Transvenous left ventricular lead implantation with the EASYTRAK lead system: the European experience

Snare technique for coronary sinus cannulation in cardiac resynchronization therapy

Purpose

Methods and results

Conclusion

Successful use of venovenous snare to fix the wire in a collateral vein for proper placement of the left ventricular lead during cardiac resynchronization therapy: a case report

Background

In cardiac resynchronization therapy, left ventricular (LV) lead placement at the desired position may be difficult due to abnormal coronary sinus (CS) and lateral vein anatomy. We present a case with difficult anatomy in which we used ‘an indigenous snare’ made from hardware used for coronary angioplasty procedures, which is available in any cardiac catheterization laboratory.

Case summary

A 52-year-old man presented with dyspnoea due to chronic heart failure was evaluated for cardiac resynchronization therapy. The LV lead was difficult to advance into the only target lateral branch of the CS due to a combination of angulation and proximal stenosis. Balloon dilation was tried first, but we failed to track the LV lead. We formed a venovenous loop, advancing the coronary guidewire 0.014″ into the posterolateral vein; subsequently into the middle cardiac vein via a collateral. The wire was advanced into the CS and then to superior vena cava. The guidewire then snared through the same left subclavian vein and exteriorized by using indigenous snare. Over this loop, the LV lead of the cardiac resynchronization therapy with defibrillator device was implanted successfully.

Discussion

We have used the snare technique, with the use of a snare prepared from a coronary guidewire. Use of such an indigenous snare has not been described before in the literature. The hardware used in this case is routinely used for coronary angioplasty procedures in all catheterization labs. The importance of our case is that no special hardware like dedicated snare was required to negotiate the LV lead at its desired location.

Utility of a novel pacing guidewire in pre-implantation testing at different left ventricular sites in cardiac resynchronization therapy procedures

PURPOSE

This study aimed to evaluate the utility of a novel pacing guidewire in pre-implantation testing of different left ventricular (LV) sites during cardiac resynchronization therapy (CRT) procedures.

METHODS

Ten consecutive patients (8 male, mean age 65.8 ± 4.9) undergoing CRT procedures were studied. Pacing threshold and R-wave sensing measured by the guidewire and LV lead at different LV sites were compared.

RESULTS

Thirty sites (6 apical, 13 middle, and 11 basal; 15 lateral and 15 anterior) were tested. There was significant correlation between pacing threshold (r = 0.878, p < 0.0001), and R-wave sensing (r = 0.896, p < 0.0001) obtained by guidewire and those obtained by LV lead. Separating into lateral and anterior sites, significant correlation was also found in pacing threshold (lateral r = 0.658, p = 0.008; anterior r = 0.886, p < 0.0001) and R-wave sensing (lateral r = 0.887, p < 0.0001; anterior 0.865, p < 0.0001). For basal and middle sites, significant correlation was found in pacing threshold (basal r = 0.890, p < 0.0001; middle r = 0.878, p < 0.0001), and R-wave sensing (basal r = 0.930, p < 0.0001; middle r = 0.823, p < 0.001). No and borderline correlation was found in pacing threshold (r = 0.548, p = 0.26) and R-wave sensing (r = 0.835, p = 0.039), respectively, for apical sites. Concordance rate for the presence of phrenic nerve stimulation at high pacing output was 87%.

CONCLUSION

The accuracy of the novel pacing guidewire in pre-implantation testing in CRT procedures is site-dependent. There was good correlation with LV lead in the measurement of pacing threshold and R-wave sensing at basal and middle sites, but not apical sites. Presence of phrenic nerve stimulation can be predicted by guidewire testing with high accuracy.

Retrograde buddy wire technique for coronary sinus lead placement--an approach to overcome coronary vein angulation

Implantation of a left ventricular pacing lead via the coronary sinus to deliver cardiac resynchronization therapy has become standard therapy for patients with New York Heart Association (NYHA) Class III or IV heart failure and significant intraventricular conduction delay. Biventricular pacing has been shown to provide both symptomatic and mortality benefit in appropriately selected patients. There is significant variability in the anatomy of the coronary sinus and the epicardial coronary venous system. Although a suitable candidate vein may be identified during coronary venography, efforts toward successful guidewire placement or lead placement may be hampered by anatomic obstacles. In this case report, we provide a solution to overcome severe tortuosity encountered at the vein-coronary sinus junction and angulation of the proximal vein. The use of a second coronary sinus sheath and a retrogradely placed guidewire may overcome this anatomic obstacle of vessel tortuosity, when placement by other means has proven unsuccessful.

[Technical innovations and limitation in cardiac electrotherapy]

Coronary sinus (CS) lead positioning is one of the main determinants of cardiac resynchronization therapy (CRT). The implantation of the CS lead is faced with several technical difficulties that may prevent the achievement of a stable position and good performance of the CS lead without phrenic nerve stimulation (PNS). New developments in catheter and lead technology to overcome these difficulties are presented.

[Optimal electrode placement. What to consider during implantation of a biventricular pacemaker?]

Since the introduction of transvenous left ventricular lead systems nearly a decade ago, resynchronization therapy has gained widespread acceptance and has become a growing field in heart failure therapy. Due to the increasing numbers of implanting centers and physicians, the need for adequate education is increasing. This article describes and illustrates the anatomical background, the technical opportunities and pitfalls, which have to be overcome, to achieve an implanting success rate of 95% to 98%, as can be achieved by well-trained physicians under optimal conditions.

Phrenic Stimulation

Background— Phrenic stimulation (PS) may hinder left ventricular (LV) pacing. We prospectively observed its prevalence in consecutive patients with cardiac resynchronization therapy (CRT) devices.

