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Observations on the development of congestive heart failure in Irish wolfhounds with dilated cardiomyopathy
1Department of Small Animal Medicine and Surgery, Royal Veterinary College, Hatfield, Hertfordshire.
Insights
Certain electrocardiographic (ECG) abnormalities, particularly atrial fibrillation (AF), and progressive cardiac dilation may indicate
Area of Science:
- Veterinary Cardiology
- Canine Cardiology
Background:
- Dilated cardiomyopathy (DCM) is a significant cause of congestive heart failure (CHF) in Irish wolfhounds.
- Early identification of prognostic indicators for DCM in this breed is crucial for timely intervention.
Purpose of the Study:
- To determine if pre-existing electrocardiographic (ECG) and echocardiographic abnormalities predict the development of CHF due to DCM in Irish wolfhounds.
Main Methods:
- Retrospective analysis of ECG and echocardiographic records from 39 Irish wolfhounds diagnosed with CHF over a 10-year period.
- Evaluation of previously detected ECG abnormalities (e.g., atrial fibrillation, arrhythmias, blocks) and echocardiographic findings (e.g., chamber dilatation).
Main Results:
- All 39 dogs developed atrial fibrillation (AF) by the onset of CHF; 46% had AF at their initial examination.
- Progressive left atrial and left ventricular dilatation was observed in echocardiograms up to five years prior to CHF diagnosis.
- Mean age at CHF diagnosis was 77 months (males) and 86 months (females); mean age of AF detection was 45 months (males) and 59 months (females).
Conclusions:
- Electrocardiographic abnormalities, especially atrial fibrillation (AF), and progressive cardiac chamber dilatation are potential indicators of 'occult' DCM in Irish wolfhounds.
- These findings suggest that regular cardiac monitoring in Irish wolfhounds may help identify early signs of DCM.
Abstract:
Records of previous electrocardiographic (ECG) and echocardiographic examinations of 39 Irish wolfhounds with cardiac failure, obtained during a 10-year survey, were examined to establish whether previously detected abnormalities might be prognostic indicators for the development of congestive heart failure (CHF) due to dilated cardiomyopathy (DCM) in later life. Eighteen dogs (46 per cent) had had atrial fibrillation (AF) at their first examination. Other ECG abnormalities detected at previous examinations were ventricular and supraventricular premature contractions, first and second degree atrioventricular block, P mitrale and left anterior fascicular and right bundle branch blocks. All 39 dogs had developed AF by the time of onset of CHF. The mean age at which CHF was diagnosed was 77 months in males and 86 months in females. The mean age at which AF was first detected was 45 months in males and 59 months in females, and the mean time from the first detection of AF to CHF was 27 months in males and 24 months in females. Previous echocardiographic examinations in eight dogs, over a period of up to five years, revealed progressive left atrial and left ventricular dilatation. Fractional shortening was reduced to below the normal range at the onset of CHF compared with previous examinations in three cases but increased in five. It appears, therefore, that certain ECG abnormalities, especially AF, and/or progressive ventricular and atrial dilatation, may be indicators of 'occult' DCM in wolfhounds.