The LQTS mutant KCNE1-D76N prolongs the QT interval in guinea pigs
in vivo, whereas HERG-G628S does not affect QT interval
duration. ECG recordings were performed after widespread myocardial
infection with HERG-G628S or KCNE1-D76N. ECGs revealed a prolongation
by ≈23% of QTc 48 h after KCNE1-D76N infection
(D) compared with immediate postoperative recordings
(C) (QTc 286.7 ± 10.4 ms vs. 353.3 ± 24.5
ms, n = 3; P = 0.04),
consistent with the marked prolongation of action potentials in
KCNE1-D76N-infected ventriculocytes. Conversely, no change in QTc was
observed 48 h after infection with HERG-G628S (B)
compared with immediate postoperative ECGs (A)
(305.0 ± 11.4 ms vs. 293.0 ± 9.5 ms, n
= 3; P = 0.38), in agreement with the overall
unchanged APD of HERG-G628S-infected cells.