In primary MR patients, LV fibrosis is more prevalent in MVP than non-MVP, suggesting a unique pathophysiology beyond volume overload in MVP. LV fibrosis in primary MR may represent a risk marker of arrhythmic events.

Patients determined to have a normal SPECT on the basis of stress imaging alone have a similar mortality rate as those who have a normal SPECT on the basis of evaluation of both stress and rest images. Our results support that additional rest imaging is not required in patients who have a normally appearing initial stress study. A significant reduction in radiation exposure can be achieved with such an approach.

The CACS and SPECT findings are independent and complementary predictors of short- and long-term cardiac events. Despite a normal SPECT result, a severe CACS identifies subjects at high long-term cardiac risk. After a normal SPECT result, our findings support performing a CACS in patients who are at intermediate or high clinical risk for coronary artery disease to better define those who will have a high long-term risk for adverse cardiac events.

Background: Non-ischemic cardiomyopathy (NICM) is a leading cause of reduced left ventricular ejection fraction (LVEF) and is associated with high mortality risk from progressive heart failure and arrhythmias. Myocardial scar on cardiovascular magnetic resonance imaging (CMR) is increasingly recognized as risk marker for adverse outcomes, however LV dysfunction remains the basis for determining a patient's eligibility for primary prophylaxis implantable cardioverter-defibrillator (ICD). We wanted to investigate the relationship of LVEF and scar to long term mortality and mode of death in a large cohort of patients with NICM. Methods: This study is a prospective, longitudinal outcomes registry of 1020 consecutive patients with NICM who underwent clinical CMR for the assessment of LVEF and scar at three centers. Results: During a median follow-up of 5.2 (IQR 3.8, 6.6) years 277 (27%) patients died. On survival analysis LVEF≤35% and scar were strongly associated with all-cause (log-rank test p=0.002 and p<0.001, respectively) and cardiac death (p=0.001 and p<0.001, respectively). While scar was strongly related to sudden cardiac death (SCD) (p=0.001), there was no significant association between LVEF≤35% and SCD-risk (p=0.57). On multivariable analysis including established clinical factors, LVEF and scar are independent risk-markers of all-cause and cardiac death. The addition of LVEF provided incremental prognostic value albeit insignificant discrimination improvement by C-statistic for all-cause and cardiac death, however no incremental prognostic value for SCD. Conversely, scar extent demonstrated significant incremental prognostic value and discrimination improvement for all three endpoints. On net reclassification analysis, the addition of LVEF resulted in no significant improvement for all-cause death 11.0% (95% CI -6.2-25.9%), cardiac death 9.8% (95% CI -5.7-29.3%), and SCD 7.5% (95% CI -41.2-42.9%). Conversely, the addition of scar extent resulted in significant reclassification improvement of 25.5% (95% CI 11.7-41.0%) for all-cause death, 27.0% (95% CI 11.6-45.2%) for cardiac death, and 40.6% (95% CI 10.5-71.8%) for SCD. Conclusions: Myocardial scar and LVEF are both risk markers for all-cause and cardiac death in patients with NICM. However, while myocardial scar has strong and incremental prognostic value for SCD risk stratification, LVEF has no incremental prognostic value over clinical parameters. Scar assessment should be incorporated into patient selection criteria for primary prevention ICD placement.

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