<unk>  <unk>  is a type of<unk>  tachycardia, named for its intermittent episodes of abrupt onset and termination. Often people have no symptoms. Otherwise symptoms may include palpitations, feeling lightheaded, sweating, shortness of breath, and chest pain. The cause is not known. Risk factors include alcohol, caffeine, nicotine, psychological stress, and Wolff-Parkinson-White syndrome, which often is inherited. The underlying mechanism typically involves an accessory pathway that results in re-entry. Diagnosis is typically by an electrocardiogram (ECG) which shows narrow QRS complexes and a fast heart rhythm typically between 150 and 240 beats per minute. Vagal maneuvers, such as the Valsalva maneuver, are often used as the initial treatment. If not effective and the person has a normal blood pressure the medication adenosine may be tried. If adenosine is not effective a calcium channel blocker or beta blocker may be used. Otherwise synchronized cardioversion is the treatment. Future episodes can be prevented by catheter ablation. About 2.3 per 1000 people have<unk> . Problems typically begin in those 12 to 45 years old. Women are more often affected than men. Outcomes are generally good in those who otherwise have a normal heart. An ultrasound of the heart may be done to rule out underlying heart problems.
Paroxysmal supraventricular tachycardia
Wandering atrial pacemaker
Inappropriate sinus tachycardia
Ventricular escape beat
Junctional ectopic tachycardia
AV nodal reentrant tachycardia
Atrioventricular reentrant tachycardia
Accelerated idioventricular rhythm