Importance of anterograde visualization of the coronary venous network by selective left coronary angiography prior to resynchronization

BACKGROUND: Understanding of coronary anatomy is essential to the advancement of cardiac resynchronization therapy (CRT) techniques. We determined whether the difficulties associated with catheterization of the coronary sinus (CS) and its lateral branches could be overcome by a preliminary angiographical study of the coronary venous system carried out during a pre-operative coronary angiography with examination of venous return. METHODS AND RESULTS: All patients were scheduled for an exploratory angiography procedure and indicated for CRT. Group A patients were implanted with a CRT device after a right arterial angiographical procedure while group B patients had a selective left angiogram including examination of venous return. Data analyzed in group B were: position of CS ostium, number and distribution of lateral branches, and ability to preselect a marginal vein suitable for catheterization. Subsequent device implantation was guided by these parameters. A total of 96 and 89 patients were included in groups A and B, respectively. Implantation success rates were not different (98% and 100%, respectively), but CS catheterization time was reduced in group B (6 minutes vs 4 minutes; P < 10(-6)) as well as total time required to position the left ventricular lead (25 minutes vs 15 minutes; P < 10(-6)), fluoroscopy exposure (7 minutes vs 5 minutes; P < 10(-6)), and volume of contrast medium required (45 mL vs 15 mL; P < 10(-6)). CONCLUSION: A coronary angiographical study, including examination of the coronary venous return prior to implantation of a CRT device, can simplify the device implant and allows patient-specific preselection of appropriate tools for the procedure.     

Cardiac resynchronization therapy using a VDD lead

In heart failure patients with normal sinus node function, cardiac resynchronization therapy can be achieved with only two leads, one VDD type, and one left ventricular. This reduces the number of venous punctures, implanted leads, and possibly operation and fluoroscopic times and complication rates. We present two cases and discuss the advantages and limits of such a procedure.     

Anti-inflammatory effect of cardiac resynchronization therapy

BACKGROUND: Congestive heart failure (CHF) is associated with persistent immune activation. Medical therapy has been shown to exert only limited anti-inflammatory effects. Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in a subset of patients with heart failure, but it is not known whether this treatment affects the immune system as well. To test this hypothesis, eight patients with heart failure scheduled for CRT were investigated for immune activation before and 6 months after CRT treatment. METHODS AND RESULTS: After 6 months, all patients had improved in NYHA-class and LVEF, and there was a statistically significant reduction in serum N-terminal pro brain natriuretic peptide (BNP). Furthermore, there was a statistically significant reduction in plasma levels of the chemokines monocyte chemoattractant protein 1 (MCP-1) and interleukin 8 (IL-8) and the cytokine interleukin 6 (IL-6). We observed no changes in the levels of interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), interleukin 10 (IL-10), or complement activation products. There was a significant correlation between changes in BNP and IL-6 (r = 0.74, P = 0.037). CONCLUSION: Although based upon a limited number of patients, this report indicates that CRT reduces peripheral markers of immune activation in patients with CHF. Further large scale studies are warranted to verify these findings.     

Activation sequence modification during cardiac resynchronization by manipulation of left ventricular epicardial pacing stimulus strength

BACKGROUND: Success of cardiac resynchronization therapy (CRT) depends on altering electrical ventricular activation (VA) to achieve mechanical benefit. That increases in stimulus strength (SS) can affect VA has been demonstrated previously in cardiomyopathy patients undergoing ablation. OBJECTIVE: To determine whether increasing SS can alter VA during CRT. METHODS: In 71 patients with CRT devices, left ventricle (LV) pacing was performed at escalating SS. Timing from pacing stimulus to right ventricular (RV) electrogram, ECG morphology, and maximal QRS duration on 12 lead ECG were recorded. RESULTS: Demographics: Baseline QRS duration 153 +/- 25 ms, ischemic cardiomyopathy 48%, ejection fraction 24%+/- 7%. With increased SS, conduction time from LV to right ventricle (RV) decreased from 125 +/- 56 ms to 111 +/- 59 ms (P = 0.006). QRS duration decreased from 212 +/- 46 ms to 194 +/- 42 ms (P = 0.0002). A marked change in QRS morphology occurred in 11/71 patients (15%). The RV ring was the anode in 6, while the RV coil was the anode in 5. Sites with change in QRS morphology showed decrease in conduction time from LV to RV from 110 +/- 60 ms to 64 +/- 68 ms (P = 0.04). Twelve patients (16%) had diaphragmatic stimulation with increased SS. CONCLUSIONS: Increasing LV SS reduces QRS duration and conduction time from LV to RV. Recognition of significant QRS morphology change is likely clinically important during LV threshold programming to avoid unintended VA change.     

