Practical approach to implanting left ventricular pacing leads for cardiac resynchronization

Left ventricular lead placement using inner guiding catheter alone in cardiac resynchronization therapy device implantation

BACKGROUND

Subselection inner catheters (Inner-Cath) are used adjunctively with outer guiding catheters (Outer-Cath) during cardiac resynchronization therapy (CRT) device implantation. This study aims to investigate the feasibility and efficacy of left ventricular lead placement (LV-LP) guided by Inner-Cath alone.

METHODS

A total of 74 patients undergoing de novo CRT implantation were investigated. LV-LP was initially guided by Inner-Cath in 42 patients (Inner-Cath group) and Outer-Cath in 32 patients (Outer-Cath group). In the Inner-Cath group, a 7Fr Inner-Cath was advanced to the coronary sinus through a 7 Fr sheath inserted in a subclavian vein. In the Outer-Cath group, 9Fr or 10Fr Outer-Caths were used. Success rate of LV-LP, additional use of inner or outer catheters and procedure-related complications were compared between groups.

RESULTS

LV-LP was successful in all patients in the Inner-Cath group, while LV-LP had to be abandoned in two patients (6.3%) of the Outer-Cath group due to CS perforation caused by Outer-Cath manipulation. Procedure time was significantly shorter in the Inner-Cath group (148 vs. 168 min; p = .024). Deployment of both an inner and outer cath became necessary less frequently for the Inner-Cath group (4.8% vs. 56.3%; p < .001). Mechanical CS injuries due to guiding catheter manipulation were only observed in the Outer-Cath group (0% vs. 15.6%, p = .013).

CONCLUSION

LV-LP guided by Inner-Cath alone was feasible in over 95% of the patients without severe complications. This methodology for LV-LP may be preferable in CRT candidates with severe LV dysfunction in terms of shorter procedure time, smaller guiding sheath, and less procedure-related complications.

Electrophysiology Catheter-Facilitated coronary sinus cannulation and implantation of cardiac resynchronization therapy systems

BACKGROUND

Cardiac resynchronization therapy (CRT) device implantation is hampered by difficult placement of the left ventricular (LV) lead. We have routinely used a steerable electrophysiology catheter to guide coronary sinus (CS) cannulation and facilitate LV lead positioning. The aim of this prospective study is to present our results with this approach in 138 consecutive patients receiving a CRT device over 10 years.

METHODS

The study included 120 men and 18 women, aged 64.8±11.4 years, with coronary disease (n=63), cardiomyopathy (n=72), or other disease (n=3), and mean ejection fraction of 24.5±4.5%. Devices were implanted for refractory heart failure and dyssynchrony, all but 2 in the presence of left bundle branch block. Implanted devices included biventricular pacemakers (CRT-P) (n=33) and cardioverter defibrillators (CRT-D) (n=105).

RESULTS

Using the electrophysiology catheter, the CS could be engaged in 134 (97.1%) patients. In 4 patients failing CS cannulation, a dual-chamber device was implanted in 2, and bifocal right ventricular pacing was effected in 2. Bifocal (n=2) or conventional (n=1) systems were implanted in another 3 patients, in whom the LV lead got dislodged (n=2) or removed because of local dissection (n=1). