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Biomedical subjects

Barry J Maron

Publications and source records attributed to Barry J Maron.

At least 37 records · Page 2Linked to original sources
PubMed2005

Medical and legal issues in the cardiovascular evaluation of competitive athletes.

Healthy-appearing competitive athletes may harbor unsuspected cardiovascular disease with the potential to cause sudden death. This fact raises issues of physician responsibility in preparticipation screening and eligibility/disqualification decisions. A number of medical-legal cases now represent a framework for screening and eligibility decision making in high school and college athletes. Physicians screening competitive athletes should strictly adhere to recommendations from the American Heart Association. Precedent exists for disqualifying athletes with heart disease from competition to prevent unnecessary exposure to risk of injury or death. By virtue of the court decision in Larkin v Archdiocese of Cincinnati, high school students with heart disease have no compelling right to participate in interscholastic sports without medical clearance. In Knapp v Northwestern University, an appellate court ruled that college athletes can be medically disqualified from sports and supported the use of national association medical guidelines by team physicians in formulating eligibility/disqualification decisions. This medical-legal analysis provides guidelines for physicians participating in medical evaluations of competitive athletes by clarifying the standard of care, potential pitfalls, and the evolving liability associated with this clinical practice.

Cardiovascular Diseases↗
PubMed2005

Gene mutations in apical hypertrophic cardiomyopathy.

BACKGROUND: Nonobstructive hypertrophy localized to the cardiac apex is an uncommon morphological variant of hypertrophic cardiomyopathy (HCM) that often is further distinguished by distinct giant negative T waves and a benign clinical course. The genetic relationship between HCM with typical hypertrophic morphology versus isolated apical hypertrophy is incompletely understood. METHODS AND RESULTS: Genetic cause was investigated in 15 probands with apical hypertrophy by DNA sequence analyses of 9 sarcomere protein genes and 3 other genes (GLA, PRKAG2, and LAMP2) implicated in idiopathic cardiac hypertrophy. Six sarcomere gene mutations were found in 7 samples; no samples contained mutations in GLA, PRKAG2, or LAMP2. Clinical evaluations demonstrated familial apical HCM in 4 probands, and in 3 probands disease-causing mutations were identified. Two families shared a cardiac actin Glu101Lys missense mutation; all members of both families with clinical manifestations of HCM (n=16) had apical hypertrophy. An essential light chain missense mutation Met149Val caused apical or midventricular segment HCM in another proband and 5 family members, but 6 other affected relatives had typical HCM morphologies. No other sarcomere gene mutations identified in the remaining probands caused apical HCM in other family members. CONCLUSIONS: Sarcomere protein gene mutations that cause apical hypertrophy rather than more common HCM morphologies reflect interactions among genetic etiology, background modifier genes, and/or hemodynamic factors. Only a limited number of sarcomere gene defects (eg, cardiac actin Glu101Lys) consistently produce apical HCM.

Adult↗
PubMed2005

Prevalence and clinical significance of left atrial remodeling in competitive athletes.

OBJECTIVES: In the present study we assessed the distribution and clinical significance of left atrial (LA) size in the context of athlete's heart and the differential diagnosis from structural heart disease, as well as the proclivity to supraventricular arrhythmias. BACKGROUND: The prevalence, clinical significance, and long-term arrhythmic consequences of LA enlargement in competitive athletes are unresolved. METHODS: We assessed LA dimension and the prevalence of supraventricular tachyarrhythmias in 1,777 competitive athletes (71% of whom were males), free of structural cardiovascular disease, that were participating in 38 different sports. RESULTS: The LA dimension was 23 to 50 mm (mean, 37 +/- 4 mm) in men and 20 to 46 mm (mean, 32 +/- 4 mm) in women and was enlarged (i.e., transverse dimension > or = 40 mm) in 347 athletes (20%), including 38 (2%) with marked dilation (> or = 45 mm). Of the 1,777 athletes, only 14 (0.8%) had documented, symptomatic episodes of either paroxysmal atrial fibrillation (n = 5; 0.3%) or supraventricular tachycardia (n = 9; 0.5%), which together occurred in a similar proportion in athletes with (0.9%) or without (0.8%; p = NS) LA enlargement. Multivariate regression analysis showed LA enlargement in athletes was largely explained by left ventricular cavity enlargement (R2 = 0.53) and participation in dynamic sports (such as cycling, rowing/canoeing) but minimally by body size. CONCLUSIONS: In a large population of highly trained athletes, enlarged LA dimension > or = 40 mm was relatively common (20%), with the upper limits of 45 mm in women and 50 mm in men distinguishing physiologic cardiac remodeling ("athlete's heart") from pathologic cardiac conditions. Atrial fibrillation and other supraventricular tachyarrhythmias proved to be uncommon (prevalence < 1%) and similar to that in the general population, despite the frequency of LA enlargement. Left atrial remodeling in competitive athletes may be regarded as a physiologic adaptation to exercise conditioning, largely without adverse clinical consequences.

