For normal people, banana is a kind of food rich in potassium, and consuming banana will not cause harm to the heart in general. However, for patients with renal failure, if a large number of bananas are consumed within a short period of time and the kidney’s ability to excrete potassium is reduced, it may cause potassium ion accumulation in the patient’s body, resulting in serious cardiac arrhythmia, or even causing cardiac arrest. 1. Serious cardiac arrhythmia, potassium ion accumulation causes hyperkalemia, which leads to the decrease of myocardial conductivity, causing conduction delay and one-way block, and at the same time, the effective period of refractory period is shortened, so it is easy to form the excitation folding back, which leads to serious cardiac arrhythmia. 2. Cardiac arrest, when acute severe hyperkalemia, myocardial excitability is reduced, myocardial autoregulation is reduced, myocardial excitability conductivity is reduced, which can cause cardiac arrest. Therefore, for patients with impaired kidney function, it is not recommended to consume potassium-rich foods such as bananas, or under the guidance of a doctor, but healthy people can consume them normally.