Arrhythmia

• The heart consists of 4 chambers, 2 upper – atria – which receives blood, and 2 lower chambers – ventricles – which push the blood out from the organ.
• They alternately contract and relax to pump blood through the heart and to the rest of the body
• A heartbeat is an electrical impulse generated and passed through a pre-determined pathway in the heart
• These pulses originate in the sinoatrial (SA) node – a small mass of specialised tissue in the right atrium, known as the hearts pacemaker.
• The pulses cause the atria to contract and squeeze blood to the ventricles
• The atrioventricular (AV) node – makes the ventricles contract, where blood was pumped in by the atria, and forces blood out to the rest of the body
• A normal resting heart rate is more or less 60-100 beats per minute, 80 beats per minute may be a cause for concern for heart disease.
• Irregularities in the heart rhythm may affect how the heart pumps blood to the body, and can cause damage in various tissues and organs
• Normal heart contractions depend on the amount of electrolytes in the body.
• Sodium, potassium, calcium, and magnesium are ions that are required to produce these electrical impulses. Low levels could prevent the proper formation of these impulses and may result in arrhythmias.
• Anti-arrhythmic drugs act by mimicking these ion channels. 

1. Enhanced or suppressed automaticity:

• It’s the ability of the heart muscle cells to produce an electrical impulse.
• SA node determines when an impulse must be fired, impulses from anywhere else in the heart before the SA node firing, could lead to premature heartbeats, or abnormal heartbeats.
• Factors, including electrolyte imbalances, medication, and age could alter automaticity in some areas of the heart, which then could lead to arrhythmias

2. Triggered activity:

• The abnormal functioning of electrical activity in individual heart cells, which may result in abnormal heart rhythms
• These triggers are rare, but occur due to problems in the ion channels in the heart muscles.
• It is also a side effect from anti-arrhythmic drugs

3. Re-Entry:

• Common mechanism for a rapid irregular heartbeat
• It happens when electrical pulses travel backwards from the ventricles to the atria, producing another heartbeat when the first one is still moving into the ventricles.

1. Premature beats

• Common and mostly harmless
• It occurs in the atria – called premature atria contractions
• Caused by excess consumption of caffeine, alcohol, sympathomimetic medications, present in people who have heart disease
• Premature ventricular contractions – often in people who have structural heart disease but also in people who do not have any identifiable heart conditions.
• They cause a feeling of a “skipped beat” in the chest, and is more common in elderly people
• Common causes are – electrolyte imbalance, coffee, alcohol and exercise
• Typically asymptomatic – cause signs and symptoms of chest pain, palpitations and heart failure
• PVC-induced cardiomyopathy – condition where the heart becomes enlarged and not able to pump blood due to very frequent PVC’s.

2. Supraventricular Arrhythmia's

These types of Arrhythmia start in the atria and have different types:

• Atrial Flutter – This is a very common occurrence. Electrical signals move through the atria, with a fast and regular rhythm. The symptoms and complications are similar to atrial fibrillation.

• Paroxysmal Supraventricular Tachycardia – Fast heart rate that happens from time to time. Symptoms begin and end suddenly. The electrical signals happen in a reverse direction from the ventricles to the atria, which cause extra heartbeats. This happens as a result of toxicity due to medication digitalis, in conditions like Wolff-Parkinson-White syndrome. This is when signals travel along an extra pathway from the atria to the ventricles that disrupt the timing of signals and cause rapid beating of the ventricles. This could be life threatening, and could occur without any symptoms.

Ventricular Arrhythmia's start off in the ventricles, with the common cause being a sudden cardiac death.

• This could be life threatening and require medical care, it usually occurs in people with structural heart problems, as well as people who have no evidence of cardiac disease.
• 2 different types:
• 1: Ventricular Tachycardia – It’s a fast but regular beating of the ventricles which may last a few seconds to much longer. It is not life threatening, but if it persists for more than a few seconds, could become dangerous and become fatal.
• 2: Ventricular Fibrillation – Causes the ventricles to work abnormally due to the disorganised electrical signals. The heart then does not pump blood to the body, and may result in death within minutes. A defibrillator is used to treat this by an electrical shock to the heart that restores the rhythm to normal

Bradyarrthythmia is a heart rate in adults that is less than 60 beats per minute.

