Non-deflating balloon during pulmonary valvuloplasty.

A 3-year-old, 4.8 kg, male intact, mixed breed dog was referred for balloon pulmonary valvuloplasty (BPV). Echocardiography was consistent with severe type A pulmonic stenosis and BPV was recommended. During BPV, the balloon catheter failed to deflate despite multiple attempts at repositioning and the use of different deflation syringes. After approximately two minutes of cardiopulmonary arrest, forceful retrograde traction resulted in removal of the fully inflated balloon. Cardiopulmonary resuscitation was unsuccessful. Post-mortem evaluation by a board-certified pathologist identified rupture of the cranial vena cava and hemothorax, suspected to be secondary to forceful removal of the fully inflated balloon. Manufacturer's evaluation of the balloon catheter used in the procedure identified multiple kinks and a segment of stretched catheter shaft suspected to be the cause for the inability to deflate. A manufacturing defect present prior to use or predisposing to stretching of the catheter segment could not be ruled out. Kinking and/or stretching of the catheter during BPV were possible causes as well. Although the inability to deflate a balloon catheter seems to be a very rare occurrence, it should be considered as a potential complication of BPV.

Heart rate distribution in dogs with third degree atrioventricular block and rate responsive pacemakers.

INTRODUCTION: In dogs, single lead ventricular pacing, ventricular sensing, inhibition response, rate adaptive (VVIR) pacemakers are routinely used to treat third degree atrioventricular block. The objectives of this study were to investigate the heart rate distribution in dogs with VVIR pacemakers, and report changes when activity settings were adjusted. ANIMALS: Eighteen client-owned dogs with VVIR pacemakers for third degree atrioventricular block. MATERIALS AND METHODS: This observational study consisted of a review of medical records of dogs with VVIR pacemakers. For dogs with >50% of paced beats at the lower pacing rate, the activity daily living (ADL) and exertion responses were increased. Re-evaluations were performed after 6-12 months. RESULTS: Heart rate distribution similar to healthy dogs was absent for all dogs. In nine dogs, the ADL and exertion responses were increased to the highest level. Of these, three dogs showed no improvement in heart rate distribution; for two dogs, one with an epicardial pacemaker, several activity settings were adjusted and pacing at higher heart rates was observed at re-evaluation. Four dogs died or were lost to follow-up. Clinical signs had resolved for all dogs after pacemaker implantation. CONCLUSION: Default activity settings of VVIR pacemakers do not result in heart rate distribution equivalent to healthy dogs. Increasing the ADL and exertion response settings to the highest levels did not improve the pacemaker rate response. Further investigations into the role of dog size, generator positioning, pacemaker settings, and whether rate responsiveness is required for dogs' quality and quantity of life are warranted.

Total bilirubin is an independent predictor of death in dogs with degenerative valvular disease and dilated cardiomyopathy.

INTRODUCTION: There is little published regarding the association between canine cardiovascular disease and the hepatic system. The objective of the study was to evaluate the relationship between hepatic parameters, survival, and disease stages of dogs with either dilated cardiomyopathy (DCM) or degenerative valvular disease (DVD). ANIMALS, MATERIALS, AND METHODS: Retrospective study analyzing hepatic parameters in dogs with DVD or DCM in American College of Veterinary Internal Medicine stage B or C and healthy control dogs. Associations between liver parameters, type and stage of disease, and survival were investigated. RESULTS: Ninety-nine dogs were included in the study: 61 DVD, 22 DCM, and 16 controls. Differences in liver parameter concentrations between DCM, DVD, and disease stages were found. Univariate analysis identified alanine aminotransferase (P < 0.001), aspartate aminotransferase (P = 0.02), and total bilirubin (P = 0.005) as predictors of mortality. In the multivariate analysis, total bilirubin remained an independent predictor of mortality. CONCLUSIONS: The observed differences between DCM, DVD, and disease stages are likely consistent with disease-specific hemodynamics and progression of disease. This and the role of total bilirubin as an independent predictor for mortality indicate that in dogs with DVD and DCM the cardiovascular-hepatic interaction might be of relevance for disease progression and outcome, as reported for humans with cardiac disease. Further studies into the role of hepatic function in canine cardiac disease are required.

Characteristics and outcomes of cats with and without pacemaker placement for high-grade atrioventricular block.

INTRODUCTION: Available information on characteristics and outcome in cats with high-grade atrioventricular block (AVB) that receive a pacemaker is limited. ANIMALS: Twenty-two privately owned cats presenting with high-grade AVB. MATERIALS AND METHODS: Medical records were retrospectively examined. Cats were grouped as having received a pacemaker (PACE group) or not having received a pacemaker (non-PACE group). Clinical characteristics and outcomes of groups were evaluated. RESULTS: There were 10 cats in the PACE group and 12 cats in the non-PACE group. At presentation, syncope or seizure-like behavior (p = 0.004) and bradycardia (p = 0.043) were more common in the PACE than the non-PACE group. Historical lethargy (p = 0.015) and dull mentation (p = 0.045) were more common in the non-PACE group, as was clinically relevant systemic disease. Pacemaker placement improved syncope or seizure-like behavior in 100% of cats. The degree of AVB at presentation was not associated with pacemaker placement nor the future degree of AVB. The major complication rate of pacemaker placement was 40%. Intergroup survival was not significantly different (PACE group 1278 days, 95% confidence interval: 0-2145 days; non-PACE group 213 days, confidence interval: 1-not available, p = 0.77). CONCLUSIONS: Pacemaker placement improved clinical signs in cats with high-grade AVB. A difference in survival time could not be demonstrated between cats that received and did not receive a pacemaker in this retrospective study. High-grade AVB can be transient and accompanied by systemic disease in some cats.

Echocardiographic parameters for the assessment of congestive heart failure in dogs with myxomatous mitral valve disease and moderate to severe mitral regurgitation.

The objective of this study was to evaluate the influence of congestive heart failure (CHF) on echocardiographic variables in dogs with moderate or severe mitral valve regurgitation (MR) secondary to myxomatous mitral valve disease (MMVD). The secondary objective was to investigate the preliminary use of left ventricular early inflow-outflow index (LVEIO) and L-waves as indicators of CHF. Forty-five dogs with moderate or severe MR without (n = 23) or with (n = 22) CHF were retrospectively included. Echocardiographic variables of elevated left ventricular (LV) filling pressures and cardiac function, LVEIO and the presence of L-waves were obtained and statistically compared between the two groups. On general linear model analysis, mitral inflow peak E-wave velocity, E:A ratio, ratio of E to isovolumic relaxation time (IVRT) and LVEIO were increased, while left atrium (LA) fractional shortening was reduced, in dogs with CHF. Peak E-wave velocity, peak A-wave velocity, E:A ratio, LA minimum diameter, LA diameter before the P-wave, LA fractional shortening and LVEIO were found to be predictive of CHF. The absence of L-waves indicated a reduced risk of CHF. Several echocardiographic variables may be useful in identifying elevated LV filling pressures, consistent with CHF, in dogs with moderate and severe MR. Left ventricular early inflow-outflow index and L-waves might be of interest as clinical and prognostic markers in dogs with MMVD and require further investigation.