Table 2.

Prospective studies (or sub-studies) investigating heart rate turbulence as a post-infarction risk-predictor.

	ISAR-HRT (Barthel et al., 2003)	REFINE (Exner et al., 2007)	ISAR-RISK‡‡ (Bauer et al., 2009a)	CARISMA (Huikuri et al., 2009)	ISAR-Sweet‡‡ (Barthel et al., 2011)
Number of patients	1,455	322	2,343	312	481
Inclusion criteria*	MI ≤4 weeks, age ≤75 years	MI, LVEF <50%	MI ≤4 weeks, age ≤75 years	MI <21 days, LVEF ≤40%	MI ≤4 weeks, age ≤80 years, diabetes
Follow-up (months)	22	47	60	24	60
Endpoint	Mortality	Cardiac death†	Mortality	VF/sustained VT on loop recorder	Mortality
Endpoints reached (%)	5	9	8	8	17
Time of HRT assessment after MI	2nd week	2nd to 4th and 10th to 14th week	2nd week	1st and 6th week	2nd week
Treatment of acute MI	90% PCI, 6% lysis	45% PCI, 21% lysis	92% PCI, 3% lysis	14% PCI, 34 lysis	89% PCI
Mean LVEF (%)	56	47	55	31	51
Betablockers (%)	93	92	94	96	94
UNIVARIATE ANALYSIS
HRT category 2	11.4 (5.7–22.8)	2.9 (1.1–7.5)††	7.5 (5.3–10.7)	2.8 (1.1–7.2)||	6.6 (3.9–11.0)
LVEF ≤30%	7.1 (4.2–12.1)	3.3 (1.4–7.6)	6.1 (4.2–8.7)	1.3 (0.5–3.0)#	4.7 (2.8–7.8)
MULTIVARIATE ANALYSIS
HRT category 2	5.9 (2.9–12.2)	Not specified	3.1 (2.1–4.6)	Not specified	4.1 (2.3–7.2)
LVEF ≤30%	4.5 (2.6–7.8)	Not specified	3.0 (2.0–4.4)	Not specified	2.4 (1.4–4.1)

*Sinus rhythm was inclusion criterion in all studies.

^†Cardiac mortality included fatal and non-fatal cardiac arrest.

^||Relative risks presented for turbulence slope ≤2.5 ms/RR interval.

^#LVEF was dichotomized at 35%.

^††HRT category ≥1 vs. 0 tested; HRT was assessed 10–14 weeks after MI.

^‡‡ISAR-RISK primarily tested the combination HRT category 2 and abnormal deceleration capacity (Bauer et al., 2006a).