Effects of endurance training on standard and signal-averaged electrocardiograms of sled dogs

Constable, Peter D.; Hinchcliff, Kenneth W.; Olson, J.; Stepien, Rebecca L.

doi:10.2460/ajvr.2000.61.582

Cited by 27 publications

(27 citation statements)

References 33 publications

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“…Commonly, exercise may cause a decrease in heart rate and increased ventricular relaxation which presents as longer QT intervals. A study investigating the effects of a seven month endurance training program in dogs revealed an increase in QT intervals [52]. An acute resistance exercise resulted in a similar effect on QT c intervals [53].…”

Section: Discussionmentioning

confidence: 99%

Electrocardiographic changes with the onset of diabetes and the impact of aerobic exercise training in the Zucker Diabetic Fatty (ZDF) rat

VanHoose

Sawers

Loganathan

et al. 2010

Cardiovasc Diabetol

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BackgroundEarly markers of diabetic autonomic neuropathy (DAN) in an electrocardiogram (ECG) include elevated R wave amplitudes, widening of QTc intervals and decreased heart rate variability (HRV). The severity of DAN has a direct relationship with mortality risk. Aerobic exercise training is a common recommendation for the delay and possible reversal of cardiac dysfunction. Limited research exists on ECG measures for the evaluation of aerobic exercise training in Zucker Diabetic Fatty (ZDF) rat, a model of type 2 diabetes. The objective of this study was to assess whether aerobic exercise training may attenuate diabetes induced ECG changes.MethodsMale ZDF (obese fa/fa) and control Zucker (lean fa/+) rats were assigned to 4 groups: sedentary control (SC), sedentary diabetic (SD), exercised control (EC) and exercised diabetic (ED). The exercised groups began 7 weeks of treadmill training after the development of diabetes in the ED group. Baseline (prior to the training) and termination measurements included body weight, heart weight, blood glucose and glycated hemoglobin levels and ECG parameters. One way repeated measures ANOVA (group) analyzed within and between subject differences and interactions. Pearson coefficients and descriptive statistics described variable relationships and animal characteristics.ResultsDiabetes caused crucial changes in R wave amplitudes (p < 0.001), heart rate variability (p < 0.01), QT intervals (p < 0.001) and QTc intervals (p < 0.001). R wave amplitude augmentation in SD rats from baseline to termination was ameliorated by exercise, resulting in R wave amplitude changes in ED animals similar to control rats. Aerobic exercise training neither attenuated QT or QTc interval prolongation nor restored decreases in HRV in diabetic rats.ConclusionThis study revealed alterations in R wave amplitudes, HRV, QT and QTc intervals in ZDF rats. Of these changes, aerobic exercise training was able to correct R wave amplitude changes. In addition, exercise has beneficial effect in this diabetic rat model in regards to ECG correlates of left ventricular mass.

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Section: Discussionmentioning

confidence: 99%

Electrocardiographic changes with the onset of diabetes and the impact of aerobic exercise training in the Zucker Diabetic Fatty (ZDF) rat

VanHoose

Sawers

Loganathan

et al. 2010

Cardiovasc Diabetol

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show abstract

“…29 Both inhibition of the parasympathetic and activation of the sympathetic nervous system act to increase heart rate and strength of contraction during exercise. 37,38 Murmurs evident on auscultation are frequently heard in highly trained dogs compared with untrained dogs. Venous return to the heart enhances vagal tone and causes left-and right-ventricular enlargement.…”

Section: Cardiovascular Systemmentioning

confidence: 99%

“…Changes such as physiologic murmurs, bradyarrhythmias, and cardiac chamber enlargement are thought to be associated with cardiac adaptations to sustained endurance exercise and not pathologic conditions. 38 Hypertrophy of the canine heart as a result of endurance training is believed to be a reversible event. 37,38 Murmurs evident on auscultation are frequently heard in highly trained dogs compared with untrained dogs.…”

Section: Cardiovascular Systemmentioning

confidence: 99%

Exercise Physiology of the Canine Athlete

Millard¹

2014

Canine Rehabilitation and Physical Therapy

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“…not in mice and rats. Some of these studies observed slowed heart rate, prolonged QT interval and ECG signs of cardiac hypertrophy in such animals [43], [44]. Whether a ventricular electrical remodeling leading to decreased repolarization reserve develops in these animals is not known, however, it has been speculated that in top endurance athletes, downregulation of potassium channels might occur [45].…”

Section: Discussionmentioning

confidence: 99%

Increased Short-Term Variability of the QT Interval in Professional Soccer Players: Possible Implications for Arrhythmia Prediction

et al. 2011

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BackgroundSudden cardiac death in competitive athletes is rare but it is significantly more frequent than in the normal population. The exact cause is seldom established and is mostly attributed to ventricular fibrillation. Myocardial hypertrophy and slow heart rate, both characteristic changes in top athletes in response to physical conditioning, could be associated with increased propensity for ventricular arrhythmias. We investigated conventional ECG parameters and temporal short-term beat-to-beat variability of repolarization (STVQT), a presumptive novel parameter for arrhythmia prediction, in professional soccer players.MethodsFive-minute 12-lead electrocardiograms were recorded from professional soccer players (n = 76, all males, age 22.0±0.61 years) and age-matched healthy volunteers who do not participate in competitive sports (n = 76, all males, age 22.0±0.54 years). The ECGs were digitized and evaluated off-line. The temporal instability of beat-to-beat heart rate and repolarization were characterized by the calculation of short-term variability of the RR and QT intervals.ResultsHeart rate was significantly lower in professional soccer players at rest (61±1.2 vs. 72±1.5/min in controls). The QT interval was prolonged in players at rest (419±3.1 vs. 390±3.6 in controls, p<0.001). QTc was significantly longer in players compared to controls calculated with Fridericia and Hodges correction formulas. Importantly, STVQT was significantly higher in players both at rest and immediately after the game compared to controls (4.8±0.14 and 4.3±0.14 vs. 3.5±0.10 ms, both p<0.001, respectively).ConclusionsSTVQT is significantly higher in professional soccer players compared to age-matched controls, however, further studies are needed to relate this finding to increased arrhythmia propensity in this population.

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Effects of endurance training on standard and signal-averaged electrocardiograms of sled dogs

Cited by 27 publications

References 33 publications

Electrocardiographic changes with the onset of diabetes and the impact of aerobic exercise training in the Zucker Diabetic Fatty (ZDF) rat

Electrocardiographic changes with the onset of diabetes and the impact of aerobic exercise training in the Zucker Diabetic Fatty (ZDF) rat

Exercise Physiology of the Canine Athlete

Increased Short-Term Variability of the QT Interval in Professional Soccer Players: Possible Implications for Arrhythmia Prediction

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