Left Axillary Implantation of Loop Recorder

Background: We compared the clinical course of 10 patients who received an implantable loop recorder (ILR) at a traditional site with 11 patients whose ILRs were implanted via a subpectoral site via a left axillary approach without complications. Methods and Results: R‐wave amplitude was determined at implantation and during follow‐up. Each patient was followed after 7 days to optimize device setting and then at 1 and 3 months. The R‐wave amplitude obtained with the new technique was significantly higher and more stable than that obtained with the standard procedure. Our preliminary experience suggests that axillary access for ILR implantation is feasible, safe, well tolerated, and reliable in terms of sensing function and device performance. Moreover, it is superior aesthetically to the standard approach and carries the potential of minimizing permanent scarring after ILR extraction. (PACE 2010; 999–1002)     

Sensing Performance of a New Wireless Implantable Loop Recorder: A 12‐Month Follow Up Study

Background: The implantable loop recorder (ILR) is a cost‐effective tool with a high diagnostic yield in the evaluation of unexplained recurrent syncope. The Sleuth ILR (Transoma Medical, St. Paul MN, USA) is a new‐generation ILR with wireless transmission capability approved by the Food and Drug Administration. We report the feasibility of achieving appropriate sensing over 1‐year follow‐up at the traditional midclavicular and alternative inframammary implantation sites without preimplant electrocardiogram (ECG) mapping. Methods and Results: We studied 32 patients with unexplained syncope, aged 58.4±18.44 years, with an ILR implanted at the left midclavicular location (n = 17) or the left inframammary site (n = 15) over 1‐year post implant. No preimplant electrocardiogram (ECG) mapping was performed. The highest R‐wave amplitudes were observed at the inframammary site, but over the entire follow‐up period, amplitudes were not significantly different from those at the midclavicular site. At both sites, R‐wave amplitudes at the 6‐month follow‐up were significantly higher than those measured at 1 week. P‐waves were visible in 80–90% of the patients. There was no discernible difference in P‐waves (amplitude) relative to implant location. Body mass index, left ventricular ejection fraction, and age did not significantly influence the R‐wave amplitude or the ability to discern P‐waves. Conclusion: Our findings show that the Sleuth ILR implanted at both the midclavicular and inframammary locations without preimplant ECG mapping achieves acceptable “R” waves. This may simplify implantation procedures and improve patient satisfaction. (PACE 2010; 834–840)     

Maturation of the Sensed Electrogram Amplitude Over Time in a New Subcutaneous Implantable Loop Recorder

The cause of recurrent syncope may be difficult to determine if the diagnosis is not establisbed from initial noninvasive and invasive testing. Eighteen patients with recurrent syncope and negative tilt table and electrophysiological testing underwent implantation of a left pectoral subcutaneous loop recorder. This device "freezes" the preceding 7.5 or 15 minate rhythm strip after magnet application after spontaneous syncope. Baseline and follow-up electrograms were routinely recorded, and patients were followed until syncope recurred. Three patients bad syncope within 1 month of implantation and were excluded from this report. Implantation electrogram amplitude was 250 ±124 /μV and increased to 291 ±114 μV at 2–3 months, and increased further to 353 ± 167 μV at 4–6 months (P < 0.001, ANOVA). Syncope recurred in 14 of the 15 patients. An arrhythmic basis for syncope was established (n = 7) or excluded (n = 7) in every patient who had recurrent syncope. All syncopal episodes were associated with diagnostic sensed electrograms. The increase in sensed electrogram amplitude over time suggests a maturation of the device-tissue interface. These results support the long-term viability of this implantable monitoring technique.     

