Supraventricular Tachycardia - Overview
Supraventricular tachycardia, also known as paroxysmal supraventricular tachycardia, refers to any tachycardia rhythm that originates from above the ventricular tissue. Fast heart rates caused by supraventricular tachycardia may be rather serious. There are two types of supraventricular tachycardia, atrioventricular nodal reentrant tachycardia- AVNRT and atriventricular reciprocating tachycardia - AVRT which also includes Wolff- Parkinsons-White syndrome.
During the episode of supraventricular tachycardia, there is an evident abnormality in functioning of the heart's electrical system. This results in rapid heart beat. Patients may experience up to 100 beats per minute and in severe cases the heart rate can even reach 300 beats per minute. The treatment must be urgent and the goal is to normalize the heart rate to normal value of 60 to 100 beats per minute.
The problem related to supraventricular tachycardia is that the episode can start and end quickly and the patients may not have any symptoms at all. Once the condition becomes serious and the attacks last longer or happen often the symptoms of tachycardia fully develop.
The actual cause of supraventricular tachycardia is in majority of cases associated with faulty electrical connections in the heart. It may also occur in people who take high levels of the heart medication digoxin or theophyline, a medication used in some lung conditions. Furthermore, a type of supraventricular tachycardia called Wolff-Parkinson-White syndrome may run in families. And finally, this condition can develop as a consequence of certain illnesses such as COPD and pneumonia.
Even though some patients may be asymptomatic the symptoms of supraventricular tachycardia usually include palpitations (feeling of rapid heart beat), pounding pulse and feeling of dizziness and lightheadedness. Syncope, shortness of breath, chest pain and sweating are possible as well.
Diagnosis of supraventricular tachycardia is set after thorough questioning of the patient, physical exam and the most significant test which confirms the presence of rapid heart rate and its characteristics called EKG (electrocardiogram). The patients additionally undergo an electrophysiology study.
Medicamentous and Surgical Treatment for Supraventricular Tachycardia
Supraventricular tachycardia can be initially treated with vagal maneuvers including gagging, holding one's breath or bearing down etc. These maneuvers actually stimulate the vagus nerve and slow the heart action. If these maneuvers do not work patients are given fast-acting medications such as adenosine or verapamil. And finally, if even these medications cannot slow down rapid heart rate the patient undergoes electrical cardioversion. This is a technique in which application of an electrical current is included to reset the heart rhythm.
People who have frequent attacks are prescribed certain medications which are supposed to be taken on regular basis. These medications can successfully prevent reoccurrence of the attacks. Still many of these drugs have many side effects.
Surgical treatment for supraventricular tachycardia includes a procedure called catheter ablation. The goal of the procedure is to block abnormal electrical impulses. However, the procedure is very risky and may cause bleeding, infections and even injury to the heart. This is why open heart surgery for supraventricular tachycardia is performed in rather rare cases.