Fahad Almehmadi

Prevalence of Myocardial Fibrosis Patterns in Patients With Systolic Dysfunction Prognostic Significance for the Prediction of Sudden Cardiac Arrest or Appropriate Implantable Cardiac Defibrillator Therapy

Background—Late gadolinium enhancement-cardiac magnetic resonance is increasingly performed in patients with systolic dysfunction. Numerous patterns of fibrosis are commonly reported among this population. However, the relative prevalence and prognostic significance of these findings remains uncertain. Methods and Results—Three hundred eighteen consecutive patients referred for late gadolinium enhancement-cardiac magnetic resonance and a left ventricular ejection fraction <55% were followed up for the primary end point of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy. Late gadolinium enhancement images were blindly interpreted for the presence of 6 distinct pattern(s) of myocardial fibrosis in addition to signal threshold-based quantification of total fibrosis volume. The mean age and left ventricular ejection fraction of participants were 62.0±12.9 years and 32.6±11.9%, respectively. Any pattern of myocardial fibrosis was seen in 248 patients (78%) with ≥2 patterns present in 25% of patients. During follow-up (median of 467 days), 49 patients (15%) had a primary outcome. After adjustment for left ventricular ejection fraction, cardiomyopathy pathogenesis, and total fibrosis volume, the presence of a midwall striae pattern of fibrosis was an independent predictor of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy with a hazard ratio of 2.4 (95% confidence interval, 1.2–4.6; P=0.01); this finding is present in 30% of patients with nonischemic and 15% of patients with ischemic cardiomyopathy. Cumulative event rate was significantly higher among those with midwall striae, particularly among those with a left ventricular ejection fraction >35% (40% versus 6%; P=0.005). Conclusions—Patients with systolic dysfunction frequently demonstrate multiple patterns of myocardial fibrosis. Of these, a midwall striae pattern of fibrosis is the strongest independent predictor of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy.Background— Late gadolinium enhancement-cardiac magnetic resonance is increasingly performed in patients with systolic dysfunction. Numerous patterns of fibrosis are commonly reported among this population. However, the relative prevalence and prognostic significance of these findings remains uncertain. Methods and Results— Three hundred eighteen consecutive patients referred for late gadolinium enhancement-cardiac magnetic resonance and a left ventricular ejection fraction 35% (40% versus 6%; P =0.005). Conclusions— Patients with systolic dysfunction frequently demonstrate multiple patterns of myocardial fibrosis. Of these, a midwall striae pattern of fibrosis is the strongest independent predictor of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy.

Right Ventricular Ejection Fraction Is Incremental to Left Ventricular Ejection Fraction for the Prediction of Future Arrhythmic Events in Patients With Systolic Dysfunction

Background— Left ventricular ejection fraction remains the primary risk stratification tool used in the selection of patients for implantable cardioverter defibrillator therapy. However, this solitary marker fails to identify a substantial portion of patients experiencing sudden cardiac arrest. In this study, we examined the incremental value of considering right ventricular ejection fraction for the prediction of future arrhythmic events in patients with systolic dysfunction using the gold standard of cardiovascular magnetic resonance. Methods and Results— Three hundred fourteen consecutive patients with ischemic cardiomyopathy or nonischemic dilated cardiomyopathy undergoing cardiovascular magnetic resonance were followed for the primary outcome of sudden cardiac arrest or appropriate implantable cardioverter defibrillator therapy. Blinded quantification of left ventricular and right ventricular (RV) volumes was performed from standard cine imaging. Quantification of fibrosis from late gadolinium enhancement imaging was incrementally performed. RV dysfunction was defined as right ventricular ejection fraction ⩽45%. Among all patients (164 ischemic cardiomyopathy, 150 nonischemic dilated cardiomyopathy), the mean left ventricular ejection fraction was 32±12% (range, 6–54%) with mean right ventricular ejection fraction of 48±15% (range, 7–78%). At a median of 773 days, 49 patients (15.6%) experienced the primary outcome (9 sudden cardiac arrest, 40 appropriate implantable cardioverter defibrillator therapies). RV dysfunction was independently predictive of the primary outcome (hazard ratio=2.98; P=0.002). Among those with a left ventricular ejection fraction >35% (N=121; mean left ventricular ejection fraction, 45±6%), RV dysfunction provided an adjusted hazard ratio of 4.2 (P=0.02). Conclusions— RV dysfunction is a strong, independent predictor of arrhythmic events. Among patients with mild to moderate LV dysfunction, a cohort greatly contributing to global sudden cardiac arrest burden, this marker provides robust discrimination of high- versus low-risk subjects.

