Clinical profile of hypertrophic cardiomyopathy identified de novo in rural communities.

OBJECTIVES: The purpose of this study was to assess the extent to which hypertrophic cardiomyopathy (HCM) exists unsuspected and undetected in the general population. BACKGROUND: Hypertrophic cardiomyopathy is a disease with diverse natural history for which the potential to produce adverse consequences has been emphasized. However, the possibility of this disease remaining clinically dormant for many years has not been as widely appreciated. Certainly, the clinical recognition of previously undiagnosed patients with HCM may be advantageous by permitting risk stratification for sudden cardiac death or for timely pharmacologic therapy when symptoms intervene. METHODS: We prospectively conducted an echocardiographic survey in 64 primarily rural communities within Minnesota (populations < 10,000) over a 33-month period. RESULTS: A total of 15,137 echocardiograms were performed at the request of primary care physicians for the purpose of excluding cardiovascular abnormalities. Hypertrophic cardiomyopathy was identified in 44 patients during the survey (0.29%), and 29 of these patients (0.19% of the 15,137 echocardiograms) had not been previously identified as having cardiac disease or HCM. At diagnosis, ages were 16 to 87 years (mean 57); 14 patients were > or = 60 years of age, and only two were < 30 years. Twenty-four patients (83%) had either no or only mild or transient symptoms; 5 (17%) evidenced severe functional limitation; in eight patients the onset of symptoms had been deferred until > or = 70 years of age. Basal left ventricular outflow obstruction (gradients 20 to 82 mm Hg) was evident in 11 patients (38%). Relatively mild phenotypic expression of the disease was substantiated by localized patterns of left ventricular wall thickening occurring more commonly than diffusely distributed hypertrophy (48% vs. 7%, respectively), and electrocardiograms that were frequently normal (about 25%) and rarely showed evidence of left ventricular hypertrophy (10%). CONCLUSIONS: These prospectively assembled data show that HCM may remain clinically dormant and undetected within community-based rural populations for many years (often to advanced ages) with a not inconsequential prevalence similar to that of HCM in the general population.

Clinical course of hypertrophic cardiomyopathy in a regional United States cohort.

CONTEXT: Hypertrophic cardiomyopathy (HCM) has been regarded as a disease that causes substantial disability, with annual mortality rates of up to 6%, based largely on reports from tertiary referral centers. OBJECTIVE: To assess the clinical course of HCM in a patient cohort more closely resembling the true disease state. DESIGN: Retrospective cohort study. SETTING: A regional cohort from Minnesota and adjoining regions, free of referral center bias, studied at Minneapolis Heart Institute. PATIENTS: Two hundred seventy-seven consecutively studied HCM patients, none referred for specialized HCM care, managed clinically in a standard fashion. MAIN OUTCOME MEASURES: Mortality and clinical course of HCM. RESULTS: During a mean (SD) follow-up of 8.1 (6.6) years, 45 patients died and 29 of these deaths were directly related to HCM; however, 8 of the 29 HCM deaths were not premature (occurring >75 years of age). Annual HCM mortality rate was 1.3% (0.7% for sudden cardiac death). Patients identified in adulthood (n = 234) showed no statistically significant difference in mortality when compared with expected mortality, as calculated for the general US or Minnesota populations (P=.17). Patients identified as children (n=43) showed decreased survival compared with the general population (P<.001). At most recent clinical evaluation, 192 patients (69%) had no or mild symptoms and 69 (25%) experienced incapacitating symptoms or HCM-related death; 53 (19%) of the patients had achieved estimated life expectancy of 75 years or older. More advanced symptoms at diagnosis-occurrence of atrial fibrillation (often associated with stroke), the presence of basal outflow obstruction of at least 30 mm Hg, and marked left ventricular wall thickness of more than 25 mm-were clinically important independent predictors of HCM mortality. CONCLUSIONS: In a regionally selected patient population most closely resembling the true disease state, HCM did not significantly increase the risk of premature death or adversely affect overall life expectancy. Prevailing misconceptions of HCM as a generally unfavorable condition may largely be related to the skewed patient referral patterns characteristic of tertiary care centers. Hypertrophic cardiomyopathy is nevertheless a highly complex disease capable of serious clinical consequences and premature death in some patients.

Survival following blunt chest impact-induced cardiac arrest during sports activities in young athletes.

Blunt chest impact-induced cardiac arrest on the athletic field (commotio cordis) is not necessarily fatal. The 3 survivors reported here emphasize the importance of recognizing this syndrome so that emergency resuscitative measures are more likely to be implemented promptly, and such catastrophes avoided.

Risk for sudden cardiac death associated with marathon running.

