Objective—To determine the feasibility for use of a 6-
minute walk test (6-MWT) in dogs with congestive
heart failure (CHF) and document that the distance
walked in 6 minutes decreases when a dog has CHF.
Animals—16 young mature male hound-crossbred
dogs weighing between 25 and 37 kg.
Procedure—An unobstructed path (22.73 m) was
measured in a hallway. Each dog was walked on a
leash for 6 minutes; each dog was allowed to set its
own pace. At the end of 6 minutes (as measured by
use of a stopwatch), the total distance walked was
measured. Heart rate (HR) obtained by auscultation
and mean systemic arterial pressure (MAP) obtained
by oscillometry were recorded before and after the 6-
MWT. Heart failure was induced by use of rapid ventricular
pacing. Mean of the distance walked, HR, and
MAP before and after the 6-MWT were compared
between the control period and after dogs developed
Results—Dogs with CHF had a significant increase in
resting HR, significant decrease in MAP, and a significant
decrease in the distance walked in 6 minutes.
The MAP increased slightly after exercise during the
control period but decreased slightly after exercise
during the CHF period. Fractional shortening
decreased significantly when dogs had CHF.
Conclusions and Clinical Relevance—Analysis of
these results indicated that the distance walked in 6
minutes decreased significantly when a dog had CHF.
The 6-MWT requires little time, space, or equipment
and may replace the treadmill exercise test. ( Am J Vet Res 2004;65:311–313)
Objective—To determine whether plasma cardiac troponin I (cTnI) concentrations can be used to discriminate cardiac from noncardiac causes of dyspnea in cats.
Design—Prospective, multicenter study.
Animals—Client-owned cats with dyspnea attributable to congestive heart failure (D-CHF; n = 31) or to noncardiac causes (D-NCC; n = 12).
Procedures—For each cat, plasma cTnI concentration was analyzed by use of a solid-phase radial partition immunoassay; values in cats with D-CHF and D-NCC were compared. A receiver operating characteristic curve was analyzed to determine the accuracy of plasma cTnI concentration for diagnosis of D-CHF.
Results—Median plasma concentration of cTnI in cats with D-CHF (1.59 ng/mL; range, 0.20 to 30.24 ng/mL) was significantly higher than in cats with D-NCC (0.165 ng/mL; range, 0.01 to 1.42 ng/mL). With regard to the accuracy of plasma cTnI concentration for diagnosis of D-CHF, the area under the receiver operating characteristic curve was 0.84. At plasma concentrations ≥ 0.2 ng/mL, cTnI had 100% sensitivity but only 58% specificity for identification of CHF as the cause of dyspnea. At plasma concentrations ≥ 1.43 ng/mL, cTnI had 100% specificity and 58% sensitivity for identification of CHF as the cause of dyspnea.
Conclusions and Clinical Relevance—On the basis of the derived diagnostic limits, CHF as the cause of dyspnea could be ruled in or ruled out without additional diagnostic testing in > 50% of the study cats. Measurement of plasma cTnI concentration may be clinically useful for differentiation of cardiac from noncardiac causes of dyspnea in cats.