Selected hematological, biochemical, and echocardiographic variables as predictors of survival in canine patients with myxomatous mitral valve disease and congestive heart failure.

INTRODUCTION/OBJECTIVES: We investigated the association of breed, age, weight, duration of therapy, and selected blood and echocardiographic variables with the survival of dogs with congestive heart failure (CHF) due to myxomatous mitral valve disease. We also sought to identify differences in selected echocardiographic and routine blood variables between dogs with stable and unstable CHF and between hospitalized and non-hospitalized patients. ANIMALS, MATERIALS AND METHODS: This retrospective study included dogs with a complete cardiovascular workup. Blood analysis and the initial and final echocardiographic results were included. Covariates were analyzed using Cox proportional hazards models. RESULTS: One hundred sixty-five dogs with myxomatous mitral valve disease were evaluated in this study: 96 stable patients and 69 unstable CHF patients. In total, 107 dogs (64.8%) died, and 58 (35.2%) were censored. The median survival time of the dogs that died was 11.5 months (range 11 days to 4.3 years). Unstable CHF patients had significantly higher neutrophils and lower potassium concentrations than stable CHF patients, and hospitalized patients had higher white blood cell, neutrophil, and monocyte counts and urea and creatinine concentrations than non-hospitalized patients. Variables negatively associated with survival were older age, unstable CHF, duration of therapy, white blood cell count, urea concentration, and left atrium to aorta ratio. Chihuahuas had a lower risk of death. CONCLUSIONS: Selected blood and echocardiographic variables distinguish dogs with stable and unstable CHF and predict survival.

Holter monitoring of small breed dogs with advanced myxomatous mitral valve disease with and without a history of syncope.

BACKGROUND: Syncope is a transient loss of consciousness occasionally occurring in dogs with advanced myxomatous mitral valve disease (MMVD). OBJECTIVE: (1) To study ECG changes during syncopal episodes in dogs with advanced MMVD and (2) to compare the occurrence of arrhythmias and changes in heart rate variability (HRV) between dogs with advanced MMVD with and without a history of syncope. ANIMALS: Forty-three privately owned dogs (<15 kg) with advanced MMVD: 21 with and 22 without a history of syncope. METHODS: Prospective study with dogs recruited for an evaluation including history, physical examination, echocardiography, and arrhythmia and HRV analysis performed on 24-hour Holter recordings. RESULTS: A syncopal episode was observed during Holter monitoring in 4 dogs: 3 dogs had sinus rhythm and 1 dog had sinus arrest followed by escape rhythm. An arrhythmia variable representing sinus arrhythmia was significantly lower in dogs with a history of syncope than in those without (P = .008). Eight of 26 HRV variables were significantly different between dogs with and without a history of syncope. CONCLUSIONS AND CLINICAL IMPORTANCE: Compared with dogs without a history of syncope, dogs with advanced MMVD and a history of syncope did not have a higher occurrence of arrhythmias, but had less sinus arrhythmia, and had changes in HRV variables representing decreased overall HRV, decreased parasympathetic, and increased sympathetic modulation of heart rate.

Advanced electrocardiographic parameters change with severity of mitral regurgitation in Cavalier King Charles Spaniels in sinus rhythm.

BACKGROUND: Multiple advanced resting ECG (A-ECG) techniques have improved the diagnostic or prognostic value of ECG in detecting human cardiac diseases even before onset of clinical signs or changes in conventional ECG. OBJECTIVE: To determine which A-ECG parameters, derived from 12-lead A-ECG recordings, change with severity of mitral regurgitation (MR) caused by myxomatous mitral valve disease (MMVD) in Cavalier King Charles Spaniels (CKCSs) in sinus rhythm. ANIMALS: Seventy-six privately owned CKCSs. METHODS: Dogs were prospectively divided into 5 groups according to the degree of MR (estimated by color Doppler mapping as the percentage of the left atrial area affected by the MR jet) and presence of clinical signs. High fidelity approximately 5-minute 12-lead ECG recordings were evaluated using custom software to calculate multiple conventional and A-ECG parameters. RESULTS: Nineteen of 76 ECG parameters were significantly different (P < .05) across the 5 dog groups. A 4-parameter model that incorporated results from 1 parameter of heart rate variability, 2 parameters of QT variability, and 1 parameter of QRS amplitude was identified that explained 82.4% of the variance with a correlation coefficient (R) of 0.60 (P < .01). When age or murmur grade was included in the statistical model the prediction value further increased the R to 0.74 and 0.85 (P < .01), respectively. CONCLUSION: In CKCSs with sinus rhythm, 4 selected A-ECG parameters further improve prediction of MR jet severity beyond age and murmur grade, although the predictive increment in this study probably is not sufficient to warrant utilization in clinical veterinary practice.