Smartphone-based six-lead ECG: A new device for electrocardiographic recording in dogs.

Smartphone-based technology for electrocardiographic recording is now part of the new concept of mobile health in both human and veterinary medicine. Although smartphone-based ECG for electrocardiographic screening in dogs is reliable, one-lead ECG devices have mainly been evaluated. This prospective study assessed the feasibility and the diagnostic reliability of a new smartphone-based six-lead electrocardiograph (smECG) in dogs, in comparison to a standard six-lead electrocardiograph (stECG). All ECG tracings were blindly reviewed by an expert operator, who judged whether tracings were acceptable for interpretation, performed the electrocardiographic measurements, and assigned a diagnosis. The agreement in the electrocardiographic interpretation and diagnosis between smECG and stECG was assessed using the Bland-Altman test and Cohen's k test. The study included 108 client-owned dogs. The tracings obtained by the smECG were interpretable in 100 % of cases. No clinically relevant differences between smECG and stECG were found in the assessment of heart rate, interval duration, and QRS mean electrical axis. The smECG tended to underestimate the amplitude of the P and R waves. Perfect agreement was found in the detection of sinus rhythm, atrial fibrillation, ventricular arrhythmias, atrioventricular blocks, and bundle branch blocks. Our study suggests that the tested smartphone-based six-lead ECG is a clinically reliable device for the assessment of heart rate and heart rhythm in dogs, and thus could be used in a clinical setting in dogs and for telemedicine.

Echocardiographic reference intervals of the dimensions of the main pulmonary artery and the right pulmonary artery: a prospective study in 269 healthy dogs.

INTRODUCTION: No data are available on the echocardiographic reference intervals (RIs) for the main pulmonary artery (MPA) and right pulmonary artery (RPA) dimensions in a large sample of dogs. Therefore, we aimed to describe the echocardiographic RIs of the MPA and RPA dimensions in normal dogs. ANIMALS, MATERIALS, AND METHODS: Two hundred and sixty nine healthy dogs of different breeds, age and body weight (BW) were prospectively enrolled in this multicenter, observational study. The MPA diameter, RPA maximum diameter (RPAmax), and RPA minimum diameter (RPAmin) were measured from the right parasternal short axis view. Prediction intervals (PIs) for MPA, RPAmax and RPAmin were generated using allometric scales. Reference intervals (RI) of MPA indexed to the ascending aorta (MPA/AO), and RPAmax and RPAmin indexed to the aortic annulus (RPAmax/Aod and RPAmin/Aod), were defined. RESULTS: A positive linear relationship between MPA, RPAmax, RPAmin and BW was evident after logarithmic transformation (R2 = 0.859, R2 = 0.787 and R2 = 0.725, respectively; P<0.0001). According to allometric scales, the PI for the MPA normalized for BW (MPA_N) was between 5.50 and 8.07, the PI for the RPAmax normalized for BW (RPAmax_N) was between 3.23 and 5.62, while the PI for the RPAmin normalized for BW (RPAmin_N) was between 1.62 and 3.30. The median MPA/AO was 0.92 (RI, 0.78-1.01), the median RPAmax/Aod was 0.70 (RI, 0.53-0.98) and the median RPAmin/Aod was 0.40 (RI, 0.29-0.61). DISCUSSION AND CONCLUSIONS: The reported RIs of the MPA and RPA dimensions in normal dogs could increase the diagnostic accuracy of transthoracic echocardiography in the identification of pulmonary artery enlargement in dogs.

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..

Prognostic relevance of left cardiac enlargement in dogs with preclinical myxomatous mitral valve disease.

