Diseases of the Cardiovascular System I 2024 PDF

Diseases of the Cardiovascular System I: Congenital Diseases Dr Paul Pollard MVB Cert AVP(VC) MSc Vet Ed SFHEA MRCVS [email protected] Learning Objectives » Review cardiac anatomy, foetal circulation and cardiac imaging modalities » Understand cardiac murmur grading and recognise com...

Diseases of the Cardiovascular System I: Congenital Diseases Dr Paul Pollard MVB Cert AVP(VC) MSc Vet Ed SFHEA MRCVS [email protected] Learning Objectives » Review cardiac anatomy, foetal circulation and cardiac imaging modalities » Understand cardiac murmur grading and recognise common murmur types » Review both common and uncommon congenital defects and how they influence blood flow patterns » Understand and describe the pathophysiology, clinical presentation, diagnosis, treatment/management and prognosis for common congenital cardiac conditions: Patent ductus arteriosus Pulmonic stenosis Subvalvular aortic stenosis Atrial and ventricular septal defects #universityofsurrey 2 #universityofsurrey 3 Review: Anatomy Aortic arch Pulmonary artery Cranial vena cava Left atrium Pulmonary veins Left atrio-ventricular Right atrium (Mitral) valve Pulmonic valve Chordae tendinae (semi-lunar) Right AV valve Papillary muscles Right ventricle Caudal vena cava Left ventricle Trabecula Pericardium septomarginalis (moderator band) #universityofsurrey 4 Review: Anatomy Aortic arch Pulmonary artery Cranial vena cava Left atrium Pulmonary veins Left atrio-ventricular Right atrium (Mitral) valve Pulmonic valve Chordae tendinae (semi-lunar) Right AV valve Papillary muscles Right ventricle Caudal vena cava Left ventricle Trabecula Pericardium septomarginalis (moderator band) #universityofsurrey 5 Review: Conduction System Starts at SA node (normal pacemaker of the heart) Spreads throughout the right and left atria via internodal pathways To the AV node Then down through the Bundle of His To the Left and Right Bundle Branches Into the Purkinje fibres Spreading through the ventricular myocardium https://mdmedicine.wordpress.com/2011/04/24/heart-conduction-system/ #universityofsurrey 6 Review: The Heart as a Pump » The heart consists of two pumps that work in series Left heart draws oxygenated blood from the lungs and pumps it around the body LEFT = HIGH PRESSURE Right heart draws deoxygenated blood from the veins and pumps it to the lungs for reoxygenation RIGHT = LOW PRESSURE #universityofsurrey 7 Review: The Heart as a Pump #universityofsurrey https://teachmephysiology.com/cardiovascular-system/cardiac-cycle-2/cardiac-cycle/ 8 Refresher: Foetal Circulation » In utero the following structures are normal: Ductus arteriosus (R-L shunt) Foramen ovale (R-L shunt) Ductus venosus (hepatic portal shunt) Umbilical arteries and veins » After birth, these structures should close » Congenital heart defects: either persistent foetal structures, or dysplasia #universityofsurrey 9 Refresher: Basic Echocardiography » Right parasternal long axis view » Right parasternal short axis view Papillary muscles Chordae tendinae Mitral valve Aortic valve » Subcostal view » Left apical 4 and “5” chamber view William P. Thomas, DVM, Cathy E. Gaber, DVM, Gilbert J. Jacobs, DVM, Paul M. Kaplan, DVM, Christophe W. Lombard, Dr Med Vet, N. Sydney Moise, DVM, and Bradley L. Moses, DVM, Recommendations for Standards in Transthoracic Two- Dimensional Echocardiography in the Dog and Cat #universityofsurrey 10 Right Parasternal Long Axis View #universityofsurrey 11  Right Parasternal Short Axis View » From the long axis view, the transducer is rotated 90° in a clockwise direction so the ultrasound beam is perpendicular to the long axis of the ventricles Mitral valve (D) Chordae tendinae (C) The “fish mouth” Papillary muscles (B) Aorta (E) The Thomas W. P., et al. (1993) The “mushroom” “Mercedes Benz sign” Recommendations for standards in transthoracic two-dimensional echocardiography in dogs and cats. J Vet Intern Med, 7, 247–252 The level of the apex (A) Pulmonary artery (F) #universityofsurrey 12 Left Apical “5” Chamber View #universityofsurrey 14 Learning Objectives » Review cardiac anatomy, foetal circulation and cardiac imaging modalities ✔ » Understand cardiac murmur grading and recognise common