Trial | # Patients | Inclusion criteria | Randomization arms | Follow-up | Results | ||||
Trial | # Patient | Inclusion criteria | Randomization arms | Follow-up | |||||
ADOPT [42] | 319 enrolled 288 analyzed |
≥2 AF episodes within 1 month prior to implant, sinus node dysfunction | DDDR @60bpm with continuous overdrive ON vs. OFF | 6 months | Reduction in AF burden from 2.5 to 1.87% (p=0.005). No difference in QOL or # AF episodes | ||||
Puglisi et al.[43] | 149 enrolled 98 analyzed |
1 episode AT within 6 months, bradycardia | DDD@70bpm closed loop system vs. DDD@70bpm with continuous overdrive vs. DDDR@70bpm |
6 months | Decreased AT burden in closed loop system (20.3min/d) vs. overdrive (56min/d) or DDD (63min/d) (p<0.01) | ||||
PIRAT[44] | 70 enrolled 37 analyzed |
Device-documented AT, bradycardia | DDDR + all therapies with ERAF suppression ON vs OFF (atrial overdrive, short-long prevention, burst+ATP, ramp ATP active in both phases) | 3 months | No difference in median number AT episodes, AT burden, % ERAF, symptoms, or QOL | ||||
3/4[45] | 107 | PAF, bradycardia | 3 triggered algorithms (PAC suppression, short-long prevention, post-exercise response) vs. 4 (3 triggered + continuous overdrive) | 3 months | Decreased AF burden in 3 vs. 4 from (5.1 vs. 12.7, p=0.026). Decreased AF episodes in 3 vs. 4 (405 vs. 621, p=0.05). | ||||
SAFARI[28] | 554 enrolled 187 analyzed |
AF, bradycardia | All algorithms ON vs. OFF (continuous overdrive, short-long prevention, post-exercise response, PAC suppression, ERAF suppression, VRS) | 6 months | Decrease in AF burden with algorithms ON (decrease by 0.11h/d vs. increase of 0.01in OFF group). No difference AF frequency, avg sinus duration, hospitalizations, or cardioversions. |
Table 1: Trials evaluating pacing algorithms for prevention of AF (bradycardia indication required)
Trial | # Patient | Inclusion criteria | Randomization arms | Follow-up | Results | ||||
PAF-PACE[46] | 42 enrolled 35 analyzed |
≥2 episodes/month during prior 3 months | No pacing vs. medium overdrive vs. high overdrive pacing | Variable depending on severity of PAF | Medium (p=0.01) and high (p=0.002) overdrive pacing reduced symptomatic AF versus no pacing. | ||||
PIPAF[47] | 95 enrolled 55 analyzed |
≥1 episode AF within 3 months, 49% bradycardia | DDDR@70bpm with algorithms ON vs. OFF (atrial overdrive, short-long prevention, PAC suppression) | 6 months | No difference in AT duration, frequency, or symptoms. Decrease in AT duration with low ventricular pacing (p<0.04) and decrease in AT number with increased atrial pacing (p<0.03). | ||||
PAFS[48] | 182 enrolled 79 analyzed |
≥3 AF episodes within 1 month, AF burden 1-50% | Atrial overdrive vs. VRS vs. atrial overdrive + VRS + ERAF suppression vs. OFF (DDR@60bpm) | 1 month | No difference in AF burden. PAC triggered AF reduced with atrial overdrive. |
>Table 2: Trials evaluating pacing algorithms for prevention of AF (bradycardia indication not required)
Figure 1: Heart rate trend over 24 hours that shows a patient with persistent AF. Note that the ventricular rate regularization algorithm is initially turned “on” and the average heart rate is around 90 bpm. Once this algorithm is turned “off”, the average heart rate is in the range of 70 bpm.
Figure 2: Stored histogram of atrial high rate episodes over a period of several months. Initially, AF is recorded by the device as occurring daily for approximately 24 hours per day. This is consistent with the patient history of persistent AF. After AF ablation, no further AF is recorded. This information is potentially useful in patient management.
Figure 3: An example of far field over sensing on the atrial channel of a dual chamber device (arrow points to one example). Far field over sensing may result in false automatic mode switch or atrial high rate episodes. While programming the sensitivity may sometimes eliminate far field sensing, in this example the far field R wave is too large.
Figure 4: A) Pacemaker interrogation reveals multiple episodes of mode switch during a single day. This most likely represents a single episode of AF, with intermittent under sensing of atrial electrograms which results in counting multiple episodes rather than one. B) Atrial electrogram in atrial fibrillation. Note the irregular amplitude of the signals leading to intermittent under detection. This figure illustrates some of the challenges in utilizing the pacemaker to detect the amount of AF the patient is having.