Second Degree Heart Block: Symptoms, Cause, Type, Treatment

According to a 2023 study by Nicholas Huerta et al., the incidence of second-degree heart block is 0.18%. 1 It is a worsened cardiac rhythm disruption than first-degree AV block. If left untreated, the condition can result in consistent and chronic symptoms. 

If you are experiencing issues like fainting, dizziness, and chest pain, it may be indicative of cardiovascular conduction impairment. The second-degree heart block ECG is an essential tool for diagnosis. The following blog discusses the signs, causes, diagnosis, and treatment of the condition. Continue reading to find out. 

Healthy cardiac activity is characterised by an electrical impulse moving from the upper cavity (atria) to the lower chambers (ventricles). It signals the heart to contract and circulate blood. With second-degree heart block or AV (atrioventricular) block, these signals occasionally fail to reach the ventricles. This results in a skipped heartbeat, creating an irregular rhythm that can disrupt the distribution of oxygenated blood throughout the body.

Two types of second-degree heart block involve irregular signals from the sinus node (the natural cardiac pacemaker) in the atria to the ventricles. When the impulses are transmitted, they trigger muscle contractions to pump blood to the lungs and other organs. The different categories include: 

1. Mobitz Type 1: Also known as Wenckebach block, second-degree heart block type 1 is a less severe form of this condition. Explained as the occasional failure of electrical conduction between the heart chambers. This causes a skipped heartbeat. 
2. Mobitz Type 2: Most impulses reach the ventricles, but sometimes, some signals are lost. This can cause an irregular and slower heartbeat. Unlike type 1, the electrical signals in second-degree heart block type 2, the missed beat can be unpredictable and sudden.

2nd-degree heart block can be asymptomatic or have varying degrees of severity. Common indications and signs include:

1. Fainting: This is a common symptom where the patient may lose consciousness temporarily due to reduced blood flow to the brain.
2. Lightheadedness: Due to irregular heart rhythms and potentially reduced cardiac output, individuals might experience dizziness.
3. Angina: Some individuals suffer chest pain. It can occur if the heart and other organs are not receiving enough oxygen due to irregular cardiac activity.
4. Fatigue: Patients often report feeling unusually tired. This can be attributed to the reduced efficiency of blood and oxygen transfer to the body tissues.
5. Respiratory Issues: Difficulty breathing can occur, particularly during physical activity or even at rest in severe cases. Hyperventilation (quick breathing) is observed to promote oxygen delivery to compensate for impaired cardiac output.
6. Arrhythmias: Irregular heart rhythm or skipped beat is another symptom commonly experienced as palpitations. 
7. Nausea: It can sometimes accompany heart block due to reduced blood flow and the innate response to other symptoms.

Second-degree AV block can be caused by various factors. Understanding these causes is crucial for diagnosing and managing the condition. These causes include: 

1. Cardiovascular Disease: This is a primary cause. Conditions such as heart attacks can lead to cardiac tissue damage, contributing to the development of second-degree heart block. Complications arising from heart surgery can also lead to this issue.
2. Inherited Causes: Some people may have AV block because they were born with it (congenital heart block). It is usually associated with genetic defects or if the mother has an autoimmune disease such as lupus. 
3. Electrolytic Imbalances: Abnormal levels of electrolytes, like sodium or potassium, can affect the electrical impulses in the heart, potentially leading to heart block.
4. Systemic Diseases: Sarcoidosis (lumps development due to autoimmunity response) and rheumatic fever (inflammation of joints and other parts) can impact the heart. Thus, it can cause second-degree AV block. These conditions often affect the metabolic system, including cardiac tissue.
5. Inflammatory Cardiac Conditions: Infections or inflammation of the heart, such as myocarditis (cardiac muscle swelling), can disrupt the normal cardiovascular electrical pathway. 
6. Endocrine Issues: Low levels of thyroid hormones (hypothyroidism) can affect the cardiac rhythm and cause heart block.
7. Lyme Disease: This bacterial infection caused by Borrelia burgdorferi can sometimes affect the heart. 
8. Medication Side Effects: Certain medicines, especially those used to treat cardiovascular conditions (like beta-blockers or calcium channel blockers), can influence rhythmic activity and cause heart block.

Several factors can increase the chances of second-degree heart block. However, having one or more such facilitators does not necessarily mean a person will develop this condition. Aspects that increase the likelihood of the problem include: 

1. High Blood Pressure and Diabetes: According to a study by Tuomas Kerola et al. in 2019, people with hypertension and elevated blood glucose levels are at a higher risk of heart block.
2. Advancing Age: As people grow older, the electrical system of the heart naturally undergoes changes, which can subsequently lead to cardiac issues.
3. Structural Cardiac Issues: Type 2 AV block is often found in individuals with structure-associated cardiovascular problems. These can result from a heart attack or autoimmune diseases that cause scarring of the myocardium (thickening of cardiac muscle tissues).

