Transcript EP show 2
The EP show: State-of-the-art in athlete’s heart Eric Prystowsky MD Director Clinical Electrophysiology Laboratory St Vincent Hospital Indianapolis, IN Barry Maron MD Director Hypertrophic Cardiomyopathy Center Minneapolis Heart Institute Foundation Minneapolis, Minnesota Athlete’s heart A case history: presentation Identification 16 year-old boy History 2 year history of sudden onset and termination of a regular, rapid palpitation causing dizziness, occurring at rest Holter monitoring revealed 1 asymptomatic 6beat run of nonsustained VT at 140 bpm Echocardiogram and MRI of his heart are normal Athlete’s heart Hypertrophic cardiomyopathy Cardiovascular diseases in a healthy, young person who is also an athlete are all uncommon in the general population. Most such diseases are complex and often require sophisticated testing for diagnosis. The single most common disease causing sudden death in young athletes (responsible for 1/3 of all cases) is hypertrophic cardiomyopathy (HCM). Athlete’s heart Congenital coronary anomalies The second most frequent group of diseases are the congenital coronary anomalies of wrong sinus origin. Of these, the anomalous origin of the left main coronary from the anterior or right sinus of Valsava is the most frequent. This is a surgically correctable condition, and a high index of suspicion is required in any young athlete with impaired consciousness on exertion. Athlete’s heart Additional diagnoses Additional diseases account for no more than 5% of the overall population of sudden death. These include aortic valve stenosis, atherosclerotic coronary disease, dilated cardiomyopathy, and arrhythmogenic right ventricular (RV) dysplasia. A small subset of these athletes at autopsy are found to have grossly normal hearts on anatomic and histological examination. This group of diseases includes the long-QT syndrome. Athlete’s heart Arrhythmogenic RV dysplasia For > 20 years Italy has instituted a systematic annual screening program of all athletes in organized sports, which includes a 12-lead ECG and echocardiogram if necessary. Arrhythmogenic RV dysplasia is the most common cause of athlete sudden death in the Veneto region of the country. Screening, coupled with a genetic substrate, are likely responsible for the low incidence of HCM as a cause of sudden death. Corrado D, et al. N Engl J Med 1998;339:364-9 Athlete’s heart An Italian cohort Causes of sudden death in athletes 35 years in the Veneto region, Italy, 1979-1996 (N=49) Arrhythmogenic RV dysplasia Atherosclerotic coronary artery disease Anomalous origin of coronary artery Conduction system disease Mitral valve prolapse Hypertrophic cardiomyopathy Other 11 9 6 4 5 1 13 Corrado D, et al. N Engl J Med 1998;339:364-9 Athlete’s heart Prevalence data Over a 12-year period in Minnesota, the prevalence of sudden death in young athletes (interscholastic sports, grades 912), was 1 per 200 000. This has become a significant public health issue, not because of the absolute numbers, but because of the symbolism of the death of a young adult who is otherwise the epitome of perfect health. The visibility of these events is also increased substantially by the news media. Athlete’s heart The issue of screening “Anytime you have rare diseases that constitute a very small proportion of the population…it's sort of like looking for a needle in a haystack... But this is part of our customary practice in the United States and has been for 50 years…high school and collegiate athletes have the advantage at least of attempting to identify abnormalities that could be injurious.” Barry Maron MD Director Hypertrophic Cardiomyopathy Center Minneapolis Heart Institute Foundation Athlete’s heart The difficulty in screening A screening system is already in place, but the diseases in question are difficult to detect from a history and physical alone. For example, patients with nonobstructive HCM may not present with syncope or have a family history of sudden death. A loud murmur may not be present on exam. In addition, a large proportion of colleges and states (>30%) do not have in place the questionnaires recommended by the American Heart Association as guides for history taking and physical examination. Athlete’s heart The results of screening Due to confidentiality restrictions, the actual effectiveness of screening interventions in the United States has not been determined. The Italian experience demonstrates the involvement of government in the screening process. If funded by government sources, an ideal screening intervention would include echocardiograms in addition to 12-lead ECGs. Newer, handheld 2-dimensional echocardiographic instruments may be useful additions to screening programs. Athlete’s heart The ECG as screening test Hypertrophic cardiomyopathy may be identified by a screening 12-lead ECG. Coronary anomalies which are difficult to identify clinically may appear normal on ECG testing, because of the presence of periodic, or “burst” ischemia. Altogether, the ECG is empowered, and a reasonable compromise based on cost comparisons. Athlete’s heart Screening is not cost-effective “…it is one of those discussions that truly pits money against saving lives. Because it will never, I don't care how you do it, be cost effective. You said to begin with, 1 in 200 000. My goodness, I don't care if the test costs a dollar. If the test costs a dollar, it's not cost effective, according to the current guidelines.” Eric Prystowsky MD Director Clinical Electrophysiology Laboratory St Vincent Hospital Athlete’s heart Commotio cordis: etiology This is the phenomenon of a blunt blow to the chest causing instantaneous sudden death. Commotio cordis occurs in the absence of heart disease, and is a circumstance in which mechanical energy is immediately converted to an electrical distortion. The blow (hockey puck, baseball) is positioned directly above the heart on the left side of the chest and is precisely timed to the vulnerable part of repolarization, 1520 msec prior to the T-wave peak. Athlete’s heart Commotio cordis: prevention Any “chest barrier” used for protection needs to be compatible with the game in question, and should be effective in preventing the transfer of mechanical-electrical energy. Softer than normal balls may also be an effective preventive measure. Experimental models have not yet validated these possibilities. An automated external defibrillator (AED), if present in a public facility (sports stadium, for example), could certainly be lifesaving in this situation. Athlete’s heart A case history: diagnosis Differential diagnosis Wolfe-Parkinson-White syndrome versus AV-node reentry A normal MRI of the heart does not show fat replacement in the wall of the RV, and is therefore not consistent with arrhythmogenic RV dysplasia. Occasionally, a work-up requires diagnostic coronary angiography. Athlete’s heart A case history: management Electrophysiologic testing is the diagnostic procedure of choice, and very likely would be followed by an ablation procedure if the diagnosis of paroxysmal supraventricular tachycardia were confirmed. Nonsustained VT in this normal heart is not a risk factor for sudden death and this 16-year old boy should be able to return to a normal life in sports.