Brian Halliday

Association between mid-wall late gadolinium enhancement and sudden cardiac death in patients with dilated cardiomyopathy and mild and moderate left ventricular systolic dysfunction

Background: Current guidelines only recommend the use of an implantable cardioverter defibrillator in patients with dilated cardiomyopathy for the primary prevention of sudden cardiac death (SCD) in those with a left ventricular ejection fraction (LVEF) <35%. However, registries of out-of-hospital cardiac arrests demonstrate that 70% to 80% of such patients have an LVEF >35%. Patients with an LVEF >35% also have low competing risks of death from nonsudden causes. Therefore, those at high risk of SCD may gain longevity from successful implantable cardioverter defibrillator therapy. We investigated whether late gadolinium enhancement (LGE) cardiovascular magnetic resonance identified patients with dilated cardiomyopathy without severe LV systolic dysfunction at high risk of SCD. Methods: We prospectively investigated the association between midwall LGE and the prespecified primary composite outcome of SCD or aborted SCD among consecutive referrals with dilated cardiomyopathy and an LVEF ≥40% to our center between January 2000 and December 2011 who did not have a preexisting indication for implantable cardioverter defibrillator implantation. Results: Of 399 patients (145 women, median age 50 years, median LVEF 50%, 25.3% with LGE) followed for a median of 4.6 years, 18 of 101 (17.8%) patients with LGE reached the prespecified end point, compared with 7 of 298 (2.3%) without (hazard ratio [HR], 9.2; 95% confidence interval [CI], 3.9–21.8; P<0.0001). Nine patients (8.9%) with LGE compared with 6 (2.0%) without (HR, 4.9; 95% CI, 1.8–13.5; P=0.002) died suddenly, whereas 10 patients (9.9%) with LGE compared with 1 patient (0.3%) without (HR, 34.8; 95% CI, 4.6–266.6; P<0.001) had aborted SCD. After adjustment, LGE predicted the composite end point (HR, 9.3; 95% CI, 3.9–22.3; P<0.0001), SCD (HR, 4.8; 95% CI, 1.7–13.8; P=0.003), and aborted SCD (HR, 35.9; 95% CI, 4.8–271.4; P<0.001). Estimated HRs for the primary end point for patients with an LGE extent of 0% to 2.5%, 2.5% to 5%, and >5% compared with those without LGE were 10.6 (95% CI, 3.9–29.4), 4.9 (95% CI, 1.3–18.9), and 11.8 (95% CI, 4.3–32.3), respectively. Conclusions: Midwall LGE identifies a group of patients with dilated cardiomyopathy and an LVEF ≥40% at increased risk of SCD and low risk of nonsudden death who may benefit from implantable cardioverter defibrillator implantation. Clinical Trial Registration: URL: http://clinicaltrials.gov. Unique identifier: NCT00930735.

Usefulness of periprocedural bleeding to predict outcome after transcatheter aortic valve implantation.

Bleeding is a known predictor of poor outcome after a number of cardiac interventions. We investigated whether using the new bleeding definition of the Valve Academic Research Consortium predicts a poor outcome after transcatheter aortic valve implantation. In addition, we sought to identify those patient characteristics that predict periprocedural bleeding and investigated the effect of blood transfusion. This was a retrospective study of 101 patients undergoing transapical or transfemoral transcatheter aortic valve implantation at Kings College Hospital from August 2007 to November 2010. The association among bleeding, blood transfusion, and in-hospital and 6-month mortality was examined. Of the 101 patients, 5 (4.9%) had life-threatening periprocedural bleeding related to vascular or apical complications, 17 (17%) had major bleeding, and 79 (78%) had minor or no bleeding. The in-hospital mortality rate for the cohort was 9.9% (n = 10) and the 6-month mortality rate was 18.8% (n = 19). Those patients with life-threatening bleeding and those who were transfused had significantly greater in-hospital mortality rates than the patients without life-threatening bleeding or transfusion (60.0% vs 7.3%, p <0.05; and 14.8% vs 4.3%, p <0.05, respectively). Life-threatening bleeding, a decrease in hemoglobin >5 g/dl, and a blood transfusion of >2 U were associated with increased mortality at 6 months. In a logistic regression model, coexisting vascular disease, diabetes, and preprocedural anemia significantly affected the incidence of life-threatening or major bleeding. In conclusion, consistent with many other cardiac interventions, life-threatening periprocedural bleeding after transcatheter aortic valve implantation is associated with poorer outcomes.