Methods and Results— In the years 2003 to 2006, 197 patients received a CRT device. PS and LV threshold measurements were carried out at implantation and at 6-month follow-up. LV reverse remodeling was assessed by echocardiography before implantation and at follow-up. LV lead placement was lateral/posterolateral in 86% of patients. Both PS and LV reverse remodeling occurred most frequently at the lateral/posterolateral LV pacing sites ( P <0.001). PS was detected in 73 (37%) of patients and was clinically relevant in 41 (22%). The detection of PS at implantation had a poor sensitivity, as it occurred only in left lateral or sitting position in 27 patients. Ten patients (5%) underwent repeated surgery and 4 (2%) had their CRT turned off because of PS. At follow-up, we could manage PS noninvasively in 32 patients with a small PS-LV threshold difference: in 20 by cathode programmability (3 also thanks to automatic management of LV output) and in 12 (without cathode programmability) by programming the LV output as threshold +1 V.

Conclusions— PS may seriously hinder CRT. A bipolar LV lead and cathode programmability are mandatory to avoid PS by changing the LV pacing vector at target sites for CRT. LV stability at target sites despite PS should also be pursued by these means. The automatic adjustment of LV pacing output is complementary in patients with a small PS-LV threshold difference.

[Which patients with heart failure should be offered cardiac resynchronization?]

Chronic heart failure is a very prevalent disease in developed countries. In recent decades, very important advances in drug therapy have occurred. However, mortality is still very high. One third of patients with a low ejection fraction and New York Heart Association (NYHA) functional class IIII-IV have a wide QRS. This means that there is often resynchronization of contraction and higher mortality. In order to improve the prognosis, the therapy based on cardiac resynchronization device has bee4n shown to be a complementary medical treatment and has contributed to clinical, hemodynamic and mortality improvements. In this article, we aim to show the results of clinical trials and recommendations of the main guidelines regarding this therapy.

The use of telescoping guide catheters for coronary sinus cannulation and sub-selecting tributaries in left ventricular lead placement

INTRODUCTION

Failure to enter the coronary sinus (CS) with a guiding catheter and entering its tributaries remains challenging in left ventricle (LV) pacing lead implants for cardiac resynchronization therapy (CRT). A dual telescoping catheter system (8F outer/6F inner) is designed to provide the ability to adjust the catheter curve size, shape and/or reach to the patients' anatomy avoiding the need for catheter change.

METHODS

Five different designs for CS cannulation were randomly tested in 64 patients scheduled for CRT device implant.

RESULTS

In 33 consecutive patients three adaptable telescoping guiding catheter systems were tested per patient, the adaptable catheters had higher overall cannulation success rates (68, 63 and 62%) compared to the fixed shape catheter (46%) and an greater cannulation success rate when the CS location was not known (70, 53 and 72% vs 33% for the fixed shape). In a second group of 31 CRT patients the two telescoping catheters had similar high levels of success (71-80%), with or without using the inner catheter.

CONCLUSIONS

The telescopic system is adaptable to a wide range of anatomical variations in patients and can result in a higher CS cannulation success rate due to its adjustability in the RA in search for the CS ostium. On top of this the inner catheter allows for sub-selecting the CS tributaries.

N.-phrenicus-Stimulation bei biventrikulären Schrittmachern

BACKGROUND

Phrenic nerve stimulation (PNS) complicates the positioning of the left ventricle lead. We present a step-by-step approach to correct PNS during implantation, as established in our daily routine.

METHODS

The incidence of PNS, its successful correction, and long-term results (median 27 months) were analyzed retrospectively in 266 lead positions.

RESULTS

Phrenic nerve stimulation occurred in 13.9% of the lead positions. Multivariate analysis (P<0.02) showed that PNS only depended on the place of stimulation (coronary sinus side branch). Lead type, CRT indication, and patient's sex had no significant correlation. Following the step-by-step approach presented here, PNS was corrected satisfactorily in all cases.

CONCLUSIONS

Approach in case of PNS: 1. push or pull the lead within the same vein, 2. change to a different vein, 3. maintain position in case of a safe distance between the phrenic nerve and the pacing threshold, 4. change the lead type to achieve stable anchorage at adequate positions, 5. use a device featuring electronic repositioning.

Ventricular dyssynchrony in dilated cardiomyopathy: the role of biventricular pacing in the treatment of congestive heart failure

Despite advances in pharmacologic therapy, the prognosis of patients with advanced congestive heart failure (CHF) remains poor. Many of these patients have cardiac conduction abnormalities, such as left bundle-branch block or interventricular conduction delays, that can lead to ventricular dyssynchrony (abnormal ventricular activation that results in decreased ventricular filling and abnormal ventricular wall motion). Biventricular pacing is an alternative, nonpharmacologic therapy under active investigation for the treatment of CHF. Resynchronization devices with transvenous leads in the right atrium, right ventricle, and left ventricle (via the coronary sinus) have been implanted in patients to provide atrial triggered biventricular pacing. The use of such devices has been associated with improvement in ejection fraction, dP/dt, stroke work, and functional class. The proposed mechanisms involved in improving ventricular function with biventricular pacing include improved septal contribution to ventricular ejection, increased diastolic filling times, and reduced mitral regurgitation. This article reviews the pathophysiology of ventricular dyssynchrony and examine insights from clinical trials that are evaluating cardiac resynchronization therapy for CHF.

The deleterious consequences of right ventricular apical pacing: time to seek alternate site pacing

BACKGROUND

The purpose of this article is to critically review the data accumulated to date from studies evaluating the hemodynamic and clinical effects of right ventricular apical pacing during conventional permanent cardiac pacing. The data from studies comparing the effects of right ventricular apical pacing and alternate site ventricular pacing are also reviewed.

METHODS

We conducted a MEDLINE and journal search of English-language reports published in the last decade and searched relevant papers.

