Circus Totem

Supraventricular tachycardia (SVT) is an umbrella term for fast heart rhythms arising from the upper part of the heart. This is in contrast to the other group of fast heart rhythms – ventricular tachycardia, which starts within the lower chambers of the heart. There are four main types of SVT: atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia (PSVT), and Wolff–Parkinson–White syndrome. The symptoms of SVT include palpitations, feeling of faintness, sweating, shortness of breath, and/or chest pain. These abnormal rhythms start from either the atria or atrioventricular node. They are generally due to one of two mechanisms: re-entry or increased automaticity. Diagnosis is typically by electrocardiogram (ECG), Holter monitor, or event monitor. Blood tests may be done to rule out specific underlying causes such as hyperthyroidism, pheochromocytomas, or electrolyte abnormalities. A normal resting heart rate is 60 to 100 beats per minute. A resting heart rate of more than 100 beats per minute is defined as a tachycardia. During an episode of SVT, the heart beats about 150 to 220 times per minute. Specific treatment depends on the type of SVT and may include medications, medical procedures, or surgery. Directing patients to execute Vagal maneuvers such as the Valsalva maneuver, or conducting a procedure known as catheter ablation, may be effective in certain types. For atrial fibrillation, calcium channel blockers or beta blockers may be used for rate control, and selected patients benefit from blood thinners (anticoagulants) such as warfarin or novel anticoagulants. Atrial fibrillation affects about 25 per 1000 people, paroxysmal supraventricular tachycardia 2.3 per 1000, Wolff-Parkinson-White syndrome 2 per 1000, and atrial flutter 0.8 per 1000.