murmur types » Review both common and uncommon congenital defects and how they influence blood flow patterns » Understand and describe the pathophysiology, clinical presentation, diagnosis, treatment/management and prognosis for common congenital cardiac conditions: Patent ductus arteriosus Pulmonic stenosis Subvalvular aortic stenosis Atrial and ventricular septal defects #universityofsurrey 15 Cardiology in two pictures #universityofsurrey 16 Murmurs #universityofsurrey 17 Cardiac Murmurs Grade of Murmur Description I Very soft, localised murmur, detected in a quiet room after intently listening II Soft murmur, but immediately obvious, quieter than S1 and S2 III Moderate intensity, as loud as S1 and S2 IV Louder than S1 and S2, but no palpable thrill V Very loud murmur with palpable thrill VI Very loud murmur with palpable thrill and still audible when stethoscope removed from chest #universityofsurrey 18 Cardiac Murmurs » Cardiac Sounds S1-S2 – “Lub-Dup” – enclosing systole Closing of AV valves, then closing of semi-lunar valves https://depts.washington.edu/physdx/audio/normal.mp3 S3 – “Lub-Dup-ud” – early filling of ventricle(s) in early diastole https://depts.washington.edu/physdx/audio/s31.mp3 S4 – “ooh-Lub-Dup” – late diastolic filling (atrial kick) https://depts.washington.edu/physdx/audio/s41.mp3 » S3 and S4 “gallops” are always abnormal in small animals https://depts.washington.edu/physdx/heart/demo.html #universityofsurrey 19 Cardiac Murmurs » Murmurs: Turbulent blood flow Pitch (frequency) Intensity (loudness) Duration Quality » Harsh (ejection) murmurs are associated with stenosis of the semi-lunar valves Aortic stenosis https://depts.washington.edu/physdx/audio/as-early.mp3 Pulmonic stenosis https://depts.washington.edu/physdx/audio/ps.mp3 » Soft (blowing) murmurs are associated with valvular regurgitation Mitral regurgitation https://depts.washington.edu/physdx/audio/mr.mp3 Tricuspid regurgitation » Continuous (“washing machine”) murmurs Patent ductus arteriosus https://depts.washington.edu/physdx/audio/pda.mp3 #universityofsurrey 20 Cardiac Murmurs: “Innocent” Murmurs » The intensity of the murmur doesn’t necessarily correlate with severity of disease, but is always important for serial examinations » Almost all murmurs are clinically significant – especially in adult animals » In young animals (e.g. puppies and kittens ~6-15 weeks) the murmur may be “innocent” Low grade (I-II/VI) Systolic Often dynamic (louder with increase in HR/excitement) Exacerbated by physiologic anaemia of adolescence Disappear by 4-5 months » However… A low intensity murmur could also be very bad - e.g. large septal defect or severe valvular incompetence » Echocardiography to confirm! #universityofsurrey 21  Comparison of auscultatory and echocardiographic findings in healthy adult cats. Wagner, T., Fuentes, V. L., Payne, J. R., McDermott, N. & Brodbelt, D. 2010. Comparison of auscultatory and echocardiographic findings in healthy adult cats. Journal of Veterinary Cardiology, 12, 171-182. PubMed ID 21075067 #universityofsurrey 22 In Summary: - A very rough estimate…… Disease does not mean clinical signs! Significance of a murmur in cats: 6-12 months 1 in 5 have disease 1-3 years 1 in 4 have disease 3-9 years 1 in 3 have disease 9+ years 1 in 2 have disease Significance of no murmur If less than 3 years old – there is no disease If over 3 years old 1 in 10 will have disease 1 in 10 cats over 9 years old with no murmur will have heart disease #universityofsurrey 23 Stephen Ettinger, D.V.M. - Canine Heart Sounds » https://blog.wfmu.org/freeform/2007/04/365_days_93_ste.html #universityofsurrey 24 Learning Objectives » Review cardiac anatomy, foetal circulation and cardiac imaging modalities ✔ » Understand cardiac murmur grading and recognise common murmur types ✔ » Review both common and uncommon congenital defects and how they influence blood flow patterns » Understand and describe the pathophysiology, clinical presentation, diagnosis, treatment/management and prognosis for common congenital cardiac conditions: Patent ductus arteriosus Pulmonic stenosis Subvalvular aortic stenosis Atrial and ventricular septal defects #universityofsurrey 25  PollEv.com/paulpollard090 #universityofsurrey 26