RESULTS

Although intraventricular conduction delay in the form of left bundle branch block (LBBB) has traditionally been viewed as an electrophysiologic abnormality, it has now become abundantly clear that it has profound hemodynamic effects due to ventricular dyssynchrony, especially in patients with heart failure. These deleterious effects can be significantly ameliorated by cardiac resynchronization therapy effected by biventricular or left ventricular pacing. However, not only is spontaneous LBBB harmful, but the iatrogenic variety produced by right ventricular apical pacing in patients with permanent pacemakers may be equally deleterious. In this review new evidence from recent studies is presented, which strongly suggests a harmful effect of our long-standing practice of producing an iatrogenic LBBB by conventional right ventricular apical pacing in patients receiving permanent pacemakers. This emerging strong new evidence about the adverse hemodynamic and clinical effects of right ventricular apical pacing would dictate a reassessment of our traditional approach to permanent cardiac pacing and direct our attention to alternate sites of pacing, such as the left ventricle and/or the right ventricular outflow tract or septum, if not for all patients, at least for those with left ventricular dysfunction. Indeed, current convincing data on alternate site ventricular pacing are encouraging and this approach should be actively pursued and further investigated in future studies.

CONCLUSIONS

Not only is spontaneous permanent LBBB harmful to our patients, but the iatrogenic variety produced by right ventricular apical pacing during conventional permanent pacing may also be deleterious to some patients. The compelling evidence presented herein cannot be ignored; it may dictate a change of attitude toward right ventricular apical pacing directing our attention to alternate sites of ventricular pacing and avoidance of the right ventricular apex.

Use of a modified introducer sheath with a side-hole to improve access to left ventricular veins with proximal origin

AIMS

Despite technical advances in tools used to facilitate implantation of cardiac resynchronization therapy (CRT) devices, there are many hurdles related mainly to the variation in the anatomy of the coronary veins. One such difficulty is the presence of a very proximal origin of the lateral or postero-lateral cardiac vein.

METHODS AND RESULTS

We describe an alteration of existing left ventricular (LV) lead delivery sheath with the creation of a side-hole 35-50 mm from its tip. This modification is made to provide access to proximal cardiac vein ostia, while maintaining adequate support for the delivery system. The modified introducer sheath was used in the implantation of six CRT systems (four defibrillators and two pacemakers) in patients who had a proximal origin of the lateral or postero-lateral cardiac vein, all of which were successful and without complications.

CONCLUSION

In those patients with unusual proximal origin of target LV veins, modifications of the introducer sheath with the creation of a side-hole facilitate the successful implantation of the LV pacing lead. Until this modified sheath is tested, this technique is considered experimental and may carry unknown risks.

[Strategies to avoid complications and to solve technical problems during the implantation of CRT and CRT-D systems]

Cardiac resynchronization with or without antitachycardiac treatment is now an established option to improve the functional status, morbidity and mortality of patients with severe symptomatic systolic heart failure, ventricular conduction delay and asynchrony. Increasing implant numbers are to be expected. The transvenous left ventricular lateral lead placement can now be achieved in up to 97% of patients. But due to the coronary venous anatomy it may still constitute a challenge even for experienced pacemaker and ICD implanters. In addition, it confers a considerable risk for complications like coronary sinus dissection and perforation, diaphragmatic stimulation and lead dislodgement. An overview is given on possible technical problems, solutions, complications and preventive strategies.

[From guiding catheter to coronary sinus lead]

Biventricular pacing system implantation is a challenging procedure. The first-choice technique to initiate left ventricular pacing consists of a transvenous approach via the coronary sinus (CS) tributaries. Different techniques to achieve CS access using dedicated guiding catheters and left ventricular leads are described. New developments in catheter and lead technology are presented. The most common procedure-related complications are reported.

The Anatomic Barriers in the Coronary Sinus: Implications for Clinical Procedures

BACKGROUND

Coronary sinus (CS) catheterization is often used in cardiac resynchronization therapy. Failure to enter the CS is the most common reason for LV pacing lead implant failure.

METHODS

We evaluated the anatomic barriers, Thebesian and Vieussens valves, the CS and its tributaries in 52 adult human cadaver hearts.

RESULTS

The average diameter of CS ostiums was 9.47 mm. In 20 of the hearts heavier than 300 g, the average CS os diameter was 10.76 mm, whereas in the remaining hearts was 8.72 mm (p<0.005). The Thebesian valves were observed in 35(67%) of the hearts. In 39(75%) of the hearts Vieussens valves were observed and noted that 6(11%) of them were qualitatively well developed and 33(63%) diminutive. Twenty cases (38%) had 3 vein branches, 19(37%) had 4 branches, 6(11%) had 5 branches, 6(11%) had 2 branches and 1(2%) had 6 branches between great and middle cardiac veins. The anatomic barriers in coronary sinus i.e., Thebesian and Vieussens valves and their branchings were evaluated and found optimal, suboptimal and worst for catheterization in 33, 15 and 4 Thebesian valves; 40, 8, 4 Vieussens valves, respectively. The coronary sinus tributaries between great and middle cardiac veins were found to be optimal, suboptimal and worst for catheterization in 88, 60 and 38 veins, respectively.

CONCLUSIONS

Careful evaluation of anatomic barriers is important for treatment success. Thus, knowledge of these functional anatomic features and barriers allows for better utilization of the human coronary sinus for diagnostic and therapeutic purposes.

How close are the phrenic nerves to cardiac structures? Implications for cardiac interventionalists

BACKGROUND

Phrenic nerve injury is a recognized complication following cardiac intervention or surgery. With increasing use of transcatheter procedures to treat drug-refractory arrhythmias, clarification of the spatial relationships between the phrenic nerves and important cardiac structures is essential to reduce risks.

