Dengue fever: an additional cause for bradycardia.

Sir, S Eastern part of Rajasthan state “Hadoti Zone” faced an outbreak of dengue fever during the months of September to December 2012. A total number of 48 patients were admitted with ELISA IgM/IgG positive for dengue fever.We report a series of 8 cases of dengue fever with sinus bradycardia, age ranging between 15 years and 34 years. Apart from typical clinical features and laboratory parameters of all the 48 cases, in 8 patients bradycardia (42/min to 52/min) was demonstrated from day 3rd day 9th of the illness in all except one, in whom it developed on day 13th. Lowest heart rate was noticed in 2nd week of illness (day 9-14) in all except one, who developed pulse rate of 45/ min on day 5th. ECG revealed sinus bradycardia without any ST-T changes. There were no hidden P waves and every P wave was followed by QRS complex. Echocardiography done in one symptomatic case showed decreased ejection fraction (LVEF 42%). The patients were managed as per world heal th organisat ion (WHO) recommendations. No specific treatment was given for bradycardia as it was asymptomatic. All the 8 cases were discharged (day 9 to day 16 of illness) after symptomatic improvement with normal platelet count but with pulse rate less than 60 per minute. Patients were followed up weekly and pulse became normal during third and fourth week of their illness.