Personalizing Risk Stratification for Sudden Death in Dilated Cardiomyopathy: The Past, Present, and Future

Results from the DANISH Study (Danish Study to Assess the Efficacy of ICDs in Patients With Non-Ischemic Systolic Heat Failure on Mortality) suggest that for many patients with dilated cardiomyopathy (DCM), implantable cardioverter-defibrillators do not increase longevity. Accurate identification of patients who are more likely to die of an arrhythmia and less likely to die of other causes is required to ensure improvement in outcomes and wise use of resources. Until now, left ventricular ejection fraction has been used as a key criterion for selecting patients with DCM for an implantable cardioverter-defibrillator for primary prevention purposes. However, registry data suggest that many patients with DCM and an out-of-hospital cardiac arrest do not have a markedly reduced left ventricular ejection fraction. In addition, many patients with reduced left ventricular ejection fraction die of nonsudden causes of death. Methods to predict a higher or lower risk of sudden death include the detection of myocardial fibrosis (a substrate for ventricular arrhythmia), microvolt T-wave alternans (a marker of electrophysiological vulnerability), and genetic testing. Midwall fibrosis is identified by late gadolinium enhancement cardiovascular magnetic resonance imaging in ≈30% of patients and provides incremental value in addition to left ventricular ejection fraction for the prediction of sudden cardiac death events. Microvolt T-wave alternans represents another promising predictor, supported by large meta-analyses that have highlighted the negative predictive value of this test. However, neither of these strategies have been routinely adopted for risk stratification in clinical practice. More convincing data from randomized trials are required to inform the management of patients with these features. Understanding of the genetics of DCM and how specific mutations affect arrhythmic risk is also rapidly increasing. The finding of a mutation in lamin A/C, the cause of ≈6% of idiopathic DCM, commonly underpins more aggressive management because of the malignant nature of the associated phenotype. With the expansion of genetic sequencing, the identification of further high-risk mutations appears likely, leading to better-informed clinical decision making and providing insight into disease mechanisms. Over the next 5 to 10 years, we expect these techniques to be integrated into the existing algorithm to form a more sensitive, specific, and cost-effective approach to the selection of patients with DCM for implantable cardioverter-defibrillator implantation.Results from the DANISH Study (Danish Study to Assess the Efficacy of ICDs in Patients with Nonischemic Systolic Heat Failure on Mortality) suggest that, for many patients with dilated cardiomyopathy (DCM), implantable cardioverter defibrillators (ICD) do not increase longevity. Accurate identification of patients who are more likely to die of an arrhythmia and less likely to die from other causes is required to ensure improvement in outcomes and wise use of resources. Until now, left ventricular ejection fraction (LVEF) has been used as a key criterion for selecting patients with DCM for an ICD for primary prevention purposes. However, registry data suggest that many patients with DCM and an out-of-hospital cardiac arrest do not have a markedly reduced LVEF. Additionally, many patients with reduced LVEF die from non-sudden causes of death. Methods to predict a higher or lower risk of sudden death include the detection of myocardial fibrosis (a substrate for ventricular arrhythmia), microvolt T-wave alternans (MTWA; a marker of electrophysiological vulnerability) and genetic testing. Mid-wall fibrosis is identified by late gadolinium enhancement cardiovascular magnetic resonance imaging in around 30% of patients and provides incremental value in addition to LVEF for the prediction of SCD events. MTWA represents another promising predictor, supported by large meta-analyses that have highlighted the negative predictive value of this test. However, neither of these strategies has been routinely adopted for risk stratification in clinical practice. More convincing data from randomized trials are required to inform the management of patients with these features. Understanding of the genetics of DCM and how specific mutations affect arrhythmic risk is also rapidly increasing. The finding of a mutation in LMNA, the cause of around 6% of idiopathic DCM, commonly underpins more aggressive management due to the malignant nature of the associated phenotype. With the expansion of genetic sequencing, the identification of further high-risk mutations appears likely, leading to better informed clinical decision-making as well as providing insight into disease mechanisms. Over the next 5-10 years we expect these techniques to be integrated into the existing algorithm to form a more sensitive, specific and cost-effective approach to the selection of DCM patients for ICD implantation.

