Parent and Coache Guide to Self-Diagnosing Hypertrophic Obstructive
Cardiomyopathy (hypertrophe obstruktive kardiomyopathie)
first draft, 04/18/2007
This is developed as a public service. If you have suggestions on how to improve this document please contact us at . Several days ago I had attended public lecture at Stanford University on Advances in Pediatric Cardiology. There I met parents of young 25 year old athlete and Silicon Valley engineer who died suddenly at work after morning work-out in gym. This meeting had inspired me to attempt to develop self-help guide for young athletes, their parents, coaches and primary care physicians.
HOCM is considered a rare genetic disease, with 2 cases out of thousand live births, and not all of them are deadly. But if it develops then the risk of mortality is very high and it is often without symptoms. In some cases, the first and only manifestation of hypertrophic cardiomyopathy is sudden death, caused by a chaotic heartbeat. Patients can take certain medications (such as beta blockers), wear implantable cardiac defibrillator (ICD) and should avoid active physical exercises, competitive team sports, etc. It is important to diagnose this disease early on.
2. HOW TO DIAGNOSE
a)This disease can be easily diagnosed using 2D ultrasound and Doppler C Ultrasound exam (Echo Exam). Cost of this exam is approximately $400-1200, so health care system can not possibly absorb conducting it to 8-10 million young athletes.
b)EKG exam can diagnose abnormal EKG that is typical to HOCM patients. EKG costs $80 and can be conducted on much wider scale, however it can only show heart conduction abnormality, can not really diagnose HOCM. But it is a start. In Italy EKG is "prescribed" to all athletes, and if abnormal then Echo Exam is conducted.
c)HOCM has characteristic systolic murmur that sound similarly with murmur of aortic stenosis. It can be diagnosed simply by using stethoscope! Stethoscope is to be applied to the chest at the lower left sternal border (tricuspid location). You should be able to hear this murmur clearly when patient is in supine position.
3. DO IT YOURSELF RATIONALE
Health care costs rationale suggests that there is not enough of pediatric cardiologists
to do (a), (b) and may be even (c). In modern health care delivery it is difficult to rationalize mass screening of a very rare disease. Your general practitioners should be able to detect the disease during a routine physical exam, but regrettably it was shown that in general physicians have low heart auscultation skills(article1, article2) and they are at 20-30% of what they should be. This is also a rare condition, so physicians to do not get much practice in detecting it. Recent research demonstrated that with repetitive listening of specific heart sounds heart auscultation skills can be improved considerably. All humans are capable to differentiate sound, so anyone with some training can detect this specific murmur.
Parents of athletes should learn how to detect it and team coaches and school medical
officers should learn as well.
4. HOW TO DO IT AND WHAT DO I NEED TO KNOW.
|First of all you need listening device. I suggest inexpensive electronic stethoscope used for pre-natal listening. It is called Bebe Sounds and costs $25 in Wal-Mart (or less on eBay) and allows up to 2 people to listen. List of more expensive options can be found on http://www.bsignetics.com/hardware.htm|
Place patient in supine position and listen for heart sound at the lower left
sternal border location. Normal heart will have characteristic
two component sound.
Heart sound of HOCM will have (Anthony Don Michael, MD - Heart Auscultation, 1998)
LU tRRR drup
three component sound with RRR being responsible for midsystolic murmur of HOCM.
Please download wave sound track files below and listen to it repeatedly
to memorize for later identification.
EXAMPLES (right click, "save as" to download, listen in "loop" mode):
HOCM (70 mm Hg), 11kHz recording
HOCM (130mm Hg), 11kHz recording
This murmur can be mild to severe causing 10-15 mm Hg to 100 mmHg pressure gradients (with murmurs being grade II to grade IV). Gradient and obstruction can increase during or after physical exercise.
If murmur is detected you should immediately visit pediatric cardiologist for a further
workup. Note that this is genetic deficiency, so other relatives may be affected.
Some murmurs are benign (innocent). You may mistakenly identify innocent murmur
as HOCM. But even in this case visit to a physician is well justified.
5. ADVANCED TECHNIQUES
HOCM murmur is rather unique. As opposite to innocent and many other heart murmurs
it increases in intensity on standing. Usually most of murmurs decrease its intensity on
standing or even completely disappear. So if you hear this murmur in standing position and hear it much better than in supine position then there is a good chance that you in fact detected HOCM.
Even more advanced technique involve so-called Valsalva maneuvere (see appendix).
It produces immediate increase in the loudness of HOCM murmur.
6) Other considerations
Not all cases of sudden deaths are due to HOCM, but many are. Even if one single life can be saved - then it is worth doing! Not all cases of HOCM can be manifested with a strong easily detectable murmur. But all cases with high degree of obstruction (pressure drop) will have a clear diagnosable murmur, the larger obstruction - the higher the risk. Finally, advanced techniques (such as Valsalva or hand grip) can help to identify cases even with a low degree of obstruction.
If we are capable to listen music, use computer or change channels with remote control
then we should be able to hear HOCM coming and possibly save young life this way.
A) Review article below published by American Family Physician -
Cardiovascular Screening of Student Athletes
B) page 177, Anthony Don Michael, MD, Auscultation of the Heart
To detect HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY HOCM, the diaphragm of
the stethoscope is used in combination with dynamic auscultation at the left lower sternal border. ... Valsalva maneuvre , IN WHICH THE PATIENT LIES
SUPINE AND PUSHES THE ABDOMEN AGAINST THE HANDS OF THE EXAMINER WHILE THE
EXAMINER LISTENS OVER THE HEART; or by having the patient strain, producing the immediate increase in the loudness of the murmur. Having patient to stand accentuates the murmur, while having the patient squat, lie supine decreases it.
C)Importance of intracavitary gradient. (M. Borggrefe, Mannheim , DE )
M. Borggrefe, MD (Mannheim, Germany) discussed the importance of the intracavitary gradient. The pathophysiology of left ventricular obstruction was outlined, discussing all variables that may enter in the mechanism of the obstruction (anterior mitral valve motion and pushing of the leaflet onto the septum, orifice reduction, abnormal intracavitary pressure generation, the flow that invests the mitral valve (angle of attack), cordal slack, the extent of left ventricular hypertrophy, as well as elongated mitral valve). The increase of the left ventricular pressure actually increases wall stress, and induces myocardial ischemia and cell death. Interventions aimed at reducing the obstruction and lowering the intraventricular pressure could positively reflect on the risk of sudden death. Dr. Borggrefe reported a series of 10 patients with obstructive HCM: their history was characterised by sustained ventricular tachyarrhythmias. They all were SD survivors and all had inducible VT/VF at PES. The post-operative follow-up (13±2 years) documented the absence of inducible VT/VF. He concluded his presentation by stating that that although the gradient is not the disease, it is associated with less favourable outcome.
Dynamic Left Ventricular Outflow Obstruction, Cardiology in Review, 1998
Medical Treatment ... Cardiology in Review, 2000
Right and Left Ventricular Outflow tract Obstruction, Circulation, 2002
Hypertrophic Cardiomyopathy, Circulation, 2002
Computer Assisted Detection of Systolic Murmurs ...(HOCM)