PracticeUpdate: Cardiology

MYOCARDIAL DISEASE

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Outcomes after catheter ablation of ventricular tachycardia in nonischaemic dilated cardiomyopathy Comment by Marmar Vaseghi MD, PhD O utcomes of patients with non-ischaemic cardiomyopathy undergoing ventricular tachycardia (VT) ablation are generally reported to be worse than those of ischaemic

Long-term outcome after catheter ablation of ventricular tachycardia in patients with nonischemic dilated cardiomyopathy Circulation: Arrhythmia and Electrophysiology Take-home message • This study (282 participants) evaluated the long- term outcomes after catheter ablation of ventricular tachycardia (VT) in patients with nonischemic dilated cardiomyopathy. At 60-month follow-up, 69% of patients were VT-free and 76% had achieved transplant-free survival. The researchers also noted a reduction in VT burden even in patients who experienced a recurrence, with most patients receiving only medication therapy including beta blockers or no treatment (45%), class I antiarrhythmics (15%), or amiodarone (22%). • The researchers concluded that catheter ablation which provides either freedom from VT or significantly reduced VT burden, is an effective treatment for VT in patients with nonischemic dilated cardiomyopathy. Abstract BACKGROUND Catheter ablation (CA) of ventricular tachycardia (VT) in patients with nonischemic dilated cardiomyopathy can be chal- lenging because of the complexity of underlying substrates. We sought to determine the long-term outcomes of endocardial and adjuvant epicardial CA in nonischemic dilated cardiomyopathy. METHODS AND RESULTS We examined 282 consecutive patients (aged 59±15 years, 80% males) with nonischemic dilated cardiomyopathy who underwent CA. Ablation was guided by activation/entrainment mapping for tolerated VT and pacemapping/targeting of abnormal electrograms for unmappable VT. Adjuvant epicardial ablation was performed for recurrent VT or persistent inducibility after endocardial- only ablation. Epicardial ablation was performed in 90 (32%) patients. Before ablation, patients failed a median of 2 antiarrhythmic drugs), including amiodarone, in 166 (59%) patients. The median follow-up after the last procedure was 48 (19–67) months. Overall, VT-free survival was 69% at 60-month follow-up. Transplant-free survival was 76% and 68% at 60- and 120-month follow-up, respectively. Among the 58 (21%) patients with VT recurrence, CA still resulted in a significant reduction of VT burden, with 31 (53%) patients having only isolated (1–3) VT episodes in 12 (4–35) months after the procedure. At the last follow-up, 128 (45%) patients were only on β-blockers or no treatment, 41 (15%) were on sotalol or class I antiarrhythmic drugs, and 62 (22%) were on amiodarone. CONCLUSIONS In patients with nonischemic dilated cardio- myopathy and VT, endocardial and adjuvant epicardial CA is effective in achieving long-term VT freedom in 69% of cases, with a substantial improvement in VT burden in many of the remaining patients. Circ Arrhythm Electrophysiol 2016 Oct 01;9:e004328, Muser D, Santangeli P, Castro SA, et al.

Comment by Roderick Tung MD A s the field of scar-related VT ablation continues to grow, the nonischaemic cardiomyopathy (NICM) represents a large proportion of patients referred for advanced therapies. However, these patients, where aetiology is often presumed or incompletely understood, present a major challenge as ablation targets are not predictable as they are with postinfarct scar. Patients with NICM frequently have mixed or heterogeneous scar with variable locations and nontransmural patterns with a propensity toward epicardial or midmyocardial involvement. Although several centres have shown that ablation outcomes in NICM are inferior to ICM, the study by Muser et al. gives us reason to feel optimistic about this challenging population. In a single centre tertiary centre that is well known for advanced ablation strategies for VT, 282 consecutive patients were followed out to a median of 48 months. This is an impressive feat as the majority of VT outcomes are reported out to 6–24 months. The overall VT-free survival was 69%, with transplant-free survival of 76% and 68% at 60 and 120 months, respectively. More importantly, in patients that had recurrence, the burden was significantly shifted toward isolated episodes and amiodarone usage was reduced to 22% of the cohort from 59% pre-procedurally. These data are difficult to keep systematically and the authors should be congratulated on this rigorous nature of their follow-up. What is not known from this experience is what the optimal role of epicardial approach is, as 32% underwent ablation from the pericardial space. The results could be interpreted as supporting a more restricted role, although refining selection is necessary. There are important clinical messages that catheter ablation is effective at achieving long-term rhythm control and reducing VT recurrence may have mortality benefit, as the risk was increased 12-fold for death with recurrent VT. Prospective studies will be needed to more definitively tease out association from potential causation and whether other centres can achieve similar outcomes to elevate the overall success rates of ablation.

