Cardiac Arrhythmias

Ventricular Tachycardia (VT)

 

Ventricular tachycardia occurs when electrical impulses originating either from the ventricles cause rapid ventricular depolarization (140-250 beats per minute). Since the impulse originates from the ventricles, the QRS complexes are wide and bizarre. Ventricular impulses can be sometimes conducted backwards to the atria. in which case, P-waves may be inverted. Otherwise, regular normal P waves (60-100 beats per minute) may be present but not associated with QRS complexes (AV dissociation). The RR intervals are usually regular.

 

The EKG on the top shows normal sinus rhythm. The two EKGs at the bottom show ventricular tachycardia

 

Ventricular tachycardia is often due to some form of heart disease. Ventricular tachycardia can occur rarely in response to exercise or anxiety. In this case, the electrical impulses and rhythmic beats is similar is a normal beat but at a much faster rate.

During ventricular tachycardia pumping blood is less efficient because the rapid ventricular contractions prevent the ventricles from filling adequately with blood. As a result, less blood is pumped to the body. The reduced blood flow to the body causes weakness, dizziness, and fainting. If left untreated, ventricular tachycardia may lead to a more life-threatening condition. Note, because of the decreased diastolic time, coronary blood flow is decreased, increasing the chances of a myocardial infarction.

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