Personalizing sudden death risk stratification in dilated cardiomyopathy: past, present and future

Results from the DANISH Study (Danish Study to Assess the Efficacy of ICDs in Patients With Non-Ischemic Systolic Heat Failure on Mortality) suggest that for many patients with dilated cardiomyopathy (DCM), implantable cardioverter-defibrillators do not increase longevity. Accurate identification of patients who are more likely to die of an arrhythmia and less likely to die of other causes is required to ensure improvement in outcomes and wise use of resources. Until now, left ventricular ejection fraction has been used as a key criterion for selecting patients with DCM for an implantable cardioverter-defibrillator for primary prevention purposes. However, registry data suggest that many patients with DCM and an out-of-hospital cardiac arrest do not have a markedly reduced left ventricular ejection fraction. In addition, many patients with reduced left ventricular ejection fraction die of nonsudden causes of death. Methods to predict a higher or lower risk of sudden death include the detection of myocardial fibrosis (a substrate for ventricular arrhythmia), microvolt T-wave alternans (a marker of electrophysiological vulnerability), and genetic testing. Midwall fibrosis is identified by late gadolinium enhancement cardiovascular magnetic resonance imaging in ≈30% of patients and provides incremental value in addition to left ventricular ejection fraction for the prediction of sudden cardiac death events. Microvolt T-wave alternans represents another promising predictor, supported by large meta-analyses that have highlighted the negative predictive value of this test. However, neither of these strategies have been routinely adopted for risk stratification in clinical practice. More convincing data from randomized trials are required to inform the management of patients with these features. Understanding of the genetics of DCM and how specific mutations affect arrhythmic risk is also rapidly increasing. The finding of a mutation in lamin A/C, the cause of ≈6% of idiopathic DCM, commonly underpins more aggressive management because of the malignant nature of the associated phenotype. With the expansion of genetic sequencing, the identification of further high-risk mutations appears likely, leading to better-informed clinical decision making and providing insight into disease mechanisms. Over the next 5 to 10 years, we expect these techniques to be integrated into the existing algorithm to form a more sensitive, specific, and cost-effective approach to the selection of patients with DCM for implantable cardioverter-defibrillator implantation.Results from the DANISH Study (Danish Study to Assess the Efficacy of ICDs in Patients with Nonischemic Systolic Heat Failure on Mortality) suggest that, for many patients with dilated cardiomyopathy (DCM), implantable cardioverter defibrillators (ICD) do not increase longevity. Accurate identification of patients who are more likely to die of an arrhythmia and less likely to die from other causes is required to ensure improvement in outcomes and wise use of resources. Until now, left ventricular ejection fraction (LVEF) has been used as a key criterion for selecting patients with DCM for an ICD for primary prevention purposes. However, registry data suggest that many patients with DCM and an out-of-hospital cardiac arrest do not have a markedly reduced LVEF. Additionally, many patients with reduced LVEF die from non-sudden causes of death. Methods to predict a higher or lower risk of sudden death include the detection of myocardial fibrosis (a substrate for ventricular arrhythmia), microvolt T-wave alternans (MTWA; a marker of electrophysiological vulnerability) and genetic testing. Mid-wall fibrosis is identified by late gadolinium enhancement cardiovascular magnetic resonance imaging in around 30% of patients and provides incremental value in addition to LVEF for the prediction of SCD events. MTWA represents another promising predictor, supported by large meta-analyses that have highlighted the negative predictive value of this test. However, neither of these strategies has been routinely adopted for risk stratification in clinical practice. More convincing data from randomized trials are required to inform the management of patients with these features. Understanding of the genetics of DCM and how specific mutations affect arrhythmic risk is also rapidly increasing. The finding of a mutation in LMNA, the cause of around 6% of idiopathic DCM, commonly underpins more aggressive management due to the malignant nature of the associated phenotype. With the expansion of genetic sequencing, the identification of further high-risk mutations appears likely, leading to better informed clinical decision-making as well as providing insight into disease mechanisms. Over the next 5-10 years we expect these techniques to be integrated into the existing algorithm to form a more sensitive, specific and cost-effective approach to the selection of DCM patients for ICD implantation.

