Sinus bradycardia in dengue: prevalence and clinical implications—an observational study

OBJECTIVES: To estimate the frequency of sinus bradycardia in hospitalized adults with dengue, and assess its association with clinical outcomes. METHODS: This prospective observational study enrolled consecutive adults hospitalized with dengue at a tertiary hospital in Brazil. Patients with and without sinus bradycardia (heart rate <60 bpm) were compared. An exploratory post hoc analysis assessed the correlation between bradycardia onset and platelet recovery. RESULTS: Among 33 patients, 12 developed sinus bradycardia (36.4%; 95% CI, 20.4%-54.9%). Baseline characteristics were similar except for lethargy, which was less frequent with bradycardia (8.3% vs 52.4%; P=.022). ICU admission did not differ significantly (16.7% vs 28.6%; risk ratio, 0.58; 95% CI, 0.14-2.45; P=.678). In 11 patients with complete temporal data, bradycardia onset correlated positively with platelet recovery (Spearman's ρ=0.61; 95% CI, 0.00-0.92; P=.048). CONCLUSIONS: Sinus bradycardia was common in this small cohort, without a detected association with ICU admission. Its correlation with platelet recovery suggests possible occurrence during a later phase of dengue. Larger studies are needed.