Sudden death in young athletes

[Clinical picture and therapy of hypertrophic cardiomyopathy]

Hypertrophic cardiomyopathy is defined as a primary, sometimes familial and genetically fixed myocardial hypertrophy. In the obstructive form of the disease (HOCM) a dynamic outflow tract obstruction of the left, occasionally also the right ventricle can be found. HOCM is the most frequent cause of stress-induced syncope or sudden cardiac death in younger patients. An individual estimation of prognosis is difficult although several risk factors have been identified. In addition to standard therapy of symptomatic patients (medical treatment with betablockers and calcium-antagonists of verapamil-type as well as surgical myotomy/myectomy) DDD-pacemaker implantation and percutaneous transluminal septal myocardial ablation (PTSMA) by alcohol-induced septal branch occlusion have been introduced. After PTSMA significant outflow tract gradient reduction can be achieved in > 90% of patients. Due to remodeling after circumscribed myocardial necrosis further gradient reduction has been observed during follow-up. Optimization of ablated septal area by echocardiographic monitoring resulted in reduction of the most important complication (trifascicular block with need of permanent pacemaker implantation) and improvement of acute and follow-up results. Long-term follow-up and comparison with established treatment options are necessary to evaluate the definitive importance of the promising new treatment.

Percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy: acute results and 3-month follow-up in 25 patients

OBJECTIVES

We report the acute results and midterm clinical course after percutaneous transluminal septal myocardial ablation (PTSMA) in symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM).

BACKGROUND

In the treatment of HOCM, surgical myectomy and DDD pacemaker therapy are considered the standard procedural extensions to drug therapy with negatively inotropic drugs. As an alternative nonsurgical procedure for reducing the left ventricular outflow tract (LVOT) gradient, PTSMA by alcohol-induced septal branch occlusion was introduced. However, clinical follow-up has not been sufficiently described.

METHODS

In 25 patients (13 women, 12 men; mean [+/- SD] age 54.7 +/- 15.0 years) who were symptomatic despite sufficient drug therapy, 1.4 +/- 0.6 septal branches were occluded with an injection of 4.1 +/- 2.6 ml of alcohol (96%) to ablate the hypertrophied interventricular septum. After 3-months, follow-up results of LVOT gradients and clinical course were determined.

RESULTS

The invasively determined LVOT gradients could be reduced in 22 patients (88%), with a mean reduction from 61.8 +/- 29.8 mm Hg (range 4 to 152) to 19.4 +/- 20.8 mm Hg (range 0 to 74) at rest (p < 0.0001) and from 141.4 +/- 45.3 mm Hg (range 76 to 240) to 61.1 +/- 40.1 mm Hg (range 0 to 135) after extrasystole. All patients had angina pectoris for 24 h. The maximal creatine kinase increase was 780 +/- 436 U/liter (range 305 to 1,810) after 11.1 +/- 6.0 h (range 4 to 24). Thirteen patients (52%) developed a trifascicular block for 5 min to 8 days requiring temporary (n = 8 [32%]) or permanent (DDD) pacemaker implantation (n = 5 [20%]). An 86-year old woman died 8 days after successful intervention of uncontrollable ventricular fibrillation in conjunction with beta-sympathomimetics in chronically obstructive pulmonary disease. The remaining patients were discharged after 11.3 +/- 5.4 days (range 5 to 24), after an uncomplicated hospital course. Clinical and echocardiographic follow-up was achieved in all 24 surviving patients after 3 months. No cardiac complications occurred. Twenty-one patients (88%) showed clinical improvement, with a New York Heart Association functional class of 1.4 +/- 1.1. A further reduction in LVOT gradient was shown in 14 patients (58%).

CONCLUSIONS

PTSMA of HOCM is a promising nonsurgical technique for septal myocardial reduction, with a consecutive reduction in LVOT gradient. Possible complications are trifascicular blocks, requiring permanent pacemaker implantation, and tachycardiac rhythm disturbances. Clinical long-term observations of larger patient series and a comparison with conventional forms of therapy are necessary to determine the conclusive therapeutic significance.

