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Re-entry ventricular arrhythmia is a type of paroxysmal tachycardia occurring in the ventricle where the cause of the arrhythmia is due to the electric signal not completing the normal circuit, but rather an alternative circuit looping back upon itself. [1] There develops a self-perpetuating rapid and abnormal activation.
The underlying mechanism typically involves an accessory pathway that results in re-entry. [3] 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. [3] Vagal maneuvers, such as the Valsalva maneuver, are often used as the initial treatment. [4]
They are generally due to one of two mechanisms: re-entry or increased automaticity. [3] Diagnosis is typically by electrocardiogram (ECG), Holter monitor, or event monitor. [4] Blood tests may be done to rule out specific underlying causes such as hyperthyroidism, pheochromocytomas, or electrolyte abnormalities. [4]
The main symptom of AVNRT is the sudden development of rapid regular palpitations. [1] These palpitations may be associated with a fluttering sensation in the neck, caused by near-simultaneous contraction of the atria and ventricles against a closed tricuspid valve leading to the pressure or atrial contraction being transmitted backwards into the venous system. [2]
Lown–Ganong–Levine syndrome is a clinical diagnosis that came about before the advent of electrophysiology studies. It is important to be aware that not all WPW ECGs have a delta wave; the absence of a delta wave does not conclusively rule out WPW.
Cardiology Atrioventricular reentrant tachycardia ( AVRT ), or atrioventricular reciprocating tachycardia , is a type of heart arrhythmia with an abnormally fast rhythm ( tachycardia ); it is classified as a type of supraventricular tachycardia (SVT).
Invasive testing, such as electrophysiology studies, are not helpful in making the diagnosis, but they may be useful in ruling out a concomitant supraventricular tachycardia mechanism. [3] Inappropriate sinus tachycardia is a diagnosis of exclusion that is rarely made in an asymptomatic patient. [2]
The re-entry phenomenon may cause rapid heart rates (ventricular tachycardia and even ventricular fibrillation), and ischemia in the electrical conduction system of the heart may cause a complete heart block (when the impulse from the sinoatrial node, the normal cardiac pacemaker, does not reach the heart chambers).