Best predictor of sudden cardiac death
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In 2002 we learn that the best noninvasive predictor of sudden cardiac death in young men is exercise-related fainting.
Although the direct medical costs of sudden cardiac death are much less than for lingering illnesses, its economic and social impacts are huge. Sudden death is cheap for the HMO, leading the layman to suspect that public policies and practices may be unwise to include so little cardiac screening. Perhaps also health clubs with their treadmills could provide some self-administered screening?
Among young athletes, about 1 in 200,000/year die from unexpected, sudden cardiac arrest. Of 10,000 male students at my university, this happens only about once every 20 years. All but one of 20,000 youths would pass from age 18 to age 28. The number of days Jos should have had remaining in his life is about 20,000. Thus, any test or preventive action that would require more than about a day is not economically defensible, while simpler measures should be.
Although Jos was a lifelong member of expensive HMO's, we believe he never had an electrocardiogram (ECG) -- a test performed by a technician in five minutes. Since five minutes is less than a day, we believe it is irresponsible for our HMO not to routinely take ECGs. Yet we know they do not, even for older people. As for "reading" the ECG, that would be best done at a national lab, or by a computer program supplied by experts in statistics and signal processing because physicians commonly fail to recognize the symptoms. And the ECG is an imperfect test producing perhaps 2000 false positives for each real positive. (Those false positives go on to other exams.)
What happens: A rapid and/or chaotic activity of the heart (ventricular tachycardia or fibrillation) often leads to cardiac arrest.
Why it happens: The cardiac community seems divided in two camps, the mechanical and the electrical (the plumbers and the electricians). Most health practitioners are of the mechanical group (regard the root cause as congenital cardiovascular structural abnormalities) although death is generally electrical (fibrillation). Although the electrical side is not well understood, we do know that the heart can often be fixed by the thousand volt shock of a defibrillator (which is akin to rebooting a computer). First we'll look at the medical practitioner side and then we'll return to the electrical side.
The American Family Physician (1998) says congenital cardiovascular disease is the leading cause of nontraumatic sudden death in young athletes. Screening athletes for disorders capable of provoking sudden death is a challenge because of the low prevalence of disease, and the cost and limitations of available screening tests.
An editorial in The New England Journal of Medicine (August 10, 1995 -- Vol. 333, No. 6) says, "We know little or nothing about the pathophysiologic mechanisms that trigger sudden death, effective screening techniques, or preventive strategies."
Barry J. Maron, MD, frequently publishes on the topic. Two quotes from him:
Researchers (as contrasted to clinicians) work in a variety of fields, pharmacology, biophysics, electrical engineering, electrophysiology, and applied mathematics. They view heart attack as an electrical process akin to wave theory. I have written a simplified introduction to Spiral Waves. After my introduction, you might like to see the technical literature. Some of it is clearly written (because it is proposals for funding). You could do a search on cardiac spiral waves. Here are some characteristic links: (1), (2), (3).
I am suggesting that fibrillation might perhaps be predicted more reliably by electrical measurements than by imaging. And presumably, electrical measurements could be made in conjunction with exercise at a health club. Modern electronics should allow much more extensive measurements to be taken unobtrusively.
Search on interpretation of Holter Monitor, search on ambulatory electrocardiography. Cardiovascular annotated bibliography
If the HMO had given Jos an ECG, he might have had some warning. He was a very prudent person and would have taken practical steps to fend it off (such as reducing heavy exercise and stress). The ECG does not always provide a warning, and even if warned, defensive steps are not always effective.
Adding it all up, however, the HMOs were negligent because the cost of an ECG is five minutes compared the much greater loss of a 20,000 day life with probability 1/20,000. The cost effectiveness is five minutes of prevention for one day saved.
The medical records of my son are not today centralized in any web-based data base. Consequently, records of his health and death are virtually inaccessible to researchers.