INTRODUCTION: According to the most recent consensus guidelines on canine myxomatous mitral valve disease (MMVD), dogs with only left atrial enlargement (LAE) or left ventricular enlargement are classified as stage B1. The concomitant presence of LAE and left ventricular enlargement is needed to be classified as stage B2. The primary aim of the study was to evaluate the prognosis in stage B1 and stage B2 according to the revised definition. The secondary aim was to assess the prognostic relevance of LAE in stage B1. ANIMALS: A total of 440 dogs with MMVD, 276 in stage B1 and 164 in stage B2. MATERIALS AND METHODS: Retrospective and observational study. The left atrium-to-aorta ratio and the left ventricular end-diastolic diameter normalized were used to define cardiac dimensions. The long-term outcome was assessed by telephone interviews with owners and referring vets. Both cardiac-related and all-cause mortality were evaluated. RESULTS: Stage B1 dogs had a longer median survival time than stage B2, considering both cardiac-related death (2344 vs. 1341 days; P<0.001) and all-cause mortality (1832 vs. 855 days; P<0.001). Age, left atrium-to-aorta ratio, and the left ventricular end-diastolic diameter normalized were independent predictors of cardiac-related death and all-cause mortality. Among stage B1, dogs with LAE lived shorter than those without LAE (1183 vs. 1882 days; P=0.005) considering all-cause mortality. DISCUSSION AND CONCLUSIONS: Stage B1 dogs lived longer than stage B2 dogs. Among stage B1, LAE had prognostic relevance considering all-cause mortality. This finding could add useful prognostic information in the management of preclinical MMVD.

Fatal acute lung injury after balloon valvuloplasty in a dog with pulmonary stenosis.

A one-year-old French Bulldog was referred for the management of a severe form of pulmonary valve stenosis (PS) complicated by right-sided congestive heart failure. Echocardiography showed severe valvular PS with right ventricular concentric hypertrophy, dilatation and severe right atrial enlargement. A pulmonary balloon valvuloplasty (PBV) was performed with a balloon-to-pulmonary annulus ratio of 1.36. Echocardiography immediately after PBV showed a significant reduction in right atrial and ventricular size, improved opening and mobility of the pulmonary valve leaflets, and a 75% reduction in the pulmonary pressure gradient from 158 mmHg pre-operative to 40 mmHg post-operative. The dog recovered well from anesthesia, but 2 h later, it suddenly showed severe respiratory distress. Focus cardiac ultrasound showed increased left cardiac size with echocardiographic signs of high left ventricular filling pressure. Bedside lung ultrasound showed diffuse numerous-to-confluent B lines, compatible with a severe alveolar-interstitial syndrome. The dog was treated with furosemide, helmet continuous positive airway pressure, and then mechanical ventilation but without success. At post-mortem evaluation, histological examination of the lung showed diffuse, severe broncho-alveolar edema with mixed leukocyte, fibrin, and red blood cell infiltrate. Moreover, severe congestion and multifocal alveolar hemorrhages were evident. All findings were compatible with fatal acute lung injury after PBV secondary to pulmonary reperfusion-ischemia injury and increased pulmonary capillary hydrostatic pressure. Based on the present case, acute lung injury should be considered as a rare but serious complication of PBV.

Echocardiographic parameters in 50 healthy English bulldogs: preliminary reference intervals.

INTRODUCTION/OBJECTIVES: The objective of the study was to provide echocardiographic reference intervals for English bulldogs (EBs) and to assess if age, sex, body weight (BW), and heart rate have an influence on echocardiographic variables. ANIMALS: We prospectively enrolled client-owned EBs that were considered healthy based on unremarkable history, normal physical examination, six-lead electrocardiography, and transthoracic echocardiography. MATERIALS AND METHODS: Breed-related reference intervals were provided, and associations between age, sex, BW, and heart rate and echocardiographic variables were tested using a multivariate analysis. Allometric scales were generated for echocardiographic variables showing correlation with BW. Moreover, echocardiographic variables obtained in our population of EBs and previous published reference ranges were compared. RESULTS: Echocardiographic reference intervals were generated from 50 healthy adult EBs. As per the multivariate analysis, left atrial diameter (p = 0.015), left ventricular internal end diastolic diameter (p = 0.002), aortic valve annulus (p = 0.032), and pulmonary valve annulus (p = 0.017) resulted influenced by BW, and reference intervals were generated using allometric scales. Our study suggests that EBs tend to have a smaller aortic root and sphericity index than other breeds. In addition, EBs seem to have smaller indexed left ventricular volumes and higher left ventricular ejection fraction than boxers and Doberman. CONCLUSION: Preliminary reference intervals in the EBs are reported, which might be helpful for accurate echocardiographic interpretation and screening purposes in this breed.