Adaptation, Physiological↗
PubMed2005

Utility of cardiac magnetic resonance imaging in the diagnosis of hypertrophic cardiomyopathy.

BACKGROUND: Two-dimensional echocardiography is currently the standard test for the clinical diagnosis of hypertrophic cardiomyopathy (HCM). The present study was undertaken to determine whether cardiac MRI (CMR) affords greater accuracy than echocardiography in establishing the diagnosis and assessing the magnitude of left ventricular (LV) hypertrophy in HCM. METHODS AND RESULTS: Forty-eight patients (age 34+/-16 years) suspected of having HCM (or with a confirmed diagnosis) were imaged by both echocardiography and CMR to assess LV wall thickness in 8 anatomic segments (total n=384 segments) and compared in a blinded fashion. Maximum LV thickness was similar by echocardiography (21.7+/-9.1 mm) and CMR (22.5+/-9.6 mm; P=0.21). However, in 3 (6%) of the 48 patients, echocardiography did not demonstrate LV hypertrophy, and CMR identified otherwise undetected areas of wall thickening in the anterolateral LV free wall (17 to 20 mm), which resulted in a new diagnosis of HCM. In the overall study group, compared with CMR, echocardiography also underestimated the magnitude of hypertrophy in the basal anterolateral free wall (by 20+/-6%; P=0.001), as well as the presence of extreme LV wall thickness (> or =30 mm) in 10% of patients (P<0.05). CONCLUSIONS: CMR is capable of identifying regions of LV hypertrophy not readily recognized by echocardiography and was solely responsible for diagnosis of the HCM phenotype in an important minority of patients. CMR enhances the assessment of LV hypertrophy, particularly in the anterolateral LV free wall, and represents a powerful supplemental imaging test with distinct diagnostic advantages for selected HCM patients.

Adolescent↗
PubMed2005

Long-term effects of surgical septal myectomy on survival in patients with obstructive hypertrophic cardiomyopathy.

OBJECTIVES: This study sought to determine the impact of surgical myectomy on long-term survival in hypertrophic cardiomyopathy (HCM). BACKGROUND: Left ventricular (LV) outflow tract obstruction in HCM increases the likelihood of heart failure and cardiovascular death. Although surgical myectomy is the primary treatment for amelioration of outflow obstruction and advanced drug-refractory heart failure symptoms, its impact on long-term survival remains unresolved. METHODS: Total and HCM-related mortality were compared in three subgroups comprised of 1,337 consecutive HCM patients evaluated from 1983 to 2001: 1) surgical myectomy (n = 289); 2) LV outflow obstruction without operation (n = 228); and 3) nonobstructive (n = 820). Mean follow-up duration was 6 +/- 6 years. RESULTS: Including two operative deaths (procedural mortality, 0.8%), 1-, 5-, and 10-year overall survival after myectomy was 98%, 96%, and 83%, respectively, and did not differ from that of the general U.S. population matched for age and gender (p = 0.2) nor from patients with nonobstructive HCM (p = 0.8). Compared to nonoperated obstructive HCM patients, myectomy patients experienced superior survival free from all-cause mortality (98%, 96%, and 83% vs. 90%, 79%, and 61%, respectively; p < 0.001), HCM-related mortality (99%, 98%, and 95% vs. 94%, 89%, and 73%, respectively; p < 0.001), and sudden cardiac death (100%, 99%, and 99% vs. 97%, 93%, and 89%, respectively; p = 0.003). Multivariate analysis showed myectomy to have a strong, independent association with survival (hazard ratio 0.43; p < 0.001). CONCLUSIONS: Surgical myectomy performed to relieve outflow obstruction and severe symptoms in HCM was associated with long-term survival equivalent to that of the general population, and superior to obstructive HCM without operation. In this retrospective study, septal myectomy seems to reduce mortality risk in severely symptomatic patients with obstructive HCM.

