Felis ISSN 2398-2950

Heart: restrictive cardiomyopathy

Synonym(s): Intermediate cardiomyopathy

Contributor(s): Serena Brownlie, Phil Fox, Philip K Nicholls, Penny Watson

Introduction

  • Cause: diastolic failure sometimes secondary to endomyocardial fibrosis.
  • Signs: usually vague chronic course of weight loss, anorexia, lethargy, +/- dyspnea  Natom Explorer: Cardiomyopathies .
  • Diagnosis: radiography, ultrasonography.
  • Treatment: diuretics, vasodilators.
  • Prognosis: generally poor, thromboembolism is a risk in many cases.

Pathogenesis

Etiology

  • Unknown.

Pathophysiology

  • Endocardial, subendocardial or myocardial fibrosis   →   prevents stretch (compliance), of left ventricle and ventricular filling.
  • Abnormal blood flows   →   predispose to formation of thromboemboli Thromboembolism: aorta.
  • Lack of compliance of left ventricle and reduced ventricular filling   →   left atrial dilation, decreased preload, decreased cardiac output and increased pulmonary venous pressure   →   pulmonary edema and pleural effusion (seen commonly with left-sided failure in cats).
  • Turbulence   →   damages cardiac endothelium   →   endocardial collagen induces platelet adhesion and aggregation, extrinsic pathway activation Hemostatic disorders: acquired.
  • Circulation of blood through heart is abnormal   →   areas of sluggish flow allow aggregation of platelets particularly in dilated left atrium.
  • Higher levels of serotonin in felines due to larger platelets than dogs and humans, felines more sensitive to effects of serotonin   →   higher susceptibility to aggregation.

Timecourse

  • ?Weeks to months.

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.
  • Bright J M, Herrtage M E & Schneider J F (1999) Pulsed doppler asessment of left ventricular diastolic function in normal and cardiomyopathic cats. JAAHA 35 (4), 285-291 PubMed.


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