PubMed Health⌕ Search

Biomedical subjects

Barry J Maron

Publications and source records attributed to Barry J Maron.

100 records · Page 6Linked to original sources
PubMed2002

Sarcomere protein gene mutations in hypertrophic cardiomyopathy of the elderly.

BACKGROUND: Hypertrophic cardiomyopathy, a familial myocardial condition caused by sarcomere protein mutations, is usually recognized by early adulthood. Hypertrophic cardiomyopathy of the elderly has similar clinical features but, notably, a later age of onset and noncontributory family history. Causes of elderly-onset hypertrophic cardiomyopathy are unknown. METHODS AND RESULTS: Eighteen women and 13 men diagnosed with late-onset hypertrophic cardiomyopathy were studied. Initial symptoms occurred at 59.3 (+/-12.3) years, and diagnosis was made at 62.8 (+/-10.8) years. None had family histories of cardiomyopathy. Echocardiography demonstrated maximal left ventricular wall thickness of 19.9+/-3.8 mm, systolic anterior motion of the mitral valve (58%), and, in 11 individuals, left ventricular outflow tract gradients (average, 63+/-42.8 mm). Sarcomere protein gene analyses revealed 8 sequence variants in cardiac myosin binding protein-C (1 nonsense, 1 splice acceptor site, and 3 missense), cardiac troponin I (2 missense), and alpha-cardiac myosin heavy chain (1 missense). Seven variants were not found in over 170 normal chromosomes; 1 variant (cardiac myosin binding protein-C Arg326Gln) also occurred in a healthy adult. CONCLUSIONS: Hypertrophic cardiomyopathy of the elderly can be a genetic disorder caused by dominant sarcomere protein mutations. The distribution of mutations in elderly-onset disease is strikingly different (P<0.00001) from that of familial, early onset hypertrophic cardiomyopathy. Whereas defects in beta-cardiac myosin heavy chain, cardiac troponin T, and alpha-tropomyosin account for > 45% of familial hypertrophic cardiomyopathy, none were found here. Rather, mutations in cardiac myosin binding protein-C, troponin I, and alpha-cardiac myosin heavy chain caused elderly-onset hypertrophic cardiomyopathy.

Age of Onset↗
PubMed2002

Clinical profile of stroke in 900 patients with hypertrophic cardiomyopathy.

OBJECTIVES: We sought to assess the occurrence and clinical significance of stroke and peripheral arterial embolizations at non-central nervous system sites in a large, community-based cohort with hypertrophic cardiomyopathy (HCM). BACKGROUND: Such vascular events are insufficiently appreciated complications of HCM for which there is limited information on occurrence, clinical profile and determinants. METHODS: We assessed the clinical features of patients with stroke and other peripheral vascular events in a consecutive group of patients with HCM from four regional cohorts not subject to significant tertiary referral bias. RESULTS: Of the 900 patients, 51 (6%) patients experienced stroke or other vascular events over 7 +/- 7 years, including 44 patients with stroke; 21 (41%) of these 51 patients died or were permanently disabled. The overall incidence was 0.8%/year and 1.9% for patients >60 years old. Age at first event ranged from 29 to 86 years (mean 61 +/- 14 years). Most (n = 37; 72%) events occurred in those >50 years, although 14 (28%) younger patients (< or = 50 years) also had events. Multivariate analysis showed stroke and other peripheral vascular events to be independently associated with congestive symptoms and advanced age, as well as with atrial fibrillation (in 45 [88%] of 51 patients), at the initial evaluation. The cumulative incidence of these events among patients with atrial fibrillation was significantly higher in non-anticoagulated patients as compared with patients receiving warfarin (31% vs. 18%; p < 0.05). CONCLUSIONS: Stroke and peripheral embolizations showed a 6% prevalence rate and an incidence of 0.8%/year in a large, unselected HCM group. These profound complications of HCM, which may lead to disability and death, were substantially more common in the elderly, occurred almost exclusively in patients with paroxysmal or chronic atrial fibrillation and appeared to be reduced in frequency by anticoagulation.

Adult↗
PubMed2002

Reduced risk of sudden death from chest wall blows (commotio cordis) with safety baseballs.

