Quasi-imprevisible and relentless, SIDS is a sudden onset of often unsuspected heart problems. Not to be confused with the sudden infant death syndrome, these ‘accidents’ kill 40,000 people each year. But the evolution of the heart rate may help identify patients at risk.
The sudden death of the adult is, as its name suggests, an unexpected death in apparently healthy person and occurring in the minutes following the onset of the first symptoms. Little-known, it appears only rarely in front of the media scene. However the death of footballer Marc-Vivien Foé marked the spirits.
The terrible results of sudden death
In France, the sudden death represents 5-10% of the number of deaths and nearly half of death from cardiac cause. Each year, nearly 40,000 adults die from sudden death. It is often the first (and unfortunately the last) manifestation of unsuspected heart problems. The unexpected occurrence of a death is less than an hour after the start of symptoms suggestive of ischemia (lack of irrigation) of the heart muscle (pain in the chest, shortness of breath…).
One of the challenges is to identify more vulnerable. Several risk factors are identifiable today including the overweight and obesity,high blood pressure, cholesterol and smoking. In each of these settings, it is possible to intervene by promoting good nutrition, physical exercise, smoking cessation and drug treatment. But French Inserm researchers come to identify a new risk factor for sudden death linked to heart rate1.
Keep the good heart rate
The team of Professor Xavier Jouven has highlighted the risk of sudden death was directly linked to the heart rate, or rather its modifications during and after exercise. The researchers collected 5 713 records of men aged 42 to 53. Free of any troubled heart, all had undergone a stress test standardized between 1967 and 1972. Exercise is supposed to replicate the efforts of everyday life while pedaling on a bicycle ergonomic or walking on a treadmill.
An electrocardiogram, blood pressure and responses to see how the heart reacts2.
After 23 years of follow-up, 81 patients have died a sudden death. By carefully studying the results of their stress test, it turns that they possessed a small difference between the level of maximum heart rate and resting heart rate level. The results attest as well as:
Men whose heart rate was more than 75 beats at rest have four times the risk of sudden death; At the effort, an increase in the heart rate less than 89 beats per minute multiplied by four the risk of sudden death.
A decrease of less than 25 beats per minute after the effort does more that double the risk of sudden death.An inadequate response of the heart rate during exercise is thus directly related to the risk of sudden death, but not to the other causes of cardiac death (and in particular the death by myocardial infarction).
Yet an argument to wear its sneakers!
What are the medical consequences can have this discovery? In the same way that the voltage or cholesterol levels are checked regularly, one can imagine that tomorrow, the use of a stress test allows identification of persons at risk of sudden death. An option which, according to the researchers, “deserves to be studied”. Furthermore, these results argue for a hygiene of life.