Identification and management of a subacute right ventricular perforation by an active-fixation permanent pacemaker lead in a dog.

A 5-year-old short-haired dachshund was referred with a history of repeated syncope associated with a third-degree atrioventricular block. A permanent transvenous pacemaker with an active-fixation lead was implanted. In the following 3 weeks, the syncopal episodes reappeared owing to a loss of ventricular capture. The pacemaker was reprogrammed to higher output, and effective pacing was re-established. Thoracic radiographs and echocardiography failed to identify any evidence of lead displacement. One month later, the patient presented a new episode of loss of capture. After fluoroscopy, cardiac perforation was suspected and subsequently confirmed by thoracotomy. An epicardial pacemaker lead was implanted without removing the perforating lead as there were no bleeding complications or damage to adjacent organs, and the length of time elapsed since implantation was assumed to have allowed for significant fibrotic adhesions to develop. Nineteen months after epicardial pacemaker implantation, endocardial lead dislodgement occurred. Simultaneously, the dog presented with gastrointestinal and respiratory abnormalities and severe thrombocytopenia. Once the dog was stabilized, the endocardial lead was percutaneously removed. One month later, loss of ventricular capture recurred. The owners declined any further treatment, and euthanasia was elected. Cardiac perforation after pacemaker implantation is an infrequent complication. In this case, the dog lived 22 months after subacute right ventricular perforation. Despite the poor prognosis associated with cardiac perforation by pacemaker leads, different approaches are possible to successfully manage this major complication. Extraction of the displaced lead remains controversial as, if the lead is not removed, late lead migration can occur.

Is Wolbachia participating in the bronchial reactivity of cats with heartworm associated respiratory disease?

Heartworm associated respiratory disease is a pulmonary syndrome in cats that results from the vascular and parenchymal inflammatory response associated with the arrival and death of Dirofilaria immitis worms into the distal pulmonary arteries. This parasite harbors intracellular Wolbachia, an endosymbiont bacteria. The association between the parasite and the bacteria is obligatory. Some studies suggest the involvement of Wolbachia in the development of the inflammatory reaction and in the polarization of the host immune response against the parasite. Barometric whole-body plethysmography is a non-invasive pulmonary function test that allows a dynamic study of breathing patterns and is useful to study airway disease and the response to different treatments. The aim of this prospective non-blinded study was to compare the influence of Wolbachia upon the respiratory function variables in a population of cats seropositive to D. immitis by use of Barometric whole-body plethysmography. Fourteen seropositive cats to Wolbachia and eight seronegative cats were put into the plethysmograph chamber and different respiratory variables were measured. The results were analyzed and compared between the two groups of animals. Significant differences were found for bronchoconstriction index variables PAU (pause) (P-value<0.05) and Penh (enhanced pause) (P-value<0.05). The results obtained in our study suggest that Wolbachia seems to produce a greater acute inflammatory response at bronchial, vascular and parenchymal level worsening the state of broncho-reactivity associated with the presence of seropositivity to D. immitis in cats.

Arrhythmogenic right ventricular cardiomyopathy in boxer dogs: a retrospective study of survival.

The aim of the present study was to retrospectively evaluate survival in a population of 62 boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC), without left ventricular systolic failure, based on the following factors: age at diagnosis, presence of syncopal episodes, Holter arrhythmia classification and administered treatment. Medical records of boxer dogs with a diagnosis of ARVC between 2000 and 2010 were reviewed. Results showed that median survival time (MST) was longer in younger ARVC dogs than in the older ones P<0.001). MST was statistically different (P=0.012) between dogs with syncope (365 days) and dogs without syncope episodes (693 days), the probability of death within a year being 4.8 times greater in dogs with syncope (95% CI 1.48 to 15.99) than in dogs without syncope. Regarding Holter classification results, MST was 547.5 days in Holter class-2 dogs and 365 days in Holter class-4 dogs (P=0.030). There were no differences regarding treatment options; MST was 365 days (95% CI 193.615 to 536.4) in the sotalol group, 365 days (95% CI 92.86 to 637.14) in the mexiletine plus atenolol group, and 547.50 days (95% CI 170.45 to 924.55) in the procainamide group (P=0.383). According to this study, the best prognosis is for the younger boxer dog without syncope. There were no differences in survival times in relation to the different treatment options used.

Evaluation of pulmonary function in European land tortoises using whole-body plethysmography.

The aim of this study was to evaluate the use of whole-body plethysmography as a non-invasive method to determine the respiratory parameters and profiles in two tortoise species belonging to the genus Testudo. Pulmonary functions and volumetric parameters were determined in 10 adults of Testudo hermanni and in seven Testudo marginata animals, using whole-body plethysmography. A profile pattern was regularly observed: an inspiratory flow peak, an expiratory peak, an apnoea phase and a second expiratory peak, previous to the beginning of the next respiratory cycle. Positive and significant correlation was observed between the inspiratory time, weight and length of the tortoises. Larger tortoises showed a higher time of inhalation. The peak of inspiratory flow was correlated with the sex, being longer in the females. T. marginata had an inspiratory time longer than that of T. hermanii. In T. hermanii, differences related to the sex were observed in the tidal volume, peak inspiratory flow, peak expiratory flow, expiratory flow of 50 per cent and enhanced pause, which could be related to the smaller size of males. The results suggest that additional information on new technologies currently used in pet medicine or even in human medicine should be developed and adjusted as alternative ways to support the rehabilitation of turtles and tortoises.

Evaluation of pulmonary function variables by using plethysmography in cats with respiratory disease associated to Dirofilaria immitis.

Heartworm Associated Respiratory Disease (HARD) is a pulmonary syndrome that results from the vascular and parenchymal inflammatory response associated with the arrival and death of Dirofilaria immitis in the distal pulmonary arteries. Barometric whole-body plethysmography (BWBP) is a non-invasive pulmonary function test (PFT) that allows a dynamic study of breathing patterns and is useful to study airway disease and the response to different treatments. The aim of this prospective non-blinded study was to compare respiratory function variables between healthy cats and HARD cats (seropositive to D. immitis) by use of BWBP. Twenty-five healthy cats and six HARD cats were put into the plethysmograph chamber and different respiratory variables were measured. The results were analyzed and compared between the two groups of animals. There were significant differences for bronchoconstriction index variables Pause (P-value<0.001) and enhanced pause (P-value<0.001), minute volume (P-value<0.05) and tidal volume (P-value<0.05) between healthy and HARD cats. There were no significant differences in respiratory rate and inspiratory and expiratory times between both groups of animals. The results obtained in our study support that HARD cats show significant differences in pulmonary function variables obtained by BWBP due to an acute inflammatory response at bronchial, vascular and parenchymal level. This PFT could be a useful method to facilitate the diagnosis of pathological states of bronchoconstriction in HARD cats.