Partial Heart Block

Heart block can be partial or complete and may result from various situations. The electrical impulses, that are transported from the atria to the ventricles, produce heartbeats and regulate their rhythm. The situation is reported as 'first degree heart block or first-degree Atrioventricular (AV) heart block', when there is a considerable increase in the conduction time of an impulse. The impulse is blocked between the atrium and ventricle. Atrium is the upper chamber and ventricle is the lower chamber of the heart. Due to the slow moving impulse, skipped beat (irregular heartbeat) or weak heartbeat is noticed. When some atrial impulses are not transferred, the situation is referred to as second degree partial heart block. When no atrial impulses are transferred, the condition is termed as third degree or complete heart block.

AV Heart Block

Causes
Drugs and Stimulants: Certain medications affect the normal beating of the heart or the heart rate. For example, beta blockers slow down the heart rate while consumption of ephedrine that is used as an appetite suppressant or used to treat asthma, bronchitis, can lead to tachycardia (high heart rate) or cardiac arrhythmias (irregular heart rate). Calcium channel blockers also affect the heart health seriously. So you should be extremely cautious while taking more than one medicine at a time. You should discuss the side effects of the medicines with your doctor to avoid serious conditions. Consumption of stimulants like caffeine, nicotine, cocaine also leads to rapid heart rate. The medicine 'digitalis' slows down the transfer of impulses from atrium to ventricle.

Heart Diseases: Certain diseases of the heart can make the heart muscle weak (called cardiomyopathy). A heart attack (myocardial infarction) can leave a weak heart muscle. Coronary artery diseases can also affect the transfer of impulses in the heart. A defect in the heart valve, diseased sinus node (pacemaker of the heart), can lead to disturbed heartbeats.

Genetic Disorder: Genetic disposition is many times responsible for structural defects in the heart that lead to impaired conduction of impulses in the heart. Congenital heart diseases are quite common. Structural abnormalities of atrioventricular node can lead to blockage of heart.

Other Diseases and Disorders: Diseases like arthritis, diabetes, atherosclerosis, ventricular heart attack, ischemic heart disease, too much potassium in the blood, high cholesterol levels, inflammation of the heart and electrolyte imbalance can result in heart block. Increased tone of the vagus nerve can lead to second degree heart blockage. High blood pressure, bacterial infection in the heart, development of the scar tissue after surgery, viral infections of the heart, and congenital heart defects can be the cause of blocked heart.

Intensive Exercise: Athletes who train rigorously or sports persons who undergo endurance training may suffer from heart blockage.

Symptoms
First degree partial heart block usually does not exhibit any symptoms. As the condition worsens, symptoms are noticed. Abnormally slow heart rate and cardiac arrhythmia are the main symptoms noticed. Depending upon the severity of the condition, symptoms like fainting, seizures, dizziness, breathlessness (shortness of breath) and chest pain can be experienced. Nausea can also be experienced along with chest pain and breathing difficulty.

When the impulses of the heart do not reach ventricles, the condition becomes more serious. A pacemaker helps correct abnormal or slow heartbeat. Third degree heart blockage can be permanent (chronic) or temporary (transient). Degenerative changes of the heart or effects of a heart attack are usually responsible for chronic heart block, which significantly affects the capacity of the heart to pump blood. It can result in serious situations such as cardiac arrest and cardiac death. If you notice any symptoms of weak heart or heart block, you should immediately consult your physician. Prompt medication and treatment can help avoid worsening of the situation.

ECG (Electrocardiogram), Electrophysiologic study, Invasive Electrophysiologic testing (a type of cardiac catheterization) and Implantable Loop Recorder help diagnose affected conduction of electrical impulses in the heart. Doctors may prescribe medicines and place a pacemaker to lower the symptoms of partial heart block. The patient has to take proper care and rest. Follow-ups are quite important for these patients. Consumption of alcohol, drugs or smoking can worsen the situation. Even excessive emotional stress can affect conduction of impulses in the heart. A healthy diet and regular exercise can help prevent all unwanted situations that come along with heart diseases.