Small animal Cardiology
Overview
· Acquired Valvular Diseases
o Endocardiosis
o Endocarditis
· Myocardial Diseases
o Dilated Cardiomyopathy
o Hypertrophic Cardiomyopathy
o Other cardiomyophathies
· Congestive heart failure
· Congenital cardiac defects
Endocardiosis
· Small breed older dog, except YOUNG Cavalier King Springer Spaniel (murmur @ 18 mos age is a sign of this disease)
· Presenting complaint:
o often no clin signs
o later: cough, tachypnea, dyspnea, exercise intolerance, syncope, weight loss
· Physical exam: routine physical exams are
o systolic murmur-left side chest @ apex over mitral valve, weak pulses, cyanotic mm
o tachycardia
o (arrhythmia, cyanosis, weak pulses)
· DX: rads-chest
o heart silhouette- large; cardiomegaly caudal waist gone, left atrium enlarged, see large tissue density. rads (enlarged left atrium). normal: heart 2/3 chest on VD view
o ECG: no spec changes
§ P-mitrale:widened P wave or P-pulmonale:taller P wave
§ widened QRS complex-->left ventr enlargement
o Echocardiography
· Tx:
o none unless symptoms
o ACE inhibitor:
§ enalapril/benzapril/lisinopril may cause renal damage
o diuretics:
§ furosemide + spirnolactone
o positive inotropes:digoxin
Valvular Endocarditis
· uncommon
· young, LARGE breed dogs: German Shephard
· no clin signs; usually present because they are sick
· present with fever, arthritis, wt loss, PU/PD
· murmur often soft, disastolic murmur
· no assoc with dental and endocarditis dz: signalment young dogs, not older
Dilated Cardiomyopathy
· Primary
o *-idiopathic;most common
o Familial *-nutritional-carnitine/taurine:Cocker spaniel
· Secondary
o infection-Trypansoma cruzei, parvovirus:rare
o toxicity-doxorubicin lg breed dogs- 1) Doberman, 2) Boxer, 3) Cocker spaniel. cough on exam:cardiomyopathy, males>females, young
o Nutritional (Carnitine/Taurine)
o Toxin
o Neoplasia
· Large breed dogs:
o Doberman Pinscher, Boxer, Cocker Spaniel
o Almost certainly genetic component
o Males>females
o Young to old
o presenting complaint:
§ few signs until CHF:
§ cough, short breath, nasal discharge, dyspnea
§ exercise intoler, fainting,
§ wt loss,
§ ascites
· Physical Exam:
o pale, cyanotic mm
o tachycardia, dysnpea, pulse deficits,
§ + crackles
o murmur:systolic-over left apex;
o arrhythmia/gallop;
o normal to weak pulses + deficits
o hepatomegaly, jugular distension
o early stages may have normal PE
· Diagnosis
o rads:eccentric hypertrophy;all chambers dilated, globoid, inc left atrium (all chambers dilate)
o ECG:may see VPC's-ventr premature complexes:wide bizarre QRS complexes;not preceded by T wave; tachycardic also see atrial fibrillation (no P wave); rapid normal looking QRS complexes-fibrillation of atrium being cancelled out
· Treatment:
o ACE inhibitor: enalapril/benzapril/lisopril
o diuretic: furosemide + spironolactone--volume overload
o positive inotrope: digoxin
o +negative chronotrope: digoxin, Ca channel blocker/b-blocker:to slow rate
o never achieve converting to normal sinus rhythmn in dog, want to slow heart rate
Hypertropic Cardiomyopathy
o cats; more common
o males more common
o median age: 7yrs
o breeds: Maine Coon, American, British shorthair, Ragdoll, Norwegian Forest, Persian over represented
o probably genetic component
o tachypnea/dyspnea: most common
o syncope
o acute paresis/paraplegia (thromboembolism)
o cough: uncommon (in cat cough in not common but dogs common)
o wt loss, anorexia, vomiting
o Tachycardia
o inc heart rate, systolic murmur
§ loudest over cranial sternum or left apex)
o gallop
o tachypnea/dyspnea:
§ exacerbated by minor strees
· Chest Rads
o concentric hypertrophy (in gogs it was excentric); laying down layers muscle inner portion, heart looks normal, not necessarily pulmonary edema
· ECG:
o Occasional arrhythmias
§ may see left bundle branch block: huge QRS complexes
o thromboembolism:turbulent blood flow due to flaccid atrium-> embolism, also need to measure:
o Additional Diagnostics
§ blood pressure
§ T4 (beware of sick euthyroid syndrome) T4 maybe normal due to animal being sick
· Tretament:
o b-blocker:
§ propanolol, atenolol: slow hr, so heart can fill before contraction
o Ca channel blocker:
§ Diltiazem
o diuretics: nitroglycerin: only if in CHF
o aspirin: if left atrium severly enlarged--->thromboembolism
Heart Failure
Heart Disease # Heart Failure
· Definition: “clin syndrome caused by heart dz results in systolic and/or diastolic dysfunction, overwhelms cardiovasc sys compensatory mechanism”.
· Systolic
o Myocardial failure (dilated cardiomyopathy)
o Increased cardiac workload
§ Volume overload
§ Pressure overload
o Arrhythmias
· Diastolic (cats)
o impaired filling
o Obstruction to filling
o decr ventricular compliance
Myocardial Failure
· Poor contraction
o reduced stroke volu...
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