Study	N	Years	Randomized?	Controlled?	NYHA Functional Class*	Follow-up Months	Results
MIRACLE Abraham et al., 2002 (40)	453	1998–2002	Yes/parallel Pace/no pace	Yes	III–IV	6	Improved 6-min walk test (P <.005) Improved QoL* (P < .001) Improved NYHA class (P < .001) Largest study to date. Mortality < 10% in both treatment arms at 6 months. Hospitalization significantly lower in active treatment group.
PATH-CHF Auricchio et al., 2002 (41)	41	1995–1998	Yes/crossover 4 wks active pacing (LV or BiV)*, then 4 weeks no pacing 2nd 4 week active pacing period Continued for 12 months after crossover period Single blind	Yes	III–IV	3	No significant difference between BiV and univentricular (mostly LV) stimulation found for clinical effects: 6-min walk test, P= .345 QoL, P= .069 NYHA class, P= .360 Oxygen uptake at peak exercise, P= .324 Oxygen uptake at anaerobic threshold, P= .290
MUSTIC SR Cazeau et al., 2001 (42)	67	1998–1999	Yes/single blind crossover 3 months stimulation on or off; mode then switched for the 2nd 3 month period	Yes	III	3/3	Improved 6-min walk test, P < .001 Improved QoL, P < .001 Improved peak oxygen uptake, P < .03 Decreased hospitalization, P < .05 Mortality 5% during 6-month crossover phase

^*NYHA indicates New York Heart Association; QoL, quality of life; LV, left ventricular; BiV, biventricular.