Optimization Of Device Settings Research Articles

Optimizing Inspire Hypoglossal Nerve Stimulator Settings in Pediatric Obstructive Sleep Apnea.

Hypoglossal nerve stimulation (HGNS) is an effective therapy for carefully selected pediatric patients with Down syndrome (DS) and obstructive sleep apnea (OSA), but optimization of device settings has been focused on stimulation settings. The potential benefits of sensing lead setting optimization have not been investigated. We describe a series of three cases of HGNS in children with DS where optimization of both the stimulation lead and sensing lead settings, as well as utilization of drug-induced sleep endoscopy (DISE), when indicated, was more effective than stimulation lead optimization alone. Using our novel titration algorithm, among the three identified pediatric patients with DS in whom HGNS initially failed to reduce the apnea-hypopnea index (AHI), two patients in whom sleep studies were characterized as hypopnea-dominant were assigned to advanced titration (optimization of stimulation settings and sensing lead settings). The third patient, with an obstructive apnea-dominant sleep study, was referred for interrogated DISE. Advanced titration included adjustment of both stimulation settings and sensing lead settings. Application of the advanced titration algorithm, tailored to obstructive apnea- versus hypopnea-dominant sleep patterns, resulted in approximately 50% or greater reduction in AHI in all three patients. "Normal to mild OSA" AHI (AHI <5) was achieved in two patients. A novel diagnostic and therapeutic titration algorithm for the Inspire HGNS system significantly reduced AHI in three pediatric patients with DS and OSA who had failed to respond to the standard device titration that focused solely on stimulation settings. 4 Laryngoscope, 134:5164-5169, 2024.

Ventricular fibrillation episodes related to managed ventricular pacing algorithm in a patient with mitral valve prolapse - "Arrhythmic MVP due to MVP".

We report a case of an implant cardiac defibrillator (ICD) patient who an ICD implanted for ventricular fibrillation (VF) related to mitral valve prolapse. He has 2 episodes of VF in his device lives. First episode of VF in year 2016 was initiated after a pause related to the MVP™ algorithm with a critically timed PVC. MVP™ was turned off which prevented further VF episodes. However, MVP™ was turned back on at the device replacement in 2018. A second VF episode developed with similar mechanism in 2021 and MVP™ was subsequently turned off with no further VF recorded. This case highlights the importance of recognizing the mechanism of initiation of tachy-arrhythmia episodes and serves as an important reminder regarding optimization of device settings at the time of replacement.

The Comprehensive Assessment of Left Ventricular Assist Devices by Echocardiography

Echocardiography is the imaging modality of choice for patient selection prior to left ventricular assist device (LVAD) implantation, assessment of device placement, optimization of device settings, diagnosis of device-related complications, and assessment of LV recovery. The key echocardiographic features of these devices will be highlighted in the following review. With increased utilization of LVADs as well as the development of centrifugal continuous-flow pumps, familiarity with echocardiographic imaging of LVADs is essential to optimal care of these complex patients. All echocardiographic evaluations both before and after LVAD implantation should assess for biventricular function and cavity size, valvular function and pathology, intracardiac thrombi, intracardiac shunting, cannula position and flow, aortic pathology, and pericardial effusion. RAMP testing may be utilized when device complications are suspected.

Predictors of nonsimultaneous interventricular delay at cardiac resynchronization therapy optimization.

Cardiac resynchronization is a well tolerated and effective therapy for heart failure, but 30% of patients still do not respond to biventricular pacing. Optimization of device settings, in particular interventricular delay value, represents a plausible target for improving these results, but available literature is discordant. We aimed our study at the identification of the best suitable candidates to interventricular delay optimization. A total of 77 consecutive patients with optimized drugs therapy underwent clinical, echocardiographic and electrocardiographic evaluation before and after 6 months from implantation of a biventricular defibrillator in accordance to current guidelines. In each patient, atrioventricular and interventricular delay values were optimized at predischarge with echocardiogram. The only predictor of an optimized interventricular delay value different from simultaneous (i.e. standard shipment setting), at both univariate and multivariate analyses, was a QRS duration greater than 160 ms (odds ratio 22.958; P = 0.003) with a sensitivity of 70.9%. Candidates to cardiac resynchronization therapy with a basal QRS greater than 160 ms have a higher chance of requiring echo-guided tailoring of interventricular delay value. A strategy based on these data can potentially improve device programming, reducing by one-third the need for optimization, according to our findings, and at the same time avoid unnecessary time-consuming procedures.

