Sex Hormone Levels Linked to Sudden Cardiac Arrest Risk

The measurement of the levels of sex hormones in patients' blood may identify patients likely to suffer a sudden cardiac arrest, a heart rhythm disorder that can be fatal in most patients.

Unlike heart attacks or myocardial infarction, which are typically caused by clogged coronary arteries reducing blood flow to the heart muscle, sudden cardiac arrest is the result of defective electrical impulses and patients may have little or no warning, and the disorder usually causes nearly instantaneous death.

Scientists at the Cedars-Sinai Medical Center (Los Angeles, CA, USA) and their colleagues measured blood hormone levels in 149 patients whose mean age was 64.1 ± 11.7 years, 73.2% of which were males who had a sudden cardiac arrest (SCA), and compared them with levels in 149 patients of a similar age and sex ratio, who had coronary artery disease but did not have sudden cardiac arrest. Testosterone and estradiol levels were measured from blood samples drawn at the time of the SCA event in cases and during a routine visit in controls.

Among SCA cases the median testosterone levels were significantly lower in males at 4.4 ng/mL compared to controls who did not have sudden cardiac arrest at 5.4 ng/mL. Median estradiol levels were higher in male SCA patients at 68 pg/mL compared to the controls at 52 pg/mL and female SCA cases median was 54 pg/mL compared to 36 pg/mL. Higher testosterone levels were associated with lower SCA risk only in males and higher estradiol levels were associated with higher SCA risk in both males and females.

Sumeet Chugh, MD, director of the Heart Rhythm Center in the Cedars-Sinai Heart Institute, said, “This is the first time it has been reported that there is an association between sex hormone levels and sudden cardiac arrest. While these findings need to be confirmed by other studies, they suggest that higher testosterone levels in men may offer protection from sudden cardiac arrest and lower levels of estrogen may protect both men and women.” The study was published on August 23, 2014, in the journal Heart Rhythm.

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Cedars-Sinai Medical Center