The Dual Role of Implantable Loop Recorder in Patients with Potentially Arrhythmic Symptoms: A Retrospective Single-Center Study

Background: Unexplained and potentially arrhythmic symptoms often lead to electrophysiology referral for evaluation. Implantable loop recorder (ILR) correlation of the symptom to the rhythm can secure a definitive arrhythmic diagnosis after a standard, yet nondiagnostic workup.
Methods: This large single-center retrospective study sought to assess the role of ILR in the evaluation of potentially arrhythmic symptoms, both in terms of diagnosis of an arrhythmia as well as to rule out an arrhythmic cause. Clinical data, indications for ILR, interrogation reports, and further management strategies were collected in all 86 patients who received ILR from June 1999 to April 2008 at the University of Iowa Hospitals and Clinics. The indications for ILR were unexplained syncope (76%), palpitations (14%), and presyncope or dizziness (10%).
Results: During a mean follow-up period of 10 ± 7 months, 53 patients (62%) had recurrent symptoms after ILR placement with the mean time to recurrence of 12 ± 17 weeks. Of these, an arrhythmic diagnosis was established in 12 patients (14%). Forty-one patients (48%) did not have any arrhythmia during their symptoms. These patients were discharged from the electrophysiology clinic. Thirty-three patients (38%) did not have any symptoms following ILR placement. Out of these, device was explanted in 10 patients, while the rest are still being followed.
Conclusions: In patients with potentially arrhythmic symptoms, ILR plays an important role not only in diagnosing an arrhythmia, but also to rule out an arrhythmic cause.     

Holter, Loop Recorder, and Event Counter Capabilities of Implanted Devices

The current generation of cardiac pacemakers and implantable cardioverter defibrillators almost all have some capabilites to store data regarding device activity and patient events for future retrieval. This information may provide valuable information regarding device function and whether this is proving valuable in patient management. Examples include "pace-sense" counters, which can reveal under sensing of patient events, and serial lead impedance measurements, which are able to demonstrate trends not seen on isolated measurements. Holter capabilities become vital in more advanced devices for documenting the utility of, and fine tuning the programming of, features such as antitachycardia pacing, rate-responsiveness, and mode-switching. Finally, the ability to store patient events as marker channels and even intrac-ardiac electrograms adds a diagnostic capability not available through external monitoring. This role has now been advanced by the development of a purely diagnostic implantable loop recorder.     

Heart Rhythm During Syncope and Presyncope: Results of Implantable Loop Recorders

NIEROP, P.R., et al. : Heart Rhythm During Syncope and Presyncope: Results of Implantable Loop Recorders. Ambulatory ECG monitoring in patients with recurrent syncope is nondiagnostic in the majority of cases. Recently, an ECG implantable loop recorder (ILR) has been introduced. The ILR performs continuous ECG monitoring over a period of at least 14 months. From February 1997 to September 1999, 35 patients underwent implantation of an ILR. During a mean follow-up of  11 ± 8 months  , 24 (69%) patients had recurrent syncope or presyncope events. Four (11%) patients were not capable of activating the ILR to save the event. A symptom-rhythm correlation could be studied in 20 (83%) of 24 patients. Forty of 44 recurrences were captured by the ILR. There were 14 (40%) patients with at least one syncopal episode. An arrhythmic cause for syncope was found in eight of them (bradycardia in four and tachycardia in four). In the other six patients the heart rhythm was normal. In 17 (49%) patients with 1-year follow-up, the mean syncope event rate 12 months before ILR implantation was  4.7 ± 2.4  , whereas the mean syncope event rate 12 months after ILR implantation was  1.3 ± 0.7  (  P < 0.01  ). Resolution of symptoms was observed in 6 (17%) patients. These patients were significantly younger than patients without resolution (  50 ± 18 vs 69 ± 14 years, p < 0.01  ) and five were women. Three (9%) patients died during follow-up, all of them were noncompliant during their follow-up. In conclusion, the ILR made symptom—rhythm correlation possible in 83% of patients with recurrent syncope. Syncope recurrences decreased significantly after implantation of the device, especially in the younger patients. Noncompliant patients had a high mortality rate.     