Cardiac resynchronization therapy and obstructive sleep-related breathing disorder in patients with congestive heart failure

Objectives: To assess the impact of cardiac resynchronization therapy (CRT) with or without atrial overdrive pacing, on sleep‐related breathing disorder (SRBD). Introduction: CRT may have a positive influence on SRBD in patients who qualify for the therapy. Data are inconclusive in patients with obstructive SRBD. Methods: Consenting patients eligible for CRT underwent a baseline polysomnography (PSG) 2 weeks after implantation during which pacing was withheld. Patients with an apnea hypopnea index (AHI) ≥15 but <50 were enrolled and randomized to atrial overdrive pacing (DDD) versus atrial synchronous pacing (VDD) with biventricular pacing in both arms. Patients underwent two further PSGs 12 weeks apart. Results: Nineteen men with New York Heart Association class III congestive heart failure participated in the study (age 67.2 ± 7.5, Caucasian 78.9%, ischemic 73.7%). The score on Epworth Sleepiness Score was 7.3 ± 4.0, Pittsburgh Sleep Quality Index 7.4 ± 3.1, and Minnesota Living with Heart Failure Questionnaire 36.9 ± 21.9. There were no differences between the groups. At baseline, patients exhibited poor sleep efficiency (65.3 ± 16.6%) with nadir oxygen saturation of 83.5 ± 5.3% and moderate to severe SRBD (AHI 21.5 ± 15.3) that was mainly obstructive (central apnea index 3.3 ± 6.7/hour). On both follow‐up assessments, there was no improvement in indices of SRBD (sleep efficiency [68.3 ± 17.9%], nadir oxygen saturation of 82.8 ± 4.6%, and AHI 24.9 ± 21.9). Conclusion: In a cohort of elderly male CHF patients receiving CRT, CRT had no impact on obstructive SRBD burden with or without atrial overdrive pacing. (PACE 2011; 34:593–603)     

Inhibition of biventricular pacemakers by oversensing of far-field atrial depolarization

This report describes two patients who exhibited far-field oversensing of the P wave by the ventricular channel of a DDD biventricular pacemaker implanted for the treatment of congestive heart failure. Oversensing probably occurred secondary to slight displacement of the left ventricular lead in the coronary venous system. Long-term reliable pacing was restored by decreasing the sensitivity of the ventricular channel.     

Effect of cardiac resynchronization therapy on endothelium-dependent vasodilatation in the cutaneous microvasculature

Aims: Cardiac resynchronization therapy (CRT) improves hemodynamic parameters, exercise capacity, symptoms, functional status, and prognosis among patients with chronic heart failure (CHF). The role of the vascular endothelium in these improvements is largely unknown. In this study, we aimed to investigate whether the endothelium‐dependent reactivity of the peripheral microcirculation improves in CHF patients during the first 2 months of CRT. Methods: We used local heating and iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) to measure endothelial function and smooth muscle function in the cutaneous microvasculature of 11 CHF patients before and 2 months after CRT. Results: We found that the perfusion response in the skin to local heating was increased 2 months post‐CRT compared with baseline, both in terms of maximum perfusion (baseline: 113 [90–137] vs 2‐months post‐CRT: 137 [98–175], P = 0.037) and area under curve (baseline: 1,601 [935–2,268] vs 2‐months CRT: 2,205 [1,654–2,757], P = 0.047). Also, the perfusion response to iontophoresis of ACh was improved (E_max: 23.9 [20.6–26.2]vs at 2‐months CRT: 31.2 [29.3–33.4], P = 0.005). No difference was found between the responses to SNP before and after CRT. Conclusion: These results show that CRT improves endothelium‐dependent vasodilatory capacity in the peripheral microcirculation within 2 months of therapy. The improvement in functional capacity that is seen in patients treated with CRT may, therefore, be in part mediated by an improvement of endothelium‐dependent vasodilatory capacity. PACE 2012; 35:377–384)     

Transmyocardial voyage of a temporary epicardial lead: an unusual long-term complication

Although the majority of temporary epicardial leads used during cardiac surgery are removed in the perioperative period, occasionally, the wires are cut and allowed to retract into the subcutaneous tissue. Complications arising from such retained epicardial wires are rare. We present a case of transmyocardial migration of a retained epicardial wire through the right ventricular myocardium into the pulmonary artery in a patient who had undergone coronary artery bypass graft surgery 13 years ago. We describe the presentation and successful management of this case.     

