%, improved in 43.6%, and was unchanged in 35.1% of the patients. Baseline LVEF and myocardial scar characteristics were the strongest determinants of LVEF trajectory with high scar burden and increasing lack of myocardial viability associated with a greater decline in LVEF. There was a trend toward an association between both changes in LVEF and scar extent with subsequent appropriate ICD shock. Changes in LVEF were also strongly associated with heart failure (HF) hospitalizations. CONCLUSIONS Scar burden and characteristics were strong determinants, independent of baseline LVEF and other traditional cardiovascular risk factors, of changes in LVEF. Both worsened LVEF and high scar extent were associated with a trend toward increased risk of appropriate shock. These findings suggest that baseline CMR imaging of the myocardial substrate may provide important prognostic information regarding subsequent LV remodeling and adverse events.

Relationship between Extension or Texture Features of Late Gadolinium Enhancement and Ventricular Tachyarrhythmias in Hypertrophic Cardiomyopathy

“…Previous studies show that intermediate-signal-intensity LGE (i.e., gray zone) or inhomogeneous LGE, probably reflecting the mixture of fibrosis and normal myocardium, is significantly related to serious ventricular arrhythmia associated with ischemic cardiomyopathy and HCM [ 9 , 22 ]. By contrast, Zhang et al [ 23 ] have indicated that the clinical significance of gray zone and LGE burden may differ between ischemic and nonischemic cardiomyopathies. Fukushima et al [ 24 ] have shown that scarred apical aneurysm can induce ventricular tachyarrhythmias in patients with HCM.…”

Updating the Risk Stratification for Sudden Cardiac Death in Cardiomyopathies: The Evolving Role of Cardiac Magnetic Resonance Imaging. An Approach for the Electrophysiologist

“…Focal myocardial fibrosis detected by LGE imaging substantially increases the risk for life threatening arrhythmias in ICM [32][33][34]72]. Histologically, a myocardial scar is not always a uniform lesion.…”

“…Cardiac magnetic resonance (CMR) is a highly effective imaging modality for the characterization of myocardial tissue as well as for the anatomical and the functional evaluation of the heart [23]. Several CMR findings are associated with arrhythmogenic substrates in CMs, with the late gadolinium enhancement (LGE) quantification and distribution pattern being the most well established [24][25][26][27][28][29][30][31][32][33][34]. The addition of CMR in the field of risk stratification for SCD of the CM patients is promising.…”

Uses and potential for cardiac magnetic resonance imaging in patients with cardiac resynchronisation pacemakers

“…Advanced predictive modelling would show the expected outcome not only with CRT therapies active but also with other device parameters. Ideal device settings could be generated which may evolve with the pa I to accurately predict degradation in ventricular function and hospitalisation as evidenced in patients with ICDs [32].…”