METHODS AND RESULTS

We examined by gross dissection the courses of the right and left phrenic nerves in 19 cadavers. Measurements were made of the minimal and maximal distances of the nerves to the superior caval vein, superior cavoatrial junction, right pulmonary veins, and coronary veins. Histologic studies were carried out on tissues from six cavaders. Tracing the course of the right phrenic nerve revealed its close proximity to the superior caval vein (minimum 0.3 +/- 0.5 mm) and the right superior pulmonary vein (minimum 2.1 +/- 0.4 mm). The anterior wall of the right superior pulmonary vein was <2 mm from the right phrenic nerve in 32% of specimens. The left phrenic nerve passed over the obtuse cardiac margin and the left obtuse marginal vein and artery in 79% of specimens. In the remaining specimens, its course was anterosuperior, passing over the main stem of the left coronary artery or the anterior descending artery and great cardiac vein.

CONCLUSIONS

The right phrenic nerve is at risk when ablations are carried out in the superior caval vein and the right superior pulmonary vein. The left phrenic nerve is vulnerable during lead implantation into the great cardiac and left obtuse marginal veins.

A new endocardial "over-the-wire" or stylet-driven left ventricular lead: first clinical experience

Transvenous left ventricular (LV) leads are primarily inserted "over-the-wire" (OTW). However, a stylet-driven (SD) approach may be a helpful alternative. A new polyurethane-coated, unipolar LV lead can be placed either by a stylet or a guide wire, which can be inserted into the lead body from both ends. The multicenter OVID study evaluates the clinical performance of this new steroid- and nonsteroid eluting lead. The primary endpoint is the LV lead implant success rate after identification of the coronary sinus (CS). Secondary endpoints include complication rate, short- and long-term lead characteristics, overall procedure and LV lead placement duration, total fluoroscopy time, and lead handling characteristics ratings. To date, 96 patients with heart failure (68 +/- 9 years old, 76% men) are enrolled. The CS was identified in 95 patients and, in 85 (88.5%), the LV lead was successfully implanted. The final lead positioning was lateral in 41%, posterolateral in 35%, anterolateral in 18%, and great cardiac vein in 6% of patients. In 70%, the 85 successful implantations, both stylet-driven and guide-wire techniques were used, a stylet only was used in 22%, and a guide wire only in 8%. Mean overall duration of 85 successful procedures was 112 +/- 40 minutes, total fluoroscopy time 28 +/- 15 minutes, and the duration of LV lead placement was 35 +/- 29 minutes. During a 3-month follow-up, the loss of LV capture occurred in three and phrenic nerve stimulation in six patients. The mean long-term pacing threshold is 0.8 V/0.5 ms and pacing impedance is 550 Omega. The OVID data suggest that these new leads are safe and effective. The choice of both OTW and SD techniques during lead implantation offers greater procedural flexibility.

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.

Use of Preshaped Sheath to Plan and Facilitate Cannulation of the Coronary Sinus for the Implantation of Cardiac Resynchronization Therapy Devices: Preshaped Sheath for Implantation of Biventricular Devices

OBJECTIVES

The aim of the study is to describe a new technique for facilitating the implantation of cardiac resynchronization therapy (CRT) devices.

BACKGROUND

CRT, by simultaneous pacing of the right and left ventricles has proven to be a useful treatment for patients with advanced heart failure and left ventricular (LV) systolic dysfunction, who have concomitant LV dyssynchrony. One of the greatest challenges to the wide applications of this therapy has been the technical difficulty encountered with implantation of the left ventricular lead. This is mainly due to the varied anatomy of the coronary venous system, which is further complicated by distortion of the anatomy in patients with advanced heart failure.

METHODS

Details of the coronary venous anatomy are initially assessed by cannulating the coronary sinus (CS) using a specialized long preshaped sheath introduced from the femoral approach. Occlusive venography is performed in three views, and then the guide wire or the deflated balloon catheter is left in the CS for guidance. The most suitable equipment for the anatomy is chosen. Then, the operative site is prepped and the CS is approached from above.

RESULTS

From November 2003 until December 2004, we have used this approach on all patients presenting for CRT device implantation at Prince Sultan Cardiac Center (n = 25). The CS was cannulated using the preshaped catheter in less than 5 minutes in all cases. After delineation of the anatomy, successful CRT implantation was achieved in all patients. Mean procedure time for the implantation was 110 +/- 18 minutes. Uncomplicated minor CS dissection related to the use of the preshaped sheath was observed in 1 patient without consequences.

CONCLUSIONS

The use of preshaped sheath from the femoral approach facilitates planning the successful and safe implantation of CRT systems.

Comparison of stimulation sites within left ventricular veins on the acute hemodynamic effects of cardiac resynchronization therapy

OBJECTIVES

The purpose of this study was to study the acute hemodynamic effect of left ventricular (LV) stimulation sites within a coronary vein.

BACKGROUND

Access to LV stimulation sites for resynchronization therapy is achieved using specialized lead systems navigated through a coronary vein. The effects of stimulation in different coronary veins have been evaluated previously, but less is known about stimulation sites within a coronary vein.

METHODS

Twenty-four patients (New York Heart Association functional class II-IV, age 59 +/- 10 years, ejection fraction 21 +/- 7%, QRS 166 +/- 30 ms) were enrolled in the study. A novel over-the-wire lead system was used to access an anterior or lateral coronary vein. At each lead location, a randomized stimulation protocol was executed. Hemodynamic responses were evaluated using LV dP/dtmax.

RESULTS

The mean time to cannulate the coronary sinus and position the LV lead was 19 +/- 30 minutes and 17 +/- 18 minutes, respectively. Data from stimulation at two sites within a coronary vein were obtained in 19 patients (anterior vein 11; lateral vein 8). Of these patients, 14 (anterior vein 9; lateral vein 5) showed large improvement in dP/dtmax (22%-25% in anterior vein, 37%-40% in lateral vein). Overall, there were no group differences in hemodynamic effects among different stimulation sites within a coronary vein, although significant variability among sites was observed in individuals.