Two radiographic methods for assessing left atrial enlargement and cardiac remodeling in dogs with myxomatous mitral valve disease.

INTRODUCTION: Two radiographic measures of the left atrial (LA) size, the vertebral left atrial size (VLAS) and the radiographic left atrial dimension (RLAD), have been described in dogs. The aim of this study was to determine their feasibility and diagnostic value in the prediction of LA enlargement and clinical stage in dogs with myxomatous mitral valve disease (MMVD). ANIMALS: 111 client-owned dogs affected by MMVD. METHODS: Retrospective study. In each dog, VLAS, RLAD, vertebral heart score (VHS), and left atrium-to-aorta-ratio (LA/Ao) were measured. The correlation between VLAS, RLAD, and LA/Ao was evaluated. The diagnostic accuracy of VLAS and RLAD was assessed for the detection of LA enlargement and clinical staging using the receiver operating characteristic curve analysis. RESULTS: A positive correlation was observed between VLAS, RLAS, and LA/Ao (r = 0.816 and r = 0.855, respectively; p<0.0001). Both VLAS (area under the curve [AUC], 0.93; p<0.0001) and RLAD (AUC, 0.98; p<0.0001) showed high diagnostic accuracy in the detection of LA enlargement. In the stage B, the RLAD (AUC, 0.99; cutoff, ≥1.8; sensitivity, 100%; specificity 93%) performed better than VLAS (AUC, 0.90; cutoff, ≥2.4; sensitivity, 66%; specificity 100%) and VHS (AUC, 0.89; cutoff, ≥10.7; sensitivity, 88%; specificity 83%) in the detection of dogs fulfilling the echocardiographic criteria for stage B2. CONCLUSIONS: VLAS and RLAD represent useful radiological tools for the detection of LA enlargement in dogs with MMVD. In asymptomatic dogs, the RLAD performs better than VLAS and VHS in the prediction of those fulfilling the echocardiographic criteria for stage B2.

Closure of an unusual morphology patent ductus arteriosus with a covered stent in a dog.

Patent ductus arteriosus (PDA) with unusual morphology was diagnosed in a 3-year-old German shepherd presented for exercise intolerance. Two interventional PDA closure procedures with various Amplatzer devices and one surgical ligation were attempted to close the PDA. However, PDA closure failed with both methods due to the unusual morphology and the severe enlarged ductus ampulla. Therefore, the patient underwent an aortic covered stent placement, and successful closure of the PDA was achieved. Eight months after the procedure, the dog was free of clinical signs and no residual flow was identified through the PDA on transthoracic echocardiography. Moreover, computed tomography angiography demonstrated correct stent positioning, with no evidence of thrombus formation, damage to the stent, nor any aortic wall abnormalities. Aortic covered stent placement is a viable option in dogs with unusual PDA morphology.

Adipositas Cordis in Two Cats with Sudden Death.

Adipositas cordis (AC) is a rare cardiomyopathy characterized by fatty infiltration of the myocardium without signs of tissue destruction or inflammation. Its diagnosis is challenging and requires histopathological examination. This study describes such cardiomyopathy in two cats that died suddenly. In both cases, anatomopathological examination showed gross lesions indicative of acute heart failure, associated with an increase in subepicardial fat, particularly in the right ventricle. Microscopically, there was an increased amount of subepicardial and intramyocardial adipose tissue in the right ventricular free wall, without signs of cellular degeneration, inflammatory infiltration, necrosis or fibrosis, confirmed by histochemical staining. AC is a rare cardiac pathology, but it should be taken into consideration in feline medicine when a sudden death occurs.

Surgical embolectomy in a cat with cardiogenic aortic thromboembolism.