Preventing second-degree atrioventricular block involves addressing the risk factors and maintaining overall heart health. While not all cases can be averted, especially those due to congenital conditions, here are some general strategies to help reduce the risk:

1. Healthy Lifestyle: Adopting heart-healthy life choices is crucial. This includes eating a balanced diet of vegetables, fruits, whole grains, and lean proteins. High-risk individuals should avoid excessive salt and sugar and limit their intake of saturated fats.
2. Physical Activity: Regular exercise helps strengthen the heart and improve cardiovascular health. At least 2.5 hours of workout per week is recommended.  
3. Quit Tobacco and Limit Alcohol: Smoking can increase the risk of heart disease due to increased plaque deposition. Thus, quitting it and limiting alcohol intake are significant to achieving healthy cardiac function.  
4. Manage Stress: Chronic distress can affect heart health. Stress-reduction methods like mindfulness, meditation, and yoga can be beneficial.
5. Medications Caution: Patients who are prescribed medicines like beta-blockers or calcium channel blockers should regularly consult a doctor for monitoring. These medications can contribute to heart block. 
6. Regular Health Assessment: Getting routine check-ups with a doctor is important, especially for those with existing heart conditions or risk factors. It helps in early detection and management of potential problems.

Diagnosing 2nd-degree heart block involves a series of evaluations and tests to assess the electrical activity of the heart. It helps identify any disruptions in the transmission of electrical impulses. The process usually includes the following steps:

1. Medical History: The healthcare specialist will inquire about the patient's symptoms, cases of heart disease in the family, and any underlying health conditions. 
2. Physical Examination: The next step is a thorough vital evaluation. It includes checking the pulse, listening to the heart and lungs, and looking for signs of heart failure.
3. Blood Tests: These can check for underlying conditions that might contribute to heart block, such as electrolyte imbalances, calcium, and magnesium.
4. Electrocardiogram (ECG): It is the primary tool for diagnosing heart block. A second-degree heart block ECG records the electrical signals in the heart. It can show the pattern and speed of the heartbeat to detect any irregularities. For this condition, the results show that some electrical signals are not reaching the ventricles.
5. Holter Monitor: This portable device is worn for 24 hours or longer to record the electrical activity of the heart continuously. It is used if the issue does not appear during a standard ECG.
6. Electrophysiologic Testing: The test may be performed to determine the blockage level and the need for a pacemaker. It involves threading catheters through the blood vessels to the heart to evaluate its electrical system in detail.

How to Prepare for Doctor Consultation? 

Preparing for a doctor’s consultation for second-degree heart block involves several steps to ensure the patients make the most of their appointments. Here’s a guide to help them prepare:

1. Consultation: It is best to make a prior appointment and ask the doctor about any pre-evaluation restrictions or requirements. 
2. List of Indications: Write down any symptoms they are experiencing, even if they seem unrelated to the heart. Include details like when it started, how often it occurs, the intensity, and if anything seems to trigger or alleviate it.
3. Medical History: Prepare a detailed health profile, including any other medical conditions the patients have been diagnosed with. Include a family history of heart disease.
4. Previous Tests and Procedures: If the individual has undergone any previous heart-related diagnosis or treatment, they must bring the results or reports.
5. Current Medications: Make a list of all supplements, vitamins, and over-the-counter medicines they are taking, including dosages. This helps the doctor understand if any of these might affect the heart.
6. Diet and Lifestyle Habits: Patients should be ready to discuss their diet, exercise habits, alcohol use, smoking habits, and any other lifestyle factors. These can influence heart health and are important for the doctor to know.
7. Questions for the Doctor: Prepare a list of concerns to ask the doctor. This can include inquiries about the diagnosis, treatment options, lifestyle changes, etc.
8. Bring a Support Person: Consider bringing a family member or friend along. They can help remember details from the consultation and provide support.

What to Expect from the Doctor? 

The doctor will likely ask several queries during a second-degree heart block consultation. This helps them better understand the patient’s condition, plan diagnosis and treatment. The following are some common questions to expect:

Can you describe the symptoms you have been experiencing?

1. When did these issues first start?
2. How often do you experience these indicators?
3. Have you noticed anything that makes your symptoms better or worse?
4. Do you have any other medical conditions, especially related to the heart, blood pressure, or cholesterol?
5. Are you currently taking any medications, supplements, or over-the-counter drugs?
6. Is there a history of heart or cardiovascular disease in your family?
7. Can you describe your diet and exercise habits?
8. Do you smoke or consume alcohol? If so, how often and how much?
9. Have you noticed any changes or challenges while performing daily activities or exercise?

Being prepared to answer these questions can provide the doctor with valuable information and help make an accurate diagnosis.

