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Compute ECG Intervals from Delineation

Source: R/ecg-morphology.R
ecgIntervals.Rd

Calculates standard clinical ECG intervals from the waveform delineation produced by ecgDelineate: PR interval, QT interval, QTc (Bazett correction), QRS duration, and RR interval.

Usage

ecgIntervals(delineation, sr)

Arguments

delineation

A data.frame as returned by ecgDelineate, with columns channel, beat, r_peak, qrs_onset, qrs_offset, p_peak, t_peak, t_end.

sr

Sampling rate in Hz.

Value

A data.frame with one row per beat and the following columns:

channel

Integer channel index (1-based).

beat

Integer beat number within the channel.

pr_ms

PR interval in milliseconds (P-wave peak to QRS onset), or NA if the P wave was not detected.

qt_ms

QT interval in milliseconds (QRS onset to T-wave end), or NA if the T wave was not detected.

qtc_ms

Corrected QT interval using Bazett's formula (QT / sqrt(RR_sec)), or NA if QT or RR is unavailable. Kept as a backward-compatible alias of qtc_bazett.

qtc_bazett, qtc_fridericia, qtc_framingham, qtc_hodges

QT corrected for heart rate by, respectively, Bazett (QT / sqrt(RR)), Fridericia (QT / RR^(1/3)), Framingham (QT + 154 * (1 - RR)) and Hodges (QT + 1.75 * (HR - 60)); QT in ms, RR in seconds. All four equal qt_ms at RR = 1 s.

qrs_ms

QRS complex duration in milliseconds.

rr_ms

RR interval in milliseconds to the next beat, or NA for the last beat in each channel.

Returns a zero-row data.frame with the same column structure if no beats are present.

References

Goldberger, A.L., et al. (2000). "PhysioBank, PhysioToolkit, and PhysioNet: Components of a new research resource for complex physiologic signals." Circulation, 101(23), e215–e220. doi:10.1161/01.CIR.101.23.e215

See also

ecgDelineate for waveform delineation, ecgDetectRpeaks for R-peak detection, ecgRRintervals for RR interval computation.

Examples

set.seed(1)
pe <- make_ecg_pqrst(n_time = 5000, sr = 500, heart_rate = 72)$pe
peaks <- ecgDetectRpeaks(pe)
delin <- ecgDelineate(pe, peaks)
intervals <- ecgIntervals(delin, samplingRate(pe))
head(intervals)
#>   channel beat pr_ms qt_ms   qtc_ms qtc_bazett qtc_fridericia qtc_framingham
#> 1       1    1   118   414 453.3330   453.3330       439.8234        439.564
#> 2       1    2   118   476 521.2234   521.2234       505.6907        501.564
#> 3       1    3   118   410 448.9530   448.9530       435.5739        435.564
#> 4       1    4   104   498 545.3136   545.3136       529.0629        523.564
#> 5       1    5   106   504 551.8836   551.8836       535.4372        529.564
#> 6       1    6   120   566 619.7741   619.7741       601.3044        591.564
#>   qtc_hodges qrs_ms rr_ms
#> 1   434.8993     92   834
#> 2   496.8993     86   834
#> 3   430.8993     88   834
#> 4   518.8993    104   834
#> 5   524.8993    104   834
#> 6   586.8993     96   834