• May cause insufficient blood to reach the brain.
• People who are very fit, may have a slower heart rate, which is normal.
• This condition could occur due to serious medical conditions such as heart attacks, medication, hypothyroidism, and electrolyte imbalances in the blood.

• There are no visible symptoms, which prevents diagnosis and treatment.
• Yet some of these symptoms could be prevalent – racing, or pounding heart, chest pain, shortness of breath, dizziness, light headedness, anxiety, fainting, reducing capacity for exercise, that impair quality of life.
• Symptoms could be dangerous and life threatening, and may lead to cardiac death.

• It’s a sensation or feeling of a racing or pounding heart, felt in the chest, neck and throat.
• May be accompanied by an abnormal heart rhythm
• They are usually harmless, where there is also no underlying causes are found.
• Are mainly caused by anxiety, drug use, low blood sugar, electrolyte imbalance, fever
• Caffeine, alcohol, tobacco and some drugs, could lead to palpitations and panic attacks.
• When feeling dizzy or fainting, palpitations could indicate a more serious condition
• Non-Arrhythmia causes of palpitations may include coronary heart disease and congestive heart failure.
• An electrocardiogram could help determine the cause of palpitations.

Sleep-related breathing disorders are highly prevalent in patients with established cardiovascular disease. Obstructive sleep apnoea (OSA) affects an estimated 15 million adults in America, and is present in a large portion of patients with hypertension and other cardiovascular diseases such as atrial fibrillation. Sleep apnoea is a major cause of atrial fibrillation.

These risk factor can cause chronic structural and functional damage over time, and temporarily alter the biochemistry of the body and trigger arrhythmias.

• Imbalance of electrolytes – Arrhythmias may be caused due to altering levels of sodium and potassium in the body.
• High blood pressure – Causes thickness and stiffening of the ventricle walls causing the pulses to change going through the heart.
• Obesity – By increasing lipid levels, , blood pressure and glucose intolerance, or the increase in blood volume, may cause the heart to overwork and make the heart muscles thicker.
• Smoking – Causes coronary artery disease and pulmonary chronic disease, which leads to Arrhythmias.
• Alcohol abuse – Causes dysfunction of the heart muscle, making the heart beat less efficiently.
• Stress – Emotional and psychological stress could lead to deadly arrhythmias.
• Diabetes – Uncontrolled may lead to coronary artery disease and hypertension, as well as episodes of low blood sugar.
• Thyroid dysfunction – Patients with hyperthyroidism are at risk for atrial fibrillation.
• Stimulants – Caffeine, prescription drugs could lead to arrhythmias, as well as illegal drugs such as cocaine, and methamphetamine.
• Oxidative stress – Following a heart attack the development of ventricular tachycardia and fibrillation could occur.
• Performance sports – Autonomic nervous system alterations, systemic inflammation and increased atrial size are some factors that may cause this especially in athletes.
• Certain medications – Antidepressants and antipsychotic drugs may be the cause of arrhythmias

Doctors study the wave patterns of heartbeats, where they can determine what kind of arrhythmia is present.

Diagnosis may be done in the following manners:

• History and physical examination
• History or presence of heart disease, thyroid problems, high blood pressure in patients and family members, have an increased risk.
• History of sudden death, diabetes, and other illnesses are also high risk factors. Listening to the heart and the rhythm, listening for heart murmurs, swelling of the feet and also by taking the pulse all aid in diagnosis for arrhythmias.
• Electrocardiogram (ECG or EKG): A test that can detect and record the electrical activity of the heart
• Intracardiac electrophysiology study (EPS): A procedure used to test the hearts electrical system, and is used in cases of serious arrhythmia.
• Echocardiography: A test that is used with sound waves for the visualization of the heart to observe the blood flow. This allows you to see the size and shape of the heart, chambers and the valves, and recognize where the heart does not function normally.
• Stress test: Involves testing for arrhythmias while patients are exercising on treadmills or stationary bicycles, as it makes the diagnosis easier when the heart is working hard.
• Coronary angiography: It’s a procedure that uses a dye with X-Rays to show the inside of the coronary arteries
• Tilt table test: Recommended for patients that have fainting spells. Heart rate and pressure is measured while a patient is lying flat on a table.
• Blood tests: Thyroid and electrolyte levels are measured, and when abnormal there is a high risk for arrhythmias.
• Electromechanical wave imaging: New non-invasive method that uses ultrasound imaging that maps electrical circuits of the heart. Doctors can detect problems in real time feedback.

