A heart block affects the electrical signals of the heart, which control the heart rate and rhythm, as well as pump blood throughout the body. In the absence of electrical signals, the heart may beat too slowly, irregularly, or completely. Several complications may occur as a result, including fainting, chest pain, heart failure, or sudden cardiac arrest.
Heart block is classified by degrees, depending on how severe the blockage of the electrical signals is. There are three main types of heart block:
A first-degree heart block is the mildest form of heart block in which electrical signals are delayed but still reach the lower chambers of the heart (ventricles). This type of block usually does not cause symptoms or require treatment.
A second-degree heart block is characterized by a blockage of electrical signals that prevents some of those signals from reaching the ventricles of the heart. It is possible for the heart to skip beats or beat irregularly as a result of this. A second-degree heart block can be classified into two subtypes, Types I and II. Type I is less severe and may not require treatment, whereas Type II is more severe and often requires a pacemaker.
A third-degree heart block occurs when no electrical signals reach the ventricles, causing the ventricles to beat on their own, but at a very slow and unreliable rate. It is extremely dangerous and requires immediate medical attention and a pacemaker in order to treat it.
Heart block can be caused by various factors, such as:
Age-related changes in the heart's electrical system
Heart diseases or conditions, such as coronary artery disease, heart attack, myocarditis, cardiomyopathy, or congenital heart defects
Medications that affect the heart rate, such as beta blockers, calcium channel blockers, or digoxin
Surgery or procedures that damage the heart's electrical system, such as heart valve replacement, coronary bypass, or ablation
Genetic factors or inherited disorders, such as muscular dystrophy or Kearns-Sayre syndrome
The symptoms of heart block depend on the type and severity of the blockage. Some people with heart block may not have any symptoms, while others may experience:
Dizziness or lightheadedness
Fainting or loss of consciousness
Fatigue or weakness
Shortness of breath or difficulty breathing
Chest pain or discomfort
Palpitations or feeling the heart skip beats
Confusion or memory problems
Swelling in the legs or ankles
Heart block can be diagnosed by a doctor using various tests, such as:
Electrocardiogram (ECG or EKG): This is a test that records the electrical activity of the heart and shows the heart rate, rhythm, and any abnormalities in the electrical signals.
Holter monitor: This is a portable device that records the heart's electrical activity continuously for 24 to 48 hours. This can help detect any episodes of heart block that may not show up on a regular ECG.
Event monitor: This is a device that records the heart's electrical activity when the person experiences symptoms or presses a button. This can help capture any abnormal heart rhythms that may be related to heart block.
Electrophysiology study (EPS): This is a test that involves inserting catheters (thin, flexible wires) into the heart through a vein in the groin or neck. The catheters can stimulate the heart and measure its electrical response. This can help locate the site and cause of the heart block.
The treatment of heart block depends on the type and severity of the blockage, as well as the symptoms and overall health of the person. Some of the possible treatments include:
Medications: Some medications can help improve heart rate and rhythm, like antiarrhythmics, anticoagulants, and diuretics. However, some medications can worsen the heart block or cause side effects, so they should be used with caution and under the supervision of a doctor.
Pacemaker: This is a small device that is implanted under the skin near the collarbone. It regulates the heart rate and rhythm by sending electrical signals to the heart. Heart block of second and third degrees, as well as heart blocks of first and second degrees that cause symptoms or complications, are treated primarily with this procedure.
CRT (cardiac resynchronization therapy): Two or three wires are attached to the different chambers of the heart as a pacemaker. CRT is a form of pulse therapy that synchronizes heart contractions and improves heart pumping efficiency. It is sometimes used to treat heart block caused by heart failure or reduced ejection fraction.
The implantable cardioverter-defibrillator (ICD) is similar to a pacemaker, but can detect and treat life-threatening arrhythmias such as ventricular tachycardia and ventricular fibrillation. The ICD can deliver a shock to the heart to restore a normal rhythm. This can help prevent sudden cardiac arrest in people with heart block who are at high risk of these arrhythmias.
Heart block can be prevented or delayed by taking care of the heart and reducing the risk factors for heart disease, such as:
Eating a healthy diet that is low in saturated fat, cholesterol, salt, and sugar, and high in fruits, vegetables, whole grains, lean protein, and healthy fats
Exercising regularly for at least 150 minutes per week of moderate-intensity aerobic activity, such as brisk walking, cycling, or swimming
Quitting smoking and avoiding exposure to secondhand smoke
Limiting alcohol intake to no more than one drink per day for women and two drinks per day for men
Managing stress and practicing relaxation techniques, such as meditation, yoga, or deep breathing
Maintaining a healthy weight and avoiding obesity
Controlling blood pressure, cholesterol, blood sugar, and other medical conditions that can affect the heart
Taking medications as prescribed and following the doctor's advice
Having regular check-ups and screenings for heart problems
Seeking immediate medical attention if any symptoms of heart block occur
