CRT Response in Patients with Renal Dysfunction
Introduction
Renal dysfunction is associated with increased morbi‐mortality in heart failure patients. Data regarding functional and clinical efficacy ...of cardiac resynchronization therapy (CRT) in this population are limited.
Methods and Results
We aimed to evaluate the rate of functional response to CRT in patients with renal dysfunction and its association with long‐term mortality.
Our study included a total of 179 consecutive patients implanted between 2007 and 2010. The rate of functional response to CRT (defined by a composite score using New York Heart Association functional class, 6‐minute walk test, and quality of life) was compared between patients with and without renal dysfunction (defined as eGFR < or ≥60 mL/min/1.73 m2). Survival analysis estimates were constructed according to the Kaplan–Meier method, with results comparison using the log‐rank test.
During a median follow‐up of 4.2 years, 73 patients (40%) died. Patients with low eGFR were older (72 ± 8 years vs. 64 ± 12 years; P < 0.001), and had higher prevalence of ischemic heart disease (75% vs. 53%; P = 0.003). Functional response rates did not differ significantly between patients with and without renal dysfunction (58% and 69%, respectively; P = 0.14). Despite overall higher mortality in patients with low eGFR (53.8% vs. 22.7%; P < 0.001), the presence of functional response at 1 year among patients with renal dysfunction was still independently associated with an improved long‐term survival (HR = 0.49 95%CI: 0.28–0.83; P = 0.009).
Conclusion
Functional response to CRT at 1 year does not differ significantly between patients with or without kidney disease, and is an independent predictor of improved long‐term survival in patients with renal dysfunction.
Background: High left ventricular pacing (LVP) thresholds and phrenic nerve stimulation (PNS) are common problems with cardiac resynchronization (CRT). Newer systems capable of multiple LVP ...configurations may help overcome these problems without the need for reoperation.
Methods: CRT systems capable of multiple LVP configurations (Guidant models H155 and H145) were implanted in 43 patients (study group). An additional 49 patients (control group) received CRT systems (Guidant, Medtronic, Biotronik, St. Jude Medical, various models) lacking this feature.
Results: Overall, acute high (≥2.5 V/0.5 ms) LVP thresholds were encountered in 13 (30%) of the study group, and 25 (50%) of control group patients (P = 0.03). PNS was encountered in 5 (12%) of the study group and 12 (24%) of control group patients (P = 0.13). All cases of high LVP thresholds and PNS in the study group were managed by switching to a different LVP configuration, while high thresholds remained in control group patients, and PNS was managed by replacing the lead. The CS lead was successfully placed in a lateral branch in 95% of study group, compared to only 77% of control group patients (P = 0.004).
Conclusions: Multiple LVP configurations were clinically useful in a significant number of patients undergoing CRT system implantation by helping to overcome high LVP thresholds and PNS, and by providing more flexibility in placing the LV lead.
Background: In this prospective, randomized, controlled study, we compared the performance of J‐shaped active fixation (AF) atrial leads with J‐shaped passive fixation (PF) leads, over a 1‐year ...follow‐up period.
Methods: A total of 200 consecutive patients were prospectively randomized for implantation with a Medtronic 5568 AF lead model (n = 103; Minneapolis, MN, USA) versus a Medtronic 5592 PF model (n = 97), and all lead‐related measurements and complications were recorded over one year.
Results: All leads were successfully implanted with a nonsignificant difference in crossover rate to the alternative lead due to failed implantation (1 in the AF and 4 in the PF group, P = NS). Fluoroscopy time during implantation procedure was significantly shorter in the PF group (2.1 ± 3.6 vs 3.3 ± 4.5 minute, P < 0.05). Pacing thresholds during implantation were significantly lower in patients with PF leads (0.7 ± 0.3 V vs 0.9 ± 0.3 V, P < 0.001) and this difference persisted at 1‐year follow‐up (0.8 ± 0.6 V vs 1.3 ± 0.9 V in PF and AF leads respectively, P < 0.05). Lead‐related complications occurred in PF and AF with similar frequency (4% and 9% respectively, P = 0.2). However, pericardial complications occurred only in the AF group (6 cases, P = 0.01). Lead dislodgement was observed in only two cases—both in the PF group (P = 0.3).
Conclusion: Both types of J‐shaped atrial leads had reasonable performance. PF leads required shorter fluoroscopy time for implantation, demonstrated a better pacing threshold over a 1‐year follow‐up period and had no pericardial complications, while AF lead implantation was complicated by pericardial irritation and/or effusion in 6% cases (P = 0.01).
Aims: To compare the clinical response of patients with right ventricular apical pacing (RVAP) upgraded to cardiac resynchronization therapy (CRT) to that of previously nonpaced heart failure (HF) ...patients who had de novo CRT implantation.
Background: The role of CRT in patients with wide QRS and HF due to RVAP is less well established than in other CRT candidates.