Should Single-Coil Implantable Cardioverter Defibrillator Leads Be Used in all Patients?

The historical preference for dual-coil implantable cardioverter defibrillator leads stems from high defibrillation thresholds associated with old device platforms. The high safety margins generated by contemporary devices have rendered the modest difference in defibrillation efficacy between single- and dual-coil leads clinically insignificant. Cohort data demonstrating worse lead extraction outcomes and higher all-cause mortality have brought the incremental utility of an superior vena cava coil into question. This article summarizes the current literature and re-evaluates the utility of dual-coil leads in the context of modern device technology.

Cardiac resynchronization is pro-arrhythmic in the absence of reverse ventricular remodelling: a systematic review and meta-analysis

Aims Cardiac resynchronization therapy (CRT) has been shown to reduce mortality and heart failure (HF) hospitalization but its effects on the rate of ventricular arrhythmias (VAs) appears to be neutral. We hypothesize that CRT with LV epicardial stimulation is inherently pro-arrhythmic and increases VA rates in the absence of reverse ventricular remodelling while conferring an anti-arrhythmic effect in mechanical responders. Methods and results In this systematic review and meta-analysis, we considered retrospective cohort, prospective cohort, and randomized controlled trials comparing VA rates between cardiac resynchronization therapy-defibrillator (CRT-D) non-responders, CRT-D responders and those with implantable cardioverter-defibrillator (ICD) only. Studies were eligible if they defined CRT-D responders using a discrete left ventricular volumetric value as assessed by any imaging modality. Studies were identified through searching electronic databases from their inception to July 2017. We identified 2579 citations, of which 23 full-text articles were eligible for final analysis. Our results demonstrated that CRT-D responders were less likely to experience VA than CRT-D non-responders, relative risk (RR) 0.49 [95% confidence interval (CI) 0.41-0.58, P < 0.01] and also less than patients with ICD only: RR 0.59 (95% CI 0.50-0.69, P < 0.01). However, CRT-D mechanical non-responders had a greater likelihood of VA compared with ICD only, RR 0.76 (95% CI 0.63-0.92, P = 0.004). Conclusion CRT-D non-responders experienced more VA than CRT-D responders and also more than those with ICD only, suggesting that CRT with LV epicardial stimulation may be inherently pro-arrhythmic in the absence of reverse remodelling.

Prevalence of Myocardial Fibrosis Patterns in Patients With Systolic DysfunctionCLINICAL PERSPECTIVE

