Plasma N-terminal pro-brain natriuretic peptide concentrations before and after pericardiocentesis in dogs with cardiac tamponade secondary to spontaneous pericardial effusion.

OBJECTIVE: To determine if concentrations of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) are increased in dogs with cardiac tamponade and if there is a significant increase in plasma NT-proBNP after pericardiocentesis. ANIMALS: Ten client-owned dogs with spontaneous cardiac tamponade. METHODS: Prospective clinical study. Cardiac tamponade was suspected from physical examination and confirmed with echocardiography. Blood was collected and plasma NT-proBNP concentrations were measured before and 30-60 min following pericardiocentesis and resolution of cardiac tamponade. Within-subject changes in plasma NT-proBNP were compared by the Wilcoxon signed-rank test. RESULTS: The plasma NT-proBNP concentrations measured within the reference interval in seven of 10 dogs before pericardiocentesis and in six of 10 dogs following pericardiocentesis. Following pericardiocentesis, there was a statistically significant increase in median NT-proBNP concentration (733 pmol/L, range 250-3,297) compared with the values measured before (643 pmol/L, range 250-3,210, P = 0.004). The NT-proBNP concentration increased in 90% of the dogs following pericardiocentesis. CONCLUSIONS: An upper reference limit of 900 pmol/L for plasma NT-proBNP is insensitive for the diagnosis of pericardial effusion and cardiac tamponade in dogs. Plasma NT-proBNP concentration commonly increases following pericardiocentesis, perhaps related to improved ventricular filling and stretch.

Systolic arterial blood pressure estimated by mitral regurgitation velocity, high definition oscillometry, and Doppler ultrasonography in dogs with naturally occurring degenerative mitral valve disease.

INTRODUCTION: To determine if systolic blood pressure estimated by mitral regurgitation (MR) velocity can be used interchangeably with that estimated by high definition oscillometry (HDO) and Doppler ultrasonography (DU) in dogs with naturally occurring mitral valve disease (MVD). ANIMALS: Forty-nine client-owned dogs with naturally occurring MVD. MATERIALS AND METHODS: This is a retrospective study. Medical records were reviewed and dogs with MR caused by degenerative MVD were included if systolic blood pressure was estimated from MR velocity determined by continuous wave Doppler (CW), DU and HDO at the same visit. A Pearson product moment correlation coefficient was determined for each combination of measures and tested for significance with a paired t-test. Limits of agreement between 2 measures were determined by the 95% confidence interval of the average difference of the means and illustrated by Bland-Altman plots. RESULTS: Systolic pressure estimated from CW was significantly but only moderately correlated to DU (r = 0.42, p=0.0015) and HDO (r = 0.40, p=0.0021). Pressure estimated from DU was significantly but only moderately correlated to HDO (r = 0.57, p≤0.0001). Limits of agreement were wide for all measures including DU and CW (-61.9to 44.6 mmHg), HDO and CW (-65.2to 26.9 mmHg), and HDO and DU (-63.1 to 42.06 mmHg). DISCUSSION: Systolic blood pressure estimated by CW cannot be used interchangeably with HDO or DU in dogs with naturally occurring MVD.

Natural history of arrhythmogenic right ventricular cardiomyopathy in the boxer dog: a prospective study.

