Assessment of Myocardial Scarring Improves Risk Stratification in Patients Evaluated for Cardiac Defibrillator Implantation

Duke Cardiovascular Magnetic Resonance Center, Duke University Medical Center, Durham, NC 27710, USA.
Journal of the American College of Cardiology (Impact Factor: 15.34). 07/2012; 60(5):408-20. DOI: 10.1016/j.jacc.2012.02.070
Source: PubMed

ABSTRACT We tested whether an assessment of myocardial scarring by cardiac magnetic resonance imaging (MRI) would improve risk stratification in patients evaluated for implantable cardioverter-defibrillator (ICD) implantation.
Current sudden cardiac death risk stratification emphasizes left ventricular ejection fraction (LVEF); however, most patients suffering sudden cardiac death have a preserved LVEF, and many with poor LVEF do not benefit from ICD prophylaxis.
One hundred thirty-seven patients undergoing evaluation for possible ICD placement were prospectively enrolled and underwent cardiac MRI assessment of LVEF and scar. The pre-specified primary endpoint was death or appropriate ICD discharge for sustained ventricular tachyarrhythmia.
During a median follow-up of 24 months the primary endpoint occurred in 39 patients. Whereas the rate of adverse events steadily increased with decreasing LVEF, a sharp step-up was observed for scar size >5% of left ventricular mass (hazard ratio [HR]: 5.2; 95% confidence interval [CI]: 2.0 to 13.3). On multivariable Cox proportional hazards analysis, including LVEF and electrophysiological-study results, scar size (as a continuous variable or dichotomized at 5%) was an independent predictor of adverse outcome. Among patients with LVEF >30%, those with significant scarring (>5%) had higher risk than those with minimal or no (≤5%) scarring (HR: 6.3; 95% CI: 1.4 to 28.0). Those with LVEF >30% and significant scarring had risk similar to patients with LVEF ≤30% (p = 0.56). Among patients with LVEF ≤30%, those with significant scarring again had higher risk than those with minimal or no scarring (HR: 3.9; 95% CI: 1.2 to 13.1). Those with LVEF ≤30% and minimal scarring had risk similar to patients with LVEF >30% (p = 0.71).
Myocardial scarring detected by cardiac MRI is an independent predictor of adverse outcome in patients being considered for ICD placement. In patients with LVEF >30%, significant scarring (>5% LV) identifies a high-risk cohort similar in risk to those with LVEF ≤30%. Conversely, in patients with LVEF ≤30%, minimal or no scarring identifies a low-risk cohort similar to those with LVEF >30%.


Available from: Michele Parker, Dec 29, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Sudden cardiac death (SCD) is a leading cause of mortality in patients with cardiomyopathy. Although angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs) decrease cardiac mortality in these cohorts, their role in preventing SCD has not been well established. We sought to determine whether the use of ACEi or ARB in patients with cardiomyopathy is associated with a lower incidence of appropriate implantable cardiac defibrillator (ICD) shocks in the Genetic Risk Assessment of Defibrillator Events study that included subjects with an ejection fraction of ≤30% and ICDs. Treatment with ACEi/ARB versus no-ACEi/ARB was physician dependent. There were 1,509 patients (mean age [SD] 63 [12] years, 80% men, mean [SD] EF 21% [6%]) with 1,213 (80%) on ACEi/ARB and 296 (20%) not on ACEi/ARB. We identified 574 propensity-matched patients (287 in each group). After a mean (SD) of 2.5 (1.9) years, there were 334 (22%) appropriate shocks in the entire cohort. The use of ACEi/ARB was associated with lower incidence of shocks at 1, 3, and 5 years in the matched cohort (7.7%, 16.7%, and 18.5% vs 13.2%, 27.5%, and 32.0%; RR = 0.61 [0.43 to 0.86]; p = 0.005). Among patients with glomerular filtration rate (GFR) >60 and 30 to 60 ml/min/1.73 m(2), those on no-ACEi/ARB were at 45% and 77% increased risk of ICD shock compared with those on ACEi/ARB, respectively. ACEi/ARB were associated with significant lower incidence of appropriate ICD shock in patients with cardiomyopathy and GFR ≥30 ml/min/1.73 m(2) and with neutral effect in those with GFR <30 ml/min/1.73 m(2). Copyright © 2015 Elsevier Inc. All rights reserved.
    The American Journal of Cardiology 01/2015; DOI:10.1016/j.amjcard.2015.01.020 · 3.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Chronic heart failure is a major public-health problem with a high prevalence, complex treatment, and high mortality. A careful and comprehensive analysis is needed to provide optimal (and personalized) therapy to heart failure patients. The main 4 non-invasive imaging techniques (echocardiography, magnetic resonance imaging, multi-detector-computed tomography, and nuclear imaging) provide information on cardiovascular anatomy and function, which form the basis of the assessment of the pathophysiology underlying heart failure. The selection of imaging modalities depends on the information that is needed for the clinical management of the patients: (1) underlying etiology (ischemic vs non-ischemic); (2) in ischemic patients, need for revascularization should be evaluated (myocardial ischemia/viability?); (3) left ventricular function and shape assessment; (4) presence of significant secondary mitral regurgitation; (5) device therapy with cardiac resynchronization therapy and/or implantable cardiac defibrillator (risk of sudden cardiac death). This review is dedicated to assessment of myocardial viability, however "isolated assessment of myocardial viability" may be clinically not meaningful and should be considered among all those different variables. This complete information will enable personalized treatment of the patient with ischemic heart failure.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Sudden death accounts for 300,000-400,000 deaths annually in the United States. Most sudden deaths are cardiac, and most sudden cardiac deaths are related to arrhythmias secondary to structural heart disease or primary electrical abnormalities of the heart. The most common structural disease leading to sudden death is ischemic heart disease. Nonischemic cardiomyopathy and other structural abnormalities such as arrhythmogenic ventricular dysplasia and hypertrophic cardiomyopathy may also be causative. Patients without structural disease have a primary electrical abnormality, such as long-QT syndrome or Brugada syndrome. Severe left ventricular systolic dysfunction is the main marker for sudden death in patients with ischemic or nonischemic cardiomyopathy. In other conditions, other markers for structural heart disease and electrical abnormalities need to be considered. It is seen that β-blocker therapy is associated with a reduction in sudden cardiac death across a broad range of disorders. Nevertheless, the implantable cardioverter defibrillator remains the most effective treatment strategy in selected patients. Copyright © 2015 Elsevier Inc. All rights reserved.
    Current Problems in Cardiology 02/2015; 40(4). DOI:10.1016/j.cpcardiol.2015.01.002 · 2.17 Impact Factor