A clinical study has found that 17.6% of people who suffered sudden cardiac death had a history of arrhythmia and that men were significantly more at risk than women, the Taiwan Heart Rhythm Society said on Monday.
Sudden death can refer to unexpected death occurring within 24 hours of the onset of symptoms and is not attributed to trauma, society chairperson and Linkou Chang Gung Memorial Hospital vice superintendent Wen Ming-shien said.
The most common type is sudden cardiac death, Wen added.
Sudden cardiac death is caused by coronary artery disease, heart failure or arrhythmia, he said.
Arrhythmia refers to an irregular heartbeat — beating too fast, too slow or skipping irregularly, Wen said.
The study conducted by five medical centers in Taiwan found that among 461 cases of sudden cardiac death, 81 (17.6%) had experienced arrhythmia and their average age was 64, Taichung-based China Medical University vice superintendent Chang Kuan-cheng said.
The study also found that the male-to-female ratio for sudden arrhythmic death was four-to-one, indicating a higher risk for men, he said.
Although the reason for the disparity is unclear, doctors believe that it could be associated with lower levels of estrogen in men, as the hormone can have a protective effect on the cardiovascular system, he added.
The male-to-female ratio for non-arrhythmic sudden deaths in the study was two-to-three, with an average age of 74 years, Chang said.
Research published in 2016 that studied 270 cases of sudden death in Taichung found that 19% were associated with arrhythmia, he said.
About 70 percent of people with arrhythmia experience symptoms including palpitations, difficulty breathing, shortness of breath, chest tightness and dizziness, Linkou Chang Gung Memorial Hospital cardiologist Chang Po-cheng said.
People who have such symptoms should seek medical attention to control the condition and prevent sudden death, Chang said.
Still, about 30% of people with arrhythmia do not experience any symptoms, and the incidence of atrial fibrillation, which is the most common type of heart arrhythmia that could cause blood clots leading to stroke, is about 10 percent in people aged 70 or older, and the condition can worsen if left uncontrolled, Chang added.
The study found that people with atrial fibrillation are 2.6 times more likely to suffer sudden death than those without it, Chang Kuan-cheng said.
The study summarized four high-risk factors for sudden arrhythmic death, abbreviated as “SACAF,” which stands for “sex” (male), “age” (65 or younger), a medical record of “cardiovascular” disease, and “atrial fibrillation,” he said, adding that if people meet all these criteria, they should see a doctor for an examination and to control their condition to prevent sudden death.
The society said it cooperated with 29 hospitals and would launch a series of lectures on arrhythmia starting on Saturday.
It would also promote the “543” principle to prevent sudden arrhythmic deaths: “five” high-risk groups — elderly people, as well as people with cardiovascular disease, heart failure, a family history of sudden death and those who have unhealthy lifestyles; “four” signs — difficulty breathing, frequent heart palpitation, unexplained chest pain or tightness and tiring easily; and “three” prevention methods — exercising regularly, maintaining a healthy diet and managing stress.