Table 3.

Device Parameter Changes Immediately after Cardiac Magnetic Resonance Imaging Study and at Follow-up Compared to Pre-scan Values

Parameter	Post change	Post percent change	p-value	Follow-Up change	Follow-up percent change	p-value
P-wave amplitude (mV)	0 (−0.3 to 0.1)	0 (−11 to 5)	0.256	0 (−0.4 to 0.7)	2.7 (−11 to 37)	0.182
R-wave amplitude (mV)	0 (−0.4 to 0.3)	0 (−5 to 3)	0.492	0 (−0.6 to 0.4)	0 (−8 to 5)	0.331
Atrial-lead impedance (Ω)	−7 (−20 to 0)	−2 (−4 to 0)	<0.0001	−18.5 (−41 to 6)	−4 (−8 to 1)	0.007
Right-ventricular lead impedance (Ω)	0 (−19 to 0)	0 (−4 to 0)	0.0001	−19 (−44 to 7)	−2.7 (−9 to 2)	0.006
Left-ventricular lead impedance (Ω)	−10 (−30 to 0)	−3 (−6 to 0)	0.023	−30 (−130 to 0)	−8 (−18 to 0)	0.003
Shock lead impedance (Ω)	0 (−2.5 to 1)	0 (−3 to 2)	0.100	−2 (−4 to 1.3)	−3 (−7 to 2)	0.219
Atrial capture threshold (V)†	0 (0 to 0)	0 (0 to 0)	0.847	0 (−0.1 to 0.125)	0 (−12.5 to 20)	0.440
Right-ventricular capture threshold (V)†	0 (0 to 0)	0 (0 to 0)	0.072	0 (0 to 0.175)	0 (0 to 17)	0.100
Left ventricular capture threshold (V)†	0 (0 to 0.175)	0 (−18 to 6)	0.4875	−0.05 (−0.22 to 0.10)	−3 (−10 to 13)	0.336
Battery‡
Voltage (V)	0 (0 to 0)	0 (0 to 0)	0.1147
Longevity (years)	0 (0 to 0)	0 (0 to 0)	0.116

^†Direct comparisons not performed if pulse width were different

^‡Battery parameters were not evaluated at follow-up due to many other unrelated intervening factors which may affect this parameter