Abstract
0BJECTIVES: This study compared the effects of beta-blockade on transmural and spatial dispersion of repolarization (TDR and SDR, respectively) between the LQT1 and LQT2 forms of congenital long QT syndrome (LQTS). BACKGROUND: The LQT1 form is more sensitive to sympathetic stimulation and more responsive to beta-blockers than either the LQT2 or LQT3 forms. METHODS: Eighty-seven-lead, body-surface electrocardiograms (ECGs) were recorded before and after epinephrine infusion (0.1 μg/kg body weight per rain) in the absence and presence of oral propranolol (0.5-2.0 mg/kg per day) in 11 LQT1 patients and 11 LQT2 patients. The Q-Tend interval, the Q-Tpeak interval and the interval between Tpeak and Tend (Tp-e), representing TDR, were measured and averaged from 87-lead ECGs and corrected by Bazett's method (corrected Q-Tend interval [cQTe], corrected Q-Tpeak interval [cQTp ] and corrected interval between Tpeak and Tend [cTp-e]). The dispersion of cQTe (cQTe-D) was obtained among 87 leads and was defined as the interval between the maximum and minimum values of cQTe. RESULTS: Propranolol in the absence of epinephrine significantly prolonged the mean cQTp value but not the mean cQTe value, thus decreasing the mean cTp-e value in both LQT1 and LQT2 patients; the differences with propranolol were significantly larger in LQT1 than in LQT2 (p <0.05). The maximum cQTe, minimum cQTe and cQTe-D were not changed with propranolol. Propranolol completely suppressed the influence of epinephrine in prolonging the mean cQTe, maximum cQTe and minimum cQTe values, as well as increasing the mean cTp-e and cQTe-D values in both groups. CONCLUSIONS: Beta-blockade under normal sympathetic tone produces a greater decrease in TDR in the LQT1 form than in the LQT2 form, explaining the superior effectiveness of beta-blockers in LQT1 versus LQT2. Beta-blockers also suppress the influence of sympathetic stimulation in increasing TDR and SDR equally in LQT1 and LQT2 syndrome.
| Original language | English |
|---|---|
| Pages (from-to) | 1984-1991 |
| Number of pages | 8 |
| Journal | Journal of the American College of Cardiology |
| Volume | 39 |
| Issue number | 12 |
| DOIs | |
| Publication status | Published - Jun 19 2002 |
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Differential effects of beta-blockade on dispersion of repolarization in the absence and presence of sympathetic stimulation between the LQT1 and LQT2 forms of congenital long QT syndrome. / Shimizu, Wataru; Tanabe, Yasuko; Aiba, Takeshi; Inagaki, Masashi; Kurita, Takashi; Suyama, Kazuhiro; Nagaya, Noritoshi; Taguchi, Atsushi; Aihara, Naohiko; Sunagawa, Kenji; Nakamura, Kazufumi; Ohe, Tohru; Towbin, Jeffrey A.; Priori, Silvia G.; Kamakura, Shiro.
In: Journal of the American College of Cardiology, Vol. 39, No. 12, 19.06.2002, p. 1984-1991.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Differential effects of beta-blockade on dispersion of repolarization in the absence and presence of sympathetic stimulation between the LQT1 and LQT2 forms of congenital long QT syndrome
AU - Shimizu, Wataru
AU - Tanabe, Yasuko
AU - Aiba, Takeshi
AU - Inagaki, Masashi
AU - Kurita, Takashi
AU - Suyama, Kazuhiro
AU - Nagaya, Noritoshi
AU - Taguchi, Atsushi
AU - Aihara, Naohiko
AU - Sunagawa, Kenji
AU - Nakamura, Kazufumi
AU - Ohe, Tohru
AU - Towbin, Jeffrey A.
AU - Priori, Silvia G.
