As the name suggests, the condition happens when the ventricles contract too soon, out of sequence with the normal heartbeat. Premature Ventricular ContractionsĪ less serious type of ventricular arrhythmia is a premature ventricular contraction (PVC). People who have heart disease or a history of heart attack have the highest risk of ventricular fibrillation. About 220,000 deaths from heart attacks each year are thought to be caused by ventricular fibrillation. If cardiopulmonary resuscitation (CPR) can be started, or if electrical energy is used to “shock” the heart back to a normal rhythm, then the heart may not be too damaged. This chaotic heartbeat means very little blood is pumped from the heart to the brain and body and can result in fainting. The result is a much faster, chaotic heartbeat that sometimes reaches 300 beats a minute. Instead of one misplaced beat from the ventricles, you may have several impulses that begin at the same time from different locations-all telling the heart to beat. The most serious arrhythmia is ventricular fibrillation, which is an uncontrolled, irregular beat. Your heartbeat quickens, and you feel as if your heart is “skipping beats.” This rhythm may cause severe shortness of breath, dizziness, or fainting (syncope). Since the new signal does not move through your heart muscle along the regular route, the heart muscle does not beat normally. Instead, other areas along the lower electrical pathway take over the pacemaking role. Ventricular tachycardia is a condition in which the SA node no longer controls the beating of the ventricles. Ventricular Arrhythmias Ventricular Tachycardia
If it begins above the ventricles, it is called supraventricular tachycardia. If it begins in the ventricles, it is called ventricular tachycardia. The many forms of tachycardia depend on where the fast heart rate begins. Tachycardia is a very fast heart rate of more than 100 beats per minute. This damage might be related to heart disease, aging, inherited or congenital defects, or it might be caused by certain medicines-including those used to control arrhythmias and high blood pressure. It may be caused by one of two sources: The central nervous system does not signal that the heart needs to pump more, or the SA node may be damaged. It happens when the electrical impulse that signals the heart to contract is not formed in your heart’s natural pacemaker, the sinoatrial node (SA node), or is not sent to the heart’s lower chambers (the ventricles) through the proper channels.īradycardia most often affects elderly people, but it may affect even the very young. Bradycardiaīradycardia is a very slow heart rate of less than 60 beats per minute.
The irregular beats can either be too slow (bradycardia) or too fast (tachycardia). Supraventricular arrhythmias occur in the area above the ventricles, usually in the upper chambers of the heart, called the atria. Ventricular arrhythmias occur in the lower chambers of the heart, called the ventricles.
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