Increasing left ventricular pacing output decreases interventricular conduction time in patients with biventricular pacing systems

OBJECTIVE: To evaluate the effect of increasing LV pacing output on interventricular timing in patients with biventricular pacing systems. BACKGROUND: Clinical improvement with biventricular pacing is likely related to reduction in ventricular dysynchrony in patients with cardiomyopathy. We hypothesized that increasing left ventricular pacing output would reduce interventricular conduction time and could affect ventricular synchrony. METHODS: Forty-two sequential patients with biventricular pacing systems that permitted independent LV pacing were selected at the time of routine device interrogation. The interval between LV pacing stimulus and onset of the RV electrogram was measured during LV pacing at capture threshold and at maximum pacing output for each patient. RESULTS: The average time from LV pacing stimulus to right ventricular electrogram onset was 142.5 +/- 32.5 ms (range 90-230 ms) at threshold and 132.3 +/- 30.4 ms (range 90-220 ms) at maximum pacing output, with a mean decrease in conduction time of 10.2 +/- 10.9 ms (range 0-45 ms). There was significantly greater interventricular conduction shortening with increased pacing output in patients with ischemic cardiomyopathy compared to others (14.9 +/- 11.9 ms vs 4.0 +/- 4.6 ms; P < 0.01). CONCLUSIONS: Conduction time from LV to RV shortens as LV pacing output is increased. This effect is seen to a greater degree in patients with ischemic cardiomyopathy, possibly related to the presence of myocardial scar near the pacing electrode. Further investigation is needed to assess the clinical outcomes related to this new method for optimizing resynchronization therapy.     

Initial single-center experience of a quadripolar pacing lead for cardiac resynchronization therapy

Background: The Quartet model 1458Q (St. Jude Medical, Sylmar, CA, USA) lead is a quadripolar left ventricular (LV) lead with pace/sense capability from four electrodes (tip and three rings). The lead is capable of pacing in 10 different configurations rather than the three that are available in conventional bipolar pacing leads. We describe a single‐center initial experience of the use of this lead in patients undergoing cardiac resynchronization therapy (CRT). Methods: Twenty‐eight patients for a CRT with cardiac defibrillator were implanted between October 2009 and May 2010 with a Quartet lead . Lead position, pacing parameters, stability, complications, and presence of phrenic nerve stimulation (PNS) data were collected at implant and predischarge. Follow‐up data were collected at 15 ± 8 weeks for all patients. Results: A Quartet lead was successfully implanted in 96% (27/28) of patients (age 61 ± 15 years; 82% male; ischemic etiology 50%; mean left ventricular [LV] ejection fraction 25 ± 7%; left bundle branch block 68%). PNS was seen at implant in 11 patients (41%) with at least one vector. In eight of these cases (72%), the need for lead repositioning was averted by programming LV pacing utilizing the additional vectors available with the Quartet lead. Conclusion: These initial data suggest that pacing with the Quartet lead is associated with a high implant success rate and stable pacing parameters acutely and at short‐term follow‐up. The 10 LV pacing vectors available with this lead may allow PNS and capture threshold problems to be easily overcome. (PACE 2011; 34:484–489)     

Addition of a left ventricular lead to conventional pacing systems in patients with congestive heart failure: feasibility,safety, and early results in 60 consecutive patients

Left bundle branch block worsens congestive heart failure (CHF) in patients with LV dysfunction. Asynchronous LV activation produced by RV apical pacing leads to paradoxical septal motion and inefficient ventricular contraction. Recent studies show improvement in LV function and patient symptoms with biventricular pacing in patients with CHF. The aim of this study was to determine the feasibility, safety, acute efficacy, and early effect on symptoms of the upgrade of a chronically implanted RV pacing system to a biventricular system. Sixty patients with NYHA Class III and IV underwent the upgrade procedure using commercially available leads and adapters. The procedure succeeded in 54 (90%) of 60 patients. Acute LV stimulation thresholds obtained from leads placed along the lateral LV wall via the coronary sinus compare favorably to those reported in current biventricular pacing trials. The complication rate was low (5/60, 8.3%): lead dislodgement (n = 1), pocket hematoma (n = 1), and wound infections (n = 3). During 18 months of follow-up (16.7%) of 60 patients died. Two patients that died failed the initial upgrade attempt. At 3-month follow-up, quality of life scores improved 31 +/- 28 points (n = 29), P < 0.0001). NYHA Class improved from 3.4 +/- 0.5 to 2.4 +/- 0.7 (P = < 0.0001) and ejection fraction increased from 0.23 +/- 0.8 to 0.29 +/- 0.11 (P = 0.0003). Modification of RV pacing to a biventricular system using commercially available leads and adapters can be performed effectively and safely. The early results of this study suggest patients may benefit from this procedure with improved functional status and quality of life.     

