Tetralogy of Fallot
Abnormalities found on special exams
- Lab--erythrocytosis, inc. PCV 60-70%
- Rads--R heart enlargement, small pulmonary vessels
- Echo
- Overriding aorta and VSD
- Hypertrophy of R ventricle
- Doppler--inc. peak flow across pulmonary valve, shunting through VSD
- Angio--ID's the VSD, R ventricular hypertrophy, pulmonic stenosis, and direction of the shunt
- Catheterization--measurement of the pressure gradient across the VSD
- ECG--possible R ventricular enlargement
- Overriding aorta and VSD
- Hypertrophy of R ventricle
Tetralogy of Fallot
DDx
Prevention
- DDx = other causes of cyanosis
- Prevention = do not breed animals w/ this defect
Tetralogy of Fallot
Treatment
Prognosis
- Surgical procedures to re-route blood--variable success
- Subclavian attached to pulmonary artery to increase oxygenation or connect aorta to pulmonary artery--like PDA
- Beta blockers--possibly lessen MVO2 of R ventricle or imrove distensibility
- Hydroxurea--anti-cancer drug, blocks RBC production
- Phlebotomies and replace blood with sterile saline; low dose aspirin to prevent thromboembolism
-
Vasodilators are contraindicated--will make R-L shunting worse and increase hypoxia
- Prognosis--depends on the severity; some dogs live a long (though inactive) life
- Subclavian attached to pulmonary artery to increase oxygenation or connect aorta to pulmonary artery--like PDA
Atrial septal defect
Pathophysiology
- "Common atrium"
- Blood flows to right atrium because of its thinner, distensible walls
- R ventricular enlargement due to volume overload
- Enlarged pulmonary vessels
- L-R shunt
Atrial septal defect
Signalment
Probable owner complaint/history
- Signalment--found in younger animals during pediatric vaccinations
- Complaint/history
- Small defects present asymptomatically
- Larger defects may present with heart failure signs
- Small defects present asymptomatically
- Larger defects may present with heart failure signs
Atrial septal defect
Common abnormalities seen on PE
Abnormalities found on special exam
DDx
- PE
- Possible murmur heard over L heart base
- May hear splitting of S2
- Rads--R heart enlargement, prominent pulmonary vessels
- DDx--pulmonic or aortic stenosis
- Possible murmur heard over L heart base
- May hear splitting of S2
Atrial septal defect
Treatment
Prognosis
Prevention
- Treatment
- Dependent on size of the defect--most with small defects will remain asymtomatic
- Surgical correction of large defects will require bypass
- Prognosis--depends on size; worse if tricuspid stenosis is also involved
- Prevention--don't breed
- Dependent on size of the defect--most with small defects will remain asymtomatic
- Surgical correction of large defects will require bypass
Atrioventricular valve malformations
Pathophysiology
- Thickened or fused valves
- Papillary muscles that are malpositioned, partially developed, or absent
- Chordae tendinae that are too long, too short, or absent
- Valvular insufficiency most commonly seen with dyslastic valves failing to meet during systole--> regurg and volume overload
- Valvular stenosis (rare)--stenotic valves decrease ventricular filling during diastole --> inc. atrial pressure and CHF
Atrioventricular valve malformations
Signalment
Probable owner complaint/history
- Signalment
- Most common congenital malformation in cats
- Large breed dogs may be predisposed
- History
- Signs depend on the valve involved--L or R CHF signs
- Most common congenital malformation in cats
- Large breed dogs may be predisposed
- Signs depend on the valve involved--L or R CHF signs
Atrioventricular valve malformations
Common abnormalities seen on PE
Abnormalities seen on special exam
Valve insufficiency--depend on valve affected
Atrioventricular valve malformations
DDx
Prevention
- DDx
- Other causes of diastolic murmurs--PDA, possible aortic stenosis
- Prevention--don't breed
- Other causes of diastolic murmurs--PDA, possible aortic stenosis
Atrioventricular valve malformations
Treatment
Prognosis
- Treatment
- Furosemide and an ACE inhibitor
- Arterial vasodilators may be helpful by reducing regurg and promoting forward flow
- Low sodium diet may be helpful
- Prognosis
- Depends on severity of defects
- Furosemide and an ACE inhibitor
- Arterial vasodilators may be helpful by reducing regurg and promoting forward flow
- Low sodium diet may be helpful
- Depends on severity of defects
Endocardial fibroelastosis
All the things
- Seen more in Burmese and Siamese kittens
- Fibrosis of ventricular endocardium--> stiffening of walls--> decrease ability to dilate and fill during diastole
- Left CHF by the time the animal is 2-4mo
- No treatment
Persistent right aortic arch (PRAA)
Pathophysiology
Signlament
- Vascular ring formed by the ligamentum arteriosus dorsally, aorta to the right, pulmonary artery to the left, and cardiac base ventrally--constricts esophagus and trachea
- Signalment: common occurrence in GSDs
PRAA
Signs
Abnormalities on special exam
- Signs
- Megaesophagus cranial to the constriction = regurg of solid food
- Asymptomatic at young age (liquid diet)
- Rads: esophageal dilation cranial to the heart base
- Megaesophagus cranial to the constriction = regurg of solid food
- Asymptomatic at young age (liquid diet)
PRAA
Treatment
Prognosis
DDx
- Treatment--surgical ligation and transection of LA
- Guarded prognosis--esophageal fx may remain abnormal
- Animals at risk for aspiration pneumonia
- DDx: congenital megaesophagus
- Animals at risk for aspiration pneumonia
Inherited ventricular arrhythmias in GSDs
All the things
- Possible genetic link in some lines of GSDs, otherwise idiopathic
- Starting at 3 months, animals may be affected w/ mild VPDs or eisodes of VT and poss. sudden death
- Severity will inc. until 7mo and then decreases
- By 18mo risk of sudden death is markedly dec.
- Severely affected animals can be given sotalol and mexiletine to dec. episodes of VT (does not prevent sudden death)
- Sotalol alone is roarrhythmogenic and mexiletine alone has no affect
- Drug trtmt until animals are 18 mo to 2 yrs
- By 18mo risk of sudden death is markedly dec.
- Sotalol alone is roarrhythmogenic and mexiletine alone has no affect
- Drug trtmt until animals are 18 mo to 2 yrs