Pathological versus physiological left ventricular hypertrophy: a review

Left ventricular hypertrophy is recognized as an independent risk factor for cardiovascular morbid events. The primary mechanisms responsible for stimulating it are unknown. Epidemiological theories suggest that left ventricular hypertrophy is a continuous variable with no threshold, while morphological studies argue that it is the structure, or quality, and function of the myocardium (and therefore non-continuous), not the quantity of the myocardial mass, that poses the cardiovascular risk. Although left ventricular hypertrophy has been classically viewed as an adaptive response of the cardiovascular system to an imposed load, it has been demonstrated that haemodynamic overloading in selected hypertensive patients is not the sole determinant of left ventricular structure and function. Pathological and physiological states of left ventricular hypertrophy have been described primarily using criteria focusing on normal chamber performance and oxygen delivery as well as the reversibility of the hypertrophy once the overload is removed. Both states are also defined by the nature of the imposed load and the resulting myocardial adaptations. This review addresses the pathological and physiological states of left ventricular hypertrophy, the hypertrophy patterns, and the corresponding structural and functional characteristics, together with some of the biochemical factors thought to influence remodelling.

Prospective screening of 5,615 high school athletes for risk of sudden cardiac death

Sudden cardiac death among high school athletes is a very infrequent though tragic occurrence. Despite widespread preparticipation screening for known causes of this event, the frequency has not changed. The ECG is an acknowledged sensitive screening tool for the common causes of sudden cardiac death in young athletes. The specificity of the ECG in this setting is believed to be relatively low in young athletes for which reason, in part, it is not used. We added an ECG to the usual preparticipation screening. An echocardiogram was performed when screening was abnormal. Outcome measures of serious or potentially serious cardiovascular abnormalities were defined by the 16th Bethesda Conference. These abnormalities either preclude sports participation or require further testing before approval for participation in sports can be considered. Over 3 yr, 5,615 male and female high school athletes were screened prospectively from 30 different high schools in northern Nevada. Outcome measures were detected in 22 athletes or one per 255. Cardiac history led to detection of outcome measures in 0 athletes, auscultation/inspection in 1/6,000 athletes, blood pressure measurement in 1/1,000 athletes, and the ECG in 1/350 athletes. Specificity was 97.8% for an abbreviated cardiac history and auscultation/inspection and 97.7% for ECG. Overall, the ECG was a much more effective screening tool than cardiac history and auscultation/inspection in detecting cardiovascular abnormalities requiring further tests before approval for participation in sports could be given. ECG and cardiovascular history/ausculation/inspection had similar specificity ECG was efficiently performed on large groups of high school athletes.

The athlete's heart. Historical perspectives--solved and unsolved problems

Clinicians are coming back to Henschen's assessment of the athlete's heart as a physiologic and positive phenomenon. An athlete's heart may be affected by clinical conditions. Regarding the extreme performance of the athlete's heart in training and competition, conditions that may be harmless in sedentary people can be fatal for the athlete. The athlete's heart therefore deserves the particular interest and care of the sports cardiologist.

Causes of sudden death in young and middle-aged competitive athletes

The incidence of sudden death in athletes is low. Some pathologic conditions may predispose to sudden death during exercise in young athletes. In older individuals, exercise may trigger terminal arrhythmias in patients with severe coronary atherosclerosis. Screening programs with a history and a physical examination are recommended for high school and collegiate sports participants. For older individuals who are likely to have undetected or overt coronary heart disease and are exercising for physical fitness, caution regarding the level of activity and type of symptoms that are frequently associated with coronary disease may help prevent sudden death.

Fibromuscular dysplasia of small coronary arteries and fibrosis in the basilar ventricular septum in mitral valve prolapse

The mechanism of sudden cardiac death in patients with mitral valve prolapse is poorly understood. Twenty-four hearts from patients with mitral valve prolapse who suddenly died (mean age 34 +/- 8 years) and 16 trauma control hearts (mean age 30 +/- 7 years) were histologically studied. Dysplasia of the atrioventricular nodal artery was present in 18 of 24 hearts with mitral valve prolapse and four of 16 controls hearts (p = 0.003). The degree of luminal narrowing, as morphometrically measured, was significantly greater in hearts with mitral valve prolapse (p = 0.003). The degree of fibrosis in the base of the ventricular septum, as calculated by computerized morphometry, was greater in hearts with mitral valve prolapse (p = 0.0002) and independent of age, sex, and heart weight (p = 0.005). We conclude that arterial dysplasia in mitral valve prolapse may contribute to sudden cardiac death mediated by ventricular fibrosis.

