Heart block refers to a delay in the conduction of electrical impulses through the atrioventricular node, which is located between the atria and the ventricles. What is atrioventricular block? Atrioventricular block can occur in sinus rhythm or in atrial, junctional, or ventricular ectopic rhythm. When the impulse is blocked from the atrium to the ventricle (antegrade conduction or downward conduction block), the ECG shows a prolonged PR interval or the absence of QRS wave groups after some or all of the P waves. In ventricular to atrial block (retrograde conduction or retrograde block), the ECG may show a prolonged RP interval or no retrograde P waves after some QRS waves. What are the symptoms? The heart block is classified into first, second and third degree conduction block according to the degree of delay in the conduction of electrical impulses to the ventricles, whether it is mild, intermittent or complete: 1. This type of block is usually asymptomatic. It is also common in well-trained athletes, adolescents, young adults, and individuals with high vagal tone. Of course, this condition is also seen in rheumatic fever, sarcoid heart disease, and the effects of some medications. Electrocardiogram can provide diagnostic evidence. 2. Second degree conduction block, when not every electrical impulse from the atria travels down to the ventricles. This will cause a slow and irregular heartbeat. Some second-degree blocks will develop into third-degree blocks. In third-degree block, the electrical impulses from the atria are completely blocked and cannot travel down to the ventricles. In this case, the frequency and rhythm of the heart are controlled by the atrioventricular node or the ventricles themselves. Without the stimulation of the heart’s normal pacing point (sinus node), the ventricular frequency is very slow, usually below 50 beats per minute. Third-degree block is a severe arrhythmia that affects the heart’s ability to pump blood. Common symptoms include vertigo, blackouts, syncope and heart failure. When the ventricular rate is greater than 40 beats/min, the patient’s symptoms are often not severe, but merely weakness, upright hypotension and shortness of breath. The pacing rate originating from the atrioventricular node and ventricles is not only slow but also irregular and unreliable. What are the treatment efforts? First-degree block also does not require treatment, even if it is caused by heart disease. Some patients with second-degree block require an artificial pacemaker. All patients with third-degree block require a pacemaker. In emergency situations, temporary pacemakers are often required. Although some patients’ heart rhythms may return to normal after aggressive treatment of the underlying heart disease, most patients will need a pacemaker for the rest of their lives. What can I do? Atrioventricular block, caused by a conduction disorder between the atria and ventricles of the heart. It is classified as Grade I, II or III depending on the condition. When conduction block is detected, the cause should be actively sought. If the medication is not effective, a permanent artificial pacemaker can be installed to maintain a normal life and work after surgery. If there is no symptom, no treatment is needed for the time being. Pay more attention to physical examination and regular life. It is also necessary to stop drinking and smoking. What can happen? The disease often occurs as a complication of other diseases, such as acute inferior myocardial infarction, hyperthyroidism, and pre-excitation syndrome. The complications of this disease are not common, but when they do occur, they are very dangerous, such as high atrioventricular block can be complicated by ventricular fibrillation. Therefore, these patients should be clinically prepared for resuscitation. Ventricular fibrillation should be resuscitated every second. Ventricular fibrillation often has aura, and ventricular tachycardia is its prelude, so antiarrhythmic drugs should be given immediately after detection to avoid serious complications.