Background—Late gadolinium enhancement-cardiac magnetic resonance is increasingly performed in patients with systolic dysfunction. Numerous patterns of fibrosis are commonly reported among this population. However, the relative prevalence and prognostic significance of these findings remains uncertain. Methods and Results—Three hundred eighteen consecutive patients referred for late gadolinium enhancement-cardiac magnetic resonance and a left ventricular ejection fraction <55% were followed up for the primary end point of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy. Late gadolinium enhancement images were blindly interpreted for the presence of 6 distinct pattern(s) of myocardial fibrosis in addition to signal threshold-based quantification of total fibrosis volume. The mean age and left ventricular ejection fraction of participants were 62.0±12.9 years and 32.6±11.9%, respectively. Any pattern of myocardial fibrosis was seen in 248 patients (78%) with ≥2 patterns present in 25% of patients. During follow-up (median of 467 days), 49 patients (15%) had a primary outcome. After adjustment for left ventricular ejection fraction, cardiomyopathy pathogenesis, and total fibrosis volume, the presence of a midwall striae pattern of fibrosis was an independent predictor of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy with a hazard ratio of 2.4 (95% confidence interval, 1.2–4.6; P=0.01); this finding is present in 30% of patients with nonischemic and 15% of patients with ischemic cardiomyopathy. Cumulative event rate was significantly higher among those with midwall striae, particularly among those with a left ventricular ejection fraction >35% (40% versus 6%; P=0.005). Conclusions—Patients with systolic dysfunction frequently demonstrate multiple patterns of myocardial fibrosis. Of these, a midwall striae pattern of fibrosis is the strongest independent predictor of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy.Background— Late gadolinium enhancement-cardiac magnetic resonance is increasingly performed in patients with systolic dysfunction. Numerous patterns of fibrosis are commonly reported among this population. However, the relative prevalence and prognostic significance of these findings remains uncertain. Methods and Results— Three hundred eighteen consecutive patients referred for late gadolinium enhancement-cardiac magnetic resonance and a left ventricular ejection fraction 35% (40% versus 6%; P =0.005). Conclusions— Patients with systolic dysfunction frequently demonstrate multiple patterns of myocardial fibrosis. Of these, a midwall striae pattern of fibrosis is the strongest independent predictor of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy.

Prevalence of Myocardial Fibrosis Patterns in Patients With Systolic DysfunctionCLINICAL PERSPECTIVE: Prognostic Significance for the Prediction of Sudden Cardiac Arrest or Appropriate Implantable Cardiac Defibrillator Therapy

Background—Late gadolinium enhancement-cardiac magnetic resonance is increasingly performed in patients with systolic dysfunction. Numerous patterns of fibrosis are commonly reported among this population. However, the relative prevalence and prognostic significance of these findings remains uncertain. Methods and Results—Three hundred eighteen consecutive patients referred for late gadolinium enhancement-cardiac magnetic resonance and a left ventricular ejection fraction <55% were followed up for the primary end point of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy. Late gadolinium enhancement images were blindly interpreted for the presence of 6 distinct pattern(s) of myocardial fibrosis in addition to signal threshold-based quantification of total fibrosis volume. The mean age and left ventricular ejection fraction of participants were 62.0±12.9 years and 32.6±11.9%, respectively. Any pattern of myocardial fibrosis was seen in 248 patients (78%) with ≥2 patterns present in 25% of patients. During follow-up (median of 467 days), 49 patients (15%) had a primary outcome. After adjustment for left ventricular ejection fraction, cardiomyopathy pathogenesis, and total fibrosis volume, the presence of a midwall striae pattern of fibrosis was an independent predictor of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy with a hazard ratio of 2.4 (95% confidence interval, 1.2–4.6; P=0.01); this finding is present in 30% of patients with nonischemic and 15% of patients with ischemic cardiomyopathy. Cumulative event rate was significantly higher among those with midwall striae, particularly among those with a left ventricular ejection fraction >35% (40% versus 6%; P=0.005). Conclusions—Patients with systolic dysfunction frequently demonstrate multiple patterns of myocardial fibrosis. Of these, a midwall striae pattern of fibrosis is the strongest independent predictor of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy.Background— Late gadolinium enhancement-cardiac magnetic resonance is increasingly performed in patients with systolic dysfunction. Numerous patterns of fibrosis are commonly reported among this population. However, the relative prevalence and prognostic significance of these findings remains uncertain. Methods and Results— Three hundred eighteen consecutive patients referred for late gadolinium enhancement-cardiac magnetic resonance and a left ventricular ejection fraction 35% (40% versus 6%; P =0.005). Conclusions— Patients with systolic dysfunction frequently demonstrate multiple patterns of myocardial fibrosis. Of these, a midwall striae pattern of fibrosis is the strongest independent predictor of sudden cardiac arrest or appropriate implantable cardiac defibrillator therapy.