After BSPM, MRI markers were applied to replace all torso electrodes. These markers were used to locate the electrode positions on the MRI images, thereby minimizing the systematic error in the inverse procedure. Before entering the MRI room, pacing thresholds, P- and R-wave amplitude, and lead impedance were determined and the pacemaker system was programmed into MRI SureScan® mode [8 ].
In order to control lung volume, breath holding was practiced with the patient prior to the examination. A stack of ECG-triggered, T2-weighted, bright blood images (slice thickness, 6 mm) was acquired to record the anatomy of the thorax and register the position of the RV lead tip and torso electrodes. Subsequently, cardiac function was assessed using steady state free precession (SSFP) short-axis, three- and four-chamber cines (slice thickness, 6 mm, temporal resolution <50 ms). All images were obtained during breath-hold on a Siemens Aera 1.5 Tesla MRI scanner (Siemens Healthcare, Erlangen, Germany). Cardiac function was analysed using CMR42® software (Circle Cardiovascular Imaging, Calgary, Alberta, Canada).
After the examination, pacing thresholds, P- and R-wave amplitude and lead impedance were determined and compared to the initial values. Finally, original programming of the pacemaker was restored.
In order to control lung volume, breath holding was practiced with the patient prior to the examination. A stack of ECG-triggered, T2-weighted, bright blood images (slice thickness, 6 mm) was acquired to record the anatomy of the thorax and register the position of the RV lead tip and torso electrodes. Subsequently, cardiac function was assessed using steady state free precession (SSFP) short-axis, three- and four-chamber cines (slice thickness, 6 mm, temporal resolution <50 ms). All images were obtained during breath-hold on a Siemens Aera 1.5 Tesla MRI scanner (Siemens Healthcare, Erlangen, Germany). Cardiac function was analysed using CMR42® software (Circle Cardiovascular Imaging, Calgary, Alberta, Canada).
After the examination, pacing thresholds, P- and R-wave amplitude and lead impedance were determined and compared to the initial values. Finally, original programming of the pacemaker was restored.