**Abstract**

Human physiological activity and condition during illness are under the control of the circadian rhythm. Circadian rhythms handle a wide diversity of physiological and metabolic functions, and the interruption of these rhythms has been linked to obesity, sleep disorders, metabolic and psychological disorders, and cardiovascular events such as myocardial infarction (MI), stroke, and vascular death. Disruption of circadian rhythms increases the risk of developing myocardial infarction, indicating that circadian genes might play an essential role in determining disease susceptibility. It is well known that many cardiovascular processes show daily variations depending on the circadian rhythm (blood pressure, heart rate), and the gene expression of the cardiomyocyte circadian clock influences myocardial contractile function, metabolism, and other gene expressions. We present a review of the latest knowledge on the impact of circadian rhythm and circadian rhythm genes on myocardial infarction. Today, in a time of personalized medicine, it is essential to know each person's circadian rhythm for its treatment and possible inclusion in the diagnostic procedures.

**Keywords:** cardiomyocytes, circadian rhythm, myocardial infarction

## **1. Introduction**

Everyday life is organized according to three different clocks: the solar clock which gives us light and temperature during the day, the social clock which determines the working day, and the biological clock which we notice during shift work or when we adjust to a reduced amount of daylight. In real life, the circadian clock is synchronized within 24 hours of the solar clock [1, 2].

It is known that almost all cardiovascular events occur in a circadian manner with a higher frequency in the morning after waking [3]. In the peripheral clocks of the cardiovascular tissues or cells, there is daily expression of the clock-controlled genes (CCG) synchronized and regulated by central clock [4, 5]. Disturbances of circadian rhythm can lead to cardiovascular disease.

Today we are facing a global epidemic of cardiovascular disease. In 2015 cardiovascular disease was the cause of 17.7 million deaths worldwide or 31% of total mortality. Of these 7.4 million deaths were caused by ischemic heart disease and 6.7 million by cerebrovascular diseases, according to World Health Organization (WHO) [6].
