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Biomedical subjects

J Rod Gimbel

Publications and source records attributed to J Rod Gimbel.

10 recordsLinked to original sources

Method and demonstration of direct confirmation of response to cardiac resynchronization therapy via preimplant temporary biventricular pacing and impedance cardiography.

Temporary resynchronization therapy pacing is feasible, and impedance cardiography (ICG) can provide evidence of hemodynamic benefit before permanent pacemaker implantation. During an electrophysiologic study performed before permanent device implantation, a guidewire was placed in a tributary of the coronary sinus to allow pacing of the left ventricle. Temporary pacing was implemented in various modalities, during which time ICG was used to document the hemodynamic consequences of atrial pacing, dual-chamber pacing, and biventricular pacing, with biventricular pacing being hemodynamically most favorable.

Cardiac Pacing, Artificial↗

A streamlined, anchored, anatomical approach to ablation of atrioventricular nodal reentry tachycardia: preliminary report of the first 25 cases.

UNLABELLED: A pseudo r' in V1 during supraventricular tachycardia (SVT), but not during sinus rhythm is pathognomonic for AV nodal re-entry tachycardia (AVNRT). During radiofrequency (RF) energy delivery, stability of the catheter tip is crucial. Intra-procedural catheter and patient movement as well as abrupt rhythm changes can lower efficacy, prolong procedural time, and contribute to the risk of AV block. OBJECTIVES: A novel streamlined approach using a single sheath and two catheters was evaluated that leverages the patient's own anatomy to help stabilize catheter position during RF application and localize RF targets. METHODS: Twenty-five consecutive patients presenting with documented SVT were ablated using a single sheath technique with only two catheters. A 12F 75 cm sheath was inserted via the right femoral vein and its tip is placed at base of the right atrium (RA). Through this sheath a 6F coronary sinus (CS) catheter and 6F ablation catheter are placed. After confirming the diagnosis of AVNRT, the ablation catheter tip is positioned anterior to the CS os in the slow pathway region. During RF application, the mobility constraints of the "sheath-catheter-catheter" complex provide excellent electrogram and catheter stability by taking advantage of the "collaring" effect of the sheath which is in turn "anchored" to the diagnostic CS catheter. RESULTS: Acute procedural success was 100% with no apparent complications. Flouroscopy time was modest (8.5 min (range 3.1-22)) as were the case times (mean 120 min (range 52-206)). Cost savings compared to "3 cath-3 sheath" approach was 113 U.S. dollars and would be much larger if compared to newer non-flouroscopic navigational systems or using alternative ablation energy sources. CONCLUSIONS: This new approach minimizes ablation catheter tip movement on the slow pathway region providing a safe, successful, speedy, and economical alternative to a traditional 3 or 4 catheter approach in appropriately selected SVT patients.

Adult↗

Strategies for the safe magnetic resonance imaging of pacemaker-dependent patients.

OBJECTIVE: To determine if strategies used to safely scan nonpacemaker-dependent patients could be applied to facilitate safe MRI of pacemaker-dependent patients. INTERVENTIONS: Ten pacemaker-dependent patients underwent a total of 11 MRI scans of the head and neck. Screening, reprogramming VOO or DOO at 60 ppm, and monitoring strategies were used to facilitate MRI. A transmit-receive coil was used and MRI pulse sequences were modified to limit the whole-body specific absorption rate (SAR). RESULTS: All scans proceeded uneventfully. No difficulties in post-MRI telemetry or interrogation were seen and no post-MRI programming changes were noted. No patient experienced arrhythmia or symptoms during or immediately after MRI. Battery status remained unchanged. No patient experienced post-MRI change in sensing thresholds. Three patients showed no change in the atrial or ventricular pacing thresholds when the pre-MRI values were compared to the immediate post-MRI values and the 3-month follow-up values. All other patients showed a rise or fall of 0.5 V in their chamber threshold values when the pre-MRI, post-MRI, and 3-month follow-up values were compared. More patients showed a fall in their pacing thresholds than a rise post-MRI. CONCLUSION: While clearly a higher risk group, like nonpacemaker-dependent patients, MRI might be performed in pacemaker-dependent patients if appropriate pacemaker reprogramming, patient monitoring, and MRI scanning techniques are implemented.

Humans↗

Outcome of magnetic resonance imaging (MRI) in selected patients with implantable cardioverter defibrillators (ICDs).

OBJECTIVE: To determine if simple strategies used to safely scan pacemaker patients could be applied to implantable cardioverter defibrillator (ICD), patients undergoing MRI allowing ICD patients to undergo MRI as well. INTERVENTIONS: Screening, reprogramming, and monitoring strategies were used to facilitate MRI. RESULTS: Seven patients underwent eight MRI scans at 1.5 T. Post-MRI, all devices demonstrated no change in pacing, sensing, impedances, charge times, or battery status. The patient undergoing a lumbar spine scan experienced a "power-on-reset" of his ICD without permanent impairment of his device. CONCLUSION: Scanning of ICD patients might be performed if appropriate reprogramming and monitoring is implemented.

Defibrillators, Implantable↗

Safe scanning, but frequent artifacts mimicking bradycardia and tachycardia during magnetic resonance imaging (MRI) in patients with an implantable loop recorder (ILR).

BACKGROUND: Patients with implantable devices are generally not permitted to undergo magnetic resonance imaging (MRI) because of potentially deleterious interactions. Little has been reported regarding the safety and effects of MRI scanning of patients with implantable loop recorders (ILRs). We evaluated the safety of scanning patients with ILRs and the output of the ILR after undergoing MRI. METHODS: Ten patients underwent 11 MRI scanning events. All patients had Reveal Plus (Medtronic, Minneapolis, MN) ILRs. Seven cranial, two lumbar-spine, one shoulder, and one knee MRI were performed. All of the MRIs were performed with the understanding that the patient had an ILR. In each patient, the ILR was cleared moments before the scan and the integrity of the signal and time date stamp were verified. The devices were reinterrogated immediately after MRI in 10 patients and two days post MR scanning in one patient. Each patient was questioned post MRI regarding any symptoms experienced during the scan. RESULTS: Both tachy and bradyarrhythmias appeared as artifacts as a result of ILR exposure to MRI. Post MRI, none of the ILRs showed diminished signal integrity, altered programmed parameters, diminished battery status, inability to communicate or be reprogrammed. No sensations of tugging or warmth at the implant site were noted. CONCLUSION: MRI was performed in ILR patients without harm to the patient or permanent damage to the ILR. MRI scanning of the Reveal appears safe. Artifact mimicking an arrhythmia was common, however, and must be excluded in any ILR patient undergoing MRI to avoid mistakenly attributing a syncopal episode, or palpitations to the artifacts produced from MRI exposure.

Artifacts↗