Relationship between intracardiac impedance and left ventricular contractility in patients undergoing cardiac resynchronization therapy

AimsCardiac resynchronization therapy (CRT) has dramatically improved the symptoms and prognosis of patients with heart failure in large randomized clinical trials. Optimization of device settings may maximize benefit on an individual basis, although the best method for this is not yet established. We evaluated the use of cardiogenic impedance measurements (derived from intracardiac impedance signals) in CRT device optimization, using invasive left ventricular (LV) dP/dtmax as the reference.Methods and resultsSeventeen patients underwent invasive haemodynamic assessment using a pressure wire placed in the LV cavity at the time of CRT device implantation. Intracardiac impedance measurements were made at different atrioventricular (AV) and interventricular (VV) delays and compared with LV dP/dtmax. We assessed the performance of patient-specific and generic impedance-based models in predicting acute haemodynamic response to CRT. In two patients, LV catheterization with the pressure wire was unsuccessful and in two patients LV lead delivery was unsuccessful; therefore, data were acquired for 13 out of 17 patients. Left ventricular dP/dtmax was 919 ± 182 mmHg/s at baseline and this increased acutely (by 24%) to 1121 ± 226 mmHg/s as a result of CRT. The patient-specific impedance-based model correctly predicted the optimal haemodynamic response (to within 5% points) for AV and VV delays in 90 and 92% of patients, respectively.ConclusionCardiogenic impedance measurements are capable of correctly identifying the maximum achievable LV dP/dtmax as measured by invasive haemodynamic assessment. This study suggests that cardiogenic impedance can potentially be used for CRT optimization and may have a role in ambulatory assessment of haemodynamics.

The role of echocardiography in cardiac resynchronization therapy

Echocardiography is the most important imaging tool for managing heart failure patients. With the advent of cardiac resynchronization therapy (CRT), its role has been broadened by data pertaining to patient selection, optimization of device settings, and outcome assessment. Beyond ejection fraction determination, echocardiographic methods that measure tissue velocity and strain may have the capability to determine degree of mechanical dyssynchrony and possibly predict likelihood of benefit with CRT. After implantation (as the ventricles are fully paced, adjusting the atrioventricular delay ), the timing of the right ventricular and left ventricular lead stimulation (ventricular-ventricular optimization) to achieve maximal cardiac filling or ejection may be clinically important. Atrioventricular and ventricular-ventricular optimization rely on echocardiography to determine optimal values. In long-term follow-up, serial measurement of left ventricular volume has significant correlation with mortality and is a reasonable measure of successful CRT; echocardiography is uniquely suited for this purpose.

Pacemaker optimization guided by echocardiography in cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) or biventricular pacing is a contemporary treatment in the management of advanced heart failure. Echocardiography plays an evolving and important role in patient selection for CRT, follow-up of acute and chronic CRT effects and optimization of device settings after biventricular pacemaker implantation. In this paper we illustrate usefulness of echocardiography for successful AV and VV timing optimization in patients with CRT. A review of up-to-date literature concerning rationale for AV and VV delay optimization, echocardiographic protocols and current recommendations for AV and VV optimization after CRT are also presented. The first case is of successful AV delay optimization guided by echocardiography in a patient with dilated cardiomyopathy treated with CRT is presented. Pulsed blood flow Doppler was used to detect mitral inflow while programming different duration of AV delay. The AV delay with optimal transmittal flow was established. The optimal mitral flow was the one with clearly defined E and A waves and maximal velocity time integral (VTI) of the mitral flow. Improvement in clinical status and reverse left ventricle remodelling with improvement of ejection fraction was registered in our patient after a month. The second case presents a patient with heart failure caused by dilated cardiomyopathy; six months after CRT implantation the patient was still NYHA class III and with a significantly depressed left ventricular ejection fraction. Optimization of VV interval guided by echocardiography was undertaken measuring VTI of the left ventricular outflow tract (LVOT) during programming of different VV intervals. The optimal VV interval was determined using a maximal LVOT VTI. A month after VV optimization our patient showed improvement in LV ejection fraction. Optimal management of patients treated with CRT integrate both clinical and echocardiographic follow-up with, if needed, echocardiographically guided optimization of AV and VV delays, which offers the possibility of additional clinical improvement in such patients.