Evaluation of a new smartphone-based digital stethoscope featuring phonocardiography and electrocardiography in dogs and cats

This study assessed a new smartphone-based digital stethoscope (DS) featuring simultaneous phonocardiographic and one-lead electrocardiogram (ECG) recording in dogs and cats. The audio files and ECG traces obtained by the device were compared with conventional auscultation and standard ECG. A total of 99 dogs and nine cats were prospectively included. All cases underwent conventional auscultation using an acoustic stethoscope, standard six-lead ECG, standard echocardiography and recordings with the DS. All the audio recordings, phonocardiographic files and ECG traces were then blind reviewed by an expert operator. The agreement between methods was assessed using Cohen's kappa and the Bland-Altman test. Audio recordings were considered interpretable in 90% animals. Substantial agreement was found in the diagnosis of heart murmur (κ = 0.691) and gallop sound (k = 0.740). In nine animals with an echocardiographic diagnosis of heart disease, only the DS detected a heart murmur or gallop sound. ECG traces recorded with the new device were deemed interpretable in 88 % animals. Diagnosis of heart rhythm showed moderate agreement in the identification of atrial fibrillation (k = 0.596). The detection of ventricular premature complexes and bundle branch blocks revealed an almost perfect agreement (k = 1). Overall, the DS showed a good diagnostic accuracy in detecting heart murmurs, gallop sounds, ventricular premature complexes and bundle branch blocks. A clinically relevant overdiagnosis of atrial fibrillation was found but without evidence of false negatives. The DS could represent a useful screening tool for heart sound abnormalities and cardiac arrhythmias..

Arrhythmogenic right ventricular cardiomyopathy in boxers

Arrhythmogenic right ventricular cardiomyopathy, formerly termed boxer cardiomyopathy, is a familial primary myocardial disease that is prevalent in boxers. Unique histopathologic changes in the myocardium lead to conduction abnormalities that typically manifest as ventricular tachyarrhythmias with left bundle branch block morphology. Affected dogs can be asymptomatic or may have syncope and/or exercise intolerance. Diagnosis can be difficult, and indications for antiarrhythmic therapy are not always clear. A small number of dogs present with systolic dysfunction and/or congestive heart failure. Screening in asymptomatic breeding dogs was difficult until the recent development of genetic testing.

Ebstein's anomaly in a beagle dog

An intact male beagle dog aged 1 year was referred because of shortness of breath, exercise intolerance and cardiac murmur. Based on the results from electrocardiography, thoracic radiography and echocardiography, the dog was diagnosed as Ebstein's anomaly. Although the orally administered digoxin, vasodilators and diuretics partially improved congestive signs, the dog became to be refractory and died 20 months after the diagnosis. Necropsy confirmed malformation and apical displacement of the basal attachment of tricuspid valve leaflets.

Right bundle-branch block in a dog

A cardiac gallop rhythm and a low-grade systolic murmur were found in an 8-year-old Miniature Poodle. Conditions had not changed 7 months later, but electrocardiographic evaluation revealed a short R wave, large S wave, prolonged QRS interval and mean electrical axis of -100 degrees, all consistent with a right bundle-branch block. The dog has remained in good condition for 2 years without right-heart enlargement, ectopic beats or tachycardia, indicating the condition was an incidental finding.

Clinical aspects of bundle branch blocks in veterinary medicine

After an extensive review of the relevant veterinary literature, the author discusses the aetiopathogenic, diagnostic and prognostic aspects of branch blocks in domestic animals.

Incomplete right bundle-branch block. An electrocardiographic enigma and possible misnomer

Incomplete right bundle-branch block (IRBBB) usually is thought to be associated with abnormalities of the peripheral Purkinje system. This paper discusses the results of a study of six dogs from the same family and three nonrelated dogs with congenital IRBBB. Cardiac catheterization data were normal, and no evidence or history of cardiac disease was found before or after death. The depolarization sequence of ventricular epicardial activation was determined, and delays in right ventricular (RV) epicardial activation times were observed. Multipoint intramural electrodes were used to study intramural activation of the ventricular septum and free walls. The "electrical thickness" near the base of the RV mass was more than double that of the normal RV mass (9 vs 4 mm). Conduction along the right bundle branch (RBB) was analyzed during cardiopulmonary bypass, and electrograms recorded simultaneously from six sites along the RBB demonstrated that conduction velocity down the bundle was normal. The normal time of activation of the endocardial RV Purkinje fibers demonstrated that conduction in the right peripheral Purkinje system also was normal. Therefore, IRBBB in these dogs did not result from conduction abnormalities within the RV specialized conduction system. Interestingly, six of these dogs were members of the F 1 generation from a mating of a female beagle with pulmonary stenosis and a male beagle with ventricular septal defect. Both defects as well as IRBBB were observed in the F 2 generation. The present findings suggest that IRBBB may be a developmental variation in thickness of the RV free wall rather than an abnormality of the RV conduction system in cases without apparent heart disease. The developmental variant appears to have a genetic basis.