Outer limits of the athlete's heart, the effect of gender, and relevance to the differential diagnosis with primary cardiac diseases

Two concepts from pathologic descriptions of myocardial hypertrophy in trained individuals merit consideration: (1) The heart of the trained athlete can be twice the normal size, but histologic structure remains intact, and (2) the weight of the trained heart does not usually surpass the limit of 500 g, defined as the critical heart weight. Even though this threshold cannot be accepted dogmatically, the concept of an upper limit for physiologic cardiac remodeling is nevertheless relevant to the clinical question of distinguishing extreme expressions of athlete's heart from primary pathologic conditions. This morphologic distinction depends on whether the magnitude of cardiac remodeling in athletes exceeds that expected as a result of athletic conditioning alone. There has also been a great interest in understanding the impact that types of athletic conditioning and gender have on defining the upper limits to which such physiologic hypertrophy may extend.

Risk profiles and cardiovascular preparticipation screening of competitive athletes

There has been heightened interest in the design and role of preparticipation screening for high school and college athletes. An American Heart Association consensus panel, composed of cardiovascular specialists and other physician experts having extensive clinical experience with athletes of all ages as well as a legal expert, assessed the benefits and limitations of preparticipation screening for early detection of cardiovascular abnormalities in competitive athletes. The panel addressed cost-efficiency and feasibility issues as well as the medicolegal implications of screening; and developed consensus recommendations and guidelines for the most prudent, practical, and effective screening procedures and strategies.

Sudden unexpected death in young adults including four cases of SADS: a 10-year review from the west of Ireland (1985-1994)

Sudden unexpected death in young adults of 18-35 years account for an important subset of deaths in our autopsy population. The case notes and autopsy reports in 44 subjects were analysed during the period 1985-94 at the Department of Histopathology, University College Hospital, Galway to establish the underlying cause of death. Subjects who were involved in road traffic accidents, cases of drowning, and patients with known congenital heart disease, chronic renal failure and malignancy were excluded. We found that a large proportion of sudden deaths in young adults were secondary to epilepsy and chemical/drug poisoning, accounting for 34 per cent and 31.8 per cent respectively. Sudden adult death syndrome (SADS) accounted for 9 per cent of the study population. Detailed case history, meticulous post-mortem examination and complete toxicological screening are recommended to arrive at the underlying cause of death.

Sudden cardiac death associated with hypoplasia of the coronary arteries and conduction system alteration

We present a case of sudden cardiac death in a 24-year-old woman with evidence of hypoplasia of the left anterior descending (LAD) and posterior descending (PDA) coronary arteries. These vessels averaged 0.7 mm in internal diameter combined, in contrast to an average of 2.4 mm in control coronary arteries (p < 0.001). The myocardium exhibited areas of acute and chronic ischemic change. Also, the cardiac conduction system (CCS) had diffuse cellular enlargement, believed to be secondary to ischemia. The cells of the sinoatrial node (SAN) and the Purkinje cells of the proximal right bundle branch (RBB) averaged 28.5 and 25.6 microns, respectively. These were significantly larger than the SAN cells (21.6 microns, p = 0.002) and larger than the Purkinje cells (15.9 microns, p = 0.012) of control cases. We report that hypoplastic coronary artery disease is a cause of sudden death, is associated with varying degrees of ischemic change in the heart, and can be associated with condition system alteration.

Echocardiographic criteria of physiological left ventricular hypertrophy in combined strength- and endurance-trained athletes

In combined strength- and endurance-trained athletes who are showing both unusual large body dimensions as well as a high physical fitness, the dimensions of the 'athlete's heart' are expected to reach physiological limits. Therefore we investigated 75 male and 77 female competitive rowers by means of doppler-echocardiography. The absolute "critical" heart weight of 500 g was exceeded by 61% of the male and 10% of the female rowers. Maximal values of the left ventricular (LV) muscle mass were measured at 170 (men) and 133 (women) g.m-2 body surface area, respectively. The LV end-diastolic internal diameter was measured to be above the upper clinical limit of 55 mm in 55% of the male and 17% of the female rowers. A LV wall thickness of 13 and 12 mm was only exceeded by 3 male and 1 female athlete, respectively (maximal values: 14 and 12.5 mm). The LV wall/internal diameter ratio did not exceed 48-50%. The systolic LV function as well as ECG and blood pressure did not reveal any pathological finding, the diastolic LV function was always measured within the normal range. The LV wall thicknesses, internal diameter and hypertrophic index (relation between wall thickness and internal diameter) of the rowers were significantly higher than those of 62 non-endurance trained athletes (pairwise matched according to the body dimensions) and similar to 28 male 'pure' endurance athletes (pairwise matched according to the absolute heart volume). In conclusion, upper limits of echocardiographic volume measurements that are considered critical may be clearly exceeded by healthy strength-endurance trained athletes with simultaneously high body dimensions. The clinical limits, however, are still valid in subjects with a body mass up to approximately 70 kg. The LV wall thickness only exceptionally exceed the clinical limits. A specific influence of the strength elements in training on the LV hypertrophy had not be found.