Treatment depends on the type of arrhythmia a patient might have.

• Vagal Manoeuvres: If arrhythmias start at the top of the ventricles, this may be used to stop the vagus nerve which is responsible for controlling the heartbeats. Some other manoeuvres that may be used is to hold your breath and strain, dunking your face in icy water and coughing to slow down the heart rate
• Medications: Could be treated with various medications. The type of medication will depend on the diagnosis from the doctor.
• New Alternatives to amiodrone – budiodarone and dronedarone
• Amiodarone: Most frequently used, as it effectively treats deadly ventricular arrhythmias, used in managing atrial fibrillation. Side effects: Fibrous tissues in the lungs and thyroid dysfunction, these side effects remain in the body for a long period of time.
• Budiodarone and Dronedarone: Similar to amiodarone in both the chemical structure and action. They are metabolised fast, which leads to less tissue accumulation and side effects.
• Electrical Cardioversion: Delivers an external electrical jolt through the chest and into the heart, to help reset the normal rhythm of the heart. The machine used for this is called a defibrillator.
• Ablation Therapy: This procedure involves an insertion of a thin wire catheter into the blood vessel in the groin, arm or neck and guided to the heart. Radiofrequency is delivered through the wire and generates heat and ablates small sections of heart tissue that causes arrhythmia. Cryoablation is a method using extreme cold.
• Implantable devices:
• 1) Pacemaker – battery operated device that is used for slow or irregular heart rates. It is implanted surgically under the skin near the collarbone.
• 2) Implantable Cardioverter-Defibrillator – This is placed near the collarbone under the skin surgically, but does not turn off and monitors the heart beats continuously.
• Surgical Treatments:
• Maze Procedure – Making surgical incisions in the atria, that heal and form scars that force the electrical impulses to travel along them, and cause the heart to beat efficiently. This requires open-heart surgery, and is only done when patients do not respond to other types of treatment.
• Coronary Bypass surgery – Is done in severe cases of coronary artery disease with frequent ventricular tachycardia. It helps to improve the blood flow to the heart and reduce the frequency of ventricular tachycardia.

1. Acupuncture: The stimulation of a variety of points on the body using needles inserted manually. Patients had a normal heart rhythm post acupuncture treatment.
2. Mediterranean diet: Helps with improvement of cardio protective effects. When the diet is not followed, arterial fibrillation developed. When diet was adhered to the heart returned to its normal rate and rhythm.
3. Lifestyle Changes: Adequate exercise, maintaining healthy body weight, stop smoking, cut back on caffeine and alcohol, reduce stress levels, and avoid stimulant medications.

1. Omega-3/Fish Oil: Lipids found in certain fish and other seafood as well as specific plant sources. Moderate consumption of fish oils/omega-3 fatty acids are heart healthy and provide protection against arrhythmias. Omega-3 fatty acids help to stabilise the electrical activity in the heart, by the reduction of sodium and calcium levels inside the heart muscle cells.
2. Magnesium and Potassium: Helps to stabilise the heart stability and maintain normal blood functional levels of these ions that are important. A low concentration of these increase the risk for developing ventricular arrhythmias
3. Magnesium: A deficiency in magnesium could be the cause for congestive heart failure, hypertension and angina.
4. Potassium: It’s important for the maintenance of cardiac electrical stability and changes.
5. Hawthorn: It’s a fruit baring shrub that helps to support cardiovascular health. It’s also rich in antioxidants, like flavonoids and anthocyanin’s that play a role in cardiovascular diseases. Supports a healthy heart by modulation of the ion channels, blood flow, inflammation, oxygen utilization and scavenging free radicals that cause oxidative stress.
6. Antioxidants, such as:
7. N-Acetyl-cysteine: Has Antioxidant and anti-inflammatory properties that effectively reduce the incidence of post-operative atrial fibrillation.
8. Vitamins C & E: Has a protective effect against post-operative atrial fibrillation, because of their antioxidant properties. And shows a huge reduction in the incidence post operatively.
9. Resveratrol: Polyphenal is found in grapes and has antioxidant and anti-inflammatory properties. Resveratrol suppresses myocardial infarction induced ventricular arrhythmias, and improves long term survival.
10. Coenzyme Q10: It’s a powerful antioxidant and important for cellular energy production. It plays a therapeutic role in impaired cardiac function like heart failure. It is beneficial for reducing premature ventricular contractions.