Table 2. Mean values of ECG Intervals with Standard Deviations and the Range of Normal Limits from the 2^nd to 98^th Percentile by Race.

	All Women	White	African-American	Hispanic	Asian/ Pacific
Heart Rate (bpm)	66; 9.2 49 → 88	66; 9.2 49 → 87	67; 9.8*** 50 → 89	66; 8.8NS 50 → 87	67; 9.1NS 51→ 88
PR (ms)	158; 33.9 118 → 212	157; 34.6 118 → 212	164; 34.9*** 124 → 220	155; 22.0** 118 → 204	158; 20.9NS 124→ 209
QRS (ms)	85; 8.1 70 → 104	85; 8.0 70 → 104	84; 8.5*** 68 → 104	85; 8.2NS 70 → 104	85; 8.1NS 70 → 104
† QTea (ms)	413; 14.2 388 → 449	413; 14.0 388 → 448	414; 14.9NS 388 → 452	414; 15.0* 389 → 451	418; 16.1*** 393 → 460
† QTpa (ms)	328; 17.0 294 → 366	328; 16.7 295; 365	326; 18.9*** 288 → 368	328; 17.6NS 294 → 366	331; 17.4*** 299 → 372
‡ QToa (ms)	236; 15.3 207 → 271	237; 15.2 208 → 271	233; 16.2*** 202 → 271	234; 15.1*** 207 → 269	232; 14.4*** 206 → 266
§ TpTxd (ms)	33; 8.5 20 → 56	33; 8.2 20 → 54	35; 10.3*** 20 → 64	34; 9.1*** 20 → 58	35; 9. 3*** 22 → 60
# (TpTe)a (ms)	85; 11.2 63 → 112	85; 10.9 64 → 111	87; 13.5*** 61 → 119	86; 11.8*** 60 → 113	87; 14.1NS 54 → 121

^***signifies P<0.0001,

^**P<0.001,

^*=P<0.05 and NS nonsignificant for mean difference from white women.

^†QT_ea and QT_pa are rate-adjusted QTend (QT_e) and QTpeak (QR_p) intervals by formulas listed in Table 1.

^‡QT_oa is the rate adjusted QTonset (QT_o) interval by formula QT_oa = QT_o +107*(1-RR).

^§T_pT_xd signifies crossmural left ventricular repolarization time gradient, equal to the interval from T_p to T_xd where T_xd is the time point of maximum slope at the global T wave downstroke (see methods).

^#T_pT_e computed as the difference (QT_ea-QT_pa) or as T_pT_e + 0.5*(HR-60).