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Patients who suffer cardiac arrest have little or no warning and just 5% survive. Reuters

Higher levels of testosterone and lower levels of estrogen could protect you from cardiac arrest, suggests a new study from the Cedars-Sinai Heart Institute.

Measuring the levels of the two sex hormones in patients' blood may identify patients likely to suffer a sudden cardiac arrest. The study showed that lower levels of testosterone, the male sex hormone, were found in men who had a sudden cardiac arrest. Higher levels of estradiol, the major female sex hormone, were strongly associated with greater chances of having a cardiac arrest in men and women.

Sudden cardiac arrest is the result of defective electrical impulses. Patients may have little or no warning and just 5% of those who suffer sudden cardiac arrest survive.

For patients at known risk, an implantable cardioverter-defibrillator can be placed in the chest to detect faulty electrical impulses and provide a shock to return normal rhythm.

The comprehensive, 16-hospital, multiyear assessment of cardiac deaths in the 1 million population of Portland, Oregon metropolitan area was led by Sumeet Chugh, director of the Heart Rhythm Center in the Cedars-Sinai Heart Institute and funded in part by the National Heart, Lung, and Blood Institute.

The study's findings include:
• Men who had sudden cardiac arrests had testosterone levels of 4.4 nanograms per millilitre, compared to 5.4 nanograms per millilitre for men who did not have sudden cardiac arrest.
• Men who had sudden cardiac arrest had estradiol levels of 68 picograms per millilitre, compared to 52 picograms per millilitre for men who did not have sudden cardiac arrest.
• Women who had sudden cardiac arrest had estradiol levels of 54 picograms per millilitre, compared to 36 picograms per millilitre for the control group.