cardiomyopathy patients, with little data on long-term survival. In this single-centre retrospective study by Muser and colleagues, catheter ablation outcomes of 282 patients with idiopathic dilated cardiomyopathy with VT were evaluated, and an overall VT-free survival of 68% and significant improvement in VT burden at a median follow-up of 48 months was observed. This is the longest follow-up reported for this patient population. Patients with known aetiology of cardiomyopathy, including hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy, LV non- compaction, sarcoidosis, and valvular cardiomyopathy were excluded. Furthermore, over one-third of patients requiredmultiple VT ablation procedures, and epicardial mapping was performed as warranted by the surface electrocardiogram of the VT, persistent inducibility, or recurrent VT in 38%. The outcomes reported in this study are in line with and even somewhat better than previously published data. It is important to keep in mind that this was a single-centre study and the patient population, in comparison with the population reported in a recent multicentre VT ablation registry of 2061 patients, for example, had less NYHA class III and IV heart failure, chronic kidney disease, diabetes mellitus, and VT storm. As compared with other studies that included a greater number of patients with more advanced heart failure, these data do suggest that ablation of ventricular arrhythmias before patients develop end-stage heart failure may lead to better outcomes. Congruent with previously published combined data of ischaemic and non-ischaemic cardiomyopathy patients, no recurrence of VT after ablation translated to a mortality benefit. Unlike ischaemic cardiomyopathy, there are no randomised trials of VT ablation in patients with non-ischaemic cardiomyopathy, and the encouraging long-term results of the current study further point to the need for a randomised trial. Dr Vaseghi is Assistant Professor of Medicine, Director of Clinical and Translational Research, UCLA Cardiac Arrhythmia Center in Los Angeles, California.

Dr Tung is Associate Professor of Medicine, The University of Chicago Medicine, Pritzker School of Medicine, Center for Arrhythmia Care, Chicago. Hospital performance and survival after myocardial infarction

Comment by Ashish K Jha MD, MPH W e know that there are large differences in short-term survival for acute myocardial infarction (AMI) based on the quality of care patients receive during the initial hospitalisation. But we know far less about whether the mortality benefits of receiving care at a high-quality hospital persist over the long run. Using data from the Cooperative

17 years. The authors found that patients who received care at a low-mortality hospital lived, on average, 0.74 to 1.14 years longer than those who received care at a high-mortality hospital. These findings were consistent across all groups of hospitals (ie, among those that care for the sickest patients as well as those that care for a relatively healthier group). This study is enormously important because it suggests that the benefits of receiving care at a high-quality hospital are not fleeting but can

Cardiovascular Project (CCP) for patients who were admitted for an AMI, Bucholz and colleagues examined the long-term effects of receiving care at a high-quality versus low- quality hospital (based on 30-day mortality rates). The authors grouped hospitals with similar case mix (clinical severity) and then, within each group of hospitals, compared the long-term effects of having gone to a low 30-day mortality hospital versus high 30-day mortality hospital. The average follow-up was

actually meaningfully impact the life expectancy of the patient. This study should provide further impetus to steer patients to high-quality hospitals or incentivise poor performers to improve. Dr Jha is Director for the Harvard Global Health Institute, K.T. Li Professor of Health Policy at the Harvard T.H. Chan School of Public Health, Professor of Medicine at Harvard Medical School, Internal Medicine physician at the VA Boston Healthcare System, Boston. survival curves of the patients admitted to hospitals in each risk-standardizedmortality rate quintile separat- ed within the first 30 days and then remained parallel over 17 years of follow-up. Estimated life expectancy declined as hospital risk-standardized mortality rate quintile increased. On average, patients treated at high-performing hospitals lived between 0.74 and 1.14 years longer, depending on hospital case mix, than patients treated at low-performing hospitals. When 30-day survivors were examined separately, there was no significant difference in unadjusted or adjusted life expectancy across hospital risk- standardized mortality rate quintiles. CONCLUSIONS In this study, patients admitted to high-performing hospitals after acute myocardial infarction had longer life expectancies than patients treated in low-performing hospitals. This survival benefit occurred in the first 30 days and persisted over the long term. N Engl J Med 2016;375:1332-1342, Bucholz EM, Butala NM, Ma S, et al.

Life expectancy after myocardial infarction, according to hospital performance The New England Journal of Medicine Take-home message

• This study investigated the long-term survival of 119,735 patients treated in 1824 hospitals following myocardial infarction. In an earlier study, data collected for the Cooperative Cardiovascular Project used the 30-day mortality rates following myocardial infarction to rate hospital performance. This study analyzed data from patients with 17 years of follow-up and determined that patients treated in high-performing hospitals, those in the top quintile, survived longer than those treated in low-performing hospitals by 0.74 to 1.14 years. • Patients treated in high-performing hospitals following myocardial infarction have an extended life expectancy, consistent with a lower 30-day risk-standardized mortality rate, when compared with patients treated in low-performing hospitals. Abstract

METHODS We analyzed data from the Cooperative Cardiovascular Project, a study of Medicare benefi- ciaries who were hospitalized for acute myocardial infarction between 1994 and 1996 and who had 17 years of follow-up. We grouped hospitals into five strata that were based on case-mix severity. Within each case-mix stratum, we compared life expectancy among patients admitted to high- performing hospitals with life expectancy among

patients admitted to low-performing hospitals. Hospital performance was defined by quintiles of 30-day risk-standardized mortality rates. Cox proportional-hazards models were used to calcu- late life expectancy. RESULTS The study sample included 119,735 patients with acute myocardial infarction who were admit- ted to 1824 hospitals. Within each case-mix stratum,

BACKGROUND Thirty-day risk-standardized mortality rates after acute myocardial infarction are com- monly used to evaluate and compare hospital performance. However, it is not known whether differences among hospitals in the early survival of patients with acute myocardial infarction are associated with differences in long-term survival.

VOL. 1 • No. 3 • 2016