Anabolic Steroids: Effect and Regulation

Extracts of the testes of man and animal have been used for some time to enhance performance of a variety of sorts. Medical use of steroids dates back several decades, and recent intense athletic and fitness (bodybuilding) competition has driven some to use and abuse of testosterone and synthetic derivatives in the quest for that extra edge, despite a knowledge that anabolic steroids carry significant risk for liver, endocrine, and psychiatric toxicity, and also carry criminal penalties and disciplinary risks for athletes and health care workers who promote and traffic these substances outside their established medical uses.

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.

Triggers for sudden cardiac death in the athlete

Sudden death on the athletic field is usually due to underlying cardiovascular disease. Coronary artery disease is most common in older athletes, and a variety of congenital cardiovascular malformations predominate in young competitive athletes. Of these lesions, the most common in North America is hypertrophic cardiomyopathy. A variety of coronary artery anomalies are next in frequency, with the most important being anomalous origin of left main coronary artery from the anterior sinus of Valsalva.

Causes of sudden unexpected cardiac death in the first two decades of life

Sudden, unexpected cardiac death in the age group 1 to 21 years usually is due to myocarditis, hypertrophic cardiomyopathy, aortic valvar stenosis, and coronary arterial abnormalities. The hearts of 70 patients <21 years of age who died suddenly were reviewed. Twenty patients were <1 year of age and 50 were 1 to 21 years old. The cardiac findings were compared with those in 68 age-matched controls with known cardiac disease who did not die suddenly. Significant cardiac abnormalities were present in 13 (65%) of the 20 infants; 10 (50%) had anomalies of the aortic origin of the coronary arteries. Among the 50 older patients, cardiac abnormalities were found in 40 (80%), among whom coronary arterial anomalies existed in 12 (24%). Anomalies of aortic origin more frequently involved the left main than the right coronary artery in both groups.

Expanding indications for pediatric coronary artery bypass

Pediatric coronary artery bypass has been done mostly for ischemic complications of Kawasaki disease. We reviewed our clinical experience between 1987 and 1994 with internal thoracic artery-coronary artery bypass in one infant and five children for varying indications. Indications for coronary bypass included Kawasaki disease (2), congenital left main coronary ostial stenosis, iatrogenic coronary cameral fistula, anomalous origin of the left coronary artery from the pulmonary artery, and single coronary artery traversing between the great arteries in a patient after cardiac transplantation. An additional cohort of 34 control patients of various ages and weights (1 day to 16.1 years, 2.6 kg to 62 kg) had angiographic measurements of the right coronary, left coronary, and left internal thoracic arteries with respect to the feasibility of performing coronary artery bypass. All six patients survived internal thoracic artery-left anterior descending coronary artery bypass without evidence of perioperative myocardial infarction. Postoperative angiographic studies in five and color Doppler echocardiography in one showed graft patency. Retrospective angiographic measurements in the 34 control patients showed that internal thoracic and coronary arteries are proportionately quite large in neonates and infants compared with those in older children and adolescents. Internal thoracic artery-coronary artery bypass should be considered for the expanding indications presented herein and when emergency intraoperative life-threatening situations present themselves. Long-term patency and reoperation rates have yet to be determined.

Sudden cardiac death in hypertrophic cardiomyopathy: risk evaluation

Mortality due to hypertrophic cardiomyopathy is only around one percent per annum in unselected patients [1]. Therefore, the incidence of sudden cardiac death is still lower. However, identification of this small subgroup is important because prophylactic intervention may reduce mortality [2-5]. Unfortunately, we still do not have an accurate method of identifying this high risk subgroup.

