Sara Saberi

Effect of Moderate-Intensity Exercise Training on Peak Oxygen Consumption in Patients With Hypertrophic Cardiomyopathy: A Randomized Clinical Trial

Importance Formulating exercise recommendations for patients with hypertrophic cardiomyopathy is challenging because of concern about triggering ventricular arrhythmias and because a clinical benefit has not been previously established in this population. Objective To determine whether moderate-intensity exercise training improves exercise capacity in adults with hypertrophic cardiomyopathy. Design, Setting, and Participants A randomized clinical trial involving 136 patients with hypertrophic cardiomyopathy was conducted between April 2010 and October 2015 at 2 academic medical centers in the United States (University of Michigan Health System and Stanford University Medical Center). Date of last follow-up was November 2016. Interventions Participants were randomly assigned to 16 weeks of moderate-intensity exercise training (n = 67) or usual activity (n = 69). Main Outcomes and Measures The primary outcome measure was change in peak oxygen consumption from baseline to 16 weeks. Results Among the 136 randomized participants (mean age, 50.4 [SD, 13.3] years; 42% women), 113 (83%) completed the study. At 16 weeks, the change in mean peak oxygen consumption was +1.35 (95% CI, 0.50 to 2.21) mL/kg/min among participants in the exercise training group and +0.08 (95% CI, −0.62 to 0.79) mL/kg/min among participants in the usual-activity group (between-group difference, 1.27 [95% CI, 0.17 to 2.37]; P = .02). There were no occurrences of sustained ventricular arrhythmia, sudden cardiac arrest, appropriate defibrillator shock, or death in either group. Conclusions and Relevance In this preliminary study involving patients with hypertrophic cardiomyopathy, moderate-intensity exercise compared with usual activity resulted in a statistically significant but small increase in exercise capacity at 16 weeks. Further research is needed to understand the clinical importance of this finding in patients with hypertrophic cardiomyopathy, as well as the long-term safety of exercise at moderate and higher levels of intensity. Trial Registration clinicaltrials.gov Identifier: NCT01127061

Physical activity and other health behaviors in adults with hypertrophic cardiomyopathy.

The clinical expression of hypertrophic cardiomyopathy (HC) is undoubtedly influenced by modifying genetic and environmental factors. Lifestyle practices such as tobacco and alcohol use, poor nutritional intake, and physical inactivity are strongly associated with adverse cardiovascular outcomes and increased mortality in the general population. Before addressing the direct effect of such modifiable factors on the natural history of HC, it is critical to define their prevalence in this population. A voluntary survey, drawing questions in part from the 2007 to 2008 National Health and Nutrition Examination Survey (NHANES), was posted on the HC Association website and administered to patients with HC at the University of Michigan. Propensity score matching to NHANES participants was used. Dichotomous and continuous health behaviors were analyzed using logistic and linear regression, respectively, and adjusted for body mass index and propensity score quintile. Compared to the matched NHANES participants, the patients with HC reported significantly less alcohol and tobacco use but also less time engaged in physical activity at work and for leisure. Time spent participating in vigorous or moderate activity was a strong predictor of self-reported exercise capacity. The body mass index was greater in the HC cohort than in the NHANES cohort. Exercise restrictions negatively affected emotional well-being in most surveyed subjects. In conclusion, patients with HC are less active than the general United States population. The well-established relation of inactivity, obesity, and cardiovascular mortality might be exaggerated in patients with HC. More data are needed on exercise in those with HC to strike a balance between acute risks and the long-term health benefits of exercise.

