The medical information necessary to determine the cause of cardiac arrest was available for 31 of the 59 runners with cardiac arrest. These 31 runners did not differ significantly with respect to age (mean, 39±12 years; range, 22 to 65) or sex (26 [84%] were men) from the entire group of 59 runners described above or from the 28 for whom consent or full medical records could not be obtained. Of the 31 runners for whom complete clinical data were obtained, 23 had died. Notably, 9 of the 15 nonsurvivors who had cardiac hypertrophy had an additional clinical factor or postmortem finding: obstructive coronary artery disease (in 3), myocarditis (in 2), bicuspid aortic valve or coronary anomaly (in 2), accessory atrioventricular nodal bypass tract (in 1), or hyperthermia (in 1). Causes of death in the absence of left ventricular hypertrophy included hyponatremia (in 1 person), hyperthermia (in 1), arrhythmogenic right ventricular cardiomyopathy (in 1), and no evident abnormality on autopsy or presumed primary arrhythmia (in 2). Data from the medical evaluation of survivors after cardiac arrest are shown in . Ischemic heart disease (in 5 of 8 runners) was the predominant cause of cardiac arrest among survivors. None of the runners with serious coronary atherosclerosis had angiographic evidence of acute plaque rupture or thrombus.
This study provides several insights into race-related cardiac arrest. First, the absolute number of race-related cardiac arrests each year increased over the past decade. This is best explained by the parallel increase in participation, because overall annual incidence rates of cardiac arrest were stable. Second, men were more likely than women to have cardiac arrest and sudden death. This finding is consistent with reports on other populations and reaffirms a male predisposition to exertional cardiac arrest. A plausible explanation for this observation is the higher prevalence of both occult hypertrophic cardiomyopathy and early-onset atherosclerosis in men. The finding that event rates among male marathon runners increased during the study period is troubling and may indicate that long-distance racing has recently been attracting more high-risk men with occult cardiac disease who seek the health benefits of routine physical exercise. Future work is needed to further characterize this group and to determine useful prevention strategies. A possible explanation is that longer races involve more physiological stress and thus a higher likelihood of precipitating an adverse event in a predisposed participant. Finally, cardiovascular disease accounted for the majority of cardiac arrests. Hypertrophic cardiomyopathy, the primary cause of death in young competitive athletes, was also the leading cause of death in this population. Alternative race-related disorders, including hyponatremia and hyperthermia, remain important concerns but are uncommon causes of cardiac arrest and sudden death.
This disease affects the myocardium (middle layer of the heart that helps it contract) by becoming abnormally thick and this doesn’t allow the heart to pump normally.
Often times people with HCM can lead a normal life with no significant problems.
The few symptoms that HCM has are: Dizziness, fatigue, flutter or pounding heartbeats, heart murmur, and shortness of breath chest pain and fainting especially during exercise.
Not everyone but some people with HCM have complications such as arrhythmias, obstructed blood flow, dilated cardiomyopathy, mitral valve problems, heart failure and sudden cardiac death.
Sammy Elmariah, Michael A. Fifer. . (2012) Medical, Surgical and Interventional Management of Hypertrophic Cardiomyopathy With Obstruction. 14:6, 665-678.
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The overall case fatality rate was 71%. This compares favorably with previous data on out-of-hospital cardiac arrests (median case fatality rate, 92%). This may be due to the fact that running races often have a high density of spectators as well as on-site medical services that facilitate timely emergency intervention. The finding that early bystander-administered CPR and use of automated defibrillators at the scene of the arrest were common for survivors of cardiac arrest underscores the notion that the race environment contributed to high resuscitation rates. There was also an association between age and cardiac-arrest outcome, with In contrast, older persons who have cardiac arrest are more likely to have had ischemic heart disease. In our study, runners with ischemic heart disease, most of whom were successfully resuscitated, had coronary angiographic and autopsy data suggesting a mismatch between oxygen supply and demand, not acute plaque rupture.
Cause of death was determined from cardiac-arrest clinical care documentation and autopsy data. Hypertrophic cardiomyopathy (left ventricular mass >500 g) and possible hypertrophic cardiomyopathy (left ventricular mass between 400 and 499 g for men and between 350 and 499 g for women) were diagnosed with the use of autopsy criteria that integrate cardiac mass with findings that supported the diagnosis, including family history of hypertrophic cardiomyopathy; characteristic features of the gross anatomical cardiac architecture, including marked asymmetry and mitral-valve elongation; markedly increased left ventricular wall thickness; and disease-specific histologic findings. Arrhythmogenic right ventricular cardiomyopathy was defined by the presence of a lipomatous transformation or a fibrolipomatous transformation of the right ventricular free wall. Diagnostic criteria for alternative causes of death were adopted from clinical guidelines. For survivors, we used the diagnostic data documented after the cardiac arrest to determine the cause of the arrest.
What causes hypertrophic cardiomyopathy?
Hypertrophic cardiomyopathy usually is inherited. It's caused by a change in some of the genes in heart muscle proteins. HCM also can develop over time because of high blood pressure or aging. Diseases such as diabetes or thyroid disease can cause hypertrophic cardiomyopathy. However, the cause of the disease isn't known.
Hypertrophic cardiomyopathy (HCM) is very common and can affect people of any age. It affects men and women equally. It is a common cause of sudden in young people, including young athletes.
Hypertrophic cardiomyopathy occurs if heart muscle cells enlarge and cause the walls of the ventricles (usually the left ventricle) to thicken. The ventricle size often remains normal, but the thickening may block blood flow out of the ventricle. If this happens, the condition is called obstructive hypertrophic cardiomyopathy.
Sometimes the septum, the wall that divides the left and right sides of the heart, thickens and bulges into the left ventricle. This can block blood flow out of the left ventricle. Then the ventricle must work hard to pump blood. Symptoms can include , dizziness, shortness of breath, or .
Hypertrophic cardiomyopathy also can affect the heart's mitral valve, causing blood to leak backward through the valve. Sometimes, the thickened heart muscle doesn't block blood flow out of the left ventricle. This is referred to as non-obstructive hypertrophic cardiomyopathy. The entire ventricle may thicken, or the thickening may happen only at the bottom of the heart. The right ventricle also may be affected.
In both obstructive and non-obstructive HCM, the thickened muscle makes the inside of the left ventricle smaller, so it holds less blood. The walls of the ventricle may stiffen, and as a result, the ventricle is less able to relax and fill with blood.
This can raise in the ventricles and the blood vessels of the lungs. Changes also occur to the cells in the damaged heart muscle, which may disrupt the heart's electrical signals and lead to .
Some people who have HCM have no signs or symptoms, and the disease doesn't affect their lives. and complications. They may have shortness of breath, serious arrhythmias or an inability to exercise.
It is rare, but some people with hypertrophic cardiomyopathy can have sudden cardiac arrest during very vigorous physical activity. The physical activity can trigger dangerous arrhythmias. Ask your doctor what types and amounts of physical activity are safe for you.
Other Names for Hypertrophic Cardiomyopathy