CONCLUSIONS

Resynchronization therapy through a coronary vein improves acute hemodynamic function of heart failure patients with LV conduction disorder. There were no significant differences between basal and apical pacing sites for this group.

Cardiac resynchronization therapy (CRT) in heart failure--a model to assess the economic value of this new medical technology

OBJECTIVES

This article describes the framework of a comprehensive European model developed to assess clinical and economic outcomes of cardiac resynchronization therapy (CRT) versus optimal pharmacological therapy (OPT) alone in patients with heart failure.

METHODS

The model structure is based on information obtained from the literature, expert opinion, and a European CRT Steering Committee. The decision-analysis tool allows a consideration of direct medical and indirect costs, and computes outcomes for distinctive periods of time up to 5 years. Qualitative data can also be entered for cost-utility analysis. Model input data for a preliminary economic appraisal of the economic value of CRT in Germany were obtained from clinical trials, experts, health statistics, and medical tariff lists.

RESULTS

The model offers comprehensive analysis capabilities and high flexibility so that it can easily be adapted to any European country or special setting. The illustrative analysis for Germany indicates that CRT is a cost-effective intervention. Although CRT is associated with average direct medical net costs of Euro 5880 per patient, this finding means that 22% of its upfront implantation cost is recouped already within 1 year because of significantly decreased hospitalizations. With 36,600 Euros the incremental cost per quality-adjusted life-year (QALY) gained is below the euro equivalent (41,300 Euros, 1 Euro = US1.21 dollars) of the commonly used threshold level of US50,000 dollars considered to represent cost-effectiveness. The sensitivity analysis showed these preliminary results to be fairly robust towards changes in key assumptions.

CONCLUSIONS

The European CRT model is an important tool to assess the economic value of CRT in patients with moderate to severe heart failure. In the light of the planned introduction of Diagnosis Related Group (DRG) based reimbursement in various European countries, the economic data generated by the model can play an important role in the decision-making process.

Beyond Coronary Sinus Angiography: The Value of Coronary Arteriography and Identification of the Pericardiophrenic Vein During Left Ventricular Lead Placement

OBJECTIVE

The purpose of this study was to define the role coronary arteriography (venous phase) for improving the success of left ventricular (LV) lead implantation and to define the value of identifying the pericardiophrenic vein for optimal LV lead placement in biventricular (bi-v) device implantation.

METHODS

Seventy-seven patients underwent bi-v device implantation between July 2002 and October 2003. If the coronary sinus (CS) could not be accessed, then left coronary arteriography was performed during the same procedure. CS access was guided by venous phase images of the coronary arteriogram. The pericardiophrenic vein was identified by selective cannulation or direct visualization. Patients with Cr > 1.5 had gadolinium used as the contrast agent.

RESULTS

Seventy-five successful implants were performed (97%). In seven patients (9%) repeated attempts at retrograde cannulation of the CS failed (attempt time 130 +/- 20 minute, mean +/- SD). In these patients, coronary arteriography helped define the location of the CS, which was subsequently successfully cannulated. In six patients the pericardiophrenic vein was identified either during occlusion venography of the CS (postthoracotomy, veno-venous collaterals, n = 2) or during selective cannulation of the pericardiophrenic vein (using a DAIG Csl catheter, n = 4). The vein was directly visualized in three patients who underwent surgical LV lead implantation. LV leads in all these cases were implanted in areas not overlying the preidentified pericardiophrenic vein. During follow-up, none of these patients had evidence of phrenic nerve stimulation.

CONCLUSIONS

Intraoperative left coronary arteriography increases the success of CS cannulation. Identification of the pericardiophrenic vein is a useful method to avoid phrenic nerve stimulation.

Novel Steerable Telescoping Catheter System for Implantation of Left Ventricular Pacing Leads

Advances in left ventricular transvenous lead delivery systems for biventricular pacing are leading to more refined techniques, shorter procedure times and higher implant success rates. Despite these advances, the inability to successfully cannulate the coronary sinus and deliver a lead to a distal location are still major causes of prolonged procedures times and implant failures. The pathophysiologic process of heart failure results in dilatation of the right atrium as well as other morphological changes in cardiac anatomy. Additionally, cannulation can be further complicated by congenital anomalous cardiac anatomy. This report describes the implant of a biventricular pacing system using a novel, steerable 7 French catheter system developed to aid in the cannulation of the coronary sinus ostium and its venous branches. The steerable catheter is used in conjunction with a 9 French braided sheath and guide-wire to create a telescoping system. The use of new tools and methods as described provides insight into available options for left ventricular transvenous lead implantation and dealing with difficult anatomy.

Cardiac resynchronization therapy in congestive heart failure: Ready for prime time?

OBJECTIVES/BACKGROUND

The aim of this article is to critically review the data accumulated to date on the application of cardiac resynchronization therapy (CRT) via biventricular pacing techniques to manage patients with advanced heart failure. The data from studies evaluating the effects of long-term right ventricular (RV) pacing are also briefly reviewed.

METHODS

MEDLINE and selective journal searches of English-language reports and a search of references of relevant papers were conducted.

RESULTS

Cardiac dyssynchrony as reflected by a prolonged QRS complex, often in the form of left bundle branch block, is encountered in about 30% of patients with moderate-to-advanced heart failure. Among these patients, 10% to 15% are candidates for CRT via biventricular pacing. Accumulated evidence from randomized controlled studies over the last few years has indicated a significant hemodynamic and clinical improvement conferred by CRT to class III or IV heart failure patients with idiopathic or ischemic dilated cardiomyopathy having a low left ventricular ejection fraction (</=35%) and a wide QRS complex (>/=120-150 ms). Newer data suggest a significant reduction in overall mortality and heart failure hospitalization, particularly when CRT is combined with automatic defibrillator backup. Technical advances with percutaneous methods accessing the tributaries of the cardiac veins have raised the success rate of implantation of left ventricular leads to >90%. Further confirmation from ongoing trials is awaited, and more data from cost-effectiveness studies are needed before CRT is considered for prime time therapy in the heart failure population. If the data confirm a survival benefit from CRT, use of this electrical therapy at earlier stages of heart failure might be contemplated. New evidence from recent studies suggests a deleterious effect of the long-standing practice of producing an iatrogenic left bundle branch block by conventional RV apical pacing in patients receiving permanent pacemakers. Thus, having already become poignantly aware of the harmful effects of spontaneous left bundle branch block, this emerging new evidence about RV apical pacing would dictate a change of attitude and direct our attention to alternate sites of pacing, such as the left ventricle and/or the RV outflow tract, if not for all patients then at least for those with left ventricular dysfunction.