Prospective Study of Axillary Vein Puncture with or Without Contrast Venography for Pacemaker and Defibrillator Lead Implantation

Axillary vein puncture may be used to implant pacemaker (PM) or cardioverter defibrillator leads, though usually requires venography. We prospectively compared punctures guided by venography versus a new radiological landmark. In 232 patients, the puncture was guided by injecting diluted contrast material via an ipsilateral peripheral vein (group A, n = 142), or without venography using the intersection of the lateral borders of the second and third rib as a radiological landmark, followed by contrast injection in case of failure (group B, n = 90). We implantated 1–3 leads per patient. In group A, implantation was successful in 135 patients (95%) and in group B in 55 patients (61%, P < 0.001 vs group A). Subsequent contrast injection allowed successful implantations in 34 of 35 patients, with an success rate of 97% for the overall study population of 224 patients. Venous access was achieved after a mean of 10.4 ± 3.2 minutes of skin incision in group A versus 9.4 ± 3.0 minutes in group B (ns). Pneumothorax occurred in two patients (1% overall). Thus non-contrast guided puncture using a new radiological landmark was successful in a majority of patients. This technique may be useful in absence of ipsilateral peripheral vein access, or presence of contrast allergy.     

ICD Implantation in Noncompaction of the Left Ventricular Myocardium: A Case Report

Isolated noncompaction of the ventricular myocardium (INVM) is an uncommon cardiomyopathy characterized by the persistence of fetal myocardium with prominent trabecular meshwork and deep intertrabecular recesses, often associated with systolic dysfunction and ventricular dilatation. A 23-year-old man from Burkina Faso was referred to our operative unit with a diagnosis of INVM, made with echocardiogram and magnetic resonance imaging and nonsustained ventricular tachycardia. The literature reports the incidence of malignant ventricular arrhythmias in as many as 47% of the patients and sudden cardiac death in almost 50% of them and this supported our decision to perform implantable cardioverter-defibrillators implantation.     

Short-and Long-Term Performance of a Tripolar Down-Sized Single Lead for Implantable Cardioverter Defibrillator Treatment: A Randomized Prospective European Multicenter Study

A new, thinner (10 Fr) and more flexible, single-pass transvenous endocardial ICD lead, Endotak DSP, was compared with a conventional lead, Endotak C, as a control in a prospective randomized multicenter study in combination with a nonactive can ICD. A total of 123 patients were enrolled, 55 of whom received a down-sized DSP lead. Lead-alone configuration was successfully implanted in 95% of the DSP patients vs 88% in the control group. The mean defibrillation threshold (DFT) was determined by means of a step-down protocol, and was identical in the two groups, 10.5 ± 4.8 J in the DSP group versus 10.5 ± 4.8 J in the control group. At implantation, the DSP mean pacing threshold was lower, 0.51 ± 0.18 V versus 0.62 ± 0.35 V (p < 0.05) in the control group, and the mean pacing impedance higher, 594 ± 110 Ω vs 523 ± 135 Ω (p < 0.05). During the follow-up period, the statistically significant difference in thresholds disappeared, while the difference in impedance remained. Tachyarrhythmia treatment by shock or antitachycardia pacing (ATP) was delivered in 53% and 41%, respectively, of the patients with a 100% success rate. In the DSP group, all 28 episodes of polymorphic ventricular tachycardia or ventricular fibrillation were converted by the first shock as compared to 57 of 69 episodes (83%) in the control group (p < 0.05). Monomorphic ventricular tachycardias were terminated by ATP alone in 96% versus 94%. Lead related problems were minor and observed in 5% and 7%, respectively. In summary, both leads were safe and efficacious in the detection and treatment of ventricular tachyarrhythmias. There were no differences between the DSP and control groups regarding short- or long-term lead related complications.     

