Scrub Typhus and Abnormal Electrocardiography

Background: This study aimed to determine the electrocardiogram(ECG) abnormality types and frequencies and associations with disease severity in patients with scrub typhus and normal age-matched subjects.

Methods: Demographic characteristics and ECG and laboratory findings of patients with scrub typhus admitted to Chosun University Hospital and normal subjects visiting the hospital for health check-ups from January 2008 to December 2012 were retrospectively studied.

Results: ECG abnormalities at admission were observed in 76 (43.2%) of 176 patients with confirmed scrub typhus. Among these, the long QT group was most common (34 cases, 19.3%), followed by the ischemia group (26 cases, 14.8%; ST-segment changes, abnormal Q waves, and poor R progression), arrhythmia group (22 cases, 12.5%;atrial fibrillation[16 cases, 9.1%], atrial flutter[0 cases], atrial premature contraction, or premature ventricular complex), and conduction group (12 cases; 6.8%; AV block, RBBB, LBBB); compared with the age- and sex-matched control group, ECG abnormalities were significantly more common among patients(43.6% vs. 13.9%, p<0.001). Abnormal laboratory findings were significantly more common in patients with scrub typhus in the abnormal ECG group, which had a significantly higher severity score than the normal ECG group(6.47 vs. 5.05, p = 0.001); abnormal ECG also correlated with increased disease severity.

Conclusion: ECG abnormalities were more common in patients with scrub typhus than in the general population and were associated with more severe disease. As QT prolongation occurs in approximately 20% of patients with scrub typhus, clinicians should pay more attention to drugs that affect QT prolongation.