Phenotype and Clinical Outcomes of Titin Cardiomyopathy.

Background Improved understanding of dilated cardiomyopathy (DCM) due to titin truncation (TTNtv) may help guide patient stratification. Objectives The purpose of this study was to establish relationships among TTNtv genotype, cardiac phenotype, and outcomes in DCM. Methods In this prospective, observational cohort study, DCM patients underwent clinical evaluation, late gadolinium enhancement cardiovascular magnetic resonance, TTN sequencing, and adjudicated follow-up blinded to genotype for the primary composite endpoint of cardiovascular death, and major arrhythmic and major heart failure events. Results Of 716 subjects recruited (mean age 53.5 ± 14.3 years; 469 men [65.5%]; 577 [80.6%] New York Heart Association function class I/II), 83 (11.6%) had TTNtv. Patients with TTNtv were younger at enrollment (49.0 years vs. 54.1 years; p = 0.002) and had lower indexed left ventricular mass (5.1 g/m2 reduction; padjusted = 0.03) compared with patients without TTNtv. There was no difference in biventricular ejection fraction between TTNtv+/− groups. Overall, 78 of 604 patients (12.9%) met the primary endpoint (median follow-up 3.9 years; interquartile range: 2.0 to 5.8 years), including 9 of 71 patients with TTNtv (12.7%) and 69 of 533 (12.9%) without. There was no difference in the composite primary outcome of cardiovascular death, heart failure, or arrhythmic events, for patients with or without TTNtv (hazard ratio adjusted for primary endpoint: 0.92 [95% confidence interval: 0.45 to 1.87]; p = 0.82). Conclusions In this large, prospective, genotype-phenotype study of ambulatory DCM patients, we show that prognostic factors for all-cause DCM also predict outcome in TTNtv DCM, and that TTNtv DCM does not appear to be associated with worse medium-term prognosis.

Midwall Fibrosis and 5-Year Outcome in Moderate and Severe Aortic Stenosis

Aortic stenosis (AS) is characterized by progressive narrowing of the valve and the hypertrophic response of the left ventricle (LV) that ensues [(1)][1]. Although initially adaptive, the hypertrophic response ultimately decompensates and patients transition from hypertrophy to heart failure,

Sex- and age-based differences in the natural history and outcome of dilated cardiomyopathy.

To evaluate the relationship between sex, age and outcome in dilated cardiomyopathy (DCM).

Lipoprotein(a) in patients with aortic stenosis: Insights from cardiovascular magnetic resonance.

