What is Cardiac Arrhythmia?
Cardiac arrhythmia (also known as irregular heartbeat) is a group of conditions in which the heartbeat is irregular, too fast, or too slow. Normal heartbeat of an adult ranges between 60-100 beats per minute.
Our heart is made up of two distinct functional units:
1) Cardiac muscle: The one that contracts to pump blood into our arteries.
2) Electrical conduction system: It is the system that conducts electrical stimulus from its point of generation (SA Node), throughout the heart muscle. This stimulus, stimulates the heart muscle to contract. The stimulus, also called an impulse, stimulates different chambers of heart in a sequential manner, first stimulating the atria and then the ventricles as follows:
Hence, one beat of heart involves the contraction of atria followed by that of ventricles. And on an average, our heart beats 72 times a minute, pumping around 5L of blood into our arteries.
Thus, this conduction system of heart determines its heartbeat, and any damage to this system will lead to irregular heart rhythm or arrhythmias.
Broadly there are two types of arrhythmias:
1) Tachycardia: In this type, the heartbeat is higher than normal, ie. more than 100 beats per minute. This is further divided into the following types:
- Atrial tachycardia
- Atrial flutter
- Atrial fibrillation
- Ventricular tachycardia
- Ventricular fibrillation (fatal condition)
2) Bradycardia: In this type, the heartbeat is less than normal, ie. Less than 60 beats per minute. Further divided into:
- AV node blocks
- Bundle branch blocks
What are the chances of Cardiac Arrhythmia?
It is a very common ailment. (More than 10 million cases per year)
What are the symptoms of Cardiac Arrhythmia?
The term heart arrhythmias cover a very large number of very different conditions, some developing symptoms while others being silent diseases. Few common symptoms are-
1) Palpitation: Palpitation is awareness of our own heartbeat (which could be abnormal). We normally get palpitations after exercising or when we are anxious or scared. But getting palpitations at rest, without any reason is worrisome. They can occur suddenly and last for a few seconds (called paroxysmal) or can occur more frequently and continuously.
2) Light-headedness and fainting episodes: Too fast heartbeat can cause less volume of blood to pump in the circulation, leading to fainting episodes.
3) Decreased exertion capacity: Minor exercises like climbing few steps can lead to breathlessness or palpitations or fatigue, suggesting decreased exertional capacity.
Who is at risk for Cardiac Arrhythmia?
- Elderly population
- People with ischemic heart disease
- People with valvular heart disease
- People having long standing hypertension
- People with heart failure
- People with infection of heart
- People who’ve undergone heart surgery
- Chronic smokers
- Alcohol bingers
- People with diabetes mellitus
- Psychological disorders like panic attacks
- People under continuous stress
- People with thyroid problems (thyrotoxicosis)
- People with electrolyte imbalances (potassium and calcium)
What are the causes of Cardiac Arrhythmia?
1) Causes for Bradycardia
- Damaged SA node
- Blocked coronary artery (artery that supplies the heart and conduction system)
- Certain medications like beta-blockers, calcium channel blockers
- Thyroid problems like hypothyroidism (low levels of thyroid hormones)
- Electrolyte imbalance like high potassium and high magnesium levels
- Infectious diseases like endocarditis (swelling of the inner lining of heart)
- Congenital heart disease
2) Causes for Tachycardia
- Acute alcohol binge
- Hyperthyroidism (high levels of thyroid hormones)
- Structural defects in the conduction system of heart
- Fever, exercise, anxiety, fear, caffeine consumption
- Heart attack
- Certain medications like sympathomimetic agents
What are the complications in Cardiac Arrhythmia?
1) Clot formation and stroke: Irregular heartbeat causes incomplete emptying of blood from the heart chambers leading to stagnation of blood. This causes the blood to clot, which can later dislodge into the circulation and block the arteries supplying the brain, leading to stroke. Arrhythmias cause 25-35% of all strokes.
2) Heart failure: Since the heart is not able to pump adequate blood into the circulation due to ineffective contraction, it is said to be in failure.
3) Palpitations: Long standing palpitations and chest pain
4) Sudden cardiac death: Refers to sudden death occurring due to sudden cardiac arrest in an otherwise normal individual.
How is Cardiac Arrhythmia diagnosed?
- Peripheral pulse examination and auscultation (hearing the heartbeat with stethoscope) of heart can detect nature of heartbeat.
- ECG (electrocardiogram) is a simple test done to detect any conduction abnormalities and identify the type of abnormality.
- Electrophysiological study is an invasive procedure where a catheter is placed inside the heart chambers to find out the exact location of arrhythmia.
- Trans-esophageal stimulation (TAS) is also an invasive procedure where a catheter is inserted through the food-pipe (esophagus), near the atria. It can differentiate between different types of atrial tachycardias.
How is Cardiac Arrhythmia treated?
Various modalities are available for the treatment of arrhythmia:
1) Physical maneuvers: They are also called vagal maneuvers as they stimulate the vagus nerve to reduce the heart rate in a stable patient of tachycardia.
2) Anti-arrhythmic drugs (Chemical cardio-version): These are a large group of drugs involving many sub-groups that suppress abnormal heart rhythm. Your doctor will select a drug based on your type of arrhythmia.
Warning: These drugs have many side effects and hence should be used under medical supervision only.
3) Other drugs: Certain drugs like beta-blockers and calcium channel blockers can be used in patients with tachycardias to reduce heart rate (rate controlling drugs).
4) Blood thinners: These drugs (like aspirin, warfarin, heparin) are used to prevent the formation of blood clots.
5) Electrical cardioversion: Done in cases where chemical cardio version does not work. A small amount of current is given at a specific point in the cardiac cycle to convert the abnormal rhythm to normal rhythm.
6) Defibrillator: This is used in emergency situations, where a small amount of current is used to stop the abnormally contracting heart, following which the heart starts contracting normally.
7) Pacemakers: These are small implantable devices that are used in patients of bradycardia. They act as SA node, generating electrical stimulus.
8) Catheter ablation: This is an invasive procedure in which a catheter is used to damage the area of heart causing arrhythmia. Based on your condition, your doctor will individualize your therapy.
More than one of the above modalities can be used to provide maximum relief.
What are the lifestyle changes required to manage Cardiac Arrhythmia?
- Manage stress: Stress puts pressure on heart and can increase your risk of arrhythmia. Manage stress by doing activities that you enjoy. Try to meditate few times a week.
- Diet: When dealing with a heart ailment, it becomes important to have a healthy diet with more fruits and vegetables and less oil and spices. Try to manage your cholesterol and eat heart healthy diet.
- Quit smoking and drinking: Smoking and drinking are triggers and create toxins in the blood stream. Adapt a healthy lifestyle minus smoking, alcohol or any other drugs.
- Exercise: It is important to exercise to keep the heart healthy. It also helps the heart pump blood better and helps in managing cholesterol and weight.
How to take care of someone with Cardiac Arrhythmia?
- Encourage them to lead a healthy lifestyle
- Help them with eating the right diet and reducing sodium intake
- Take them for timely check-ups with the specialist
- Help them to lead an active life
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