A seven-year-old, spayed female, domestic longhair cat was referred for management of a sudden aortic thromboembolism (ATE). Echocardiography showed hypertrophic cardiomyopathy with severe left atrial enlargement. Ultrasonography of the abdominal aorta confirmed a large thrombus at the level of the aortic trifurcation, involving both iliac arteries. Considering the recent onset and bilateral involvement of the iliac arteries, the cat underwent emergent surgical embolectomy (SE) of the aortoiliac embolus. A standard caudal celiotomy was performed and the abdominal aorta was identified. Vessel loops with tourniquets were placed around the abdominal aorta proximal to the thrombus and on both iliac arteries distal to the thrombus. A full-thickness incision was made in the ventral surface of the aorta. The aortic thromboembolus was removed. The trifurcation was subsequently flushed with sterile saline. The SE resulted in a good outcome, with both clinical and ultrasound signs of complete reperfusion of the rear limbs within a few hours. Long-term treatment included antiplatelet drugs, furosemide and benazepril. Eighteen months after surgery, the cat was free of clinical signs, without recurrence of ATE or congestive heart failure. Based on the present case, SE could be considered as a feasible alternative to traditional conservative treatment in cats with a very recent onset of bilateral ATE.

Doppler-derived echocardiographic evidence of pulmonary hypertension in cats with left-sided congestive heart failure.

INTRODUCTION: Pulmonary hypertension (PH) caused by left-sided congestive heart failure (L-CHF) is common in dogs and contributes to clinical signs and outcome. The aim of this study was to evaluate the prevalence of Doppler echocardiography-derived PH in a population of cats with L-CHF. ANIMALS: The study involved 131 cats with L-CHF and 56 control cats. METHODS: The study design is retrospective, observational study. Tricuspid regurgitation velocity, right atrial dimension, right ventricular (RV) dimension and function, RV wall thickness, pulmonary artery (PA) dimension, Doppler-derived systolic time intervals of PA flow, and presence of septal flattening were evaluated. Pulmonary hypertension was considered if tricuspid regurgitation velocity was >2.7 m/s. RESULTS: Tricuspid regurgitation was present in 57/131 (44%) of cats with L-CHF and 24/56 (43%) in control cats based on color flow Doppler. Doppler-derived of PH was identified in 22/131 cats with L-CHF (17%). In 15/22 cats, PH was associated with cardiomyopathy, in 5/22 cases with congenital heart disease, and in 2/22 cases with other causes. Cats with Doppler-derived PH more often had chronic L-CHF, as opposed to acute L-CHF (p<0.05). All cats with Doppler-derived PH had subjectively-assessed right-sided heart enlargement, with larger right atrial and RV diameters (p<0.001), increased RV wall thickness (p<0.05), and higher prevalence of septal flattening (<0.001) and PA enlargement (p<0.05). CONCLUSIONS: Pulmonary hypertension identified by Doppler echocardiography is not a common finding in cats with L-CHF. Right-sided heart enlargement, more frequently observed, may raise the suspicion of PH in cats with L-CHF.

Polyarteritis Nodosa in a Cat with Involvement of the Central and Peripheral Nervous Systems.

An 18-month-old neutered male domestic shorthair cat was referred with a history of pyrexia, polyuria and polydypsia, and transient episodes of bilateral hindlimb paralysis. Cardiac evaluation revealed severe systemic hypertension and severe concentric hypertrophy of the left ventricle. One month later the cat had a new episode of hindlimb paralysis with recurrent seizures, and died in status epilepticus. At necropsy examination, the coronary arteries, arcuate renal arteries and common iliac arteries showed marked thickening with nodules segmentally located along the vessels and consequent narrowing of the lumina. Histologically, acute and chronic inflammatory infiltration of the vascular walls was associated with necrosis of the muscular layer. Lesions were consistent with polyarteritis nodosa and involved the small, medium and large arteries of the heart, kidneys, small and large intestine, mesentery, liver and thyroid. Multifocal meningeal vasculitis associated with focal infarction of the frontal lobe and necrotizing vascular polyneuropathy were detected. Involvement of the central and peripheral nervous systems in polyarteritis nodosa is a novel finding in cats.

