What are the causes and treatments for bradycardia?

Many patients usually have a slow heart rate. The normal heart rate is around 50-60 beats per minute, but a heart rate below 50 beats is considered bradycardia. Most patients with bradycardia have heart problems, immune problems, insufficient adrenaline, or improper drug intake, which are all causes of bradycardia, including physiological and pathological factors. Patients need to be examined as soon as possible and treated with a pacemaker implant when necessary.

Symptoms and signs

Some patients usually have a slow basal heart rate of about 50-60 beats per minute, or even lower than 50 beats. They usually have symptoms of dizziness, fatigue, tiredness, and poor spirits. Some patients may have a normal heart rate at ordinary times, but bradycardia may suddenly occur and drop to less than 40 beats per minute. They may experience dizziness, transient blacking out, fatigue, palpitations, chest tightness, shortness of breath, and sometimes a feeling of impact in the precordial area. In severe cases, syncope may occur. Some patients also seek medical treatment with symptoms of dizziness, fatigue, and syncope, and examination may reveal prolonged cardiac arrest.

Treatment

In the event of an acute attack of bradycardia, in addition to treating the primary cause and stopping medications that can slow the heart rate, atropine or isoproterenol can be used to increase the heart rate. For those with a heart rate of 40 beats per minute or slower, drugs are not effective in raising the heart rate, especially in patients with recurrent syncope or presyncope, in whom a temporary pacemaker should be implanted.

After actively correcting the reversible primary cause and excluding the influence of drugs, if the patient's bradycardia symptoms cannot be reversed, a pacemaker needs to be implanted. A pacemaker is the size of a matchbox and weighs between 25 and 50 grams. The pulse generator is implanted under the skin in the upper chest, and the pacing wire is delivered to the heart through the veins. The pacemaker stimulates the heart with a certain form of artificial pulse current, causing the heart to contract effectively, thereby increasing the heart rate, relieving or eliminating the patient's symptoms and saving lives.

Pathological etiology

The most common causes of bradycardia are pathological sinus bradycardia, sinus arrest, sinoatrial block, and atrioventricular conduction block.

Pathological sinus bradycardia is characterized by a slow heartbeat with uncomfortable symptoms. The causes are often sick sinus syndrome, acute myocardial infarction, hypothyroidism, increased intracranial pressure, or the use of drugs that slow down the heart rate (such as bisoprolol, isopamine, digitalis, reserpine, etc.).

Sinus arrest, sinoatrial block, and atrioventricular block are characterized by prolonged heart arrest. The causes of this condition include sick sinus syndrome, degenerative changes in the conduction system, congenital atrioventricular conduction tissue, myocarditis, myocardial infarction, etc. An arrest time of more than 3 seconds is very dangerous and may cause malignant ventricular arrhythmias and lead to sudden death.

Patients with symptomatic bradycardia, especially those that affect their quality of life, or whose heart stops beating for more than 3 seconds, or who have transient blackouts or syncope, should receive active treatment.