Methods: Ninety‐eight consecutive patients with CRT were studied (mean age 70, mean ejection fraction 0.23). Group A: patients having RVAP prior to CRT implantation (n = 25), group B: patients without prior RVAP (n = 73). Clinical and echocardiographic parameters were recorded prior to, and 3 months after, CRT implantation.
Results: Group A patients had a wider QRS at baseline compared to group B (203 ± 32 ms vs 163 ± 30 ms respectively, P < 0.001), and a shorter 6‐minute walking distance (222 ± 118 m vs 362 ± 119 m, respectively, P < 0.005). Otherwise, clinical and echocardiographic parameters were not different. At follow up, group A patients had an average 0.7 ± 0.5 decrease in their NYHA functional class, compared to 0.3 ± 0.7 in group B patients (P < 0.05). Six‐minute walking distance increased by 93 ± 113 m in group A, versus 36 ± 120 m in group B (P = 0.22). There was no difference in echocardiographic response to CRT between the groups.
Conclusions: HF patients with prior RVAP demonstrate clinical improvement after upgrading to CRT that is comparable, and in some aspects, even better than that observed in HF patients with native conduction delay who undergo de novo CRT implantation.
Introduction:
Rate smoothing algorithms, while known to help prevent ventricular tachyarrhythmias in some patients, have been shown to result in underdetection of ventricular tachycardia (VT) due to ...interaction between bradycardia pacing and tachycardia detection parameters. A new algorithm named Bradycardia Tachycardia Response (BTR) has been developed in order to prevent rate smoothing‐induced underdetection. The efficacy of BTR is not known. The aim of this study was to assess the effectiveness of BTR in preventing VT underdetection due to rate smoothing.
Methods and Results:
Two ICD models (TELIGEN and VITALITY AVT, Boston Scientific, St. Paul, MN, USA) bearing identical rate smoothing algorithms were connected to a VT simulator. Devices were programmed similarly except for the BTR feature that exists in TELIGEN only. The detection performance of both devices was tested using varying combinations of AV delay, rate smoothing down, and upper rate limit and compared between the two models. VT underdetection (delay or nondetection) occurred during pacing in 62% of the VT episodes with VITALITY AVT. In TELIGEN, all simulated VT episodes were detected appropriately as soon as their rates exceeded the programmed VT detection rate. Detection tended to be affected by higher upper rate, longer AV delays, and more aggressive rate smoothing.
Conclusion:
The BTR algorithm effectively counteracts VT detection delay caused by the interaction of rate smoothing with VT detection parameters, thus enabling safe use of the rate smoothing feature. (PACE 2012; 1–6)
Background:
Vasovagal syncope is one of the most common medical conditions in young adults. Previous trials have shown effectiveness of tilt training in treating this condition. We conducted a ...prospective, randomized study in order to evaluate the role of tilt‐training in young adults with vasovagal syncope.
Methods:
Forty‐six soldiers (mean age 19.4 ± 0.8 years, 25 males), with a clinical diagnosis of vasovagal syncope supported by positive tilt test, were randomized to either three months of daily tilt training (treatment group), or no training (control group). Patients in both groups were instructed to increase fluid and salt intake, and to refrain from syncope‐inducing situations, such as prolonged standing.
Results:
Compliance, defined as performing 50% or more of the tilt training daily sessions, was 91% during the first month, and declined to 58% during three months. Treatment group patients had a median (interquartile range) of 5.0 (0.5–16.0) syncope episodes during one‐year follow up, compared to a median of 2.0 (0–6.0) episodes in the control group (P = 0.737). Also, there was no difference in time to first syncope after randomization between groups: a median of 1.0 (0.5–2.0) month in the treatment group, compared to 0.8 (0.5–2.0) month in the control group (P = 0.336).
Conclusions:
Adding daily three‐month tilt training to modifications in lifestyle does not improve treatment results in young adults with vasovagal syncope. Good compliance is difficult to achieve in a tilt training program.
Objective: In this prospective, randomized, control study we compared performance of J‐shaped (JL) and straight atrial leads (SL) with active (screw‐in) fixation mechanism, over a 5‐year follow‐up ...period.
Subjects and Methods: A total of 208 consecutive patients were randomized for implantation with a Medtronic 4568 JL model (n = 103) versus a Medtronic 4068 SL model (n = 105), and all lead‐related measurements and complications were recorded.
Results: Lead‐related complications occurred in JL and SL with similar frequency (6% and 9%, respectively, P = 0.45). Lead dislodgment occurred in 8 (7.8%) cases in SL versus none in JL (P = 0.004). Lead malfunction and excessive pacing thresholds without macrodislodgment occurred more frequently in JL (11; 10.7%) than in SL (4; 3.8%), P = 0.055. Lead material failure (insulation break) occurred only once in SL at the 5‐year checkup. Most complications occurred during the first year after implantation. Other events occurred in both leads with similar frequency and included: death in 39 and 35, loss of follow‐up in 8 and 6, and development of atrial fibrillation in 9 and 15 patients, respectively. Of those who completed follow‐up, lead impedance and pacing threshold increased significantly in both groups. P wave decreased in SL but not in JL.