Questions to Ask the Doctor 

Patients should efficiently discuss with the cardiologist during their second-degree heart block appointment to understand their condition and treatment options. Here are some questions they might consider asking the doctor:

1. Can you explain second-degree heart block and how it differs from other types?
2. Based on my symptoms and results, what type of second-degree heart block do I have?
3. What is the possible cause of the problem? 
4. Am I at risk for developing a more severe form of heart block?
5. What symptoms should I be most concerned about?
6. What are the treatment options available for my condition?
7. Is a pacemaker necessary in my case?
8. Are there lifestyle changes I can make to improve my condition?
9. Should I avoid any specific activities?
10. Will I need regular ECGs or other heart monitoring?
11. Can I continue my normal daily activities, including work and exercise?
12. Can this condition progress or improve over time?

Patients should not hesitate to ask any other questions they may have. 

Second-degree heart block treatment depends on its type, severity, underlying cause, and the symptoms experienced by the patient. The following is an overview of the treatment options:

1. Monitoring and Observation: Treatment may not be immediately necessary for second-degree heart block type 1 with no symptoms. Instead, careful evaluation and regular follow-up appointments may be recommended. 
2. Medications: The doctor may prescribe medicines to manage blood pressure and diabetic symptoms. 
3. Underlying Conditions: To treat symptomatic Mobitz type 1 or 2 heart block with a reversible cause, the primary cure is correcting the intrinsic issue. This may include an imbalance in electrolytes or a side effect from medication. 
4. Pacemaker: For second-degree heart block type 2 with an irreversible cause, it may be recommended. It is a small device implanted in the chest under the skin. The equipment sends electrical signals to the heart to maintain a regular heartbeat.

Please Note: The treatment approach selection is based on the patient’s condition and the doctor’s opinion. 

Second-degree heart block, especially if left untreated or not managed efficiently, can result in several complications, some of which can be severe. The complexities include: 

1. Injuries from Fainting: Due to sudden drops in heart rate or pauses in heartbeats, individuals may become unconscious repeatedly. This can increase the risk of falls and related injuries. 
2. Organ Damage: If the heart cannot pump sufficient blood consistently, organs may not receive the oxygen and nutrients they need, damaging organ function.
3. Worsening Heart Block: Particularly in type 2 heart block, there is a heightened risk of progression to third-degree AV block (complete heart block). In this severe form, the electrical signals from the atria do not reach the ventricles, leading to more serious disruptions in cardiac rhythm. 
4. Heart Failure: Over time, if the heart block leads to consistently low heart rates, it can contribute to cardiac failure. It is a condition where the blood is not pumped effectively to meet the body needs.
5. Cardiac Arrest: In rare cases, severe second-degree AV block, particularly if it progresses to complete failure, can lead to sudden heart attack. This is an emergency situation where the heart suddenly stops beating effectively.

When to See a Doctor? 

Knowing when to seek medical care is vital for individuals with second-degree heart block, as timely intervention can prevent serious complications. Patients should consult a doctor if they experience the following: 

1. New or worsening symptoms
2. No symptomatic relief through traditional measures 
3. Weakness or severe dizziness
4. Fainting 
5. Chest pain or discomfort
6. Shortness of breath 

Diet for Second-Degree Heart Block 

A wholesome diet is essential for managing second-degree heart block, as it can help improve cardiovascular health and reduce the risk of complications. While there is no specific meal plan exclusively for the disease, the following dietary guidelines are generally recommended:

Fruits and Vegetables:

They provide essential minerals, vitamins, and antioxidants. Include the following either fresh, frozen, canned, or dried is recommended: 

1. Tomatoes 
2. Spinach 
3. Broccoli 
4. Apples 
5. Bananas 

Whole Grains:

Incorporate it as a good source of fibre. Examples include: 

1. Oats 
2. Brown rice
3. Whole wheat 
4. Whole-grain pasta

Proteins:

Choose the foods with a variety of lean proteins like: 

1. Seafood (fish and shellfish)
2. Poultry 
3. Lean meats like ground beef 
4. Beans and lentils
5. Eggs

Good Cholesterol:

Individuals should include healthy fats, such as olive oil, avocados, nuts, and seeds, in their diet. 

Foods to avoid include:

Saturated Fats:

Reduce intake of fatty meats and high-fat dairy products. For example: restrict the consumption of the following foods: 

1. Pizza
2. Burger
3. Creamy sauces or gravy 

Salt:

Individuals should cut down on their sodium intake. Too much consumption can increase blood pressure, a major risk factor for heart disease. Instead, choose foods that are low in sodium. 

Second-degree heart block is when the electrical signals in the heart are delayed or fail to reach the ventricles, leading to irregular cardiac rhythm. The issue, although might not be very damaging, can progress to complete cardiac failure. However, early detection and management are key to avoiding serious complications associated with the condition.

HexaHealth provides comprehensive support to patients with second-degree heart block. We offer access to expert medical consultations, personalised treatment plans, and continuous monitoring. Our team of experts is committed to enhancing the quality of life for individuals living with heart block.

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