Pulseless Ventricular Tachycardia - An Overview

Introduction:

Ventricular tachycardia is an abnormal increase in heart rhythm that arises from the ventricles of the heart. This occurs due to disruption in the electrical signals of the heart, thus leading to irregular heart rhythm (arrhythmia). Pulseless ventricular tachycardia is an emergency condition that necessitates urgent medical care due to the complications of sudden cardiac arrest and death. It is characterized by the absence of a palpable pulse. The heart beats too quickly and irregularly, thus preventing the ventricles from pumping blood efficiently. This condition shows a rapid, regular, and wide QRS complex on an electrocardiogram (ECG).

What Are the Causes of Pulseless Ventricular Tachycardia?

The common causes of monomorphic ventricular tachycardia include:

• Myocardial Infarction: Insufficient blood flow to the heart resulting from the buildup of arterial plaque can result in oxygen deprivation. This results in abnormal heart rhythms.

• Structural Disorders of the Heart: Structural abnormalities in the heart, like congenital heart diseases and cardiomyopathy, and disorders of the heart valve, like aortic stenosis, can affect the functioning of the heart, resulting in disruption of the normal electrical activity of the heart.

• Electrolyte Imbalances: Electrolytes encompass essential minerals like sodium, potassium, calcium, and magnesium, which play a pivotal role in governing the cardiac electrical processes. Abnormal levels of these minerals in the blood have the potential to disturb the regular cardiac rhythm and cause pulseless ventricular tachycardia.

• Medications: Certain medications such as antiarrhythmics, beta-blockers, and Digoxin can increase the risk of monomorphic ventricular tachycardia by altering the normal electrical activity of the heart.

• Stress: Physical or emotional stress can be a major risk factor for this condition. The exact cause of tachycardia should be identified for proper management of the condition and to reduce the risk of complications.

What Are the Signs and Symptoms of Pulseless Ventricular Tachycardia?

The following are some of the common symptoms experienced by individuals with pulseless ventricular tachycardia.

• Absence of a Pulse: The absence of a palpable pulse is a hallmark sign of this condition. The heart beats faster than normal, and irregular rhythms can cause a lack of blood supply to vital organs.

• Sudden Loss of Consciousness: Individuals with pulseless ventricular tachycardia can experience a sudden loss of consciousness.

• Increased and Rapid Heartbeat: Pulseless ventricular tachycardia can cause an increased heart rate.

• Palpitations: Individuals with pulseless ventricular tachycardia may experience a sensation of a pounding or fluttering heartbeat.

• Dyspnea: Shortness of breath is noted.

• Chest Pain: Some people can experience discomfort or pain in the chest (angina) due to reduced blood supply to the heart.

• Dizziness: Insufficient blood flow to the brain can cause symptoms like dizziness and syncope.

How Is Pulseless Ventricular Tachycardia Diagnosed?

The diagnosis of pulseless ventricular tachycardia is made by a comprehensive evaluation of the patient's medical history, physical examination, and investigations.

• Medical history reveals the symptoms experienced by the patient, and physical examination reveals abnormal heart sounds.

• The diagnosis is confirmed by an electrocardiogram that measures the electrical activity of the heart. An ECG shows a rapid and irregular ventricular rhythm with an indiscernible QRS complex, which is pathognomonic of pulseless ventricular tachycardia. ECG can also show an absence of P waves.

• Holter Monitor: This device is a portable electrocardiogram (ECG) unit designed to record the heart's functions continuously for either a 24-hour or 48-hour duration and helps in continuous monitoring of the electrical activity of the heart.

• Electrophysiology Study: This is an invasive procedure that entails the insertion of catheters into the heart for the purpose of measuring its electrical activity, locating the source of the abnormal rhythm, and determining the best treatment option.

• Echocardiogram: This is a non-invasive test utilizing sonographic technology to produce cardiac images. It can help identify any underlying structural abnormalities in the heart that may be contributing to the development of pulseless ventricular tachycardia.

• Coronary Angiography: This is indicated for patients who experienced sudden cardiac arrest.

• Laboratory Investigations: Investigations may reveal low levels of electrolytes like magnesium, potassium, and calcium in some individuals.

What Is the Treatment for Pulseless Ventricular Tachycardia?

Pulseless ventricular tachycardia is a medical emergency that requires prompt treatment. The objective is to reinstate the natural sinus rhythm and maintain adequate perfusion of vital organs, including the brain and heart. Treatment typically involves a combination of cardiopulmonary resuscitation (CPR), defibrillation, and medication.

• Cardiopulmonary Resuscitation (CPR): CPR is the first-line treatment for patients with Pulseless Ventricular Tachycardia. Cardiopulmonary resuscitation must be promptly commenced upon discovering a patient in an unresponsive state with abnormal breathing patterns. It entails performing chest compressions and delivering rescue breaths to sustain circulation and oxygenation throughout the body.

• Defibrillation: Defibrillation is a crucial intervention for patients with pulseless ventricular tachycardia. Defibrillation involves the delivery of an electrical shock to the heart to restore normal sinus rhythm. The earlier defibrillation is performed, the better the chances of survival. Defibrillation should be performed as soon as possible in patients with pVT.

• Medication: In addition to CPR and defibrillation, medications may be used to treat pulseless ventricular tachycardia. These medications may include antiarrhythmic agents, such as Amiodarone or Lidocaine, or vasopressors, such as epinephrine, to improve cardiac output and blood pressure. These medications may be administered intravenously during resuscitation.

• Management of Underlying Conditions: Treating underlying health conditions that contribute to the development of pulseless ventricular tachycardia, such as coronary artery disease, hypertension, or heart failure, can help prevent future episodes.

It is important to note that the treatment of pulseless ventricular tachycardia should be initiated quickly and continued until normal sinus rhythm is restored. If left untreated, pulseless ventricular tachycardia can quickly progress to cardiac arrest, which can be fatal.

What Are the Complications of Pulseless Ventricular Tachycardia?

• Sudden Cardiac Arrest: This is a sudden loss of the functions of the heart due to irregular electrical activity of the heart. Thus, there is diminished cerebral blood perfusion, leading to loss of consciousness, dyspnoea, and death.

• Ventricular Fibrillation: This occurs due to prolonged tachycardia and requires immediate management by cardiopulmonary resuscitation or defibrillation.

• Hypoxia: Prolonged episodes of pulseless ventricular tachycardia can cause decreased oxygen delivery to the body, leading to hypoxia or tissue damage. The heart and brain are particularly vulnerable.

• Shock: Prolonged pulseless ventricular tachycardia can lead to decreased cardiac output and inadequate tissue perfusion, leading to shock. Shock is an ominous state that poses a lethal threat, capable of inducing organ dysfunction and mortality.

Conclusion

In conclusion, pulseless ventricular tachycardia is a life-threatening condition that requires prompt recognition and treatment. Prompt action can enhance the likelihood of survival and prevent complications. It is essential for individuals to be cognizant of this condition and take appropriate action in case of an emergency.