Emergency Management of Tachyarrhythmias?

Introduction:

An abnormally fast heartbeat (greater than 100 beats per minute) with an irregular heart rhythm is known as tachyarrhythmia. The abnormal electrical activity of the heart muscles can originate from any of the heart's chambers (the upper atrium or lower ventricles) and causes the heart to flutter irregularly. It is considered tachyarrhythmia if these irregular heartbeats and a rapid racing heart (tachycardia) occur together. The rapid, irregular heartbeats keep the heart’s chambers from filling completely between contractions, compromising blood flow to the rest of the body. Abnormal heartbeats also lead to blood clots in the heart and important blood vessels. If left untreated, it can lead to critical illnesses and emergencies such as unconsciousness, cardiac arrests (the heart stops beating), and shock (low blood pressure and low oxygen supply to all body parts and organs).

What Are the Types of Tachyarrhythmias?

Based on the site of origin of the rapid, irregular heartbeat, tachyarrhythmias can be categorized into

An irregular heartbeat can begin in the heart's upper chambers (supraventricular or atrial arrhythmias). These include the following types:

1. Paroxysmal supraventricular tachycardia (PSVT).
2. Accessory pathway tachycardias (the abnormal electrical connection between the upper and lower chambers of the heart).
3. Additional electrical pathways (AV nodal reentrant tachycardia).
4. Atrial (upper chamber) tachycardia.
5. Atrial fibrillation.
6. Atrial flutter.

An irregular heartbeat can begin in the heart's lower chambers or ventricles. These include the following:

1. Premature ventricular contractions (PVCs).
2. Ventricular tachycardia (the irregular rhythm of the ventricles affecting the efficiency of the heart pumping blood).
3. Long QT interval (in the heart rhythm waves).
4. Ventricular fibrillation (V-fib or an erratic and disorganized electrical firing in the heart).

What Are the Warning Signs of Tachyarrhythmias?

The various symptoms of tachyarrhythmias include the following:

1. Fluttering and a racing heart (palpitations).

2. Lightheadedness.

3. Breathing difficulty.

4. Pounding (felt in the chest).

5. Weakness and fatigue.

6. Dizziness.

7. Chest discomfort.

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8. Unconsciousness.

What Causes an Irregular Racing Heart?

Various underlying causes can lead to tachyarrhythmias. These include:

1. Heart disease such as coronary artery disease.

2. Genetic or acquired conditions (causing irritable tissue in the heart).

3. Blood pressure problems.

4. Heart muscle diseases and conditions such as cardiomyopathy.

5. Disorders affecting the valves of the heart.

6. Blood electrolyte (sodium and potassium) imbalances.

7. Heart attack (leading to heart damage).

8. Heart surgery and healing issues.

9. Other underlying medical conditions that affect the heart.

How Are Rapid, Irregular Heartbeats Diagnosed?

Consulting a heart specialist with additional training in heart rhythm disorders is essential to diagnose and manage tachyarrhythmia. The doctor assesses the symptoms and performs a detailed examination and diagnostic tests to confirm and identify the causes of the irregular heartbeat.

The diagnostic tests include the following:

1. Electrocardiogram (ECG): The waveform of the heart's electrical activity is recorded to assess the heart rhythm.

2. Ambulatory Monitors: Ambulatory monitors are devices that the patient can wear for a longer period of time (even months to years) to check and record the heart’s electrical activity.

3. Echocardiogram: Echocardiograms are imaging tests performed at rest or with activity to check the heart, its muscles, and valves.

4. Stress Tests: These tests detect heart rhythm disorders that worsen with activity or exercise.

5. Cardiac Catheterization: This is an invasive procedure performed under local anesthesia. A hollow tube is passed through a blood vessel to the heart to check its muscles and valves with the help of an X-ray machine.

6. Electrophysiology Study: This is a special diagnostic procedure in which cardiac catheters (tubes) are inserted into the heart to assess the heart’s electrical system and record the heart rhythm.

7. Tilt Table Test: This test is done to record the patient’s heartbeat and blood pressure on a minute-by-minute basis.

How Are Tachyarrhythmia Emergencies Managed?

The treatment for tachyarrhythmias depends on its type and severity. Mild heart rhythm problems can be managed with medications, lifestyle changes, electrical devices, invasive therapies, and surgery. However, in case of life-threatening tachyarrhythmia emergencies, basic and advanced life support interventions must be initiated immediately to ensure the survival of the patient. The steps involved include the following:

1. A trained healthcare professional checks if it is appropriate to start advanced life support interventions for the patient’s clinical condition. Usually, advanced life support is provided to patients with a heart rate greater than or equal to 150 beats per minute, with a pulse.

2. Identifying and treating the underlying cause of the rapid, irregular heartbeat is crucial. First, the airway (passage to the lungs) is assessed, and interventions are initiated to keep the airways open to ensure sufficient oxygen supply. Breathing assistance is provided whenever needed to keep the person breathing normally.

3. If the patient has low oxygen levels in their blood, oxygen is supplied through interventions such as:

   • Bag-mask ventilation (oxygen is pumped through a bag attached to the mask). The chest compression-to-ventilation ratio of 30:2 is used.

   • Tubes (such as endotracheal tubes) are inserted into the windpipe, and oxygen is supplied to the lungs.

   • Noninvasive positive pressure ventilation (mild air is blown into the airway through tubes or masks to keep it open).

4. A heart monitor or defibrillator is attached to check the heart rhythms.

5. The patient’s blood pressure and pulse oximetry (oxygen levels) are monitored continuously.

6. Intravenous (IV) access is obtained to deliver emergency medications through the vein.

7. If available, a 12-lead electrocardiogram (ECG) is used to monitor the heart rhythm and electrical activity.

8. Persistent tachyarrhythmia worsens the patient’s condition and makes them unstable, causing the following:

   • Marked fall in blood pressure (hypotension).

   • Acutely altered mental status.

   • Discomfort in the chest.

   • Signs of shock (decreased oxygen and blood flow in the body).

   • Heart failure.

9. An emergency intervention known as synchronized cardioversion is performed in such scenarios to help the heart beat normally. Low-energy shocks are delivered to the patient’s chest to convert the irregular heartbeats to a regular rhythm. Cardiopulmonary resuscitations are initiated immediately without delay if required.

10. If the patient is stable, medications such as beta-blockers are administered to help with the blood flow through the body.

11. If the patient is stable, but the electrocardiogram shows abnormal waveforms such as wide QRS (a component of the heart waves) greater than or equal to 0.12 seconds, infusions of medications that can help regularize the heart rhythm are considered. These include:

    • Procainamide intravenous dose of 20 to 50 milligrams per minute until the heart rhythms regularize.

    • Amiodarone, an intravenous dose of 150 milligrams over ten minutes.

    • Sotalol, intravenous dose of 100 milligrams over five minutes.

12. If the tachyarrhythmia is refractory to treatment, treatment of the underlying cause is initiated. The intensity of the shock delivered is increased, and synchronized cardioversion is repeated.

13. Expert consultation is essential after the initial stabilization of the patient.

Conclusion:

Heart rhythm disorders such as tachyarrhythmias, which cause fast and irregular heartbeats, can lead to medical emergencies such as cardiac arrests and shock. The inefficient function of the heart causes low blood pressure and low oxygen supply to all body parts and organs. This leads to damage to vital organs, including the brain. The heart eventually fatigues and stops beating, leading to death. Advanced cardiac life support must be initiated immediately to regularize heart rate, rhythm, and function. Cardiopulmonary resuscitation, defibrillation, synchronized cardioversion, airway management, breathing assistance, oxygen supply, and emergency medications can help save lives.