Adult↗
PubMed2005

Gender-related differences in the clinical presentation and outcome of hypertrophic cardiomyopathy.

OBJECTIVES: The goal of this study was to assess gender-related differences in a multicenter population with hypertrophic cardiomyopathy (HCM). BACKGROUND: Little is known regarding the impact of gender on the heterogeneous clinical profile and clinical course of HCM. METHODS: We studied 969 consecutive HCM patients from Italy and the U.S. followed over 6.2 +/- 6.1 years. RESULTS: Male patients had a 3:2 predominance (59%), similar in Italy and the U.S. (p = 0.24). At initial evaluation, female patients were older and more symptomatic than male patients (47 +/- 23 years vs. 38 +/- 18 years; p < 0.001; mean New York Heart Association [NYHA] functional class 1.8 +/- 0.8 vs. 1.4 +/- 0.6; p < 0.001), and more frequently showed left ventricular outflow obstruction (37% vs. 23%; p < 0.001). Moreover, female patients were less often diagnosed fortuitously by routine medical examination (23% vs. 41% in male patients, p < 0.001). Female gender was independently associated with the risk of symptom progression to NYHA functional classes III/IV or death from heart failure or stroke compared with male gender (independent relative hazard 1.5; p < 0.001), particularly patients > or =50 years of age and with resting outflow obstruction (p < 0.005). Hypertrophic cardiomyopathy-related mortality and risk of sudden death were similar in men and women. CONCLUSIONS: Women with HCM were under-represented, older, and more symptomatic than men, and showed higher risk of progression to advanced heart failure or death, often associated with outflow obstruction. These gender-specific differences suggest that social, endocrine, or genetic factors may affect the diagnosis and clinical course of HCM. A heightened suspicion for HCM in women may allow for timely implementation of treatment strategies, including relief of obstruction and prevention of sudden death or stroke.

Adult↗
PubMed2005

Relation of electrocardiographic patterns to phenotypic expression and clinical outcome in hypertrophic cardiomyopathy.

Twelve-lead electrocardiography, a traditional component in evaluations of patients with hypertrophic cardiomyopathy (HC), is often regarded as a marker for the magnitude of left ventricular (LV) hypertrophy, which in turn has been linked to sudden death risk. To determine whether electrocardiographic (ECG) patterns have clinical utility by accurately reflecting phenotypic expression or predicting clinical outcome, voltages and patterns were compared with LV wall thicknesses assessed by echocardiography and with clinical outcomes in 448 consecutive patients with HC. Significant but relatively weak correlations were evident between maximum LV wall thickness and ECG voltage: r = 0.295 (p <0.01) for the sum of R- and S-wave voltages in all 12 leads, r = 0.254 (p <0.01) for the maximum R or S wave in any lead, and r = 0.210 (p <0.01) for the sum of SV(1) (or SV(2)) and RV(5) (or RV(6)). Of 55 patients with extreme LV hypertrophy (LV wall thickness > or =30 mm), only 24 (44%) showed greatly increased ECG voltage > or =30 mm in any lead. Of 102 patients with outflow gradients > or =30 mm Hg at rest, only 43 (42%) had ECG voltage > or =30 mm in any lead. Normal ECG results were uncommonly associated with HC-related death (1 of 40 patients, 2.5%) but had similar prevalence in surviving patients (17 of 376 patients, 4.5%; p = NS). In conclusion, in HC, 12-lead ECG voltages are not a reliable clinical marker for the magnitude of LV hypertrophy or outflow obstruction. Diverse ECG patterns, consistent with heterogeneous expression of this disease, did not predict HC-related death. Scalar electrocardiography has selective but limited power in routine clinical assessments of patients with HC.