OBJECTIVES: This analysis was performed to quantitatively assess the relative risks, associated with underlying cardiovascular disease, incurred in the course of intense competitive sports. BACKGROUND: Sudden cardiac death during athletic activities is a highly visible event, and controversy persists regarding the true risks associated with participation in sports. METHODS: The prevalence of sudden death was assessed in two systematically tabulated groups of endurance runners competing in the annual Marine Corps (1976 to 1994) and Twin Cities (1982 to 1994) marathons, held over a cumulative 30-year period. RESULTS: A total of 215,413 runners completed the races, and four exercise-related sudden deaths occurred, each due to unsuspected structural cardiovascular disease. Three deaths occurred during the race (after 15 to 24 miles [24 to 38.4 km]) and the other immediately after its completion. The ages were 19 to 58 years (average 37), and three were men. Three of the sudden deaths were due to atherosclerotic coronary artery disease (narrowing of two or three vessels) and one to anomalous origin of the left main coronary artery from the right sinus of Valsalva. None of the four runners had prior documentation of heart disease or experienced prodromal symptoms, and two had previously completed three marathon races each. The overall prevalence of sudden cardiac death during the marathon was only 0.002%, strikingly lower than for several other variables of risk for premature death calculated for the general U.S. population. CONCLUSIONS: Although highly trained athletes such as marathon runners may harbor underlying and potentially lethal cardiovascular disease, the risk for sudden cardiac death associated with such intense physical effort was exceedingly small (1 in 50,000) and as little as 1/100th of the annual overall risk associated with living, either with or without heart disease. The low risk for sudden death identified in long-distance runners from the general population suggests that routine screening for cardiovascular disease in such athletic populations may not be justifiable.

Sudden death in young competitive athletes. Clinical, demographic, and pathological profiles.

OBJECTIVE: To develop clinical, demographic, and pathological profiles of young competitive athletes who died suddenly. DESIGN: Systematic evaluation of clinical information and circumstances associated with sudden deaths; interviews with family members, witnesses, and coaches; and analyses of postmortem anatomic, microscopic, and toxicologic data. PARTICIPANTS AND SETTING: A total of 158 sudden deaths that occurred in trained athletes throughout the United States from 1985 through 1995 were analyzed. MAIN OUTCOME MEASURES--Characteristics and probable cause of death. RESULTS: Of 158 sudden deaths among athletes, 24 (15%) were explained by noncardiovascular causes. Among the 134 athletes who had cardiovascular causes of sudden death, the median age was 17 years (range, 12-40 years), 120 (90%) were male, 70 (52%) were white, and 59 (44%) were black. The most common competitive sports involved were basketball (47 cases) and football (45 cases), together accounting for 68% of sudden deaths. A total of 121 athletes (90%) collapsed during or immediately after a training session (78 cases) or a formal athletic contest (43 cases), with 80 deaths (63%) occurring between 3 PM and 9 PM. The most common structural cardiovascular diseases identified at autopsy as the primary cause of death were hypertrophic cardiomyopathy (48 athletes [36%]), which was disproportionately prevalent in black athletes compared with white athletes (48% vs 26% of deaths; P = .01), and malformations involving anomalous coronary artery origin (17 athletes [13%]). Of 115 athletes who had a standard preparticipation medical evaluation, only 4 (3%) were suspected of having cardiovascular disease, and the cardiovascular abnormality responsible for sudden death was correctly identified in only 1 athlete (0.9%). CONCLUSIONS: Sudden death in young competitive athletes usually is precipitated by physical activity and may be due to a heterogeneous spectrum of cardiovascular disease, most commonly hypertrophic cardiomyopathy. Preparticipation screening appeared to be of limited value in identification of underlying cardiovascular abnormalities.

Blunt impact to the chest leading to sudden death from cardiac arrest during sports activities.

BACKGROUND: Sudden death from cardiac arrest in a young person may occur during sports play after a blunt blow to the chest in the absence of structural cardiovascular disease or traumatic injury (cardiac concussion or commotio cordis). We studied the clinical features of this apparently uncommon but important phenomenon. METHODS: We identified cases from the registries of relevant agencies and organizations, as well as newsmedia accounts, and developed a clinical profile of 25 children and young adults, 3 to 19 years of age. RESULTS: Each victim collapsed with cardiac arrest immediately after an unexpected blow to the chest, which was usually inflicted by a projectile (such as a baseball or hockey puck). Incidents took place during organized competitive sports in 16 cases and in recreational settings at home, at school, or on the playground in 9. In each instance, the impact to the chest was not judged to be extraordinary for the sport involved and did not appear to have sufficient force to cause death. Twelve victims collapsed virtually instantaneously on impact, whereas 13 remained conscious and physically active for a brief time before cardiac arrest. Cardiopulmonary resuscitation was administered within about three minutes to 19 victims, but normal cardiac rhythm could be restored in only 2 (both incurred irreversible brain damage and died shortly thereafter). Seven victims (28 percent) were wearing some form of protective chest padding. CONCLUSIONS: We speculate that most sudden deaths related to impact to the chest (not associated with traumatic injury) are due to ventricular dysrhythmia induced by an abrupt, blunt precordial blow, presumably delivered at an electrically vulnerable phase of ventricular excitability. This profile of blunt chest impact leading to cardiac arrest adds to our understanding of the range of causes of sudden death on the athletic field and may help in the development of preventive measures.