[Cardiovascular evaluation in athletic children]

Although rare, sports related sudden cardiac deaths in children and adolescents justify the search for risk factors in any child or adolescent who wishes to practice sports. Each time that history and careful clinical cardiovascular examination point to a possible cardiovascular abnormality, an electrocardiogram and an echocardiography must be performed. Exercise testing is useful to appreciate the cardiovascular tolerance, either in normal subjects or in subjects with a cardiovascular abnormality; its interpretation requires good knowledge and understanding of hemodynamic responses to exercise. Indications, risks and procedures of exercise testing are discussed with reference to exercise physiology.

Regression of hypertrophic cardiomyopathy after modified Konno procedure

BACKGROUND

Septal myotomy-myectomy has been known to decrease the incidence of sudden death and produce regression in hypertrophic obstructive cardiomyopathy. Use of beta-blockers or calcium-channel blockers generally does not cause regression of the disease.

METHODS

Having successfully performed modified Konno procedures in 13 patients with effective relief of diffuse subaortic stenosis, we applied the procedure in 2 patients with hypertrophic obstructive cardiomyopathy. Both patients (18 and 12 years old, respectively) presented with syncope, angina at rest, and dyspnea despite being on calcium channel blocker therapy. The echocardiographic outflow gradients were 66 mm Hg and 88 mm Hg, respectively, with moderate mitral regurgitation.

RESULTS

Both patients had uneventful postoperative course. At 2 years and 1.5 years postoperatively, both patients were free of angina and syncopal episodes. Echocardiography showed absence of outflow gradients and mitral regurgitation. In 1 patient the septal and posterior wall thickness decreased from 3.4 and 1.7 cm preoperatively to 2.6 and 0.9 cm, respectively, postoperatively. In the other patient, the thickness decreased from 2.4 and 0.9 cm preoperatively to 0.8 and 0.7 cm, respectively, postoperatively. Left atrial diameter decreased from 5.4 to 4.7 cm in 1 patient, 3.5 to 2.6 cm in the other.

CONCLUSIONS

We believe that the modified Konno procedure could produce more effective relief of obstruction and, therefore, significant regression and further reduction in sudden death in hypertrophic obstructive cardiomyopathy. On the basis of our experience, albeit limited, we encourage its application.

Congenital heart disease and sudden death in the young

Sudden death is a frequent mode of fatal outcome in cardiac disease and does not exclude young people. The aim of this investigation was to establish whether and to what extent sudden death in the young may be ascribable to the substrate of underlying congenital heart disease. Among 182 young people (< or = 35 years) who died of cardiac sudden death and underwent postmortem examination, 58 (32%) had congenital heart disease. Seven showed an intrapericardial rupture of aortic dissection, in the setting of Marfan syndrome in two, isolated bicuspid aortic valve in two, and bicuspid aortic valve and isthmic coarctation in three; all exhibited equally severe degeneration of the aortic wall. Sixteen cases had conduction system anomalies, mostly bypass tracts; 15 coronary artery anomalies (three ostial valve-like stenosis, five origin from the wrong aortic sinus, and seven deep intramyocardial course); 12 hypertrophic cardiomyopathy; five postoperative congenital heart disease including scar following ventriculotomy, conduction system injury, and defects left unrepaired; and three congenital aortic valve stenosis. One third of sudden deaths in the young was ascribable to structural defects present since birth. A large spectrum of congenital heart disease involves the risk of sudden death, but most structural defects are usually not considered to be life threatening. Some of these concealed defects are potentially detectable in life by clinical imaging techniques.

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.

Isolated right ventricular infarction in a case of hypertrophic cardiomyopathy

A case of isolated right ventricular infarction in a young female with hypertrophic cardiomyopathy is reported. This case highlights the importance of detailed evaluation of right ventricle in cases with hypertrophic cardiomyopathy.

Clinical and prognostic evaluation of familial hypertrophic cardiomyopathy in two South African families with different cardiac beta myosin heavy chain gene mutations

BACKGROUND

Familial hypertrophic cardiomyopathy is the most common inherited cardiac disorder, with sudden cardiac death at a young age the most frequent cause of death in affected individuals. Some cases of familial hypertrophic cardiomyopathy are caused by missense mutations of the beta myosin heavy chain (beta MHC) gene on chromosome 14 and at least 17 such mutations have been described. Recent reports suggest that a correlation exists between a specific beta MHC gene mutation and prognosis in familial hypertrophic cardiomyopathy. This premise is currently being used as a basis to provide counselling for affected families. This mutation/prognosis association, however, has not been widely assessed as yet. The clinical and prognostic features of two South African families of mixed racial descent, in which different beta MHC gene mutations were segregating, were studied to evaluate this correlation. The results were compared with those of previously published reports of European families carrying the same mutations.

