Paradoxically shortened QT interval after a prolonged pause.
We analyzed Holter ECG recordings in 15 patients with episodes of prolonged RR intervals > 2.5 seconds. In 13 patients, the QT interval showed a linear prolongation when RR interval was < 1.5 seconds and became relatively flat at longer RR intervals. In the remaining two patients, the QT and RR intervals were correlated within physiological range of RR intervals. However, at longer RR intervals, the QT interval was unexpectedly shortened and constant. The paradoxically shortened QT interval observed in the present 2 cases may indicate an abnormal adaptation of repolarization time to an abrupt increase in the preceding RR intervals.
Department of Internal Medicine I, School of Medicine, Oita Medical University, Japan. takanao@oita-med.ac.jp
N
N
Takahashi
M
M
Ito
S
S
Ishida
M
M
Nakagawa
M
M
Hara
T
T
Saikawa
T
T
Sakata
D000328:Adult; D000368:Aged; D015716:Electrocardiography, Ambulatory; D005260:Female; D006327:Heart Block / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012804:Sick Sinus Syndrome / Q000503:physiopathology