Age-dependent electrocardiographic and echocardiographic changes in German Shepherd dogs

Document Type : Full paper (Original article)

Authors

1 Department of Veterinary Medicine, Faculty of Agriculture, University of Novi Sad, Novi Sad, Serbia

2 Department of Equine, Small Animal, Poultry and Wild Animals Diseases, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia

3 Department of Radiology and Radiation Hygiene, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia

Abstract

By causing numerous changes in the cardiovascular system, ageing leads to a decreased threshold for clinical manifestation of heart disease. The aim of this study was to define the existence of cardiac structural and functional changes in healthy dogs of different age. Radiographic, electrocardiographic (ECG) and echocardiographic examinations of 20 clinically healthy German Shepherd dogs were performed in order to define the values of relevant parameters. Afterwards, the values of cardio examinations were compared between young and old dogs and statistically analyzed. The ECG recordings did not show the appearance of clinically significant arrhythmias, nor was their appearance significantly different between dogs of different age. Statistically significant differences in QRS duration (P<0.05) and R wave amplitude (P<0.05) existed between groups, but all values were within the range of ECG reference values for healthy dogs. Concerning structural changes, the left ventricle wall thickness at end-diastole (LVWd) and end-systole (LVWs), and the relative wall thickness (RWT) between young and old dogs differed significantly (P<0.001, P<0.05, P<0.05, respectively). These differences in heart structure were not accompanied by systolic dysfunction, estimated by a left ventricle shortening fraction. The diastolic wall stress index (WSID) was significantly decreased in old dogs (P<0.05). Young and old dogs showed similar electrical and systolic function. Old dogs had different cardiac structure compared to the young dogs, which could result in diastolic function change.

