The World Meteorological Organization (WMO) reported in May that this year is likely to see the hottest heat on record, increasing the burden on healthcare and calling on countries to be prepared.

Hot weather is a double-edged sword for cardiovascular patients, on the one hand, higher temperature is conducive to blood vessel dilation and blood pressure decline, but on the other hand, high temperature also increases the metabolic rate and heart rate, requiring the heart to do more work, which is no problem for most healthy people, but for the elderly or patients with heart disease is a heavy burden.

As early as 1953, an analysis of the timing of heart attacks in Texas found that hot weather was associated with an increased incidence and mortality of cardiovascular disease.

Cardiovascular patients should take appropriate preventive measures in summer to better adapt to high temperature weather:

1. Avoid prolonged exposure to high temperatures, especially in patients with heart failure;

2. Regular rest, control emotions, avoid fatigue or mental tension;

3. Do a good job of secondary prevention of cardiovascular disease, actively do a good job of blood pressure, blood lipid, blood sugar management, pay attention to weight changes;

4. Adequate drinking water, timely supplementation of electrolytes (sodium, potassium, magnesium, etc.), cardiovascular patients should regularly monitor electrolyte levels.

In particular, it should be pointed out that people in the summer of beer, carbonated drinks and other intake is much larger than usual, these drinks have drainage diuretic effect, should be alert to sympathetic activation and electrolyte loss caused by heart rate and heart rhythm changes. The incidence of hypokalemia (< 3.5mmol/L) in patients with hypertension, coronary heart disease, and heart failure is generally less than 4%, but there are many in the "normal low value"; range between 3.5-4.0mmol/L, and the study statistics are more than 30%, even in patients with renal insufficiency, there is 17.9% incidence of hypokalemia.

Cardiovascular guidelines for electrolyte level testing recommendations are generally three to six months to review, the blood potassium level is recommended to maintain 4.0-5.0mmol/L, high or low blood potassium level will bring arrhythmia, sudden death and other risks, it is recommended to correct. The "Expert Consensus on ion Management of patients with heart failure in China" published this year further emphasized that "the blood potassium between 3.5-4.0 is the normal low value, should be corrected by potassium supplement", and the time interval for rechecking blood potassium is recommended to be shortened to 1-2 months.

Hypokalemia can be supplemented by oral drugs. Commonly used potassium supplements include potassium chloride sustained-release tablets, potassium citrate granules, potassium magnesium aspartate tablets, etc. Potassium chloride and potassium citrate are suitable for correcting hypokalemia quickly. Potassium magnesium aspartate is suitable for cardiovascular patients with ";low normal" blood potassium: At the same time, when potassium and magnesium ions are supplemented, aspartate has a strong affinity for cardiomyocytes and can smoothly carry potassium and magnesium ions into cardiomyocytes, promote distribution balance, and reduce the risk of ventricular arrhythmias in cardiovascular patients. Potassium and magnesium aspartate is often used clinically to treat paroxysmal ventricular or supraventricular arrhythmias.

Hypokalemia is the most common type of electrolyte disturbance in cardiovascular patients and a common cause of arrhythmia. The occurrence of hypokalemia may be related to activation of the RAAS system and some cardiovascular drugs (such as loop diuretics commonly used in patients with heart failure and thiazide or thiazine-like diuretics commonly used in patients with hypertension). In summer, many factors such as loss of appetite, perspiration, aldosterone secretion and so on are increased. It is urged to improve the awareness of blood potassium management, so that electrolyte disorders can be detected and corrected in time to avoid causing cardiovascular events.

 reference

 HE Heyer, HC Teng, W Barris. American Heart Journal, 1953; 45(5): 741-748.

 Krishnan Bhaskaran, Ben Armstrong, Shakoor Hajat, et al. BMJ, 2012; 345: e8050

Expert consensus on ion management of heart failure patients in China. Chinese Journal of Heart Failure and Cardiomyopathy, Volume 4, Issue 1, March 2020

About the author:

Hua Qi, Chief physician, professor, doctoral supervisor, Department of Cardiology, Xuanwu Hospital, Capital Medical University. In 1996, he was awarded the special government allowance by The State Council and was an expert in Beijing&apos;s outstanding contribution. He is currently president of Hypertension Branch of Chinese Geriatrics Society, standing member of Hypertension Professional Committee of Chinese Medical Doctor Association, vice chairman of Hypertension Professional Committee of Beijing Medical Doctor Association, vice president of Beijing Hypertension Prevention and Treatment Association, Chairman of Hypertension Group of Cardiovascular Professional Committee of Beijing Medical Association, and director of China Hypertension Alliance.

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