Background Aortic stenosis is the most common age-related valvular pathology. Patients with aortic stenosis and myocardial fibrosis have worse outcome but the underlying mechanism is unclear. Lipoprotein(a) is associated with adverse cardiovascular risk and is elevated in patients with aortic stenosis. Although mechanistic pathways could link Lipoprotein(a) with myocardial fibrosis, whether the two are related has not been previously explored. In this study, we investigated whether elevated Lipoprotein(a) was associated with the presence of myocardial replacement fibrosis. Methods A total of 110 patients with mild, moderate and severe aortic stenosis were assessed by late gadolinium enhancement (LGE) cardiovascular magnetic resonance to identify fibrosis. Mann Whitney U tests were used to assess for evidence of an association between Lp(a) and the presence or absence of myocardial fibrosis and aortic stenosis severity and compared to controls. Univariable and multivariable linear regression analysis were undertaken to identify possible predictors of Lp(a). Results Thirty-six patients (32.7%) had no LGE enhancement, 38 (34.6%) had midwall enhancement suggestive of midwall fibrosis and 36 (32.7%) patients had subendocardial myocardial fibrosis, typical of infarction. The aortic stenosis patients had higher Lp(a) values than controls, however, there was no significant difference between the Lp(a) level in mild, moderate or severe aortic stenosis. No association was observed between midwall or infarction pattern fibrosis and Lipoprotein(a), in the mild/moderate stenosis (p = 0.91) or severe stenosis patients (p = 0.42). Conclusion There is no evidence to suggest that higher Lipoprotein(a) leads to increased myocardial midwall or infarction pattern fibrosis in patients with aortic stenosis.

Selecting Patients With Nonischemic Dilated Cardiomyopathy for ICDs: Myocardial Function, Fibrosis, and What’s Attached?

T he benefit of implantable cardioverterdefibrillators (ICDs) in patients with nonischemic dilated cardiomyopathy (NIDCM) and heart failure (HF) with reduced left ventricular ejection fraction (LVEF) has been questioned following the DANISH (Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischemic Systolic Heart Failure on Mortality) trial (1). This landmark study of well-treated patients with NIDCM and symptomatic HF with reduced LVEF found no difference in all-cause mortality between patients who were randomized to receive an ICD and patients who were not. Notably, as well as high prescription rates of disease-modifying pharmacological therapy, 93% of patients with left bundle branch block and QRS complex duration of 150 ms or greater received a cardiac resynchronization (CRT) device (1). CRTpacemakers (CRT-P) reduce sudden cardiac death (SCD), possibly because CRT improves cardiac function, reduces neurohormonal activation, and prevents bradycardia-induced fatal arrhythmias (2). For patients with NIDCM, improvements in left ventricular function after CRT implantation are often substantial; it is unclear whether the CRT-defibrillator (CRT-D) provides incremental benefit to CRT-P in this setting.

Outcome in dilated cardiomyopathy related to the extent, location and pattern of late gadolinium enhancement

Objectives This study sought to investigate the association between the extent, location, and pattern of late gadolinium enhancement (LGE) and outcome in a large dilated cardiomyopathy (DCM) cohort. Background The relationship between LGE and prognosis in DCM is incompletely understood. Methods The authors examined the association between LGE and all-cause mortality and a sudden cardiac death (SCD) composite based on the extent, location, and pattern of LGE in DCM. Results Of 874 patients (588 men, median age 52 years) followed for a median of 4.9 years, 300 (34.3%) had nonischemic LGE. Estimated adjusted hazard ratios for patients with an LGE extent of 0 to 2.55%, 2.55% to 5.10%, and >5.10%, respectively, were 1.59 (95% confidence interval [CI]: 0.99 to 2.55), 1.56 (95% CI: 0.96 to 2.54), and 2.31 (95% CI: 1.50 to 3.55) for all-cause mortality, and 2.79 (95% CI: 1.42 to 5.49), 3.86 (95% CI: 2.09 to 7.13), and 4.87 (95% CI: 2.78 to 8.53) for the SCD endpoint. There was a marked nonlinear relationship between LGE extent and outcome such that even small amounts of LGE predicted a substantial increase in risk. The presence of septal LGE was associated with increased mortality, but SCD was most associated with the combined presence of septal and free-wall LGE. Predictive models using LGE presence and location were superior to models based on LGE extent or pattern. Conclusions In DCM, the presence of septal LGE is associated with a large increase in the risk of death and SCD events, even when the extent is small. SCD risk is greatest with concomitant septal and free-wall LGE. The incremental value of LGE extent beyond small amounts and LGE pattern is limited.