238 AJVR, Vol 66, No. 2, February 2005 R emodeling of the left ventricle with changes in ventricular geometry, an increase in stress on the ventricular wall, and an increase in oxygen con- sumption by the myocardium is a result of the pro- gression and pathogenesis of heart failure in affected patients. 1,2 The definitive treatment is cardiac trans- plantation. However, it is not always an available option because of the shortage of donors and limita- tions on the ability of a transplanted heart to adapt to its new host. 3 A novel surgical concept has been introduced to treat patients with end-stage cardiomyopathies by reducing the size of the remodeled left ventricle. 2,4 The surgery, partial left ventriculectomy, is based on Laplace’s law in which reduction of the size of the left ventricular chamber decreases stress on the wall of the left ventricle and improves left ventricular systolic function. 4–6 However, clinical applications of this pro- cedure are limited by a high mortality rate in the early postoperative period and high morbidity rate in the late postoperative period. 7 Good preliminary results have been reported 8 for an alternative technique to resection of poten- tially viable myocardium; that technique involves plication of the papillary muscles through a small incision in the apex of the left ventricle. Another technique for left ventricular reduction involved pli- cation of akinetic ventricular areas in rats with ischemic cardiomyopathy, 3 but initial improvement of left ventricular function by use of that technique was maintained for only 4 weeks. Furthermore, a device a has been used to change the shape of the left ventricle, decrease left ventricular stress, and improve left ventricular function in dogs with heart failure induced by rapid electrocardiac pacing. 2 However, that device will need to be evaluated in patients with dilated hearts. Plication of the left ventricular free wall decreases diameter of the left ventricle in dogs without the need for cardiopulmonary bypass. 9 The objective of the study reported here was to investigate the effects of plication of the free wall of the left ventricle on left ventricular func- tion of dogs with doxorubicin-induced cardiomyopathy. Materials and Methods Animals—Eight adult mixed-breed dogs (mean ± SE body weight, 14.3 ± 3.2 kg) were evaluated to ensure that the dogs were healthy and cardiac size and function were typical for the species. Evaluations included physical examination, electrocardiography, CBC count, serum biochemical analysis, and echocardiography. The study was approved by an insti- Received March 14, 2004. Accepted June 24, 2004. From the Programa de Pós-graduação em Cirurgia Veterinária (Andrade, Santos, Fantinatti), and the Departamento de Clínica e Cirurgia (Camacho, Nunes), Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Campus de Jaboticabal, São Paulo, Brazil; and the Departamento de Cirurgia, FMVZ-Universidade de São Paulo, São Paulo, Brazil (Stopiglia). Dr Andrade’s present address is R. Dep. Atílio de Almeida Barbosa, 927–CEP, Curitiba, PR 82560-460, Brazil. Supported by the Fundação de Amparo à Pesquisa no Estado de São Paulo. Presented in part at the 30th National Congress of Cardiac Surgery, Goiânia, Brazil, April 2003. Address correspondence to Dr. Andrade. Plication of the free wall of the left ventricle in dogs with doxorubicin-induced cardiomyopathy James N. B. M. de Andrade, DVM, PhD; Aparecido A. Camacho, DVM, PhD; Paulo S. P. Santos, DVM, PhD; Alexandra P. Fantinatti, DVM, PhD; Newton Nunes, DVM, PhD; Angelo J. Stopiglia, DVM, PhD Objective—To evaluate plication of the free wall of the left ventricle, which reduces the left ventricular area and volume, as a method to improve the left ven- tricular systolic function without cardiopulmonary bypass. Animals—8 mixed-breed adult dogs. Procedure—Dilated cardiomyopathy (DCM) was induced in each dog by administration of doxorubicin (30 mg/m 2 , IV, q 21 d for 168 days). Two dogs died dur- ing induction of cardiomyopathy. Plication surgery was performed in 4 dogs. Two dogs did not ondergo to surgery (control group). Values for cardiac output (CO), 2-dimensional and M-mode echocardiography, arterial blood pressure, electrocardiography, blood cell counts, and serum biochemical analyses were record- ed after induction of DCM (baseline) and 1, 2, 7, 15, 21, 30, 60, 90, 120, 150, and 180 days after plication surgery. Ambulatory ECG (Holter) recordings were conducted for 24 hours on the day of surgery. Results—1 dog died after plication surgery. The remaining dogs undergoing ventricular plication had a significant improvement in CO, ejection fraction, and fractional shortening and reductions of left ventricular area and volume after surgery. Electrocardiographic and Holter recordings revealed premature ventricular complexes, which resolved without treatment during the first week after surgery. Clinical condition of the control dogs declined, and these 2 dogs died approx- imately 40 days after induction of cardiomyopathy. Conclusions and Clinical Relevance—Plication of the free wall of the left ventricle improved left ven- tricular systolic function in dogs with doxorubicin- induced cardiomyopathy. Additional studies are need- ed to evaluate its application in dogs with naturally developing DCM. (Am J Vet Res 2005;66:238–243) Unauthenticated | Downloaded 08/14/22 02:59 PM UTC