Ventricular Tachycardia

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Original Editor - User:Justin Bryan
Top Contributors - Justin Bryan, Lucinda hampton and Kirenga Bamurange Liliane

Introduction

Ventricular tachycardia (V-Tach) is a type of cardiac arrhythmia where the ventricle beats at 100 or more beats per minute for 3 or more consecutive beats. Unlike more general tachycardia, in V-Tach the increased beat rate originates from the ventricle itself, and note from the upper part of the heart. At rates greater that 100 bpm, the pumping ability of the heart is severely degraded, resulting in significant risk for severe symptoms and even cardiac arrest. V-Tach is considered a life-threatening cardiac arrhythmia.

Types of Ventricular Tachycardia

• Sustained V-Tach - tachycardia lasting longer than 30 seconds

• Non-sustained V-Tach - tachycardia lasting less than 30 seconds; non-sustained V-Tach does no effect the hearts ability to pump to the same degree as sustained V-Tach, symptoms are often more limited and have far less impact on the heart's ability to function
• Idiopathic V-Tach - No know cause, generally considered benign
• Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) - An inherited genetic condition resulting in V-Tach

Causes and Risk Factors

A number of factors can increase the risk of developing V-Tach. Generally, these factors are associated with the pre-existance of cardiac conditions such as acute coronary syndrome or ischemic heart disease. A broad range of cardiomyopathies, including hypertrophic cardiomyopathy, infiltrative cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy have also been found to be associated with V-Tach. Certain congenital heart defects also carry risk. Other circumstances such as electrolyte imbalances and illicit drug use also increases risk. In the presence of factors such as these, V-Tach can be triggers by situations where the heart is put under certain stresses such as myocardial ischemia, sepsis, or metabolic acidosis. In general, risk is increased by conditions that change the normal conduction of electrical impulses in the heart, such conditions as a heart attach, which results in scaring of myocardial tissue.

Certain ion channel pathologies, defects that effect the functioning of the the cellular membrane and passage of ions, also carry an increased risk for V-Tach due to their impact on the conduction and generation of impulses in the heart:

• Long QT syndrome
• Brugada syndrome
• Catecholaminergic polymorphic ventricular tachycardia
• Short QT syndrome
• Malignant early repolarization syndrome

V-Tach can also be idiopathic, and in this form is considered benign. Treatment usually involved prescription of calcium channel blockers, and outcomes are generally very positive.

Clinical Presentation

Signs and symptoms of sustained V-Tach include those associated with a reduction in the ability of the heart to pump blood such as dizziness, shortness of breath, and fainting or loss of consciousness. Patients may also experience chest pain, a feeling of the heart "fluttering." Cardiac arrest can also occur as a result of V-Tach.

The exact impact and presentation of reduced cardiac function resulting from V-Tach is strongly dependent on the cardiac conditions that the patient has (i.e. cardiomyopathy vs. ischemic heart disease).

Diagnostic Procedures

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Outcome Measures

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Management / Interventions

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Differential Diagnosis

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Resources

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