BACKGROUND: Boxer arrhythmogenic right ventricular cardiomyopathy (ARVC) is a disease that may result in sudden death or heart failure. HYPOTHESIS/OBJECTIVES: To prospectively study the natural history of Boxer ARVC. ANIMALS: 72 dogs (49 ARVC, 23 controls). METHODS: Boxers >1 year of age were recruited for annual reevaluation. CONTROLS were defined as being ≥6 years of age and having <50 ventricular premature complex (VPCs)/24 h. ARVC was defined as ≥300 VPCs/24 h in the absence of other disease. Dogs were genotyped for the striatin deletion when possible. Descriptive statistics were determined for age; VPC number; annual change in VPC number; and left ventricular (LV) echocardiographic dimensions. Survival time was calculated. RESULTS: Controls: median age of 7 years (range, 6-10); number of VPCs 12 (range, 4-32). Median time in study of 6 years (range, 2-9). Seventeen of 23 were genotyped (5 positive, 12 negative). ARVC: median age of diagnosis of 6 (range, 1-11). Median time in study 5 years (range, 3-8). A total of 33% were syncopal and 43/49 were genotyped (36 positive, 7 negative). Yearly change in VPCs was 46 (range, -7,699 to 33,524). Annual percentage change in LV dimensions was 0, and change in fractional shortening (FS%) was 2%. Two dogs had FS% <20%. Although ARVC dogs died suddenly, there was no difference in survival time between groups. ARVC median age of survival was 11 years, and for controls was 10 years. CONCLUSIONS/CLINICAL IMPORTANCE: Arrhythmogenic right ventricular cardiomyopathy is a disease of middle age and frequently is associated with the striatin deletion. Syncope occurs in approximately 1/3 of affected dogs; systolic dysfunction is uncommon. The prognosis in many affected dogs is good.

Temporal variability of ventricular arrhythmias in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is prevalent in the Boxer. There is little information on the temporal variability of ventricular arrhythmias within affected dogs. OBJECTIVE: To evaluate ambulatory electrocardiograms (AECG) from Boxers with ARVC for hourly variation in premature ventricular complexes (PVC) and heart rate (HR). ANIMALS: One hundred and sixty-two Boxer dogs with ARVC. METHODS: Retrospective, observational study of 1,181 AECGs collected from Boxer dogs at The Ohio State University from 1997 to 2004 was evaluated. The proportion of depolarizations that were PVCs was compared across each hour of the day, during six 4-hour periods of day, to the time after AECG application, and to the maximum and minimum HR. RESULTS: A lower proportion of PVCs was noted during early morning (midnight to 0400 hours) as compared with the morning (0800-1200 hours) and late (1600-2000 hours) afternoon (P= .012). There was no increase in PVC proportion in the 1st hour after AECG application as compared with all other hours of the day (P= .06). There was poor correlation between maximum (rho= 0.19) and minimum (rho= 0.12) HR and PVC proportion. CONCLUSIONS AND CLINICAL IMPORTANCE: The likelihood of PVC occurrence in Boxer dogs with ARVC was relatively constant throughout the day, although slightly greater during the hours of 0800-1200 and 1600-2000. A biologically important correlation with HR was not apparent. The role of autonomic activity in the modulation of electrical instability in the Boxer with ARVC requires further study.

Magnetic resonance imaging of right ventricular morphology and function in boxer dogs with arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a myocardial disease characterized by fibrofatty replacement of the right ventricle and ventricular tachyarrhythmias, reported most commonly in the Boxer dog. Although ARVC is characterized as a myocardial disease, the impact of the disease on the function of the right ventricle has not been well studied. OBJECTIVE: To noninvasively evaluate the function and anatomy of the right ventricle in Boxer dogs with ARVC. ANIMALS: Five adult Boxer dogs with ARVC and 5 healthy size-matched hound dogs. METHODS: Magnetic resonance imaging was performed on an ECG-gated conventional 1.5-T scanner using dark blood imaging and cine acquisitions. Images were evaluated by delineation of endocardial right and left ventricular contours in the end-diastolic and end-systolic phases of each slice. Right and left end-systolic and end-diastolic volumes were generated using Simpson's rule and ejection fraction was calculated. Images were evaluated for right ventricular (RV) aneurysms and wall motion abnormalities. Spin echo images were reviewed for the presence of RV myocardial fatty replacement or scar. RESULTS: RV ejection fraction was significantly lower in Boxers with ARVC compared with the controls (ARVC 34%+/- 11 control 53%+/- 10, P < .01). There was an RV aneurysm in 1 dog with ARVC but not in any of the controls. RV myocardial gross fatty changes were not observed in dogs of either group. CONCLUSIONS AND CLINICAL IMPORTANCE: These findings could be interpreted to suggest that arrhythmias and myocardial dysfunction precede the development of morphological abnormalities in dogs with ARVC.