A Prospective Randomized Evaluation of VV Delay Optimization in CRT-D Recipients: Echocardiographic Observations from the RHYTHM II ICD Study

Background: All current cardiac resynchronization therapy (CRT) devices allow the programming of the atrioventricular (AV/PV) delays and the sequential stimulation of the ventricles via the inter ventricular (VV) delay.
Aim: This post hoc analysis of the RHYTHM II study was conducted to compare the reverse remodeling associated with VV delay optimization in patients randomly assigned to simultaneous (SIM) biventricular stimulation versus patients assigned to optimized VV delay programming (OPT) (1:3 randomization scheme).
Methods: The analysis included 14 patients assigned to the SIM group and 34 patients to the OPT group who completed the 6-month follow-up period with paired echocardiographic recordings.
Results: In both study groups, changes consistent with left ventricular (LV) remodeling were observed between baseline and 6 months, with significant improvements in LV function and decrease in LV dimensions. In the OPT group, there was also a decrease in left atrial diameter and mitral valve closure to opening time. At 6 months, the overall proportion of echocardiographic responders (≥10% decrease in LV end-systolic volume or ≥5% absolute increase in LV ejection fraction) was similar in both groups. The optimal AV/VV delays, evaluated by maximization of LV outflow tract velocity time integral, changed over time.
Conclusions: Ventriculo-ventricular delay optimization was associated with better immediate hemodynamic function than simultaneous biventricular stimulation, though did not promote additional reverse remodeling at 6 months and did not increase the proportion of echocardiographic responders to CRT. Optimization of both the AV and VV intervals was patient-specific and optimal values changed over time.     

Multicenter evaluation of implantable cardioverter defibrillator testing after implant: the Post Implant Testing Study (PITS)

To reassess the function of the implantable cardioverter defibrillator (ICD) many electrophysiology centers perform a second test after the initial test at implant. A prospective multicenter study evaluated the necessity and yield of routine postimplant defibrillator testing. The results of 843 postimplant defibrillator tests were collected from 31 centers. The 764 routine tests in which ventricular fibrillation was successfully induced were analyzed. Variables examined included patient age, presenting arrhythmia, underlying heart disease, left ventricular ejection fraction, defibrillator age, make and model of ICD, electrode system, defibrillation threshold, polarity, and waveform. The overall failure rate was 3.1% (24/764). Units tested later than 365 days after implant tended to have a higher failure rate than those tested within the first month or the next eleven months (6.5%, 3.0%, 2.3%, respectively, P = 0.374). The failure rate was higher in patients with left ventricular ejection fraction < 40% than those with higher ejection fractions (3.8% vs 2.0%, P = 0.167). These trends did not reach statistical significance. No other baseline characteristic was associated with higher failure rates. Routine testing of ICDs reveals an overall failure rate of 3.1%. While the rate was low, defibrillator failure places the patient at high risk for sudden cardiac death. As any failure in this population is associated with a high risk of sudden cardiac death, routine defibrillator testing may be justified.     

氨基葡萄糖联合布洛芬与单用布洛芬治疗髋关节骨关节炎前瞻性随机对照临床研究

目的探讨氨基葡萄糖联合布洛芬治疗髋关节骨关节炎的临床疗效。方法 2011年9月-2012年1月采用前瞻性随机对照临床试验,将198例轻、中度髋关节骨关节炎患者随机分入试验组及对照组。试验组采用氨基葡萄糖(750 mg,2次/d口服,疗程1个月)联合布洛芬(0.3 g,2次/d口服,疗程2周),对照组则单用布洛芬(0.3 g,2次/d口服,疗程2周);分别于服药后0、2、4、8及12周时采用加拿大西安大略和麦克玛斯特大学骨关节炎指数(WOMAC)进行疗效评价。并对恶心、呕吐、皮疹等药物不良反应进行观察。结果试验组与对照组WOMAC各项评分从第2周开始较0周明显下降,而两组患者间在0周及2周时WOMAC评分无统计学差异:0周总评分(45.3、45.0分,P=0.225),2周总评分(37.3、37.6分,P=0.329)。但对照组WOMAC各项评分从第4周开始逐渐呈现上升趋势,而试验组到第12周仍呈现持续性下降趋势。总不良反应发生率为7.0%,其中试验组总不良反应发生率为9.5%,但不良反应轻微,未予特殊处理而自行消失。结论氨基葡萄糖联合布洛芬可有效缓解早、中期髋关节骨关节炎各项临床症状,疗效确切,不良反应较少,且停药后仍持续表现出治疗效果。而单用布洛芬可短期缓解骨关节炎症,但停药后症状逐渐复现。