Congenital heart disease Flashcards
Define congenital heart disease
Malformations of the heart and great vessels that are present at birth
CHD occurs due to altered or arrested embryonic development of the rudimentary heart leading to potentially gross anatomical alterations
Compare innocent murmurs to those heard with CHD
Grade:
- Innocent murmur= low grade (I-II/VI)
- CHD= II-VI
Timing:
- Innocent= mid-systolic
- CHD= depends on condition but tend to be longer in duration
PMI:
- Innocent= left heart base
- CHD= depends on condition
Radiation:
- Innocent= minimal
- CHD= depends on pathology
Variability:
- Innocent= varying intensity with heart rate
- CHD= generally non-variable
Resolution:
- Innocent= usually resolve by 6 months
- CHD= no resolution
What abnormalities might be found with the arterial pulse in patients with CHD?
Hyperkinetic pulse (waterhammer):
- Abnormal diastolic run off of aortic blood
- PDA/ severe aortic regurgitation
Hypokinetic pulse:
- Left ventricular/ outflow tract obstruction
- Aortic stenosis or poor left ventricular output
What should you do in practice when you hear a murmur in a puppy or kitten?
o If loud (grade 3+) more likely to be a congenital anomaly, but loud does not necessarily mean bad (think small VSD)
o If < grade 2 then could be innocent – reassess at 3 and 6 months
o Return to breeder and get money back (rarely done, bond formed)
o Ultimately one can only assess nature and severity of lesions with a full Doppler echocardiogram
Name some common types of CHD?
- Aortic stenosis (AS)
- Patent ductus arteriosus (PDA)
- Pulmonic stenosis (PS)
- Ventricular septal defect (VSD)
What are the 3 types of aortic stenosis?
Sub-aortic stenosis (common)
Valvular aortic stenosis (uncommon)
Supra-valvular (rare)
What is sub-aortic stenosis?
Sub-valvular narrowing caused by a fibrous or fibromuscular ring
+/- mitral dysplasia as well
What is valvular aortic stenosis?
Narrowing of the valve itself
Why are myocardial ischaemia and fibrosis common sequalae to aortic stenosis?
Due to narrowed intramural coronary arteries and inadequate myocardial capillary density as the hypertrophy progresses
(These factors lead to an increased risk of ventricular arrhythmias leading to weakness, syncope, left-sided congestive heart failure and sudden death)
What may be heard on auscultation of aortic stenosis?
- Harsh systolic ejection murmur, PMI aortic valve
- Precordial thrill at the left heart base
- Radiates to right heart base
- +/- diastolic murmur depending on pressure and severity of AI
What may be seen on radiographs of aortic stenosis?
May be normal (concentric hypertrophy so external diameter of the heart not changed much)
Left sided cardiomegaly
Post-stenotic dilation in the ascending aorta
ECG can be normal or show evidence of LV hypertrophy
Echocardiographic features depend on the severity of aortic stenosis but what might be seen?
- Concentric LVH
- Rounding of LV
- Post-stenotic dilation
- +/- aortic regurgitation
- +/- LAE
- +/- MR
- Hyperechoic, hypertrophied PM
- Fibrous ring is SAS/ abnormal valve etc.
What are the five types of pulmonic stenosis?
Infundibular
Sub-valvular pulmonic stenosis (uncommon)
Valvular pulmonic stenosis (common)
Supra-valvular (rare)
Anomalous coronary artery (coronary artery loops around base of pulmonary artery)
What may be found on clinical examination of an animal with pulmonic stenosis?
- Many cases are asymptomatic on presentation, clinical signs depend on severity of lesion
- Right sided heart failure, syncope, exercise intolerance
- Sudden death does occur in some severe cases
- Prominent right apical beat
- PMI murmur left heart base (high frequency systolic ejection murmur)
- Radiation cranially and ventrally
- Prominent jugular pulses
What are radiographic signs of pulmonic stenosis?
- Right sided enlargement due to right ventricular hypertrophy
- Pulmonary trunk bulge at 1 o’clock position on the DV view
- Dilation of caudal vena cava in some dogs