METHODS

The beta MHC gene missense mutations in two affected families were identified by single strand conformation polymorphism analysis and sequencing (pedigree 106: Arg403Trp; pedigree 108: Arg249Gln). All family members were subjected to genotypic analysis using polymerase chain reaction amplification and restriction enzyme based mutation detection techniques. Clinical, electrocardiographic, and echocardiographic studies were performed on genotypically affected individuals in these two kindreds.

RESULTS

The number of individuals identified in pedigree 106 with the Arg403Trp mutation was 32.10 individuals bore the Arg249Gln mutation in pedigree 108. The penetrance rate in adults (equal to or greater than 16 years), using the strict echocardiographic criterion of maximum left ventricular wall thickness > or = 13 mm, was 25% for pedigree 106 and 33% for pedigree 108. Familial hypertrophic cardiomyopathy compatible electrocardiographic and echocardiographic abnormalities were seen in 60% of genotypically positive individuals aged > or = 16 years in pedigree 106 and 80% in pedigree 108. The prognosis was uniformly benign in the two families. For pedigree 106 this corresponded to a report of no early sudden cardiac deaths in a French family with the Arg403Trp mutation. For pedigree 108 the absence of such deaths was in apparent contrast to the four cases reported in 24 genotypically affected individuals in a study of a kindred of European ancestry bearing the Arg249Gln mutation.

CONCLUSION

This study of a large South African kindred confirmed the benign nature of the Arg403Trp mutation suggested in a previous report. The number and the relatively young age of affected individuals in a second South African family must be considered when comparing the absence of familial hypertrophic cardiomyopathy associated deaths with the intermediate survival reported for the Arg249Gln mutation in a European family. This investigation lends support to current evidence relating specific beta MHC gene mutations to prognosis, which may be used as a basis to provide counselling for affected families.

Clinical presentation and long-term follow-up of athletes with exercise-induced vasodepressor syncope

The purpose of this study is to report on a series of patients who were referred for evaluation of syncope that occurred during or immediately after exercise and in whom a diagnosis of vasodepressor syncope was established (9 women and 8 men; mean age of 28 +/- 17 years). The approach to management was individualized in each patient. All patients were monitored to determine the frequency and type of recurrent symptoms. The mean age at onset of symptoms was 23 +/- 16 years. In 10 patients syncope occurred only in association with exercise. Pharmacologic therapy was successful in normalizing the patients' response to upright tilt in each of the 10 patients in whom it was attempted. During a mean follow-up period of 35 +/- 9 months, none of the patients placed on pharmacologic therapy has had recurrent syncope. Seventeen (88%) of 19 patients have resumed participation in athletics. The results of this study demonstrate that vasodepressor syncope is a cause of syncope in athletes and that patients with exercise-related vasodepressor syncope can safely continue to participate in athletics.

Syncope associated with exercise, a manifestation of neurally mediated syncope

A retrospective review of patients evaluated at a university-based referral hospital was performed to assess the basis for syncope associated with exercise in young patients. Over an 8-year period, 54 consecutive young patients (aged 12 to 30 years) were referred for evaluation of frank syncope. Twelve patients had syncope associated with exercise (group I) and 42 patients had syncope not associated with exercise (group II). Patients underwent physical examination, chest x-ray, 2-dimensional echocardiography, and in selected cases, cardiac catheterization. Head-up tilt-table testing was performed in 11 of 12 group I patients. Ten group I patients had no evidence of structural heart disease: 9 of these 10 (90%) developed syncope with tilt-table testing. Head-up tilt-table testing was performed in 41 of 42 group II patients: 34 (83%) developed syncope with tilt-table testing. Standard cardiac electrophysiologic study was performed in 9 of 12 group I and in 30 of 42 group II patients, and identified a basis for syncope in only 2 group I and 1 group II patients. Among 9 group I patients with a positive result on head-up tilt-table testing and no evidence of structural heart disease (mean follow-up 4.3 years), 7 are without further episodes of syncope; 3 have discontinued medication and 5 have resumed at least limited exercise. In conclusion, susceptibility to tilt-induced syncope was the most frequent finding in young patients without structural heart disease referred for evaluation of exercise-associated syncope. Tilt-table testing may be an important diagnostic tool for the evaluation of these patients.

