Felis ISSN 2398-2950

Heart: aortic stenosis

Contributor(s): Mark Oyama

Introduction

  • Congenital narrowing of left ventricular outflow tract. Represents 7% of feline congenital cardiac anomalies.
  • Cause: developmental malformation. Lesion is most commonly supravalvular in the cat, but may be valvular or subvalvular.
  • Signs: asymptomatic, systolic murmur, weakness, lethargy, syncope, sudden death; left-sided congestive heart failure (CHF) Heart: congestive heart failure.
  • Diagnosis: history, clinical signs, radiography, angiocardiography, electrocardiography, ultrasonography.
  • Treatment: for mild cases none indicated; to treat CHF and arrhythmias use beta-blockers, calcium channel blockers; diuretics, anti-arrhythmics and rest.
  • Prognosis: generally poor, most develop CHF, but some cases remain asymptomatic.

Pathogenesis

Pathophysiology

  • Congenital narrowing of left ventricular outflow tract, aortic valves, or aortic root causes ventricular hypertrophy and may eventually lead to left-sided cardiac failure or sudden death.
  • Sudden death may result from myocardial hypoxia and fatal dysrhythmias Heart: dysrhythmia.
  • Syncope may result from outflow tract obstruction, hypoxia or arrythmias.

Severe cases

  • Obstructed aortic outflow   →   reduced cardiac output and increased left ventricular pressure   →   pressure overload   →   ventricular concentric hypertrophy (LaPlace Law)   →   increased myocardial oxygen consumption   →   coronary perfusion not proportional to hypertrophy   →   myocardial hypoxia   →   ventricular dysrhythmias   →   syncope/sudden death.
  • Rarely   →   myocardial failure   →   left-sided CHF.

Timecourse

  • Signs <2 years old.

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.
  • Schrope D P, Fox P R, Hahn A W et al (1995) Effects of electrocardiograph frequency filters on P-QRS-T amplitudes of the feline electrocardiogram. Am J Vet Res 56 (11), 1534-1540 PubMed.
  • Liu S K, Tilley L P (1980) Animal models of primary myocardial diseases. Yale J Biol Med 53 (3), 191-211 PubMed.
  • Liu S K (1977) Pathology of feline heart diseases. Vet Clin North Am (2), 323-339 PubMed.


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