CONCLUSIONS

CRT offers hemodynamic and clinical improvement to patients with moderate-to-advanced heart failure, and it might significantly prolong survival in selected patients, particularly if devices with defibrillation backup are used. Further confirmatory data from randomized mortality trials are needed, and issues of cost efficacy must be resolved before this vital therapeutic alternative is ready for prime time therapy of heart failure patients.

Comparison of left ventricular lead placement via the coronary venous approach versus lateral thoracotomy in patients receiving cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is a new therapeutic option in patients with heart failure and ventricular conduction delay. We compared the long-term performance of left ventricular (LV) pacing via the coronary venous (CV) approach and a limited lateral thoracotomy (LLT). Data from 81 patients (age 65 +/- 12 years; 52 men, New York Heart Association class 3.0 +/- 0.4, ejection fraction 24 +/- 6%) were retrospectively analyzed for 1 year after implantation of a CRT system. Twenty-five patients received LLT leads and 56 patients received CV leads. Postoperative hospitalization was shorter after CV lead implantation (8 +/- 4 vs 12 +/- 5 days, p <0.01). No significant differences in LV pacing and sensing performance between both approaches were observed after 12 months. Reinterventions were necessary in 7 patients after CV implantation compared with only 1 reintervention (4%) in the LLT group (p = NS). Postoperative chest radiographs revealed an anterior lead position in 11 of 25 patients (44%) in the LLT group versus 3 of 56 patients (5.4%) in the CV group (p = 0.00007). Echocardiographic data demonstrated a significant increase in LV ejection fraction in the CV group (from 26.1 +/- 5.2% to 35.3 +/- 14.3% at 12 months, p <0.001, n = 42) in contrast to the LLT group (from 24.5 +/- 6.2% to 28.5 +/- 7.5% at 12 months, p = NS, n = 16) at 12-month follow-up. Cardiopulmonary exercise testing in 35 patients showed significantly more improvement in peak oxygen consumption after 12 months in the CV group (15.5 +/- 3.1 vs 13.6 +/- 2.6 ml/min/kg at implant, n = 22) compared with the LLT group (12.7 +/- 1.5 vs 11.8 ml/min/kg at implant, n = 13, p = 0.004). At 1-year follow-up the mortality rate was 24% (6 of 25) after LLT lead implantation versus 12.5% (7 of 56) after CV implantation (p = NS). Our data show that the LLT approach for LV lead placement in CRT systems has the advantage of a lower incidence of reinterventions. Hospitalization was longer, increase in functional capacity smaller, and mortality at 1-year follow-up higher, which were potentially related to a more anterior lead position. Therefore, CV leads are preferable to LLT leads.

Epicardial left ventricular lead placement for cardiac resynchronization therapy: optimal pace site selection with pressure-volume loops

OBJECTIVES

Patients in heart failure with left bundle branch block benefit from cardiac resynchronization therapy. Usually the left ventricular pacing lead is placed by coronary sinus catheterization; however, this procedure is not always successful, and patients may be referred for surgical epicardial lead placement. The objective of this study was to develop a method to guide epicardial lead placement in cardiac resynchronization therapy.

METHODS

Eleven patients in heart failure who were eligible for cardiac resynchronization therapy were referred for surgery because of failed coronary sinus left ventricular lead implantation. Minithoracotomy or thoracoscopy was performed, and a temporary epicardial electrode was used for biventricular pacing at various sites on the left ventricle. Pressure-volume loops with the conductance catheter were used to select the best site for each individual patient.

RESULTS

Relative to the baseline situation, biventricular pacing with an optimal left ventricular lead position significantly increased stroke volume (+39%, P =.01), maximal left ventricular pressure derivative (+20%, P =.02), ejection fraction (+30%, P =.007), and stroke work (+66%, P =.006) and reduced end-systolic volume (-6%, P =.04). In contrast, biventricular pacing at a suboptimal site did not significantly change left ventricular function and even worsened it in some cases.

CONCLUSIONS

To optimize cardiac resynchronization therapy with epicardial leads, mapping to determine the best pace site is a prerequisite. Pressure-volume loops offer real-time guidance for targeting epicardial lead placement during minimal invasive surgery.

Technical Aspects of Implantation of LV Lead for Cardiac Resynchronization Therapy in Chronic Heart Failure

The goal of this study was to analyze total procedural and fluoroscopic time during initial experience with implantation of LV lead in a single center, and to assess the performance of electrophysiologically-guided approach for cannulation of the coronary sinus (CS) in a subsequent period. Over an initial period of 29 months, a total of 46 attempts to implant biventricular pacing system were revised. During the first phase, only one type of LV electrode was available for three implanters (11 attempts). The second phase covered their early experience with other stylet-controlled LV leads (10 attempts). Additional LV leads including the over-the-wire design were available in the third phase and 25 attempts were done by he most experienced implanter. In a period of advanced experience, 92 implant procedures performed by four implanters using an electrophysiologically-guided approach to CS cannulation were revised. In the first period, success rates for different phases reached 70%, 90%, and 96%, respectively. Significant decrease in both procedural and fluoroscopic times was achieved with increased experience (Phase I: 247.1 +/- 104.5 minutes and 31.2 +/- 34.3 minutes, Phase II: 219.4 +/- 85.6 minutes, and 22.9 +/- 19.1 minutes, Phase III: 116.4 +/- 89.9 minutes and 6.6 +/- 4.4 minutes, respectively, P < 0.05). Advanced experience with electrophysiologically-guided approach to CS cannulation allowed achievement of this target within a reasonable amount of time (15.4 +/- 16.3 minutes) and with minimum fluoroscopic time (2.1 +/- 2.9 minutes). In conclusion, both individual learning curve and technical advances significantly influence success rate, procedural, and fluoroscopic times for biventricular system implantation. Electrophysiologically-guided approach makes cannulation of the CS a highly reproducible procedure that requires minimum fluoroscopic time.