Ventricular tachycardias with left bundle branch block morphology

The differential diagnosis of VTs with LBBB morphology includes several well-defined syndromes. Although the majority of cases are attributable to acquired structural heart disease, including ischemia, prior infarction, or dilated cardiomyopathy, consideration of specific right ventricular processes is essential to proper evaluation and treatment. The approach to older patients or those with evidence for heart disease should begin with an evaluation for coronary artery disease and an assessment of biventricular function. Careful evaluation for bundle branch reentry should be performed during electrophysiological study, especially when there is underlying conduction system disease. Younger patients, those without overt heart disease, or those with isolated right ventricular disease, should receive a complete noninvasive evaluation of right and left ventricular size and function. An abnormal SAECG or identification of intracardiac late potentials suggest right ventricular dysplasia or cardiomyopathy, whereas responsiveness to adenosine and absence of detectable heart disease support the diagnosis of idiopathic right VT. Newer techniques, including MRI, show promise in identifying subtle right ventricular disease not otherwise detectable even in the setting of presumed idiopathic right VT. Following surgical repair of selected congenital heart defects, particularly tetralogy of Fallot, symptoms of recurrent palpitations, near syncope, syncope, or aborted sudden death may be attributable to recurrent VT, and diagnostic electrophysiological study should be considered for these patients. Finally, SVTs with LBBB morphology, particularly cases associated with right-sided or septal accessory pathways, should always be considered in this differential diagnosis.

Myocardial bars and bridges and sudden death

A congenital variant of the anatomical arrangement of the coronary arteries, that can be observed both angiographically and at autopsy, is the embedding of these vessels within a tunnel of the subepicardial myocardium. Both clinical and pathological claims and counterclaims have been made as to the functional consequences of this variation, the implication being that the contraction of the peri-vascular myocardium particularly at accentuated heart rates would cause occlusion of the blood flow within these arteries. The consensus is that this variant is only of significance when it occurs around a significant portion of a dominant left main coronary artery in which instances it may be the cause of sudden death during the course of strenuous exercise.

Medicolegal Challenges of Advising At-Risk Patients

In brief The case of a talented baseball pitcher who has Marfan's syndrome sets the stage for an examination of the medicolegal issues posed by athletes at risk for sudden death. The medical literature is somewhat unclear whether sports participation is unsafe for all individuals with Marfan's syndrome. Legal precedent has established guidelines on the "right to participate" and on informed consent. For medical and legal reasons, physicians need to establish appropriate risk management and informed consent procedures.

Role of myocarditis in athletes with minor arrhythmias and/or echocardiographic abnormalities

We report the clinical and instrumental data, including the endomyocardial biopsy findings, of six young athletes presenting with minor arrhythmias and/or echocardiographic abnormalities. In one of them, a left ventricular dilation with moderate depression of the systolic function had been attributed to an athlete's heart. A diagnosis of arrhythmogenic right ventricular dysplasia had been made in three others, one with right ventricular dilation and apical hypokinesia, and two with ventricular arrhythmias with QRS morphology of left bundle branch block. A myocarditis could be unequivocally established in four athletes (two with and two without fibrosis). In the remaining two, with a clinical history strongly suggesting a previously acute myocarditis, the endomyocardial biopsy specimen revealed a nonspecific fibrosis compatible but not definitely pathognomonic of a healed myocarditis. Our report suggests that a myocarditis may be a cause of minor rhythm disturbances and/or echocardiographic abnormalities in athletes. A prevalent localization of the inflammatory process in the right ventricle with or without the occurrence of ventricular arrhythmias with left bundle branch block morphology can mimic an arrhythmogenic right ventricular dysplasia. An early diagnosis of myocarditis in athletes is useful to avoid the risk of fatal arrhythmias, also considering that rest still keeps on being one of the most effective strategies in myocarditis management.

