I read with interest the commentary provided by Dr Wyer regarding the value of dyspnoea on exertion in congestive heart failure (HF).¹ The data reveal the pooled positive likelihood ratio (+LR) for dyspnoea on exertion to be 1.3 and the negative likelihood ratio (−LR) to be 0.48. He states, “Surprisingly, the presence of dyspnoea on exertion has little effect on raising the likelihood of HF, although as expected, its absence lowers HF likelihood.” I concur that dyspnoea on exertion is not useful in raising the probability for HF considering the low +LR, but I disagree that the absence of dyspnoea on exertion lowers the likelihood of HF below a threshold probability where neither treatment nor further diagnostic intervention is warranted. If hypothetical pretest probabilities for HF are 0.60, 0.40, and 0.20, the post-test probabilities for a negative test (lack of dyspnoea on exertion) would decrease only to 0.42, 0.24, and 0.11, respectively. I doubt that …