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How an early stage detection of heart block can save your life

How an early stage detection of heart block can save your life

author Dr. Anurag Sharma | calender January 23, 2020

Heartbeat occurs by an electrical signal produced in an area of specialized cells in the right atrium or upper right chamber of the heart that is also called the sinus node. Later this electrical signal goes to the atrioventricular (AV) node by moving down through the heart. The function of the AV node is to slow down the electrical current before passing through lower chambers of the heart. On arrival of the electrical current in the lower chambers of the heart, it helps blood to pump out to the whole body.

Condition of heart block occurs on partial or complete blockage of electrical signals that control the heartbeat. Common causes of heart block include heart attack, heart failure, rheumatic fever, heart disease or cardiomyopathy (an enlarged heart). However, it can also be the result of an accident during heart surgery or exposure to toxins.

Classification of heart block goes as first-, second- or third-degree, as per the extent of electrical signal impairment. First-degree heart block does not reveal any symptoms whereas, second and third-degree heart block reveal possible symptoms like dizziness, fatigue, fainting, shortness of breath and chest pain. Third-degree heart block is fatal and needs immediate medical attention due to severe slow heart rate. So it is ideal for visiting heart specialist doctor on apprehension to detect heart block in the initial stages for the safety of your life

What can cause first-degree heart block?

  • High dosage or prolonged usage of digitalis, which is a medicine for slowing down the heart rate can cause first-degree heart block.
  • Beta-blockers is a drug that affects your nervous system to speed up your heart. But side effects of beta-blockers can delay electrical conduction within the heart to cause first-degree heart block.
  • Calcium channel blockers can result in first-degree heart block too by slowing down the conduction within the heart's AV node.

So before taking any of these drugs, it is necessary to have a consultation with your heart care specialist.

How to detect a first-degree heart block?

As patients exhibit no symptoms in First-degree heart block, so it is difficult to detect or sometimes detection is possible on routine ECG checkup. But it should not be taken lightly, and regular checkups by a cardiologist for monitoring your condition assures your earlier recovery. It is advisable to keep notice of your slower pulse between your appointments with the doctor.

Second-degree heart block

When electrical signals or current from the heart's upper chambers(atria) of the heart don't reach the lower chambers (ventricles), then Second-degree heart block occurs. Consequently, your heartbeat can drop.

Further second-degree heart block has two types:

  • Mobitz Type 1 may not cause any noticeable symptoms. Still, it can be a significant cause for the more severe example of second-degree heart block that is Mobitz Type 2. That is why regular monitoring of Mobitz Type 1 through pulse check up by your heart surgeon is ideal.
  • Mobitz Type 2 is a kind of second-degree heart block in which the heart doesn't beat effectively. It disturbs the ability of your heart for pumping blood throughout the body. In this condition, a pacemaker helps your heart to work continuously, regularly and efficiently.

Signs to detect second-degree heart block:

  • Palpitations of heart
  • Shortness of breath (especially during exertion)
  • Chest pain
  • Fainting
  • Rapid breathing
  • Nausea
  • Excessive fatigue

Evaluation and diagnosis of second-degree heart block

For determination of a second-degree AV block, ECG examination is helpful. Also, for suspicion of ischemia based on ECG findings and clinical picture, is reliable. If ischemia is suspected based on the clinical picture and ECG findings, there can be an indication of cardiac biomarkers and chest radiography.

It is also necessary to have checkups for calcium, magnesium and serum electrolytes. For patients taking digoxin, one must evaluate the level of toxicity. Electrophysiologic testing helps to check the level of the block for the need of a pacemaker.

Diagnosis for second-degree heart block includes congenital heart block, first-degree atrioventricular block, sinoatrial exit block. It also checks myocardial infarction, non-conducted premature atrial complexes, medication toxicity, and third-degree atrioventricular block.

Third-degree heart block

When electrical signals from the heart's upper chambers (atria) do not pass at all to its lower chambers (ventricles), then it is called third-degree, or complete heart block. In this condition the ventricles contract and pump blood at a slower rate than usual though there is an absence of electrical impulses from the sinoatrial node. On the whole, the heart has difficulty to contract and pump blood to other parts of the body.

For early detection of third-degree heart block, you can notice the following symptoms:

  • Chest pain
  • Excessive fatigue
  • Shortness of breath
  • Fainting (syncope)
  • Dizziness

What are the possible causes of third-degree heart block?

  • Some medications in extreme cases can cause third-degree heart block.
  • During surgery, when there is an injury to the heart's electrical conduction system, it can also result in third-degree heart block.

Evaluation and diagnosis of third-degree heart block

Third-degree heart block patients present significant distress, so before starting evaluation, a stable condition of the patient is necessary. For evaluation, most patients have an examination by electrocardiogram. An ECG evaluation also checks for signs of ischemia.

Further, to evaluate and correct beta-blocker toxicity, it is needed to obtain a basic metabolic panel to correct electrolyte abnormalities. It is necessary to achieve a level of dioxin for patients who take dioxin to exclude dioxin toxicity. Later, to evaluate concomitant diseases, it is essential to have chest radiography and complete blood count.

Its diagnosis is straightforward on the 12-lead ECG and presence of complete AV-dissociation by faster atrial rate than ventricular rate confirms third-degree heart block.

About Dr. Anurag Sharma

Dr. Anurag Sharma is among the best cardiologists in India who excels in providing affordable, appropriate, and best quality care for all kinds of heart ailments, including heart blocks.

Patients admitted under Dr. Anurag are offered comprehensive facilities, right from acute emergency care to management of co-morbid severe conditions. The dedicated team of doctors, nurses, and technicians working with Dr. Anurag at Paras hospital are available 24X7 to provide all the services to patients of heart block.