Comparative prospective randomized efficacy testing of different guiding catheters for coronary sinus cannulation in heart failure patients

INTRODUCTION

The efficacy of different shapes of guiding catheters for coronary sinus (CS) cannulation was evaluated at implant of a cardiac resynchronization therapy device that required transvenous placement of a pacing lead in a coronary vein on the left ventricle.

METHODS AND RESULTS

Comparative testing of 5 different guiding catheter shapes was attempted in 29 consecutive patients. Four newer guiding catheters were tested in a prospective randomized manner with a reference standard catheter always tested in the last place. All of the new catheters included a distal shape that consisted of a single curve or a compound set of curves at the catheter tip, followed by a catheter shaft design which fell into one of two classes: (1). straight shaft catheters and (2). curved shaft catheters. The curved shaft class of catheters, two new and one standard, achieved higher (16/23 (70%), 17/23 (74%) and 17/22 (77%)) CS cannulation success rates than the straight shaft class catheters ((13/23 (56%) and 12/23 (52%)). The pairing of two catheters, one from each class in a single patient, or both from the curved shaft class resulted in a combined CS cannulation success rate of up to 96%. Two of the catheters were more effective from a left hand insertion than from a right hand insertion site.

CONCLUSIONS

The ability to switch between guiding catheters with different shapes and compound curves can improve the CS cannulation success rate. The selection of guiding catheters should be influenced by the intended use of the catheter either from the left or from the right hand side.

Current status of cardiac resynchronization therapy

PURPOSE OF REVIEW

Cardiac resynchronization therapy with biventricular pacing has rapidly emerged as an indispensable treatment option in patients with moderate-to-advanced heart failure and left bundle branch block. New findings on the pathophysiology of cardiac resynchronization therapy and its clinical effects are reviewed.

RECENT FINDINGS

Several randomized trials have evaluated the effects of cardiac resynchronization therapy on cardiac haemodynamics and clinical parameters in selected heart failure patients with left bundle branch block. The effects of cardiac resynchronization therapy on mechanical synchrony have been evaluated by different imaging modalities, such as echocardiography and radionuclide angiography. Cardiac resynchronization therapy leads to improved haemodynamics at a diminished energy cost, and improves functional mitral regurgitation. This haemodynamic improvement is associated with a significantly better quality of life, improved exercise capacity, and less frequent hospitalization. Recent preliminary data suggest a positive effect on cardiac mortality. However, approximately a third of implanted patients do not benefit from cardiac resynchronization therapy, and therefore additional criteria for the identification of mechanical dyssynchrony are needed to identify those patients who will respond before implantation.

SUMMARY

Many randomized trials have confirmed the benefits of cardiac resynchronization therapy in selected heart failure patients. The successful resynchronization of the ventricular activation-contraction sequence is the major determinant of acute haemodynamic and long-term clinical improvement. The diagnostic sensitivity and specificity of the non-invasive identification of mechanical dyssynchrony may be improved by echocardiography, but further research is needed to identify the optimal strategy for patient identification.

Advances in devices for cardiac resynchronization in heart failure

Patients with advanced heart failure have a high mortality and morbidity despite medical therapy. Depending on the underlying heart disease and severity of heart failure, 3.7 to 52.8% of patients have a QRS complex > or =120 ms who may have interventricular and intraventricular dyssynchrony correctible by cardiac resynchronization therapy (CRT). The latter is usually achieved with biventricular pacing, with the left ventricular lead placed in a tributary of the coronary sinus (CS), with a reported success rate between 88-92%. The technical advances for implantation include preformed guide sheaths to cannulate the CS, over the wire leads with passive fixation mechanism, and surgical placement methods. Device-specific CRT features include optimizing heart failure through insurance of a high percentage of pacing, heart failure monitoring, atrioventricular and interventricular timing, and avoiding double ventricular sensing. Furthermore, arrhythmic co-morbidities of heart failure such as atrial fibrillation and ventricular tachyarrhythmias can also be managed. Recent prospective trials suggest that there is a 30% reduction in heart failure hospitalization with CRT, and preliminary results suggest a survival benefit with CRT and implantable cardioverter defibrillator over optimal medical therapy.

Effect of left ventricular function on long-term left ventricular pacing and sensing threshold

BACKGROUND

The effect of left ventricular (LV) systolic function on the long-term left ventricular pacing and sensing threshold is unclear.

METHODS AND RESULTS

We studied the effect of LV ejection fraction (LVEF) on the LV pacing and sensing threshold in 56 patients (mean age: 70.2 +/- 10.5 years) underwent permanent LV pacing using a self-retaining coronary sinus lead (Model 1055 K, St Jude Medical, USA). In 49 patients, the LV lead was implanted for conventional pacemaker indication (sick sinus syndrome = 14, heart block = 26 or slow atrial fibrillation = 9). The remaining 7 patients were implanted for congestive heart failure. The LV pacing and sensing threshold, and lead impedance were compared between patients with LVEF <40% (Group 1, n = 28) and LVEF >40% (Group 2, n = 28) during implant and at 3-month follow up. The LV pacing lead was successfully implanted in all patients without any lead dislodgement on follow-up. At implant, Group 1 patients had a significant lower R wave amplitude, but similar LV pacing threshold and lead impedance as compared to Group 2. However, at 3-month follow-up, Group 1 patients had a significantly higher LV pacing threshold compared to Group 2 patients. There were no significant differences in the sensing threshold and lead impedance between the two groups. Furthermore, there was also a significant interval increase in LV pacing threshold in Group 1 patients (0.94 +/- 0.12 V) after 3 months, but not in Group 2 patients (0.16 +/- 0.08 V, p < 0.01).

