Congenital Heart Malformations in Mammals

The following sections are included:

• Abbreviations

• FOREWORD

• PREFACE

• CONTENTS

The following sections are included:

• Morphology and Function of the Heart and Great Vessels — General Aspects
  • Pericardium, position and shape of the heart
  • Venous duct (Ductus venosus Arantii)
  • Caval and azygous veins
  • Right atrium
  • Right ventricle
  • Pulmonary arteries and arterial duct (ductus arteriosus)
  • Pulmonary veins and left atrium
  • Left ventricle and mitral valve
  • Membranous septum
  • Coronary arteries
  • Aortic arch branches
  • Conduction system
  • The cardiac skeleton

• References

The analysis of any congenitally malformed heart is simplified by first examining each segment of the heart, namely, the atriums, the ventricles and the great arteries. By taking note of how each chamber relates and connects to one another in a sequential fashion, even seemingly complex malformations can be described readily. This approach, sequential segmental analysis,^1,3,4 provides the basic framework but is not complete until all account is taken of the associated malformations. Thus, most hearts have usual connections and relations of the chambers, but the associated lesions such as a large ventricular septal defect or severe stenosis of the pulmonary valve will dictate the clinical course. It is imperative, nevertheless, to analyse each heart sequentially before embarking on listing the associated defects.

The following sections are included:

• What is a Congenital Defect?

• Causes

• Frequency of Occurrence
  • Estimations of frequency of occurrence of congenital heart malformations in mammals
  • Estimations of prevalence of cardiovascular defects
  • Combinations of cardiovascular defects

• References

The following sections are included:

• Published Case Reports

• Comments

• Our Own Observations

• Reference

The following sections are included:

• Material

• Dysrhythmias

• Our Own Observations

• References

The following sections are included:

• Comments

• Our Own Observations

• References

The following sections are included:

• Dysrhythmias

• References

The following sections are included:

• Atrioventricular Valve Dysplasia

• Familial Defects, Breeding Experiments and Conotruncal Defect Gene

• Incidence and Breed Predilection

• Comments on the Most Frequent Anomalies
  • Persistent arterial duct
  • Porto-systemic shunts
  • Subvalvar aortic stenosis
  • Pulmonary stenosis
  • Ventricular septal defect

• Rare Anomalies

• Dysrhythmias

• Our Own Observations

• References

The following sections are included:

• Prevalence of Feline Cardiovascular Defects — Larger Series of Cases

• Other Series and Single Case Reports

• Comments on Published Cases

• Endocardial Fibroelastosis (EFE)

• Hypertrophic Cardiomyopathy (HCM)

• Excessive Moderator Bands in the Left Ventricle

• Dysrhythmias

• Our Own Observations

• References

Please refer to full text.

A 1980 review on congenital defects of zoo and wild animals included only eight animals with cardiac defects.²⁰ A 1967 description of autopsy findings in 1400 zoo and wild mammals mentioned only one unspecified heart malformation — in a zebu.¹² Literature search disclosed more than 100 cases — still a fairly low number. Lack of awareness of heart defects and also a low autopsy rate are reasonable explanations to the fact that more cardiac defects have not been recognised.

The following sections are included:

• Ectopia Cordis

• Divided Right Atrium (Cor Triatriatum Dexter)

• Abnormal Laterality

• Atrial Septal Defects

• Totally Anomalous Pulmonary Venous Connections

• Atrioventricular Septal Defects

• Porto-systemic Shunts

• Tricuspid Valve Anomalies

• Tricuspid Atresia

• Ebstein Anomaly

• Tricuspid Valvar Dysplasia

• Anomalies of the Right Ventricular Free Wall

• Pulmonary Stenosis Without Ventricular Septal Defect

• Pulmonary Atresia With Intact Ventricular Septum

• Ventricular Septal Defect (VSD)

• Fallot's Anomaly and Pulmonary Atresia With VSD

• Complete Transposition of the Great Arteries

• Malformations With Double Outlet Right Ventricle

• Common Arterial Trunk

• Left Ventricular Outflow Obstruction

• Persistent Arterial Duct, Tubular Hypoplasia, Coarctation of the Aorta and Interrupted Aortic Arch

• Vascular Ring

• Anomalies of the Coronary Arteries

• Hypertrophic Cardiomyopathy

• Concluding Remarks

• References

The following sections are included:

• APPENDIX 1: KEY REFERENCES

• APPENDIX 2: METHODS OF PREPARATION AND DISSECTION
  • Preparation of Fresh Specimen
  • Fixation
  • Dissection
  • Conclusion

• INDEX