Heart-Rate Turbulence (HRT)

Computes turbulence onset (TO) and turbulence slope (TS), the biphasic sinus-rhythm response to a ventricular premature beat (Schmidt et al. 1999). RR intervals are indexed by beat so that rr[i] is the interval between beat i and beat i+1; for a PVC at beat p the coupling interval is rr[p-1] and the compensatory pause rr[p], which are excluded. The local tachograms of all usable PVCs are averaged before TO/TS.

Usage

ecgHRT(rr, pvc_index, n_post = 15L)

Arguments

rr

RR intervals (ms): a numeric vector or a data.frame with an rr_ms column.

pvc_index

Integer beat indices of the ventricular premature beats (e.g. the beat column of ecgDetectPVC where is_pvc).

n_post

Number of post-PVC sinus intervals used for TS (default 15).

Value

A list with to (turbulence onset, percent; negative is normal), ts (turbulence slope, ms per RR interval; positive is normal), n_pvc (PVCs averaged) and tachogram (the averaged post-PVC sinus RR series).

References

Schmidt, G. et al. (1999). Heart-rate turbulence after ventricular premature beats as a predictor of mortality after acute myocardial infarction. Lancet, 353(9162), 1390-1396.

See also

ecgDetectPVC, ecgPRSA

Examples

# canonical post-PVC pattern: early acceleration then deceleration
rr <- c(rep(800, 5), 500, 1100, 780, 785, 790 + 5 * (0:12))
ecgHRT(rr, pvc_index = 7)
#> $to
#> [1] -2.1875
#> 
#> $ts
#> [1] 5
#> 
#> $n_pvc
#> [1] 1
#> 
#> $tachogram
#>  [1] 780 785 790 795 800 805 810 815 820 825 830 835 840 845 850
#> 
#> $to_per_pvc
#> [1] -2.1875
#>