OBJECTIVES: In an experimental model of sudden death from baseball chest wall impact (commotio cordis), we sought to determine if sudden death by baseball impact could be reduced with safety baseballs. BACKGROUND: Sudden cardiac death can occur after chest wall impact with a baseball (commotio cordis). Whether softer-than-standard (safety) baseballs reduce the risk of sudden death is unresolved from the available human data. In a juvenile swine model, ventricular fibrillation (VF) has been shown to be induced reproducibly by precordial impact with a 30-mph baseball 10 to 30 ms before the T-wave peak, and this likelihood was reduced with the softest safety baseballs (T-balls). To further test whether safety baseballs would reduce the risk of sudden death at velocities more relevant to youth sports competition, we used our swine model of commotio cordis to test baseballs propelled at the 40-mph velocity commonly attained in that sport. METHODS: Forty animals received up to 3 chest wall impacts at 40 mph during the vulnerable period of repolarization for VF with 1 of 3 different safety baseballs of varying hardness, and also by a standard baseball. RESULTS: Safety baseballs propelled at 40 mph significantly reduced the risk for VF. The softest safety baseballs triggered VF in only 11% of impacts, compared with 19% and 22% with safety baseballs of intermediate hardness, and 69% with standard baseballs. CONCLUSION: In this experimental model of low-energy chest wall impact, safety baseballs reduced (but did not abolish) the risk of sudden cardiac death. More universal use of these safety baseballs may decrease the risk of sudden death on the playing field for young athletes.

Animals↗
PubMedDate not supplied

The athlete's heart: remodeling, electrocardiogram and preparticipation screening.

Highly trained athletes show morphologic cardiac changes (ie, athlete's heart) that are the consequence of several determinants, including type of sport, gender, and, possibly, inherited genetic factors. The extent of physiologic cardiac remodeling may occasionally be substantial in highly trained athletes and may raise a differential diagnosis with structural cardiac disease, such as cardiomyopathies. In addition, athletes demonstrate a spectrum of alterations in the 12-lead electrocardiogram (ECG) pattern, including marked increase in precordial R-wave or S-wave voltages, ST segment or T-wave changes, and deep Q waves suggestive of left ventricular hypertrophy, that may raise the possibility of pathologic heart condition, but have also been viewed as a consequence of the cardiac morphologic remodeling induced by athletic conditioning. To evaluate the clinical significance of these abnormal ECGs, the authors compared ECG patterns to cardiac morphology and function (assessed by two-dimensional echocardiography in individual athlete) in a large population of 1005 elite athletes engaged in a variety of sporting disciplines. Forty percent of the athletes had abnormal ECGs, and a subgroup of about 15% showed distinctly abnormal and often bizarre patterns highly suggestive of cardiomyopathies, such as hypertrophic cardiomyopathy, in the absence of pathologic cardiac changes. Such alterations are likely the consequence of athletic conditioning itself and represent another potential component of athlete's heart syndrome. However, such false-positive ECGs represent a potential limitation to the efficacy of routine ECG testing in the preparticipation cardiovascular screening of large athletic populations.

Cardiomegaly↗
PubMedDate not supplied

Risk stratification and prevention of sudden death in hypertrophic cardiomyopathy.

Sudden unexpected death, often occurring in young, asymptomatic patients, is the most devastating facet of the natural history of hypertrophic cardiomyopathy, and appears to be the consequence of primary ventricular tachyarrhythmias arising in an electrically unstable myocardial substrate characterized by disorganized cellular architecture, ischemia, cell death, and replacement scarring. Although precise identification of all hypertrophic cardiomyopathy patients at high risk for a catastrophic event is a clinical challenge, effective treatment strategies for the prevention of sudden death with the implantable cardioverter-defibrillator are now available.

Cardiomyopathy, Hypertrophic↗
PubMedDate not supplied

Impact of postgraduate medical education on recognition of stroke.

Insufficient awareness persists in the general medical community regarding risk factors, warning signs, and prevention strategies for stroke. A survey of 308 internal medicine residency programs showed only 144 (46%) required neurology compared with cardiology (97%, P <0.001). Furthermore, an inverse relationship was identified between the number of medicine residents completing neurology rotations and the stroke mortality by state (r = 0.41; P = 0.001). Underrepresentation of neurology in internal medicine residency programs may contribute to stroke outcome.

Awareness↗