The complexity of diagnosing postural orthostatic tachycardia
syndrome: influence of the diurnal variability
Jangsup Moon, MD, PhD1, Han Sang Lee, MD1, Jung-Ick Byun, MD, Jun-Sang
Sunwoo, MD, Jung-Won Shin, MD, Jung-Ah Lim, MD, Tae-Joon Kim, MD,
Yong-Won Shin, MD, Keon-Joo Lee, MD, Daejong Jeon, PhD, Keun-Hwa Jung,
MD, PhD, Soon-Tae Lee, MD, PhD, Ki-Young Jung, MD, PhD, Kon Chu, MD,
PhD, Sang Kun Lee, MD, PhD
1These two authors contributed equally to this work.
Published Online: January 18, 2016
Accepted: January 9, 2016
Received in revised form: December 28, 2015
Received: October 20, 2015
•We evaluated how the diagnosis can be missed in a single orthostatic
•Orthostatic tachycardia is more prominent in the morning, but not always.
•Symptoms were more frequent in the morning, but not during majority
of the tests.
•Orthostatic hypotension can be accompanied in POTS.
•We suggest repeated orthostatic stress tests in clinically suspected
We investigated how the diagnosis of postural orthostatic tachycardia
syndrome (POTS) would be changed due to diurnal variability in
orthostatic tachycardia. The orthostatic vital sign (OVS) test was
administered to each patient twice, in the afternoon of the day of
admission and the next morning (n=113). Forty-six patients were
diagnosed with POTS, and the remaining 67 patients were assigned to
non-POTS group. Heart rate increments after standing were larger in
the morning than in the afternoon in every group (all P < 0.001).
Among the POTS patients, 82.6% fulfilled the diagnostic criteria for
POTS in the morning, and 52.2% in the afternoon. The majority of the
POTS group (65.2%) displayed normal result on single OVS test.
Orthostatic intolerance symptoms were provoked in only 45.7% of the
POTS patients, more frequently in the morning. In conclusion, diurnal
variability in hemodynamic parameters and provoked symptoms
significantly challenged the diagnosis of POTS.