Table 1. Rate-adjustment Formulas for QTpeak and QTend by Ethnicity.
| Ethnic Group | Linear Functions of RR† | R-Square | |
|---|---|---|---|
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| ‡ QTp | White | 1. QTpa =QTp +132*(1-RR) | 0.508 |
| African-American | 2. QTpa =QTp +131*(1-RR) | 0.461 | |
| Hispanic | 3. QTpa =QTp +138*(1-RR) | 0.480 | |
| Asian/Pacific | 4. QTpa =QTp +142*(1-RR) | 0.496 | |
| § QTe | White | 5. QTea =QTe +182*(1-RR) | 0.735 |
| African-American | 6. QTea =QTe +184*(1-RR) | 0.701 | |
| Hispanic | 7. QTea =QTe +187*(1-RR) | 0.701 | |
| Asian/Pacific | 8. QTea =QTe +179*(1-RR) | 0.650 | |
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| All Women | Power and Linear Functions | R-Square | |
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| QTp | Power Function of RR | 9. QTpa=QTp+319*(1-RRˆ0.40-1) | 0.505 |
| QTe | Power Function of RR | 10. QTea =QTe+319*(1-RRˆ0.40) | 0.728 |
| QTp | Linear Function of RR | 11. QTpa = QTp + 132*(1-RR) | 0.502 |
| QTe | Linear Function of RR | 12. QTea=QTe+182*(1-RR) | 0.731 |
| QTe | Linear Function of HR | 13. QTea = QTe + 2.48*(HR-60) | 0.705 |
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| ‖ QTpa from QTea and TpTe intervals | 14. QTpa = QTea - (TpTe) + 0.5* (HR-60) | ||
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| ‡‡ Other Formulas for QTe | Residual HR-dependence | r | |
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| QTbz | 15. QTbz = QT/RR1/2 | QTbz = 382 + 0.53*HR | 0.31 |
| QTfr | 16. QTfr = QTe/RR1/3 | QTfr = 446-0.53*HR | 0.31 |
| QTfrm | 17. QTfrm = QTe+154*(1-RR) | QTfrm = 436 - 0.38*HR | 0.24 |
| QThg | 18. QThg = QTe + 1.75*(HR-60) | QThg = 459 - 0.73*HR | 0.42 |
†
RR interval (=60/heart rate (HR) is in seconds, all other intervals in milliseconds in this and in the other tables.
‡
QTp and QTpa refer to QTpeak and rate-adjusted QTpeak, respectively.
§
QTe and QTea refer to QTend and to rate-adjusted QTend, respectively.
‖
A practical formula for QTpa as (QTea - TpTe) with TpTe adjusted for HR.
Formulas 17-20 show the residual dependence on HR of the rate-adjusted QTe by Bazett's (QTbz), Fridricia's (QTfr), Framingham (QTfrm) and Hodge's (QThg) formulas.