AU - Kamakura, Shiro
PY - 2002/6/19
Y1 - 2002/6/19
N2 - 0BJECTIVES: This study compared the effects of beta-blockade on transmural and spatial dispersion of repolarization (TDR and SDR, respectively) between the LQT1 and LQT2 forms of congenital long QT syndrome (LQTS). BACKGROUND: The LQT1 form is more sensitive to sympathetic stimulation and more responsive to beta-blockers than either the LQT2 or LQT3 forms. METHODS: Eighty-seven-lead, body-surface electrocardiograms (ECGs) were recorded before and after epinephrine infusion (0.1 μg/kg body weight per rain) in the absence and presence of oral propranolol (0.5-2.0 mg/kg per day) in 11 LQT1 patients and 11 LQT2 patients. The Q-Tend interval, the Q-Tpeak interval and the interval between Tpeak and Tend (Tp-e), representing TDR, were measured and averaged from 87-lead ECGs and corrected by Bazett's method (corrected Q-Tend interval [cQTe], corrected Q-Tpeak interval [cQTp ] and corrected interval between Tpeak and Tend [cTp-e]). The dispersion of cQTe (cQTe-D) was obtained among 87 leads and was defined as the interval between the maximum and minimum values of cQTe. RESULTS: Propranolol in the absence of epinephrine significantly prolonged the mean cQTp value but not the mean cQTe value, thus decreasing the mean cTp-e value in both LQT1 and LQT2 patients; the differences with propranolol were significantly larger in LQT1 than in LQT2 (p <0.05). The maximum cQTe, minimum cQTe and cQTe-D were not changed with propranolol. Propranolol completely suppressed the influence of epinephrine in prolonging the mean cQTe, maximum cQTe and minimum cQTe values, as well as increasing the mean cTp-e and cQTe-D values in both groups. CONCLUSIONS: Beta-blockade under normal sympathetic tone produces a greater decrease in TDR in the LQT1 form than in the LQT2 form, explaining the superior effectiveness of beta-blockers in LQT1 versus LQT2. Beta-blockers also suppress the influence of sympathetic stimulation in increasing TDR and SDR equally in LQT1 and LQT2 syndrome.
AB - 0BJECTIVES: This study compared the effects of beta-blockade on transmural and spatial dispersion of repolarization (TDR and SDR, respectively) between the LQT1 and LQT2 forms of congenital long QT syndrome (LQTS). BACKGROUND: The LQT1 form is more sensitive to sympathetic stimulation and more responsive to beta-blockers than either the LQT2 or LQT3 forms. METHODS: Eighty-seven-lead, body-surface electrocardiograms (ECGs) were recorded before and after epinephrine infusion (0.1 μg/kg body weight per rain) in the absence and presence of oral propranolol (0.5-2.0 mg/kg per day) in 11 LQT1 patients and 11 LQT2 patients. The Q-Tend interval, the Q-Tpeak interval and the interval between Tpeak and Tend (Tp-e), representing TDR, were measured and averaged from 87-lead ECGs and corrected by Bazett's method (corrected Q-Tend interval [cQTe], corrected Q-Tpeak interval [cQTp ] and corrected interval between Tpeak and Tend [cTp-e]). The dispersion of cQTe (cQTe-D) was obtained among 87 leads and was defined as the interval between the maximum and minimum values of cQTe. RESULTS: Propranolol in the absence of epinephrine significantly prolonged the mean cQTp value but not the mean cQTe value, thus decreasing the mean cTp-e value in both LQT1 and LQT2 patients; the differences with propranolol were significantly larger in LQT1 than in LQT2 (p <0.05). The maximum cQTe, minimum cQTe and cQTe-D were not changed with propranolol. Propranolol completely suppressed the influence of epinephrine in prolonging the mean cQTe, maximum cQTe and minimum cQTe values, as well as increasing the mean cTp-e and cQTe-D values in both groups. CONCLUSIONS: Beta-blockade under normal sympathetic tone produces a greater decrease in TDR in the LQT1 form than in the LQT2 form, explaining the superior effectiveness of beta-blockers in LQT1 versus LQT2. Beta-blockers also suppress the influence of sympathetic stimulation in increasing TDR and SDR equally in LQT1 and LQT2 syndrome.
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U2 - 10.1016/S0735-1097(02)01894-6
DO - 10.1016/S0735-1097(02)01894-6
M3 - Article
C2 - 12084597
AN - SCOPUS:0037134902
VL - 39
SP - 1984
EP - 1991
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
SN - 0735-1097
IS - 12
ER -