Adult↗
PubMed2005

Significance and relation between magnitude of left ventricular hypertrophy and heart failure symptoms in hypertrophic cardiomyopathy.

In hypertrophic cardiomyopathy (HC), an important subgroup of patients develop progressive and disabling symptoms that are related to heart failure and death. Although a direct relation has been demonstrated between left ventricular (LV) wall thickness and likelihood of sudden and unexpected death (usually in patients who are asymptomatic or mildly symptomatic), it is unresolved whether magnitude of hypertrophy is similarly associated with severity of heart failure. To determine the relation of LV wall thickness to heart failure symptoms in HC, 700 consecutive patients who had HC were assessed by 2-dimensional echocardiography. The relation between maximum level of heart failure symptoms by New York Heart Association functional class and maximum LV wall thickness was not linear but rather parabolic. Therefore, marked symptoms were most commonly associated with moderate degrees of LV hypertrophy (wall thickness 16 to 24 mm; 27%) but less frequently with extreme hypertrophy (>/=30 mm 13%) or mild hypertrophy (</=15 mm; 19%, p = 0.0001). Mean New York Heart Association functional class showed a similar pattern with respect to moderate hypertrophy (1.9 +/- 0.8), mild hypertrophy (1.6 +/- 0.9), and extreme hypertrophy (1.6 +/- 0.7, p = 0.005). Multivariable regression analysis showed the parabolic relation between heart failure symptoms and magnitude of LV hypertrophy to be independent of other hypertrophic cardiomyopathy related clinical variables. In conclusion, no direct relation was evident between symptoms of heart failure and magnitude of LV wall thickness, with implications for the natural history of HC.

Adolescent↗
PubMed2005

Multicenter study of the efficacy and safety of disopyramide in obstructive hypertrophic cardiomyopathy.

OBJECTIVES: In this study we assessed the long-term efficacy and safety of disopyramide for patients with obstructive hypertrophic cardiomyopathy (HCM). BACKGROUND: It has been reported that disopyramide may reduce left ventricular outflow gradient and improve symptoms in patients with HCM. However, long-term efficacy and safety of disopyramide has not been shown in a large cohort. METHODS: Clinical and echocardiographic data were evaluated in 118 obstructive HCM patients treated with disopyramide at 4 HCM treatment centers. Mortality in the disopyramide-treated patients was compared with 373 obstructive HCM patients not treated with disopyramide. RESULTS: Patients were followed with disopyramide for 3.1 +/- 2.6 years; dose 432 +/- 181 mg/day (97% also received beta-blockers). Seventy-eight patients (66%) were maintained with disopyramide without the necessity for major non-pharmacologic intervention with surgical myectomy, alcohol ablation, or pacing; outflow gradient at rest decreased from 75 +/- 33 to 40 +/- 32 mm Hg (p < 0.0001) and mean New York Heart Association functional class from 2.3 +/- 0.7 to 1.7 +/- 0.6 (p < 0.0001). Forty other patients (34%) could not be satisfactorily managed with disopyramide and required major invasive interventions because of inadequate symptom and gradient control or vagolytic side effects. All-cause annual cardiac death rate between disopyramide and non-disopyramide-treated patients did not differ significantly, 1.4% versus 2.6%/year (p = 0.07). There was also no difference in sudden death rate, 1.0%/year versus 1.8%/year (p = 0.08). CONCLUSIONS: Two-thirds of obstructed HCM patients treated with disopyramide could be managed medically with amelioration of symptoms and about 50% reduction in subaortic gradient over >/=3 years. Disopyramide therapy does not appear to be proarrhythmic in HCM and should be considered before proceeding to surgical myectomy or alternate strategies.

Administration, Oral↗