Ventricular arrhythmias are common and are usually benign, at least in those with a structurally normal heart. In patients with structural heart disease (usually coronary heart disease), however, ventricular arrhythmia is an adverse prognostic factor associated with cardiac arrest and cardiac mortality. Ventricular arrhythmias range from asymptomatic ventricular
ectopy to sustained ventricular tachycardia and cardiac arrest.
In ventricular tachycardia the bottom parts of the heart (the ventricles) are beating very fast. You may not be able to feel a pulse because the heart does not pump blood well at fast rates, especially when only the lower chamber is beating. Ventricular arrhythmias are fast heart rhythms that begin in the heart's lower chambers (ventricles). These usually are fast and regular (such as ventricular tachycardia) or fast and irregular (such as ventricular fibrillation) heart rhythms that make it difficult for the heart to pump enough blood to the brain or the rest of the body, which can be life-threatening. Ventricular arrhythmias may be caused by heart disease such as heart valve problems, impaired blood flow to the heart muscle (ischemia or a heart attack), a weakened heart muscle (cardiomyopathy), or heart failure.
Some people notice a skipping heart rhythm or palpitations when occasional irregular rhythms begin in the ventricles. If this irregular heart rhythm occurs often, some people also may feel lightheaded, be short of breath, or have chest pain. Heavy smoking, alcohol, or too much caffeine or other stimulants (such as diet pills) may cause your heart to skip a beat occasionally. Stopping the use of tobacco, alcohol, caffeine, or medications that increase your heart rate and cause irregular rhythms can sometimes help reduce the risk of having these changes in your heart rate or rhythm.
Ventricular tachycardia and ventricular fibrillation are the most life-threatening arrhythmias that require emergency treatment. Both of these usually cause fainting (syncope) within seconds, and you may have symptoms of a heart attack. Emergency medical treatment, such as medications and electrical shock (defibrillation), is needed. Medications can sometimes help prevent these heart rhythm changes from occurring again. An automatic implantable cardioverter-defibrillator (AICD) that controls the heart rhythm and rate can also be used to treat these rapid and sometimes irregular heart rhythms if they occur again.
The two most important ventricular arrhythmias are ventricular tachycardia and ventricular fibrillation. Both are fast heart rhythms that arise from the lower muscular chambers of the heart. These rhythms are very dangerous, accounting for most cases of sudden death from heart disease. When I see these ventricular arrhythmias, it is usually (but not always) in patients who have had heart attacks or congestive heart failure. Treatment with either medications or an implantable cardioverter defibrillator (called an ICD, see below) is often helpful.
If not treated, ventricular tachycardia may go into what is knon as ventricular fibrillation. VF can also occur by itself. In VF, the bottom chambers (the ventricles) "quiver" or "twitch". The heart does not pump blood to the body. You will not be able to feel a pulse.