Cardiac Resynchronization Therapy in the Young Patient: Current Status and Future Directions

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74749/1/j.1540-8167.2006.00591.x.pd

Delayed Response to Radiofrequency Ablation of Accessory Connections

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72240/1/j.1540-8159.1993.tb01019.x.pd

Antitachycardia Pacemakers in Congenital Heart Disease

BackgroundMany patients with congenital heart disease (CHD) acquire rhythm abnormalities related to their repair, most commonly intraatrial reentrant tachycardia (IART). Treatment of IART in CHD is often multifaceted, and may include medication, ablation, and pacing. Evidence regarding the use of antitachycardia pacing therapies is limited.ObjectiveThe aim of the study is to define the use and efficacy of antitachycardia pacing in patients with CHD at a single center.ResultsEighty implants were performed on 72 patients between 2000 and 2010. Follow‐up data of more than 3 months were available for 56 patients; median follow‐up time was 2.8 years. Twenty (36%) patients received successful antitachycardia pacing at a median 1.3 years postimplant. For those patients with IART after implant, antitachycardia pacing was successful in 57%. Patients with two‐ventricle repairs were more likely to have successful antitachycardia pacing than those with one‐ventricle palliation (45% vs. 17%, P = .04). Patients with documented IART had more successful antitachycardia pacing than those with no documented atrial tachycardia prior to implant (46% vs. 7%, P = .006). Early complications of antitachycardia pacemaker implant occurred in six patients (11%); late complications after implant occurred in three patients (5.6%). Of the initial 72 patients implanted, there were six deaths (8%).ConclusionsAntitachycardia pacing therapies were successful in the majority of CHD patients who had IART after implant. Patients without documented atrial tachycardia prior to implant were unlikely to require or receive successful therapy from antitachycardia pacemaker. Those patients postatrial switch procedure who had documented IART prior to implant had the highest incidence of successful antitachycardia pacing therapies. Antitachycardia pacemaker implantation is an adjunct to the management of IART in CHD patients, but may not benefit patients who have not yet demonstrated IART.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111221/1/chd12230.pd

Automatic Atrial Threshold Measurement and Adjustment in Pediatric Patients

Background: Automatic threshold measurement and output adjustment are used as default settings in modern pacemakers. The purpose of the study was to assess Atrial Capture Management (ACM) of Medtronic pacemakers in pediatric patients. Methods: Forty children were enrolled in two centers. Median age was 9.8 years (range 0.8–17.5 years). Half had undergone surgery for congenital heart defects; 45% of patients had an epicardial atrial lead. The pacing indication was atrioventricular block in 82% of patients and sinus node disease in 18%. Manually determined atrial thresholds and ACM measurements were compared. Results: ACM measurements were within the expected variation in 37/40 (93%) of the patients. In one patient the threshold was 0.625-V lower manually than with ACM. One patient had too high an intrinsic atrial rate for ACM to be able to measure threshold. The mean threshold at 0.4 ms was 0.69 ± 0.32 V manually and 0.68 ± 0.35 V with ACM (two-tailed paired t- test, P = 0.52) in all patients. The mean difference was 0.012 V (95% confidence interval: −0.027, 0.053). The mean endocardial threshold was 0.70 ± 0.36 V manually and 0.69 ± 0.38 V with ACM; epicardial threshold was 0.67 ± 0.27 V manually and 0.68 ± 0.32 V with ACM. The difference between the measurements was 0.012 V for endocardial and 0.014 V for epicardial leads. No atrial arrhythmias due to ACM measurements were observed. Conclusions: ACM measures atrial thresholds reliably in pediatric patients with both endocardial and epicardial leads, allowing its use in both. Constant high intrinsic atrial rate may prevent automatic threshold measurement in young children. (PACE 2010; 33:309–313)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79326/1/j.1540-8159.2009.02619.x.pd