Conclusion: More dislocations occurred in SL, but were counterbalanced by more lead malfunctions and excessive pacing thresholds in the JL group. Both leads demonstrated minor deterioration in electrical measurements during follow‐up, with only 1 case of lead material failure in SL. Overall, both groups demonstrated favorable lead performance throughout follow‐up.
Abstract
Aims
To allow timely initiation of anticoagulation therapy for the prevention of stroke, the European guidelines on atrial fibrillation (AF) recommend remote monitoring (RM) of ...device-detected atrial high-rate episodes (AHREs) and progression of arrhythmia duration along pre-specified strata (6 min…<1 h, 1 h…<24 h, ≥ 24 h). We used the MATRIX registry data to assess the capability of a single-lead implantable cardioverter-defibrillator (ICD) with atrial sensing dipole (DX ICD system) to follow this recommendation in patients with standard indication for single-chamber ICD.
Methods and results
In 1841 DX ICD patients with daily automatic RM transmissions, electrograms of first device-detected AHREs per patient in each duration stratum were adjudicated, and the corresponding positive predictive values (PPVs) for the detections to be true atrial arrhythmia were calculated. Moreover, the incidence and progression of new-onset AF was assessed in 1451 patients with no AF history. A total of 610 AHREs ≥6 min were adjudicated. The PPV was 95.1% (271 of 285) for episodes 6min…<1 h, 99.6% (253/254) for episodes 1 h…<24 h, 100% (71/71) for episodes ≥24 h, or 97.5% for all episodes (595/610). The incidence of new-onset AF was 8.2% (119/1451), and in 31.1% of them (37/119), new-onset AF progressed to a higher duration stratum. Nearly 80% of new-onset AF patients had high CHA2DS2-VASc stroke risk, and 70% were not on anticoagulation therapy. Age was the only significant predictor of new-onset AF.
Conclusion
A 99.7% detection accuracy for AHRE ≥1 h in patients with DX ICD systems in combination with daily RM allows a reliable guideline-recommended screening for subclinical AF and monitoring of AF-duration progression.
Graphical Abstract
Graphical Abstract
The AutoCapture (AC) function of new pacemakers (PM) from St Jude Medical (SJM) was originally recommended for use with low polarization (LP) ventricular leads only.However, recent reports have ...encouraged the use of the AC function with various leads, including those lacking a special LP design. The objective of this study was to analyze the reliability and safety of the AC algorithm application with different types of pacing leads. The study group comprised 30 consecutive patients with AC PMs connected to three different types of non-LP leads. Ten patients with SJM LP leads served as the control group. The study protocol included a complete AC function test using four different pulse widths (PW). The pacing threshold was independently assessed by a manual/semiautomatic check. Erratic behavior of polarization measurements with increasing PWs was demonstrated in 43% (n = 13) of the study group. Invalid polarization measurements resulted in erroneous algorithm recommendation to apply AC function in 17% (n = 5) of the study patients. Subsequent AC function activation lead to incorrect threshold determination due to missed noncapture in three patients. AC function should be applied with caution with non-LP leads. "Off label" use of these leads may cause erroneous polarization signal measurements which, in some cases, may result in incorrect pacing threshold determination, rendering a potential risk to dependent patients.
Strategically chosen ventricular tachycardia (VT)/ventricular fibrillation (VF) detection and therapy parameters aimed at reducing shock deliveries were proven effective in studies that utilized ...single manufacturer devices with a follow-up of up to 1 year. Whether these beneficiary effects can be generalized to additional manufacturers and be maintained for longer periods is to be determined. Our aim was to evaluate the durability and applicability of the programming of strategic implantable cardioverter-defibrillators (ICDs) of various manufacturers, which is aimed at reducing the shock delivery burden in primary prevention ICD recipients.
A retrospective analysis of prospectively collected data of 300 ICD recipients of various manufacturers was conducted; 160 devices were strategically programmed to reduce shocks and 140 were not. The primary endpoint was the composite of death and appropriate shocks. Additional outcomes were inappropriate shocks, syncope events, and non-sustained VTs. At a median follow-up of 24 months, 19 patients died, 31 received appropriate shocks, and 41 received inappropriate shocks. Multivariate analysis showed that strategic programming dedicated to shock reduction was associated with a 64% risk reduction in the primary endpoint hazard ratio (HR): 0.13-0.93; P = 0.03 and a 70% reduction in inappropriate shock deliveries (HR: 0.16-0.72; P = 0.01). Very few syncope events occurred (five patients, 1.6%), and there was no between-group difference in this outcome.
Utilization of strategically chosen VT/VF detection and therapy parameters was found to be effective and safe in ICDs of various manufacturers at a median follow-up period of 2 years among primary prevention patients.
PDF