Cardiac Arrhythmia: Understanding and Prevention | Wellbeing

1. What is Cardiac Arrhythmia?

• Cardiac Electrophysiology and Heart Rate: The heart is a complex organ, typically consisting of 4 chambers. The two upper chambers are the atria, and the two lower chambers are the ventricles. All heart cells have the ability to contract automatically and rhythmically. The heartbeat is generated from an electrical conduction structure within the heart, specifically from the sinus node. The Sinoatrial (SA) node is located in the wall of the right atrium; cells in the SA node transmit electrical impulses to the two atria, then to the atrioventricular (AV) node, then through the system of bundle branches and Purkinje fibers in the ventricles, and finally to the ventricular muscle cells. This continuous and rhythmic sequence helps the heart contract to create heartbeats.

• Normal Heart Rate: A normal heart rate is calculated based on the number of heart contractions per minute. For a normal person at rest, the heart rate ranges from 60 to 100 beats per minute. However, many factors affect heart rate, such as physical activity, health status, emotions, or age. Heart rate can be self-checked by counting the pulse, using a stethoscope, or using electronic devices.

• Cardiac Arrhythmia: This is a condition of disordered bio-electrical activity of the heart, leading to a heartbeat that is too fast (>100 beats/minute), too slow (<60 beats/minute), or irregular (fluctuating speed). Any factor affecting the automaticity or conductivity of the heart can cause heart rate abnormalities. Cardiac arrhythmia is a common pathology encountered in daily practice.

2. Main Causes of Cardiac Arrhythmia

Any factor affecting the heart's automaticity or conductivity can cause cardiac arrhythmia. This condition can appear for a few minutes, or shorter, but can also appear in episodes without prior warning signs. Some types of arrhythmias can last for hours, or even continuously for many years. Causes of cardiac arrhythmia include:

• Cardiovascular Diseases: Diseases such as coronary artery disease and heart failure can cause arrhythmias.

• Stress and Anxiety: Prolonged stress can affect heart rate.

• Electrolyte Imbalance: Deficiency or imbalance of electrolytes such as potassium, calcium, magnesium, and sodium can also disrupt heart rhythm.

• Oxygen Levels: Low oxygen levels can reduce the conductivity and contractility of heart muscle cells, leading to arrhythmias.

• Medication Use: Some medications like antidepressants and antihypertensives can cause this side effect. Addictive drugs like amphetamines and cocaine also have a strong stimulating effect on heart rate.

• Substances ingested via the digestive tract: Caffeine and other sympathetic stimulants can increase conductivity, while central nervous system depressants like alcohol have the opposite effect.

• Aging: The aging of cells in the heart's conduction system and heart muscle cells in the elderly; arrhythmias appear due to fibrosis in the conduction system.

3. Symptoms of Cardiac Arrhythmia

Symptoms can vary depending on the type and severity:

• Palpitations: This is a typical and common symptom. The patient may feel the heart beating strongly or fast, or feel as if the heart stops for a moment and then beats hard again, accompanied by a feeling of nervousness.

• Dizziness or Fainting: The patient feels lightheaded and off-balance.

• Shortness of Breath: The patient feels difficulty in breathing, rapid breathing, or chest tightness.

• Sudden Fatigue or Weakness: The patient feels a loss of energy and tiredness.

4. Common Types of Cardiac Arrhythmia

• Sinus Tachycardia: Electrical impulses are conducted normally, originating from the sinus node with a rate over 100 beats/minute. It can be symptomatic or asymptomatic, often described by patients as "palpitations" or "racing heart."

• Sinus Bradycardia: Electrical impulses are conducted normally from the sinus node with a rate slower than 60 beats/minute. Common in high-level athletes or cases of anterior wall myocardial infarction.

• Premature Contractions (Extrasystole): Often appear in people without heart disease; common triggers are anxiety, psychological shock, or physical activity. However, they can also appear in people with latent heart disease, cardiomyopathy, or valvular heart disease.

• Atrial Fibrillation (Afib): The most common sustained supraventricular arrhythmia, primarily a disease of the elderly, often found in patients with enlarged atria, valvular heart disease, and other chronic cardiopulmonary diseases.

• Atrial Flutter: Thought to be due to an electrical reentry circuit in the right atrium. In this case, the atria contract rapidly and regularly with a frequency of about 240 to 340 beats/minute.

• Ventricular Tachycardia (VT): An arrhythmia originating from the ventricles, defined as three or more consecutive premature ventricular contractions. There is non-sustained VT (lasting <30 seconds) and sustained VT (lasting >30 seconds).

• Torsades de Pointes: Often caused by Group 1 antiarrhythmic drugs; hypokalemia (low blood potassium) is also a favorable factor. Main symptoms are fainting and cardiovascular collapse.

• Atrioventricular (AV) Block: To maintain a normal heart rate, impulses from the sinus node must pass through pathways from the atria to the ventricles. This arrhythmia occurs when the AV pathway is damaged at critical points, causing conduction blockage.

5. Approach to Diagnosis

• Clinical Examination: Patients may have symptoms suggestive of arrhythmia; clinical examination helps find evidence of disease related to arrhythmia.

• Electrocardiogram (ECG): The main tool for diagnosing types of cardiac arrhythmias.

• Heart Monitoring: Using a monitor to record heart rate for 24 hours or longer (Holter monitor).

• Electrolyte Tests: Checking electrolyte levels in the body to identify causes.

6. Treatment of Cardiac Arrhythmia

• Adjusting Potential Causes: Use of medications or stimulants like caffeine are adjustable causes. Changing or stopping medications or stimulants can resolve the problem.

• Medications: Doctors may prescribe heart rhythm-regulating drugs or anticoagulants if necessary.

• Cardioversion: Emergency or urgent electric shock is used effectively for selective treatment of certain supraventricular arrhythmias.

• Medical Intervention: In some serious cases, methods like cardiac ablation or pacemaker implantation may be needed.

7. Prevention of Cardiac Arrhythmia

• Build a Healthy Lifestyle: Reducing stress, regular exercise, and healthy eating can help control the condition. Focus on a diet rich in fruits, whole grains, vegetables, and skinless poultry, low-fat foods, and beans. Limit foods high in cholesterol and saturated fats; limit eggs and red meat. Exercise daily, stop smoking and stimulants.

• Mental Therapy: Learn breath control and heart rate control methods to help stabilize heart rhythm. Focus on appropriate rest time alongside seeking stress-reduction therapies like meditation and yoga.

• Periodic Check-ups: Cardiac arrhythmia can occur at any age and any time. Schedule regular health check-ups; early detection can help minimize risks and protect cardiovascular health.

Cardiac arrhythmia is a condition that needs attention and timely treatment. If you or a loved one has related symptoms, seek advice from a doctor. Understanding the information and proactively caring for your health will help you maintain a healthy heart and a better quality of life.