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J Parasit Dis Diagn Ther 2017
Volume 2 Issue 3
Tropical Medicine 2017
Notes:
Page 39
September 7-8, 2017 | Edinburgh, Scotland
4
th
International Conference on
Tropical Medicine, Infectious Diseases & Public Health
RELATIVE BRADYCARDIA IN SCRUB
TYPHUS
Chang-Seop Lee
a
, Lae Young Jung
a
, Mir Jeon
a
, Joo-Hee Hwang
a
, Rosinete
Maciel Rodrigues
a
and
Wendell Gomes
a
a
Chonbuk National University, Korea
Background:
Scrub typhus is a mite-borne infectious
disease caused by Orientia tsutsugamushi. Arrhythmia is
one of the reported cardiac complications and includes
non-symptomatic electrocardiographic changes and serious
arrhythmias such as ventricular tachycardia and Torsades de
pointes. Relative bradycardia is an inappropriately low heart
rate response to every 1-degree rise in body temperature that
occurs in scrub typhus cases. To investigate the relationship
between heart rate and temperature in patients with scrub
typhus, we examined 493 febrile patients with documented
scrub typhus.
Method:
Body temperature and heart rate were recorded
upon presentation, during treatment, and following symptom
resolution. Fever was defined as temperature greater than
37.8°C. Febrile heart rate and temperature data were
documented on initial patient evaluation, before application
of antibiotic therapy. Baseline temperature and heart rate
were assessed when patients first became and then remained
afebrile following treatment. Although no uniform definition
of relative bradycardia (RB) exists, we defined it a priori
as an increase in the heart rate from a baseline of less than
10 beats/minute/°C increase in temperature. Patients
exhibiting a pulse increase greater than 10 beats/minute/°C
were classified as having non-relative bradycardia (NRB).
Results:
The general relationship between heart rate and
increased temperature was assessed in 493 patients with scrub
typhus infection: 337 (68.4%) responded to fever with a heart
rate increase <10 beats/minute/°C (RB) and 156 patients
had a heart rate response ≥10 beats/minute/°C (NRB). Basal
temperatures were not significantly different between the
two groups. Maximal temperature was significantly higher
in the RB than the NRB group. The RB group had a higher
median resting heart rate than the NRB group (RB group
vs. NRB group, 80.2 ± 11.5 vs. 77.2 ± 10.7 beats/minute;
P=0.006). The RB group had a significantly lower heart rate
than the NRB group at maximal temperature (RB group vs.
NRB group, 84.6 ± 12.5 vs .00.1 ±17.3 beats/minute, P<0.001).
ΔHeart rate/Δtemperature showed the opposite effect between
the two groups during fever (RB group vs. NRB group, 1.17
± 8.15 vs. 17.89 ± 8.65, P<0.001). Despite differences in the
heart rate response between relative bradycardia and NRB
patients, no significant differences were seen in clinical
outcomes (acute kidney injury P=0.564, SIRS P=0.523, death
P = 0.136) between the two groups.
Conclusion:
Most patients with scrub typhus present with
relative bradycardia. RB in scrub typhus should be included
as a biomarker for differential diagnosis from other infectious
diseases. In addition, relative bradycardia was not related to
clinical outcomes.
Biography
Chang-Seop Lee, currently working as an assistant professor at Chonbuk
National University, Korea. His main research interests are parasitology,
neglected tropical diseases, chest medicine and vector Bourne diseases.
lcsmd153@gmail.comChang-Seop Lee et al., J Parasit Dis Diagn Ther 2017