Equis ISSN 2398-2977

Heart: ventricular tachycardia

Contributor(s): Karen Blissit, Karen Blissitt, Christopher Brown, Wendy Furness, Lesley Young

Introduction

  • A series of repetitive VPCs, usually of sudden onset. Can be sustained or paroxysmal.
  • Cause: various, including secondary to quinidine treatment of atrial fibrillation; secondary to systemic disease and secondary to damage to myocardial tissue in aortic root rupture.
  • Signs: various from none to syncope and death.
  • Diagnosis: ECG.
  • Treatment: IV lidocaine, quinidine gluconate, popafenone, procainamide or magnesium sulfate. Coupled with treatment of any co-existing electrolyte, metabolic, fluid and systemic disorders. 
  • Prognosis: entirely dependent on inciting cause, can   →    ventricular fibrillation and death.

Pathogenesis

Etiology

  • A severe and life-threatening dysrhythmia when sustained, almost always secondary to severe underlying cardiac disease or electrolyte and metabolic disturbances.
  • Secondary to systemic disease, eg gastrointestinal disease or any cause of electrolyte imbalance.
  • Primary myocardial disease   Heart: disease - overview  , viral or bacterial myocarditis, or toxic or immune-mediated cardiomyopathies.
  • Aortic root rupture directed through the sinus of Valsalva through the intraventricular septum disrupts the myocardium and conduction tissue.
  • Drug induced, eg during anesthesia or during quinidine therapy   Quinidine  .
  • Immediately post-exercise following high intensity exercise, usually only short runs are seen   Heart: ventricular premature complex 04 - ECG    Heart: ventricular premature complex 05 - ECG  , but on occasion ventricular ectopy   →   ventricular tachycardia, fibrillation   Heart: ventricular fibrillation    Heart: ventricular fibrillation 01 - ECG  and death.
  • Due to hypoxia.

Timecourse

  • Usually sudden onset.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • MacLeay J M & Wilson J H (1998) Type-II renal tubular acidosis and ventricular tachycardia in a horse. JAVMA 212 (10), 1597-1599 PubMed.
  • Reimer J M, Reef V B & Sweeney R W (1998) Ventricular arrhythmias in horses, 21 cases (1984-1989). JAVMA 201 (8), 1237-1243 PubMed.
  • Leroux A J, Schott H C & Hines M T (1995) Ventricular tachycardia associated with exhaustive exercise in a horse. JAVMA 207 (3), 335-337 PubMed.
  • Traub-Dargatz J L, Schlipf J W, Boon J et al (1994) Ventricular tachycardia and myocardial dysfunction in a horse. JAVMA 205 (11), 1569-1573 PubMed.
  • Machida N, Nakamura T, Kiryu K, Haramaki S & Too K (1992) Cardiopathologic observation on a case of persistent ventricular tachycardia in a pony mare. J Vet Med Sci 54 (6), 1213-1216 PubMed.
  • Garber J L, Reef V B, Reimer J M & Evans L H (1992) Postsurgical ventricular tachycardia in a horse. JAVMA 201 (7), 1038-1039 PubMed.

Other sources of information

  • Reef V B (1999) Arrhythmias. In: Cardiology of the Horse. Ed: Marr C M. W B Saunders, UK. Chapter 12. pp 179-209.


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