Chest Pain in Active Young People

In brief Chest pain in children and adolescents is usually benign and noncardiac, unlike that in adults. Some of the more common causes are activity related, such as chest wall trauma and exercise-induced asthma. A careful history and physical examination will often provide a diagnosis, though about one third of causes are idiopathic. Most patients will not require extensive testing or referral. Education and reassurance are essential for relieving patient and parent anxiety.

Surviving competitive athletics with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HC) is probably the most common cause of sudden cardiac death in youthful athletes, and this diagnosis has represented a contraindication to continued participation in competitive sports. Less well appreciated is the fact that within the clinical spectrum of HC are patients who, despite having this disease, have been able to undertake particularly intensive and often extraordinary levels of training for sports competition over many years without dying suddenly. Fourteen such patients (13 men and 1 woman, aged 30 to 66 years [mean 43]) form the present study group. HC was initially identified at 24 to 57 years of age (mean 34), usually under fortuitous circumstances. Patients most often competed in distance running (including the marathon, 7), but also in swimming, triathalon, basketball, and football. The duration of training ranged from 6 to 22 years (mean 15) and 5 continue to train and compete actively. The magnitude of training, competition, and achievement was considerable in most patients; 12 of the 14 performed either at the national, collegiate or professional level in their sport, completed numerous marathon and triathalon events, or sustained particularly rigorous training regimens of > or = 50 miles/week. Echocardiographic studies demonstrated a left ventricular wall thickness of 18 to 28 mm (mean 20) in most patients (12 of 14) having a relatively localized pattern of ventricular septal hypertrophy. It is possible for some patients with HC to tolerate particularly intense athletic training and competition for many years, and even maintain high levels of achievement without incurring symptoms and disease progression or dying suddenly.(ABSTRACT TRUNCATED AT 250 WORDS)

Sudden death screening

SCD is a tragic-event that rarely affects exercising individuals. It is important for the practitioner to recognize the normal physiologic changes that occur in the exercising athlete that correspond to AHS so as to differentiate them from conditions placing an athlete at risk for SCD. Different clinical entities account for SCD in athletes under age 30 as opposed to over age 30, although there is some overlap. Comprehensive and expensive screening tests have not proved to be cost-effective, nor are they able consistently to identify athletes at risk. A quality history and thorough cardiac screening examination are the best means to identify athletes at risk for SCD and lead to a cost-effective means to pursue further workup. Table 7 lists a screening battery of tests and what the tests detect and miss. In general, a history and physical examination detect aortic stenosis and a portion of HCM and Marfan's syndrome. If the physical examination is suggestive of Marfan's syndrome and a chest roentgenogram is done, a larger portion of cystic medial necrosis will be found. When an ECG is added to the series, most of the HCM patients at risk for SCD can be diagnosed. In addition, if echocardiography is added, most patients with HCM and cystic medial necrosis can be identified. If an exercise stress test is then performed, 20% of coronary artery disease and congenital artery anomalies are identified. Additional studies, including Holter monitoring, electrophysiologic studies, and thallium scintigraphy, can be added to identify further at-risk patients. Because some asymptomatic patients present with SCD, it is virtually impossible to identify comprehensively all patients at risk. By knowing what questions to ask, performing a thorough cardiac screening examination, and being more aware of potential diagnostic clues, the practitioner can feel comfortable in identifying most patients at risk for SCD. Specific history and physical examination guidelines regarding screening for competition are included. Supplemental information is found in the 16th Bethesda Conference. In addition, a well-outlined emergency plan needs to be established when physicians, athletic trainers, or coaches are working with athletes. Proper recognition of cardiac symptoms is a key point. Appropriate education including basic first aid and cardiopulmonary resuscitation training should be encouraged for anyone working extensively with athletes. The emergency plan should include on-site treatment, mechanism to contact emergency personnel, and proper transport to a qualified facility.

Medical problems in a sports medicine setting

Becoming reliant on a diagnostic repertoire limited to common sports-related problems can result in delayed diagnoses and potential disservice to the athlete. Remaining aware of other conditions that can mimic the common disorders and maintaining an index of suspicion for their occurrence can aid both the primary care physician and the specialist when challenged with a refractory or atypical presentation in an athlete. Reliance on a thorough history and physical examination, with judicious use of ancillary testing, is the cornerstone for any medical evaluation and no less important in this scenario. When equipped with such knowledge and skills, the physician caring for athletes can provide the best possible service, insuring not only the individuals' overall health, but also their safe and complete return to their chosen sport.