Echocardiographic Evaluation of the Right Atrial Area Index in Dogs with Pulmonary Hypertension.

BACKGROUND: Right atrial area (RAA) is a prognostic factor in human patients with pulmonary arterial hypertension (PAH). Reference intervals for RAA have been described in healthy dogs. OBJECTIVES: To evaluate RAA indexed to the body surface area in dogs with PAH as an indicator of right atrial size, PAH severity and right-sided congestive heart failure (R-CHF). ANIMALS: A total of 119 client-owned dogs, 48 dogs with PAH and 71 control dogs. METHODS: Prospective observational study. Pulmonary arterial hypertension was classified according to the tricuspid regurgitation pressure gradient (TRPG) as mild (36-50 mmHg), moderate (51-75 mmHg), or severe (>75 mmHg). The RAA index was calculated as the RAA divided by body surface area. RESULTS: The RAA index was higher in dogs with moderate PAH (13.3 cm2 /m2 ; range, 3.4-24.7 cm2 /m2 ) and severe PAH (12.1 cm2 /m2 ; range, 5.4-21.8 cm2 /m2 ) than in those with mild PAH (6.7 cm2 /m2 ; range, 4.8-10.7 cm2 /m2 ) or in controls (7.3 cm2 /m2 ; range, 4.2-10.2 cm2 /m2 ; P < 0.001). The RAA index was higher (P < 0.0001) in dogs with R-CHF (17.5 cm2 /m2 ; range, 12.7-24.7 cm2 /m2 ) compared to those without R-CHF (7.6 cm2 /m2 ; range, 4.4-19.4 cm2 /m2 ). The most accurate cutoff value of the RAA index to identify R-CHF was >12.3 cm2 /m2 (sensitivity, 100%; specificity, 89.5%). In dogs with PAH, severity of tricuspid regurgitation (TR) was the only independent predictor of RAA index based on multivariate analysis (P < 0.02). CONCLUSIONS AND CLINICAL IMPORTANCE: The RAA index can be used to evaluate right atrial size in dogs and may be more effective than TRPG in predicting R-CHF in dogs with PAH. The severity of TR is the main determinant of the RAA index in dogs with PAH.

Assessment of Lung Ultrasound B-Lines in Dogs with Different Stages of Chronic Valvular Heart Disease.

BACKGROUND: In dogs with chronic valvular heart disease (CVHD), early recognition of pulmonary edema (PE) is of paramount importance. Recent studies in dogs showed that lung ultrasound examination (LUS) is a useful technique to diagnose cardiogenic PE. OBJECTIVES: To describe LUS features in dogs with different stages of CVHD, and to determine its diagnostic accuracy in detecting PE using thoracic radiography as the reference standard. ANIMALS: Sixty-three dogs with CVHD. METHODS: Prospective, multicenter, cross-sectional study. Each dog underwent physical examination, echocardiography, thoracic radiography, and LUS. The LUS findings were classified as absent, rare, numerous, or confluent B-lines. Sensitivity, specificity, and positive and negative predictive values of LUS B-lines to identify PE were calculated using thoracic radiography as the reference standard. RESULTS: Dogs in stage B1 had absent or rare B-lines in 14 of 15 cases (93.3%). Dogs in stage B2 had absent or rare B-lines in 16 of 18 cases (88.9%). All dogs in stage C, without radiographic signs of PE, had absent or rare B-lines. Dogs in stage C, with radiographic signs of PE, had numerous or confluent B-lines in 18 of 20 cases (90%). Lung ultrasound examination detected PE with a sensitivity of 90%, specificity of 93%, and with positive and negative predictive values of 85.7 and 95.2%, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Lung ultrasound examination showed good diagnostic accuracy to identify cardiogenic PE and might be helpful in staging dogs with CVHD. Lung ultrasound examination should be considered as a new, noninvasive diagnostic tool for clinicians managing CVHD in dogs.

