Physiologic VDD Versus Nonphysiologic VVI Pacing In Canine 3rd-Degree Atrioventricular Block

Abstract

Historically, ventricular demand, nonphysiologic (VVI) pacing has been the most commonly used modality to treat 3rd-degree atrioventricular (AV) block. The goal of this study was to determine the feasibility of using a commercial, single-lead, physiologic (VDD) pacemaker in dogs with 3rd-degree AV block. Furthermore, we hoped to characterize and identify differences in the radiographic, echocardiographic, neurohormonal, and quality of life consequences of physiologic versus nonphysiologic pacing. We evaluated 10 dogs during a 12-week crossover study. Acutely, rate-matched physiologic pacing reduced pulmonary capillary wedge pressure by 19% compared with nonphysiologic pacing. VDD pacing significantly reduced left atrial size normalized to body weight, left atrial-to-aortic root ratio, and left ventricular end-systolic dimension and increased fractional shortening, aortic Doppler velocity, cardiac output, and stroke volume compared with VVI pacing. Variable rate VDD pacing resulted in a significantly slower heart rate (HR) during echocardiography than fixed-rate (100 bpm) VVI pacing. AV synchronous pacing reduced circulating N-terminal proatrial natriuretic peptide (ANP), norepinephrine (NOR), and epinephrine (EPI) concentrations compared with asynchronous pacing. There were no significant differences in systemic blood pressure, thoracic radiographs, or owner-perceived quality of life. The median percentage of AV synchronous pacing during the VDD modality was 99.8% (range, 1.2 to 99.9%). This study confirms the potential to achieve physiologic pacing with a commercial, single-lead system in dogs. VDD pacing improved hemodynamics and neurohormonal profiles over asynchronous pacing although the long-term clinical benefits of these changes remain to be determined.

English springer spaniels with significant bradyarrhythmias—presentation, troponin I and follow‐up after pacemaker implantation

“…Persistent elevation of cTnI blood concentrations suggest irreversible and sustained myocardial cell damage (Stanton and others 2005, O'Brien and others 2006, Wells 2008). Progressive underlying disease or myocardial damage due to non‐physiological cardiac contraction from single chamber pacing are also possible causes for the continued elevation in cTnI levels (Frias and others 2003, Bulmer and others 2006, Hildebrandt and others 2009).…”

Permanent dual chamber epicardial pacemaker implantation in two dogs with complete atrioventricular block

“…17 The use of transvenous dual chamber pacemaker systems has been reported in veterinary medicine in various publications. 6,18,19 The use of a dual chamber single lead VDD system has been shown to significantly improve hemodynamics and neurohormonal parameters with a complication rate comparable to single chamber ventricular pacing in dogs. 18,19 There are currently no available long-term survival data on dogs with dual chamber systems.…”

Use of transcutaneous external pacing during transvenous pacemaker implantation in dogs

“…Sisson and others (1991), Oyama and others (2001), Wess and others (2006), Johnson and others (2007) and Hildebrandt and others (2009) used TTP in 10 per cent (four of 40), 46 per cent (69 of 154), 82 per cent (78 of 105), 50 per cent (52 of 104) and 24 per cent (eight of 33) of dogs that underwent PMI, respectively. There are also some reports on the use of TTP during PMI in single cases (Lombard and Buchanan 1976, Flanders and others 1999, Bulmer and others 2006, Saunders and others 2007). In addition, Darke and others (1989) attached temporary pacing leads to permanent pacing leads to perform external pacing.…”