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. There develops a self-perpetuating rapid and abnormal activation. ("Circus Movement" is another term for this.) Conditions necessary for re-entry include a combination of unidirectional block and slowed conduction. Circus movement may also occur on a smaller scale within the AV node (dual AV nodal physiology), a large bypass tract is not necessary.Re-entry is divided into two major types: [Anatomically Defined] re-entry and [Functionally Defined] re-entry. The circus movement can occur around an anatomical or functional core. Either type may occur alone, or together.Anatomically defined re-entry has a fixed anatomic pathway. Anomalous conduction via accessory pathways (APs) creates the re-entry circuit (which are also called bypass tracts), that exists between the atria and ventricles. Wolff–Parkinson–White syndrome (WPW) is an example of anatomically defined re-entry. WPW syndrome is an atrioventricular re-entrant tachycardia (AVRT), secondary to an accessory pathway that connects the epicardial surfaces of the atrium and ventricle along the AV groove. The majority of time symptomatic WPW fits the definition of AVRT (Supraventricular tachycardia) however AVNRT (dual AV nodal physiology) exist in ~10% of patients with WPW syndrome creating the possibility of spontaneous atrial fibrillation degenerating into ventricular fibrillation (VF).
Hydatid disease (aka echinococcosis) of the liver, lung, and peritoneum (caused by the larval form of the dog tapeworm, Echinococcus granulosus) or of the alveoli (caused by E. multilocularis) when surgical excision is not possible. Some suggest that alveolar and cystic echinococcosis require lifelong treatment with albendazole, which only prevents the parasites from growing and reproducing rather than killing them outright. Nematodes
Ascariasis, which can be cured with a single dose of albendazole. Baylisascariasis, caused by the raccoon roundworm. If treatment with Albendazole is initiated within 72 hours of ingestion of the egg-containing raccoon feces, good results (95%-100% efficacy, with Albendazole being orally administered for a 10-day period) can be expected. Corticosteroids are sometimes added in cases of eye and CNS infections. Enterobiasis (pinworm infection)
Filariasis; since albendazoles disintegration of the microfilarie ("pre-larva") can cause an allergic reaction, antihistamines or corticosteroids are sometimes added to treatment. In cases of lymphatic filariasis (elephantiasis) caused by Wuchereria bancrofti or Brugia malayi, albendazole is sometimes given as an adjunct to ivermectin or diethylcarbamazine in order to suppress microfilaremia. It can also be given for loa loa filariasis as an adjunct or replacement to diethylcarbamazine. Albendazole has an embryotoxic effect on Loa loa adults and thus slowly reduces microfilaremia. Gnathostomiasis when caused by Gnathostoma spinigerum. Albendazole has a similar effectiveness to ivermectin in these cases, though it needs to be given for 21 days rather than the 2 days needed for ivermectin. Gongylonemiasis
Hookworm infections, including cutaneous larva migrans caused by hookworms in the genus Ancylostoma.