Diagnostic accuracy of a smartphone electrocardiograph in dogs: Comparison with standard 6-lead electrocardiography.

The diagnostic accuracy of a smartphone electrocardiograph (ECG) in evaluating heart rhythm and ECG measurements was evaluated in 166 dogs. A standard 6-lead ECG was acquired for 1 min in each dog. A smartphone ECG tracing was simultaneously recorded using a single-lead bipolar ECG recorder. All ECGs were reviewed by one blinded operator, who judged if tracings were acceptable for interpretation and assigned an electrocardiographic diagnosis. Agreement between smartphone and standard ECG in the interpretation of tracings was evaluated. Sensitivity and specificity for the detection of arrhythmia were calculated for the smartphone ECG. Smartphone ECG tracings were interpretable in 162/166 (97.6%) tracings. A perfect agreement between the smartphone and standard ECG was found in detecting bradycardia, tachycardia, ectopic beats and atrioventricular blocks. A very good agreement was found in detecting sinus rhythm versus non-sinus rhythm (100% sensitivity and 97.9% specificity). The smartphone ECG provided tracings that were adequate for analysis in most dogs, with an accurate assessment of heart rate, rhythm and common arrhythmias. The smartphone ECG represents an additional tool in the diagnosis of arrhythmias in dogs, but is not a substitute for a 6-lead ECG. Arrhythmias identified by the smartphone ECG should be followed up with a standard ECG before making clinical decisions.

Keratoconjunctivitis sicca exacerbation in a dog treated with systemic atenolol.

A 6-year-old, intact, male English cocker spaniel was referred for treatment of chronic conjunctivitis and unilateral keratitis. The dog was diagnosed with bilateral immune-mediated keratoconjunctivitis sicca, treated with topical cyclosporine 0·2% ointment and sodium hyaluronate eye drops and improved considerably. After 2 months, pulmonic stenosis was diagnosed, and the dog commenced treatment with oral atenolol; the ophthalmological disease worsened dramatically within a few days. The ophthalmic signs rapidly improved after discontinuation of atenolol, and there was bilateral complete remission after 3 weeks. No oral ß-blocker therapy was reintroduced, and thereafter, keratoconjunctivitis sicca was well-controlled with topical therapy.

Long-term Intrinsic Rhythm Evaluation in Dogs with Atrioventricular Block.

BACKGROUND: Atrioventricular block (AVB) is a conduction abnormality along the atrioventricular node that, depending on etiology, may lead to different outcomes. OBJECTIVES: To evaluate variations of intrinsic rhythm (IR) in dogs that underwent pacemaker implantation (PMI). ANIMALS: Medical records of 92 dogs affected by 3rd degree atrioventricular block (3AVB), advanced 2nd degree AVB (2AVB), paroxysmal 3AVB, 2:1 2AVB, or 3AVB with atrial fibrillation (AF) were retrospectively reviewed. METHOD: The patient IR was documented with telemetry on the day of 1--(95% CI, 1-2), 33--(95% CI, 28-35), 105--(95%CI, 98-156), and 275 days (95%CI, 221-380) after PMI. According to AVB grade at different examinations, AVB was defined as progressed, regressed, or unchanged. RESULTS: In 48 dogs, 3AVB remained unchanged, whereas in 7 it regressed. Eight cases of 2AVB progressed, 3 regressed and 2 remained unchanged. Eight cases of paroxysmal 3AVB progressed and 3 remained unchanged. Four dogs affected by 2:1 2AVB progressed, 2 regressed, and 1 remained unchanged. All cases with 3AVB with AF remained unchanged. Regression occurred within 30 days after PMI, whereas progression was documented at any time. Variations in IR were associated with type of AVB (P < .03) and time of follow-up (P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: The degree of AVB assessed at the time of PMI should not be considered definitive because more than one-third of the cases in this study either progressed or regressed. Additional studies would be necessary to elucidate possible causes for transient AVB in dogs.