Cardiac pacemaker: In vitro assessment at 1.5 T

Response to Letter to the Editor

“…Regardless, by way of response, the gelled saline was allowed to equilibrate for an acceptable period of time prior to obtaining temperature measurements. The highest temperature changes occur at the onset of MRI, as reported in this and many prior studies [5][6][7][8]19,20]. bLaterQ temperature changes (i.e., those that occur after the first 2 min or so of MR imaging) do not tend to contribute substantially to the overall impact of DBS electrode heating.…”

“…On a different point, the effect of changing landmarks relative to the position of an implanted device with respect to heating has been described in several recent and upcoming papers [17][18][19][20][21]. As such, we do not feel that it is necessary to respond to this issue, as our goals for evaluating DBS lead heating were specific to the conditions described in the Methods section of our paper.…”

“…We would like to respectfully point out that the peer-reviewed literature, including several articles authored by the Baker et al group, has generally used this same strategy to assess MRI-related heating for various implants, including neurostimulation systems, cardiac pacemakers and other devices [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Importantly, the American Society of Testing and Materials International has a standard that specifies this approach to evaluate MRIrelated heating for implants (i.e., single acquisition, landmark location, etc.)…”

Multicenter study of the safety and effects of magnetic resonance imaging in patients with coronary sinus left ventricular pacing leads

“…Heating of the lead correlates with the SAR, is greatest with imaging of the chest, and is highest at the lead tip. 6,7 This could result in vascular complications in the CS (i.e. thrombus or perforation) or impaired CS LV lead function mediated by thermal injury.…”

Role of the lead structure in MRI‐induced heating: In vitro measurements on 30 commercial pacemaker/defibrillator leads

“…Experimental in vitro measurements of the temperature increase at the lead tip of PMs/ICDs during RF exposure show widely varying results, with values ranging from negligible degrees up to more than 60 C (11,17,18,21,30,31). Most of these studies focused only on the induced heating at the lead tip, whereas the temperature increase at the ring of bipolar leads is either considered negligible or even not mentioned.…”