Cheng-Chun Wei et al. have provided insight into the association of heart rate patterns with adverse outcomes for acute heart failure. However, the study does incur limitations and warrants further thoughts.1
Firstly, although the authors assessed the degree of heart failure according to New York Heart Association Functional Classification classification, they did not outline the stage of heart failure patients were in pre-discharge. This means those with stage IV heart failure, who were at worst outcomes irrespective of their heart rate, are likely to have conflating symptoms which affect the adverse outcomes in the long term.
Furthermore, the inclusion criteria consisted of patients who were not in sinus rhythm, such as atrial fibrillation (AF). Arrhythmias, particularly AF, are known to exacerbate left ventricular dysfunction and lead to congestive heart failure, resulting in adverse outcomes and subsequent hospital admission. As such, inclusion skews the conclusions drawn.
Additionally, the study categories heart rate as < 80 bpm (low) and > 90 bpm (high), despite heart rate range being recognized as between 60-100 bpm.2 The study’s categorization creates confusion as to why Group 4 patients whose heart rate of > 90 were considered tachycardic as opposed to > 100. For this reason, the study would have benefitted from comparing normal heart rates with pre-defined abnormal heart rates.
Finally, there is no accounting of whitecoat hypertension as a possible cause for patient’s higher heart rate pre-discharge compared to post-discharge.3 Oversight of this phenomena during the trial could have affected the trajectory modelling, making it difficult to assess the reliability of study outcome.
CONFLICT OF INTEREST
All the authors declare no conflict of interest.
REFERENCES
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