Selection of patient for cardiac resynchronization therapy: role of QT corrected dispersion

Aims : About 30 to 50% of patients undergoing cardiac resynchronization therapy (CRT) may not show clinical or echocardiographic improvement, despite fulfilling guidelines recommendations for CRT. For this reason, we need a more accurate method to assess CRT eligibility. The aims of this study were to verify, on a 12‐month follow‐up, the usefulness of QT corrected dispersion (QTcD) in a patient's selection for CRT. Methods : We stratified 53 patients who underwent CRT, into two groups based on the estimation of QTcD, that is, QTcD > 60 ms and QTcD ≤ 60 ms. In all patients were performed New York Heart Association (NYHA) class determination, six‐minute walking test, QtcD, and QRS measurements, and complete echocardiographic assessment at 1, 3, 6, and 12 months after implantation. Results : At baseline, there were no significant differences in clinical, echocardiographic, and electrocardiographic parameters duration between two groups. At 12‐month follow‐up between the two groups, there were significant differences in NYHA (1.2 ± 0.4 vs 2 ± 0.6; P < 0.01), six‐minute walking distance (422 ± 68 vs 364 ± 68; P < 0.01), left ventricular (LV) ejection fraction (34 ± 7% vs 28 ± 6%; P < 0.01), LV end‐diastolic diameter (57 ± 7 vs 63 ± 8; P < 0.01), and LV intraventricular dyssynchrony (24 ± 14 vs 39 ± 23; P < 0.01). Conclusion: This study suggests that QTc dispersion in addition to QRS duration could improve the sensitivity of electrocardiogram in a patient's selection for CRT. (PACE 2012;1–6)     

超声心动图评价心脏再同步化治疗疗效

目的探讨超声心动图在慢性充血性心力衰竭患者心脏再同步化治疗疗效评价中的应用价值。方法 27例接受心脏再同步化治疗的慢性充血性心力衰竭患者,分别于术前及术后6个月应用超声心动图测量左心室大小、左心室容积、左心室射血分数、二尖瓣反流面积、房室间、心室间及左心室内同步性。结果术后6个月患者左心室收缩末内径、左心室舒张末内径、左心室收缩末容积、左心室舒张末容积小于术前（P〈0.05或P〈0.01）,房室间、心室间、左心室内收缩同步性改善（P〈0.05或P〈0.01）。结论超声心动图可通过多项参数综合评价心脏再同步化治疗的效果。     

Atrioventricular junction ablation followed by resynchronization therapy in patients with congestive heart failure and atrial fibrillation (AVERT-AF) study design

Atrial fibrillation (AF) and congestive heart failure (CHF) affect millions of patients in the United States. Several studies suggest that AF and in particular the irregular ventricular response might be contributing to the left ventricular dysfunction. Studies that compared pharmacologic rate control to atrioventricular junction (AVJ) ablation followed by right ventricular pacing which restores a regular ventricular response, failed to show an improvement when compared to pharmacological rare control. These results might be explained by the fact that while AVJ ablation restored a regular ventricular response, it subjected patients to the detrimental effects of RV apical pacing. The AVERT-AF trial (Atrio-VEntricular Junction Ablation Followed by Resynchronization Therapy in patients with CHF and AF) is a prospective, randomized, double-blinded, multicenter trial that will be testing the hypothesis that AVJ ablation followed by biventricular pacing significantly improves exercise capacity and functional status compared to pharmacologic rate control in patients with chronic AF and depressed ejection fraction, regardless of rate or QRS duration. A total of 180 patients will be enrolled to test the primary endpoint, which is exercise duration. Patients_enrollment will begin in summer 2006 and is expected to be completed in 2008. The results of this trial should help define the best treatment option for this common arrhythmia in patients with left ventricular dysfunction.     