Genetic testing impacts the utility of prospective familial screening in hypertrophic cardiomyopathy through identification of a nonfamilial subgroup

PurposeHypertrophic cardiomyopathy (HCM) is considered a hereditary autosomal dominant condition, but genetic testing is positive in only half of patients. In patients with negative genetic tests, the inheritance pattern and utility of family screening are unclear.MethodsSubjects with HCM were prospectively enrolled in a registry. A survey at a median follow-up of 4 years determined the yield of family screening.ResultsThe outcome of cardiac screening on 267 family members was reported by 120 survey respondents. Subjects with positive genetic test or family history (n=74, 62%) reported an HCM diagnosis in 34 of 203 first-degree relatives who were screened (17%). Affected family members were diagnosed at a mean age of 30–39 years, and 22 of 34 experienced HCM-related adverse events (65%). Gene test–negative subjects with no prior family history of HCM (n=46, 38%) reported an HCM diagnosis in only 2 of 64 first-degree relatives who were screened (3%, p<0.001). These two individuals were diagnosed at age >40 years without HCM-related adverse events.ConclusionHypertrophic cardiomyopathy is a heterogeneous disorder, only half of which tracks with a Mendelian inheritance pattern. Negative genetic testing and family history indicates a more complex genetic basis corresponding to low risk for family members.

Sports and Exercise in Athletes with Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease and one of the most common causes of sudden cardiac death (SCD). Current guidelines restrict the participation of patients with HCM in competitive sports, limiting the health benefits of exercise. However, many individuals with HCM have safely participated in sports, with a low incidence of SCD. Improved stratification of patients and desired activity may allow most individuals with HCM to engage in physical activity safely. Therefore, physicians should create an individualized approach in guiding each patient with HCM eager to enjoy the benefits of physical activity in a safe manner.

Variation in practice patterns among specialties in the acute management of atrial fibrillation

BackgroundAtrial fibrillation (AF) is commonly managed by a variety of specialists. Current guidelines differ in their recommendations leading to uncertainty regarding important clinical decisions. We sought to document practice pattern variation among cardiologists, emergency physicians (EP) and hospitalists at a single academic, tertiary-care center.MethodsA survey was created containing seven clinical scenarios of patients presenting with AF. We analyzed respondent choices regarding rate vs rhythm control, thromboembolic treatment and hospitalization strategies. Finally, we contrasted our findings with a comparable Australasian survey to provide an international reference.ResultsThere was a 78% response rate (124 of 158), 37% hospitalists, 31.5% cardiologists, and 31.5% EP. Most respondents chose rate over rhythm control (92.2%; 95% CI, 89.1% - 94.5%) and thromboembolic treatment (67.8%; 95% CI, 63.8% - 71.7%). Compared to both hospitalists and EPs, cardiologists were more likely to choose thromboembolic treatment for new and paroxysmal AF (adjusted OR 2.38; 95% CI, 1.05 - 5.41). They were less likely to favor hospital admission across all types of AF (adjusted OR 0.36; 95% CI, 0.17 - 0.79) but thought cardiology consultation was more important (adjusted OR 1.88, 95% CI, 0.97 - 3.64). Australasian physicians were more aggressive with rhythm control for paroxysmal AF with low CHADS2 score compared to US physicians.ConclusionsSignificant variation exists among specialties in the management of acute AF, likely reflecting a lack of high quality research to direct the provider. Future studies may help to standardize practice leading to decreased rates of hospitalization and overall cost.

Exercise and Hypertrophic Cardiomyopathy: Time for a Change of Heart

It has been more than a decade since the 35th Bethesda Conference published guidelines recommending against competitive sports participation for individuals with hypertrophic cardiomyopathy (HCM).1 These recommendations are predicated on the view that vigorous physical exertion creates an unstable substrate that increases susceptibility to sudden cardiac death (SCD). But what precisely is the risk of SCD, and is it really higher in athletic compared with nonathletic patients with HCM? The overall incidence of SCD in young athletic cohorts is exceedingly low, ≈1 to 3:100 000 person years, and is similar to the frequency of SCD in the young general population. Despite this finding, HCM has been thought to convey a disproportionately high risk because of early registry reports that HCM was the most common cause of SCD in young athletes. However, several subsequent studies have challenged this statistic. In the US National Collegiate Athletic Association, HCM accounted for only 8% of all sudden deaths. In a meta-analysis of retrospective cohort studies, registries, and autopsy series (1990–2014), structurally normal hearts were the most common finding on autopsies of young victims of SCD (26.7%; 95% confidence interval [CI], 21.0–32.3), with HCM attributed to a much smaller proportion (10.3%; 95% CI, 8.0–12.6).2 A structurally normal heart similarly represented the largest cohort (40%) of SCD in children and young adults in a prospective population study in Australia and New Zealand, even …