Frequency of CIED remote monitoring: A quality improvement follow‐up study

BackgroundBased on the findings of a prior study of CIED (Cardiac Implantable Electrical Device) remote monitoring (RM) frequency at the same center, the University of Michigan Congenital Heart Center (UMCHC) instituted a quality improvement (QI) change to reduce the frequency of routine CIED RM from every 2 months to every 3 months. The objective of this study is to determine the impact of this QI initiative to reduce workload without compromising patient care.MethodsThis is a single‐center, retrospective cohort study of all UMCHC patients with CIEDs followed via Medtronic CareLink CIED remote monitoring system from July 2015 to June 2017, after the QI change in 2014. The primary outcome was success of transition to new monitoring schedule. Secondary outcomes included complications, incidence of actionable events (AES), patient compliance, and change in workload. Outcomes were compared to the prior study.ResultsThere were 325 patients (mean age was 24  ±  14 years) included, of who 293 (90%) completely transitioned to the new RM schedule. During the study period, 96 transmissions included AES (4% of total), of which 50 (52%) were asymptomatic and discovered on routine monitoring. No patient experienced a complication attributable to decreased RM frequency. The mean number of interrogations decreased by 1.6 per patient over the 2‐year period compared to prior study.ConclusionsThis study demonstrated successful implementation of a QI initiative to reduce CIED monitoring frequency at a single center with no patient adverse events. The intervention reduced workload and potentially improved patient compliance with routine RM.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150575/1/pace13707_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150575/2/pace13707.pd

Implantable Cardioverter Defibrillator Outcomes in Pediatric and Congenital Heart Disease: Time to System Revision

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/122425/1/pace12878.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/122425/2/pace12878_am.pd

Use of a Single Coil Transvenous Electrode with an Abdominally Placed Implantable Cardioverter Defibrillator in Children

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73702/1/j.1540-8159.2000.tb00859.x.pd

Usefulness of the doppler mean gradient in evaluation of children with aortic valve stenosis and comparison to gradient at catheterization

To assess the usefulness of the Doppler mean gradient as a noninvasive indicator of the need for intervention, 33 children (ages 3 months to 20 years) with valvular aortic stenosis (AS) underwent a 2-dimensional and Doppler echocardiographic examination a median of 1 day before cardiac catheterization. The clinical decision for intervention was based on finding a catheterization peak-to-peak pressure gradient of >75 mm Hg or from 50 to 75 mm Hg in the presence of symptoms or an abnormal exercise treadmill test result. Of the 33 patients, 23 required intervention. The decision for intervention was compared to the Doppler mean gradient, and the Doppler peak and mean gradients were compared to the catheterization peak-to-peak gradient. All 12 patients with a Doppler mean gradient >27 mm Hg had intervention and had a catheterization peak-to-peak gradient of >75 mm Hg. All 3 patients with a Doppler mean gradient From a chi-square table, a Dopppler mean gradient >27 mm Hg predicted the need for intervention with 100% specificity (no false positives) and 52% sensitivity (11 false negatives). if a Doppler mean gradient >24 mm Hg was used to predict intervention, the sensitivity increased to 91% (2 false negatives) but specificity decreased to 70% (3 false positives). To improve the ability to predict the need for intervention in patients with a Doppler mean gradient between 17 and 27 mm Hg, the presence of symptoms or an abnormal exercise treadmill test result was combined with the Doppler mean gradient as criteria for intervention. When the criteria for intervention were a Doppler mean gradient >27 mm Hg or a Doppler mean gradient from 17 to 27 mm Hg in the presence of symptoms or an abnormal exercise test, sensitivity was 96% (1 false negative) and specificity was 80% (2 false positives). Catheterization peak-to-peak gradients correlated well with Doppler mean and peak gradients (r = 0.74 and 0.73, respectively).Thus, the Doppler mean gradient is a useful indicator of the need for intervention in children with AS. A Doppler mean gradient >27 mm Hg indicates the need for intervention with 100% specificity while a Doppler mean gradient < 17 mm Hg predicts mild AS. For patients with Doppler mean gradient between 17 and 27 mm Hg, additional noninvasive data are necessary to determine the need for intervention.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27748/1/0000140.pd

Tachycardia Related Cardiomyopathy: Response to Control of the Arrhythmia

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75609/1/j.1540-8183.1989.tb00780.x.pd