Right Atrioventricular Valve Malformation in Dogs and Cats: An Electrocardiographic Survey With Emphasis on Splintered QRS Complexes

Abstract

The purposes of this study were 2-fold: (1) to determine the prevalence of splintered QRS complexes (Rr', RR', rR', rr') and other electrocardiographic abnormalities in dogs and cats with congenital right atrioventricular valve malformation (RAVM) and (2) to determine if the Labrador Retriever was at greater risk for RAVM and splintered QRS complexes.EKGs from 39 dogs and 6 cats with echocardiographically diagnosed RAVM were studied retrospectively. Splintered QRS complexes were commonly found in affected Labrador Retrievers (9 of 19,47%), non-Labrador Retrievers (12 of 20, 60%), and cats (4 of 6, 67%). Right ventricular enlargement was most commonly detected by precordial leads (CV,LL[V,], CV,LU[V,I) in the dogs and by the standard limb Congenital right atrioventricular (tricuspid) valve malformation (RAVM) is characterized by a number of structural abnormalities occurring individually or in combination. Focal or diffuse thickening of valve leaflets, hypoplasia of the chordae tendineae and papillary muscles, incomplete separation of valve components from the ventricular wall, and focal agenesis of valve tissue are classified as tricuspid valve dysplasia (TD). Apical displacement of the basal attachments of the valve leaflets is termed Ebstein's malformation (EM).'.' These anomalies may represent variable expression of a common underlying pathologic process, but the distinction between these forms of RAVM has not been investigated in veterinary medicine. In humans, classification of the degree of thickening of the valve leaflets, hypoplasia of the chordae tendineae, and postmortem measurements of the degree of tricuspid valve displacement have been assessed.'.' Echocardiographic measurements of valve displacement with indexing to body size have been used in infants and children to differentiate TD from EM.' Electrocardiographic abnormalities have been described in dogs and cats with RAVM.4.5 Abnormalities have included evidence of right atrial and right ventricular enlargement. In some dogs, splintering of the QRS complex similar to the characteristic splintering seen in children with EM has been de~cribed.~,' RAVM is believed to be overrepresented in Labrador Retrievers and in male dogs. ',' This article describes the electrocardiographic findings in 39 dogs and 6 cats with congenital RAVM. The objectives of this study were ( 1 ) to determine the prevalence of various electrocardiographic abnormalities in these patients, with particular emphasis on splintering of the QRS complex, and (2) to evaluate the association of breed and gender with RAVM. Postmortem examinations were not available in the majority of animals within this study, so no distinction was made between animals with TD, EM, or a combination of the 2. Materials and Methods AnimalsThis retrospective study was conducted at the College of Veterinary Medicine, Cornell University. All dogs and cats with a diagnosis of RAVM based on echocardiographic examination between January, 1987, and October, 1994, were included in the study. Seven animals also h...

Tricuspid valve dysplasia: A retrospective study of clinical features and outcome in dogs in the UK

“…Nonarrhythmic electrocardiographic abnormalities were relatively common. Although P mitrale was not observed and splintering of the QRS complex was observed less frequently than in other studies (Kornreich and Moïse, 1997), P pulmonale and right axial shifts occurred at frequencies similar to those previously reported despite none of the dogs having precordial recordings (Kornreich and Moïse, 1997). Cardiac arrhythmias were not frequently reported in our dogs.…”

“…Cases compatible with EM were not categorised separately from the TVD population. This was because only subjective assessment of apical displacement of the valvular apparatus was available, and not objective assessment (indexing to body weight) (Kornreich and Moïse, 1997), cardiac catheterisation with an electrophysiology study (Choi et al, 2009) or postmortem confirmation (Kornreich and Moïse, 1997) were available.…”

Chylothorax associated with Ebstein’s anomaly in a Golden Retriever dog

“…Also, in this case, 2D echo showed that a left ventricle (LV) diastolic D-shape at the level of papillary muscle suggestive for RA and RV overload, as described earlier (13)(14)(15)21). A normal septal leaflet of TV attaches 0.5 -1.0 cm more apical than the anterior mitral leaflet in the 4-chamber view.…”

“…A right atrial (RA) enlargement in a dog with right apical systolic murmur was generally pathognomonic for severe TVD and TV insufficiency (14). But this is not sensitive, small QRS complexes in dogs with TVD were reported, as well (15).…”

First Description of Tricuspid Valve Dysplasia in a Basset Hound

“…The cause of splintered QRS complexes has not been identified yet, but potential causes might be represented by fibrosis, bypass tracts and ischemia (Kornreich et al, 1997).…”