Ventricular tachycardia (ventricular arrhythmia) is a heart disease of dogs characterized by a series of ventricular premature complexes (VPC) usually greater than 100 beats per minute.
In this condition, the RR interval on the ECG is usually regular, but nonconducted sinus P waves may be superimposed on or between the ventricular complexes. This is usually unrelated to the VPCs because the AV node and/or ventricles are in a refractory period (physiological AV dissociation).
The term 'capture beat' refers to the successful conduction of a sinus P wave into the ventricles uninterrupted by another VPC. If the normal ventricular activation sequence is interrupted by another VPC, a fusion complex can result.
- Breed predisposition in the Boxer and autosomal-recessive genetic in German Shepherd
- Trypanosoma cruzi infection
- Drug overdoses - e.g. phenylpropanolamine, albuterol, digitalis
- Dilated cardiomyopathy - breed predisposition in the Doberman
- Congestive heart failure
- Cardiac hemangiosarcoma
- Subaortic stenosis
- Cor triatriatum
- Right ventricular outflow tract obstruction
- Mitral valve endocardiosis
- Gastric dilatation-volvulus
Clinically affected dogs present frequently with syncope, weak femoral pulses, pale mucous membranes, panting, weakness, exercise intolerance, sudden death and tachycardia audible on auscultation. The syncope, commonly seen in the Boxer dog with normal echocardiograms, is thought to be due to secondary ischemic bradycardia which ensues as a result of ventricular tachycardia.
This condition is life-threatening as ventricular tachycardia can quickly degenerate into ventricular fibrillation, which leads invariably to poor cardiac contractility, reduced ventricular diastolic functioning and eventual congestive heart failure.
Diagnosis can be rapidly achieved on ECG examination, but 24-hour Holter monitors are usually required to definitively confirm the suspicion.
The underlying cause of ventricular fibrillation must be address for long-term survival of cardiac patients.
- ↑ Santilli RA et al (2012) Orthodromic atrioventricular reciprocating tachycardia conducted with intraventricular conduction disturbance mimicking ventricular tachycardia in an English Bulldog. J Vet Cardiol 14(2):363-370
- ↑ Nelson, RW & Guillermo Couto, C (1998) Small animal internal medicine. Mosby, Missouri. pp:22-23
- ↑ Winter RL et al (2010) ECG of the month. Arrhythmogenic right ventricular cardiomyopathy in a Boxer. J Am Vet Med Assoc 236(9):961-963
- ↑ Cruickshank J et al (2009) Genetic analysis of ventricular arrhythmia in young German Shepherd Dogs. J Vet Intern Med 23(2):264-270
- ↑ Gelzer AR et al (2010) Combination therapy with mexiletine and sotalol suppresses inherited ventricular arrhythmias in German shepherd dogs better than mexiletine or sotalol monotherapy: a randomized cross-over study. J Vet Cardiol 12(2):93-106
- ↑ Rodríguez-Morales O et al (2012) Plasmid DNA immunization with Trypanosoma cruzi genes induces cardiac and clinical protection against Chagas disease in the canine model. Vet Res 43(1):79
- ↑ Ginn JA et al (2013) Systemic hypertension and hypertensive retinopathy following PPA overdose in a dog. J Am Anim Hosp Assoc 49(1):46-53
- ↑ Matos J et al (2012) Myocardial damage and paroxysmal ventricular tachycardia in a dog after Albuterol intoxication. Schweiz Arch Tierheilkd 154(7):302-305
- ↑ Kraus MS et al (2009) Toxicity in Doberman Pinchers with ventricular arrhythmias treated with amiodarone (1996-2005). J Vet Intern Med 23(1):1-6
- ↑ Thompson DJ et al (2011) Haemangiosarcoma of the interventricular septum in a dog. N Z Vet J 59(6):332-336
- ↑ Langs LL (2009) Budd-Chiari-like syndrome in a dog due to liver lobe entrapment within the falciform ligament. J Am Anim Hosp Assoc 45(5):253-256
- ↑ Santilli RA et al (2009) Outflow tract segmental arrhythmogenic right ventricular cardiomyopathy in an English Bulldog. J Vet Cardiol 11(1):47-51
- ↑ Santilli RA et al (2011) Ventricular tachycardia in English bulldogs with localised right ventricular outflow tract enlargement. J Small Anim Pract 52(11):574-580
- ↑ MacKie BA et al (2010) Retrospective analysis of an implantable loop recorder for evaluation of syncope, collapse, or intermittent weakness in 23 dogs (2004-2008). J Vet Cardiol 12(1):25-33
- ↑ Thomason JD et al (2008) Bradycardia-associated syncope in 7 Boxers with ventricular tachycardia (2002-2005). J Vet Intern Med 22(4):931-936
- ↑ Wu W et al (2008) Application of quantitative tissue velocity imaging to evaluate left ventricular early diastolic dysfunction in dogs with heart failure due to rapid ventricular pacing. J Am Soc Echocardiogr 21(11):1269-1276
- ↑ Santilli RA et al (2010) Evaluation of the diagnostic value of an implantable loop recorder in dogs with unexplained syncope. J Am Vet Med Assoc 236(1):78-82
- ↑ Pariaut R et al (2011) Implantable cardioverter-defibrillator in a German shepherd dog with ventricular arrhythmias. J Vet Cardiol 13(3):203-210
- ↑ Prosek R (2010) Electrical cardioversion of sustained ventricular tachycardia in three Boxers. J Am Vet Med Assoc 236(5):554-557