P wave dispersion and cardiac troponin I concantration in canine visceral leishmaniasis

Canine Visceral Leishmanisis (CVL) is mostly fatal chronic systemic disease caused by Leishmania infantum (L. infantum) in the Old World countries. In infection, dogs plays both host and reservoir role. By this context, infected dogs are a threat to both people and other dogs. In dogs infected with L. infantum, cardiac involvement in addition to the other affected organs and systems were also reported in the updated literatures. In the present study, the aim was to clinically evaluate the probable cardiac damage in dogs with CVL according to its stage via measuring atrial conduction time by use of Pd determined within computerized electrocardiography and cardiac troponin I (CTnI) level. A total of 24 dogs, of both sexes and various ages, referred with one or more of the clinical findings such as hypertrichosis, periocular alopecia, weight loss, onychogryphosis, skin lesions (severe scaling, exfoliative dermatitis compatible with alopecia) and/or anorexia, lymphadenopathy, hepatosplenomegaly. In the healthy control group for comparison and in dogs with CVL to determine presence, nature and level of cardiac damage, the evaluations were performed with computerized 12-lead ECG device [(1 mV/cm amplitude in resting and 50 mm/sec) (Pd measurement)] and serum CTnI concentrations were measured by using species specific commercial test kit. Eighteen dogs infected with CVL (IFAT positive) with/without different clinical sign were enrolled into three different groups (n=6); of the above mentioned clinical sign, to those of which with single clinical sign (oligosymptomatic) were included in the group I; those with multiple or several clinical signs (polysymptomatic) were included in the group II; and asymptomatic dogs were included group III. CVL-negative healthy dogs without any disease were left in group IV. High levels of cTnI concentration were detected in 10 of 18 dogs infected CVL with all polysymptomatic dogs. In all cases of the control group, cTnI levels were in the reference range [<0.03 ng/dL]. Even the comparison of each groups, no statistically significance (p>0.05) was found between CVL positive and control dogs. Mean ± standard deviation of Pd values were 22.76±3.12, 22.03±0.80, 22.73±0.80 and 25.67±1.41 in the control group, asymptomatic group, oligosymptomatic group, and polysymptomatic group, respectively. In comparison between groups, polysymptomatic group was significantly different than control (p = 0.026), asymptomatic (p = 0.012) and oligosymptomatic (p = 0.027) groups. As myocarditis and arrhythmias may occur in both humans and dogs with Leishmaniasis, in an attempt to evaluate ECG changes, especially assessing combination of Pd and cTnI concentration, is essential. In this study, the evaluation of this two parameters together, especially the assessment made according to stages in infected dogs CVL, is important. In human medicine, serum cTnI concentrations is used as an important marker to detect myocardial ischemia and necrosis, and it may also be reported that this parameter have high sensitivity and specificity in animals with primary or secondary cardiac disorders. Although a statistically significant difference was not found between CVL positive and control dogs in the present study, it was suggested that the individual increase may be associated with myocarditis due to disease. Besides, it may be claimed that the mean Pd values determined in especially polysymptomatic dogs was higher compared to the control group, whereas this may be accepted in the reference ranges based on mean Pd values reported in healthy dogs. However considering infected dogs population as 6 in each group, it may be safely claimed that further investigations regarding greater number of cases the may be warranted.