Exercise hemodynamics in hypertrophic cardiomyopathy identify risk of incident heart failure but not ventricular arrhythmias or sudden cardiac death

OBJECTIVE To determine whether abnormal blood pressure response (ABPR), with or without left ventricular outflow tract obstruction (LVOTO), is associated with adverse heart failure and arrhythmia outcomes in hypertrophic cardiomyopathy (HCM). METHODS A retrospective, single-center analysis was performed for adult HCM patients who underwent exercise stress testing. RESULTS Of 589 patients included in the study, 192 (33%) demonstrated ABPR. A similar proportion of patients with ABPR had LVOTO compared to those without ABPR (56% vs 63%, p = 0.11). Patients with ABPR demonstrated lower percent predicted VO2 and METs achieved than those with LVOTO (16.9 ± 6.8 vs 21.6 ± 7.9, p = 0.002 and 5.3 ± 2.4 vs 7.4 ± 3.1, p < 0.001). In a subgroup of 17 patients with LVOTO and ABPR who subsequently underwent successful myectomy, 5 (30%) demonstrated persistent ABPR. 23 patients (3.8%) experienced sudden cardiac death or ventricular arrhythmias, which were not associated with ABPR, regardless of age group. In multivariable analysis, syncope (p = 0.04), left ventricular hypertrophy (p = 0.02) and left atrial diameter (p = 0.006) were significantly associated with the composite outcome of sudden death or severe ventricular arrhythmia, whereas ABPR was not (p = 0.38). In contrast, ABPR was associated with subsequent heart failure hospitalization (p = 0.002), regardless of presence or absence of LVOTO (p = 0.04, p = 0.02). CONCLUSIONS ABPR is associated with reduced functional capacity in HCM regardless of the presence of LVOTO but is not associated with adverse arrhythmia outcomes. Patients with ABPR have a higher incidence of subsequent heart failure hospitalization.

Exercise for Patients With Hypertrophic Cardiomyopathy—Reply

Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Scheer reported travel reimbursement and conference expenses from Astellas and lecture fees from Dräger Medical and Radiometer. Dr Kuhn reported lecture fees from Dräger Medical. Dr Rehberg reported receiving travel reimbursement from Orion and Astellas, grant support from Fresenius Kabi Germany, and advisor fees from Amomed. No other disclosures are reported.

Exercise Prescription for the Athlete with Cardiomyopathy

Inherited cardiomyopathies have highly variable expression in terms of symptoms, functional limitations, and disease severity. Associated risk of sudden cardiac death is also variable. International guidelines currently recommend restriction of all athletes with cardiomyopathy from participation in competitive sports. While the guidelines are necessarily conservative because predictive risk factors for exercise-triggered SCD have not been clearly identified, the risk is clearly not uniform across all athletes and all sports. The advent of implantable cardioverter defibrillators, automated external defibrillators, and successful implementation of emergency action plans may safely mitigate risk of sudden cardiac death during physical activity. An individualized approach to risk stratification of athletes that recognizes patient autonomy may allow many individuals with cardiomyopathies to safely train and compete.

Response by Saberi and Day to Letter Regarding Article, “Exercise and Hypertrophic Cardiomyopathy: Time for a Change of Heart”

We would like to thank Drs Rajtar-Salwa and Dimitrow for their interest in our article1 and for their thoughtful comments. We wish to clarify that we did not make any claims to the safety of long-term exercise training in individuals with hypertrophic cardiomyopathy (HCM). We agree that there are a level of uncertainty about and a need for future studies to examine outcomes in individuals engaging in higher-intensity exercise or competitive sports. We highlighted recent data challenging the widely held view that HCM is the most common cause of sudden death in young athletes and the absence of data that sports participation increases sudden …