Clinical use of submaximal treadmill exercise testing and assessments of cardiac biomarkers NT-proBNP and cTnI in dogs with presymptomatic mitral regurgitation

Abstract

Exercise intolerance is the first symptom of heart disease. Yet an objective and standardised method in canine cardiology to assess exercise capacity in a clinical setting is lacking. In contrast, exercise testing is a powerful diagnostic tool in humans, providing valuable information on prognosis and impact of therapeutic intervention. To investigate whether an exercise test reveals differences between dogs with early stage mitral regurgitation (MR) and dogs without cardiac disease, 12 healthy beagles (healthy group, HG) and 12 dogs with presymptomatic MR (CHIEF B1 / B2, patient group, PG) underwent a six-stage submaximal exercise test (ET) on a motorised treadmill. They trotted in their individual comfort speed for three minutes per stage, first without incline, afterwards increasing it by 4% for every subsequent stage. Blood samples were taken at rest and during two 3-minute breaks in the course of the test. Further samples were taken after the completion of the exercise test and again after a 3-hour recovery period. Measured parameters included heart rate, lactate and the cardiac biomarkers N-terminal pro-B-Type natriuretic peptide and cardiac Troponin I. The test was performed again under the same conditions in the same dogs three weeks after the first trial to evaluate individual repeatability. Cardiac biomarkers increased significantly in both HG and PG in the course of the test. The increase was more pronounced in CHIEF B1 / B2 dogs than in the HG. N-terminal pro-B-Type natriuretic peptide increased from 435 ± 195 to 523 ± 239 pmol/L (HG) and from 690 to 815 pmol/L (PG). cTnI increased from 0.020 to 0.024 ng/mL (HG) and from 0.06 to 0.08 ng/ml (PG). The present study provides a method to assess exercise-induced changes in cardiac biomarkers under clinical conditions. The increase of NT-proBNP and cTnI is more pronounced in dogs with early-stage MR than in healthy dogs. Results indicate that measuring the parameters before and after exercise is adequate and taking blood samples between the different stages of the ET does not provide additional information. Also, stress echocardiography was inconclusive. It can be concluded that exercise testing, especially in combination with measuring cardiac biomarkers, could be a helpful diagnostic tool in canine cardiology.

Development of Novel Continuous and Interval Exercise Programs by Applying the FITT-VP Principle in Dogs

“…It is a useful tool to monitor cardiovascular fitness and to prevent overtraining and postexercise fatigue [34,35]. In a Divide R1 W1 R2 W2 R3 W3 R4 W4 R5 Duration of exercise 1 Sec 240 180 300 180 300 180 300 180 240 2,100 Grade 0 1 0 2 0 3 0 4 [22] and to determine cardiac output and maximal oxygen consumption levels, which are the typical indicators of aerobic capacity [36]. In the present study, HR was used as an indicator to verify the primary effect of continuous and interval exercise programs in Beagles.…”

“…In dogs, exercise can cause changes in many physiological parameters. In the studies using Labrador retrievers and Beagles, the incremental treadmill exercise-induced changes in the acute blood lactate, heart rate (HR) [22], and body temperature were reported [23]. Additionally, low-to-high intensity (6% to 20% slope) treadmill exercise considerably affected the physiologic regulators (i.e., cortisol, glucose, and norepinephrine) of both the peripheral and central neuroendocrine systems [24].…”

Effect of Pimobendan on NT-proBNP and c troponin I before and after a submaximal exercise test in dogs with preclinical mitral valve disease without cardiomegaly – a randomised, double-blinded trial

“…In humans and canines, it is released into the circulation four to twelve hours after acute damage [9, 12, 13]. cTnI is not increased in all individuals with mild to moderate DMVD [3, 14].…”

“…In a recent study in which different parameters (cardiac biomarkers NT-proBNP and cTnI, heart rate, lactate, acid-base-status, respiratory frequency, blood gases, echocardiography) were measured in combination with exercise testing in dogs, cardiac biomarkers showed the most reliable results [14]. Therefore, exercise in a standardised submaximal treadmill test (SSET) induces different changes in cardiac biomarkers in healthy dogs and in those animals with asymptomatic DMVD.…”

The effect of telmisartan on the ventricular systolic function in dogs with experimental supraventricular tachyarrhythmia

“…cTnI is a myocardial intracellular protein that is released by damaged and destroyed cardiomyocytes, resulting in greatly elevated concentrations in the blood [32]. Increased levels of cTnI have been reported in dogs with mitral insufficiency [27], filariasis [3], atrioventricular block [29], cardiac hemangiosarcoma [22], and administration of doxorubicin [25]. Therefore, it has been concluded that a high cTnI concentration in the blood is not only caused by infarct necrosis of the cardiomyocytes, but also by a variety of heart lesions that induce myocardial injury [11].…”