CONCLUSIONS

The results of this study suggest that the LV systolic function has a significant impact on the long-term LV pacing threshold. The long-term left ventricular pacing threshold in patients with left ventricular systolic dysfunction increased after implant and was higher than patients with normal left ventricular systolic function.

Pacing techniques in heart failure: current concepts and future outlook

In addition to the well established benefits of traditional pacing methods, newer, left ventricular-based pacing techniques appear to induce significant hemodynamic improvements, benefit cardiac remodeling, improve functional capacity, and may decrease hospitalizations in appropriately selected patients with advanced systolic heart failure and intraventricular conduction defects. Encouraging results have been suggested from preliminary observational studies as well as from controlled clinical trials. Despite the generally positive outlook, much remains to be learned about multisite pacing techniques, appropriate site and patient selection, and long-term effectiveness.

Useful tip to improve electrode positioning in markedly angulated coronary sinus tributaries

The anatomic variability of the cardiac veins limits the feasibility of cardiac resynchronization therapy. This report describes another way to position the pacemaker electrode in sharply angulated coronary sinus branches.

Biventricular pacing with coronary bypass and Dor's ventriculoplasty

We applied biventricular pacing to a patient with severe ischemic dilated cardiomyopathy (left ventricular [LV] ejection fraction 19%, LV end-diastolic volume 360 mL, and complete left bundle branch block). An epicardial LV lead was surgically implanted concomitant with on-pump beating coronary artery bypass grafting and Dor's endoventricular circular patch plasty. Biventricular pacing immediately achieved the resynchronization of the LV contraction, and improved cardiac function as well as reducing mitral regurgitation. Biventricular pacing combined with cardiac surgery for patients with cardiomyopathy and complete left bundle branch block may produce beneficial effects on LV function.

[Biventricular pacing as a treatment for advanced heart failure. Preliminary experience in a series of 22 consecutive patients]

BACKGROUND AND OBJECTIVES

Recent data suggest that biventricular pacing may play an important role in treating advanced heart failure in the presence of a significant interventricular and/or intraventricular conduction disorder by correcting cardiac dysynchrony. In this article, we review the initial technical and clinical experience with cardiac resynchronization therapy in an electrophysiology laboratory.

METHODS

The first 22 consecutive patients with severe congestive heart failure, ejection fraction < 0.35, NYHA functional class III or IV, and QRS duration > 120 ms who were implanted biventricular pacemakers were studied. Clinical, electrocardiographic, and echocardiographic evaluations were made before and three months after pacemaker implantation. Acute functional capacity testing with peak oxygen uptake was measured during biventricular pacing and during intrinsic rhythm or right ventricular pacing three months after the implantation procedure.

RESULTS

The success rate of pacemaker implantation was 95%. Pre-discharge left ventricular pacing was achieved in 91%, with an average pacing threshold of 1.53 (1.04) volts. NYHA functional class improved (p = 0.039) from 3.4 (0.7) to 2.3 (0.78). The rate of hospitalization for heart failure decreased from an average of 3.12 (0.58) three months before the procedure to 1.38 (0.34) three months after the procedure. Peak oxygen uptake was significantly greater (p = 0.028) during biventricular pacing: 14.89 (2.1) ml/min/kg, than during intrinsic rhythm or right ventricular pacing: 12.65 (2.3) ml/min/kg.

CONCLUSIONS

Cardiac resynchronization therapy can be performed safely and with a high success rate in the electrophysiology laboratory. Biventricular pacing seems to improve the symptoms of congestive heart failure in patients with evidence of atrioventricular and/or interventricular/intraventricular dysynchrony. An acute benefit in peak oxygen uptake was associated with biventricular pacing after the implantation procedure.

Cardiac contractility modulation with nonexcitatory electric signals improves left ventricular function in dogs with chronic heart failure

BACKGROUND

Nonexcitatory electrical, signals termed cardiac contractility modulation (CCM) have been shown to improve contractile force of isolated papillary muscles. In this study, we examined the effects of CCM signal delivery on left ventricular function in dogs with chronic heart failure (HF).

METHODS AND RESULTS

Chronic HF (ejection fraction </=35%) was produced in 7 dogs by intracoronary microembolizations. The CCM signal was delivered during the absolute refractory period using a lead implanted in the anterior coronary vein. A right ventricular and an atrial lead were implanted and used for timing of the CCM signal delivery. Hemodynamic measurements were made at baseline and at 1, 2, 3, 4, 5, and 6 hours after initiating CCM signal delivery. Ejection fraction increased from 31 +/- 1% at baseline to 41 +/- 1% at 1 hour (P <.05), 42 +/- 1% at 3 hours (P <.05), and 44 +/- 2% at 6 hours (P <.05). Similarly, stroke volume increased from 26 +/- 2 mL to 31 +/- 3 mL at 1 hour (P <.05), 33 +/- 3 mL at 3 hours (P <.05), and 34 +/- 3 mL at 6 hours (P <.05). There were no significant changes compared to baseline in ejection fraction or stroke volume in 5 HF control dogs studied for up to 4 hours.

CONCLUSION

In dogs with HF, CCM signal delivery for 6 hours elicited marked improvement in LV function. This novel approach may represent a useful adjunctive therapy for the treatment of patients with HF.