Simple access to the coronary venous system for left ventricular pacing

Implantation of the LV lead for biventricular pacing can be challenging, time consuming, and often requires extensive fluoroscopy time. A conventional diagnostic 5 Fr left Amplatz catheter was used to cannulate the coronary sinus in 15 consecutive patients undergoing implantation of a biventricular pacemaker. When the coronary sinus was cannulated, the proximal end of the Amplatz catheter was cut and the coronary sinus sheath was passed over the Amplatz catheter that was then removed. Coronary sinus cannulation was achieved in all 15 patients with a mean fluoroscopy time of 3.34 +/- 1.9 minutes. Subsequent implantation of a biventricular pacemaker was successful and free of complications in all the 15 patients.     

Right heart failure due to loss of right ventricular capture in a patient with atrioventricular junction ablation and biventricular pacing

We describe the case of a patient with atrioventricular (AV) junction ablation and chronic biventricular pacing in which intermittent dysfunction of the right ventricular (RV) lead resulted in left ventricular (LV) stimulation alone and onset of severe right heart failure. Restoration of biventricular pacing by increasing device output and then performing lead revision resolved the issue. This case provides evidence that LV pacing alone in patients with AV junction ablation may lead to severe right heart failure, most likely as a result of iatrogenic mechanical dyssynchrony within the RV. Thus, probably this pacing mode should be avoided in pacemaker-dependent patients with heart failure.     

Noninvasive imaging in cardiac resynchronization therapy--part 1: selection of patients

Cardiac resynchronization therapy (CRT) is an established therapy for patients with advanced heart failure, depressed left ventricular function, and wide QRS complex. However, individual response varies, and a substantial amount of patients do not respond to CRT. Recent studies observed that assessment of inter- and particularly intraventricular dyssynchrony may allow identification of potential responders to CRT. In addition, presence of scar tissue and venous anatomy may play a role in the selection of candidates. In this review, an extensive overview of the available dyssynchrony measurements is provided using echocardiography as well as magnetic resonance imaging (MRI) and nuclear imaging. Furthermore, other information derived from MRI, nuclear imaging, and computed tomography useful for the selection of potential candidates for CRT will be discussed.     

Double wire technique to catheterize sharply angulated coronary sinus branches in cardiac resynchronization therapy

Placing a pacing lead for left ventricular pacing through the coronary sinus can be hampered by anatomic obstacles. In this case report we describe a technique that can overcome the problem of sharply angulated coronary sinus branches by using simultaneously two guidewires in the target vessel.     

Does RV Lead Positioning Provide Additional Benefit to Cardiac Resynchronization Therapy in Patients with Advanced Heart Failure?

BACKGROUND AND OBJECTIVES: The left ventricular (LV) stimulation site is currently recommended to position the lead at the lateral wall. However, little is known as to whether right ventricular (RV) lead positioning is also important for cardiac resynchronization therapy. This study compared the acute hemodynamic response to biventricular pacing (BiV) at two different RV stimulation sites: RV high septum (RVHS) and RV apex (RVA). METHODS AND RESULTS: Using micro-manometer-tipped catheter, LV pressure was measured during BiV pacing at RV (RVA or RVHS) and LV free wall in 33 patients. Changes in LV dP/dt(max) and dP/dt(min) from baseline were compared between RVA and RVHS. BiV pacing increased dP/dt(max) by 30.3 +/- 1.2% in RVHS and by 33.3 +/- 1.7% in RVA (P = n.s.), and decreased dP/dt(min) by 11.4 +/- 0.7% in RVHS and by 13.0 +/- 1.0% in RVA (P = n.s.). To explore the optimal combination of RV and LV stimulation sites, we assessed separately the role of RV positioning with LV pacing at anterolateral (AL), lateral (LAT), or posterolateral (PL) segment. When the LV was paced at AL or LAT, the increase in dP/dt(max) with RVHS pacing was smaller than that with RVA pacing (AL: 12.2 +/- 2.2% vs 19.3 +/- 2.1%, P < 0.05; LAT: 22.0 +/- 2.7% vs 28.5 +/- 2.2%, P < 0.05). There was no difference in dP/dt(min) between RVHS- and RVA pacing in individual LV segments. CONCLUSIONS: RVHS stimulation has no overall advantage as an alternative stimulation site for RVA during BiV pacing. RVHS was equivalent with RVA in combination with the PL LV site, while RVA was superior to RVHS in combination with AL or LAT LV site.