Keywords


Aurigemma, GP and Gaasch, WH (2007). Quantitative evaluation of left ventricular structure, wall stress and systolic function. In: Otto, CM (Ed.), The practice of clinical echocardiography. (3rd Edn.), Philadelphia, Saunders. PP: 187-212.
Bonagura, JD (1981). Cardiopulmonary disorders in the geriatric dog. Vet. Clin. North. Am. (Small Anim. Pract.), 11: 705-726.
Buchanan, JW and Bücheler, J (1995). Vertebral scale system to measure canine heart size in radiographs. JAVMA. 206: 194-199.
Edwards, NJ (1987). Interpreting the electrocardiogram. In: Pedersen, D (Ed.), Bolton’s handbook of canine and feline electrocardiography. (2nd Edn.), Philadelphia, W. B. Saunders. PP: 32-60.
Egenvall, A; Bonnett, BN; Hedhammar, A and Olson, P (2005). Mortality in over 350000 insured Swedish dogs from 1995-2000: I. breed-specific age and survival patterns and relative risk for cause of death. Acta Vet. Scand., 46: 121-136.
Eichelberg, H and Seine, R (1996). Life expectancy and cause of death in dogs. I: The situation in mixed breeds and various dog breeds. Berl. Munch. Tierarztl., 109: 292-303.
Fleming, JM; Creevy, KE and Promislow, DEL (2011). Mortality in North American dogs from 1984 to 2004: an investigation into age-, size-, and breed-related causes of death. J. Vet. Intern. Med., 25: 187-198.
Foppa, M; Duncan, BB and Rohde, LEP (2005). Echocardiography-based left ventricular mass estimation. How should we define hypertrophy. Cardiovasc. Ultrasound. doi: 10.1186/1476-7120-3-17.
Gan, TY; Qiao, W; Xu, GJ; Zhen, XH; Tang, BP; Song, JG; Li, YD; Zhang, Y; Li, FP; Mao, T and Jiang, T (2013). Aging-associated changes in L-type calcium channels in the left atria of dogs. Exp. Ther. Med., 6: 919-924.
Ganau, A; Devereux, RB; Roman, MJ; DeSimone, G; Pickering, TG; Saba, PS; Vargin, P; Simongini, I and Laragh, JH (1992). Patterns of left ventricular hypertrophy and geometric remodeling in essential hypertension. J. Am. Coll. Cardiol., 19: 1550-1558.
Haidet, GC (1993). Effects of age on beta-adrenergic-mediated reflex responses to induced muscular contraction in beagles. Mech. Ageing Dev., 68: 89-104.
Haidet, GC; Wennberg, PW; Finkelstein, SM and Morgan, DJ (1996). Effects of aging per se on arterial stiffness: systemic and regional compliance in beagles. Am. Heart J., 132: 319-327.
Hamlin, RL (2005). Geriatric heart diseases in dogs. Vet. Clin. North Am. (Small Anim. Pract.), 5: 597-617.
Hamlin, RL and Patterson, DF (1977). Standards for canine electrocardiography. The Academy of Veterinary Cardio-logy Committee Report 1977. The Academy of Veterinary Cardiology.
Kayar, A; Gonul, R; Or, ME and Uzsal, A (2006) M-mode echocardiographic parameters and indices in the normal German Shepherd dog. Vet. Radiol. Ultrasound. 47: 482-486.
Kienle, RD (1998). Echocardiography. In: Kittleson, MD and Kienle, RD (Eds.), Small animal cardiovascular medicine. (1st Edn.), St. Louis, Mosby. PP: 95-117.
Kim, SH; Lee, KH; Won, HY; Park, S; Chung, JH; Jang, Y and Ha, JW (2013). Quantitative assessment of aortic elasticity with aging using velocity-vector imaging and its histologic correlation. Arterioscler. Thromb. Vasc. Biol., 33: 1306-1312.
Lakatta, EG and Levy, D (2003). Arterial and cardiac aging: major shareholders in cardiovascular disease enterprises. Part II: The aging heart in health: link to heart disease. Circulation. 107: 346-352.
Lamb, CR; Tyler, M; Boswood, A; Skelly, BJ and Cain, M (2000). Assesment of the value of the vertebral heart scale in the radiographic diagnosis of cardiac disease in dogs. Vet. Rec., 146: 687-690.
Lamb, CR; Wikeley, H; Boswood, A and Pfeiffer, DU (2001). Use of breed specific ranges for the vertebral heart scale as an aid to the radiographic diagnosis in dogs. Vet. Rec., 148: 707-711.
Li, L; Shigematsu, Y; Hamada, M and Hiwada, K (2001). Relative wall thickness is an independent predictor of left ventricular systolic and diastolic dysfunctions in essential hypertension. Hypertens. Res., 24: 493-499.
Miller, CW; Nealeigh, RC and Crowder, ME (1976). Evaluation of the cardiovascular changes associated with aging in a colony of dogs. Biomed. Sci. Instrum., 12: 107-110.
Minors, SL and O’Grady, MR (1998). Resting and dobu-tamine stress echocardiography factors associated with the development of occult dilated cardiomyopathy in healthy Doberman Pincher dogs. J. Vet. Intern. Med., 12: 369-380.
Morrison, SA; Moise, NS; Scarlett, J; Mohammed, H and Zeager, AE (1992). Effect of breed and bodyweight on ehocardiographic values in four breeds of dogs of differing somatotype. J. Vet. Intern. Med., 6: 220-224.
Muzzi, RAL; Muzzi, LAL; deAraujo, RB and Cherem, M (2006). Echocardiographic indices in normal German Shepherd dogs. J. Vet. Sci., 7: 193-198.
Redfield, MM; Jacobsen, SJ; Borlaug, BA; Rodeheffer, RJ and Kass, DA (2005). Age- and gender-related ventricular-vascular stiffening. Circulation. 112: 2254-2262.
Rezakhani, A; Atwell, RB and Webster, J (1990). Electro-cardiographic value of German Shepherd dogs. Aust. Vet. J., 67: 307-309.
Sahn, DJ; DeMaria, A; Kisslo, J and Weyman, A (1978). Recommendations regarding quantitation in M-mode echo-cardiography: results of a survey of echocardiographic measurements. Circulation. 58: 1072-1083.
Saunders, AB (2012). The diagnosis and management of age-related veterinary cardiovascular disease. Vet. Clin. North Am. (Small Anim. Pract.), 42: 655-658.
Savage, DD; Garrison, RJ; Kannel, WB; Levy, D; Anderson, JJ; Stones, JIII; Feinleib, M and Castell, WP (1987). The spectrum of left ventricular hypertrophy in a general population sample: the Framingham study. Circulation. 75: 125-133.
Sjogren, AL (1971). Left ventricular wall thickness determined by ultrasound in 100 subjects without heart disease. Chest. 60: 341-346.
Spasojević Kosić, Lj; Trailović, D and Krstić, N (2007). Comparison of three methods of measurement vertebral heart size in German Shepherd dogs. Acta Vet., 57: 133-141.
Strasser, A; Simunek, M; Seiser, M and Hofecker, NG (1997). Age-dependent changes in cardiovascular and metabolic responses to exercise in beagle dogs. Zentrabl. Veterinarmed., 44: 449-460.
Suzuki, R; Matsumoto, H; Testima, T and Koyama, H (2013). Effect of age on myocardial functional assessed by two-dimensional speckle-tracking echocardiography in healthy beagle dogs. J. Vet. Cardiol., 15: 243-252.
Templeton, GH; Willerson, JT; Platt, MR and Wiesfeldt, M (1976). Contraction duration and diastolic stiffness in aged canine left ventricle. Recent Adv. Stud. Card. Struct. Metabol., 11: 169-173.
Templeton, GH; Willerson, JT; Platt, MR and Wiesfeldt, ML (1979). Influence of aging on left ventricular hemo-dynamics and stiffness in beagles. Circ. Res., 44: 189-194.
Xu, GJ; Gan, TY; Tang, BP; Chen, ZH; Mahemuti, A; Jiang, T; Song, JG; Guo, X; Li, YD; Zhen, XH; Zhang, Y and Li, JX (2013a). Alterations in the expression of atrial calpains in electrical and structural remodeling during aging and atrial fibrillation. Mol. Med. Rep., 8: 1343-1352.
Xu, GJ; Gan, TY; Tang, BP; Chen, ZH; Mahemuti, A; Zhen, XH; Jiang, T; Song, JG; Guo, X; Li, YD; Miao, HJ; Zhang, Y and Li, J (2013b). Changes in microRNAs expression are involved in age-related atrial structural remodeling and atrial fibrillation. Chin. Med. J., 126: 1458-1463.