Atrial Fibrillation is a Condition Causing Fast Heart Rate
Abnormalities or damage to the structure of the heart are the most common causes. Common symptoms include palpitations, shortness of breath, reduced activity tolerance, dizziness, sweating and chest pain. Few patients are completely asymptomatic.
Atrial fibrillation is a condition where heart beats irregularly causing irregular and fast pulse. The reason behind this unusually fast heart rate is the variation in sequence of contraction of the two upper chambers of the heart (left and right atria) with the bottom chambers (left and right ventricles). In a normal heart the upper chambers are pacesetters for the lower chambers and are in synchrony.
The condition by itself is not life threatening but carries a high risk of stroke which has morbidity and mortality associated.
Due to electrical chaos the upper chambers are not squeezing rather quivering or writhing leading to stagnation of blood. Stagnant blood clots as a protective mechanism; pieces if clot break off and move into the circulation blocking blood flow to other organs. The blood vessels to the brain are anatomically straight from the heart. Therefore, there is a higher propensity of clots going to the brain giving rise to stroke.
Few patients are completely asymptomatic. Common symptoms are:
- palpitations – sense of racing heart, flip-flop, skipped beats
- shortness of breath with minimal or no activity
- reduced activity tolerance – easy fatiguability
- dizziness or lightheadedness
- chest pain/discomfort
Types of Atrial Fibrillation
- Paroxysmal – or occasional lasting few minutes to hours and self-terminating. Symptoms also last a short while.
- Persistent – atrial fibrillation persists unless treated with electrical shock or medications.
- Permanent – regular rhythm cannot be restored, and patients need to be on medications to control heart rate and therefore symptoms.
Electricity Flow in the Heart
During a normal heart rate electrical impulse starts from the upper chambers from a spot called SINOATRIAL (SA node) node and travels to ATRIOVENTRICULAR (AV node) node from there to the lower chambers of the heart – left and right ventricle. SA node produces an impulse 300 times a minute, AV node control how many impulses are needed based on various situations like physical activity, sleep, rest, flight and fight response. These impulses then travel throughout the heart to produce a heartbeat.
In atrial fibrillation impulses do not necessarily start from the SA node rather from several different places in the upper chambers and not regulated by the AV node. Lack of regulation on required impulses gives rise to fast irregular heartbeat and pulse.
Do you experience these symptoms?
Causes of Atrial Fibrillation
Abnormalities or damage to the structure of the heart are the most common causes.
Modifiable Causes usually lifestyle related:
- Sedentary lifestyle
- Heavy alcohol consumption
- Uncontrolled high blood pressure for long duration
- Uncontrolled diabetes
- Obstructive sleep apnea
- Heart attack
- Stimulant drinks and drugs
- Heart valve disease
- Lung disease
- Viral infections damaging the heart tissue – viral cardiomyopathy
- Emotional stress over long periods
- Congenital heart diseases
- Age – more common in patients older than 65 years. 70% of individual with atrial fibrillation are between 65-85 years of age.
- Genetics – genetic predisposition to common forms of atrial fibrillation has recently been recognized.
- Ethnicity – more common in Caucasians than Hispanic, African and Asian heritage.
- Holter monitor – like ECG but records rhythm for 24 hours. Patches as stuck on skin and wires attaches to device that records the rhythm.
- Mobile Cardiac Telemetry (MCT) – like Holter but for longer periods. A week to two weeks.
- Echocardiogram – ultrasound of the heart. Looks at the heart structures including heart valves, upper and lower chambers.
- Blood test – including blood count, kidney and liver function, electrolytes and thyroid panel.
- Chest X-Ray looking for lung diseases.
Schedule for an appropriate diagnosis
Goals are to revert the rhythm to sinus (normal or regular) and prevent of blood clots. Many patients at mHospital inquiring about how to lower heart rate are most likely experiencing Atrial Fibrillation.
Restoring to normal rhythm (sinus rhythm)
- Electrical cardioversion. Patient is sedated. Electrical paddles attached to the chest wall and synchronized electricity is passed.
- Pharmacological cardioversion – class of medications called anti-arrhythmic are administered intravenously in a monitored setting of a hospital or outpatient with telemetry monitor.
- A combination of above modalities.
Prevention of Stroke
A variety of blood thinners are given to patient with higher risk of stroke. Medications like Warfarin or NOAC (Novel Oral Anticoagulants) like Rivaroxaban, Apixaban, Dabigatran, Edoxaban.
Depending on the duration of Atrial fibrillation blood thinners are given prior to restoration of rhythm to sinus (normal).
Maintenance of Normal Rhythm – medications are taken long term to maintain sinus rhythm. Amiodarone, Sotalol, Propafenone, Flecainide are some examples.
Rate Control – patient in persistent Atrial Fibrillation may need heart rate control. Class of medication used are Beta blockers like Metoprolol or Calcium Channel Blockers like Diltiazem and Verapamil.
Catheter based – from the vein in the groin area small caliber tubes are passed to the heart under x-ray visualization. Treatments are then performed via the small caliber tubes.
Surgical Procedures – open heart surgery for atrial fibrillation and fast heart rate treatment is usually performed in conjunction with bypass surgery.
- 1. MAZE procedure – This is done by open surgery or catheter based. Several lines are made in the upper chambers of the heart to prevent the chaotic impulses getting to the AV node.
- 2. Catheter ablation – tube passed from the groin vessel interrogates the upper chambers for abnormal electrical activity and radiofrequency energy applied to scar the abnormal impulse producing spot/zone.
- 3. AV node ablation – this is usually last resort. After AV ablation permanent pacemaker is implanted.
- 4. Left atrial appendage closure – Left atrial appendage is area in the left upper chamber of the heart where most clots are formed. Closure/sealing of this appendage prevents clots from migrating. Closure of left atrial appendage can be by catheters from the groin or open-heart surgery.
For immediate treatment, Thrombolysis is performed only within the first 3 hours of onset of stroke. Thrombolytic drug is administered intravenously which breaks up the clot. This treatment comes with complications of bleeding and so the patient is observed for risk of bleeding.
An interventional radiologist may also be involved if one is available and a catheter can be used to give the medication closer to the brain or the clot can be removed mechanically.
At least 2.7 million Americans have Atrial Fibrillation as per the CDC statistics. mHospital provides you access to Board certified medical specialists who can assist you at the time and place of your choice. You can schedule an online doctor session via our mobile doctor app. You may also reserve an appointment with a house call doctor or at doctor office.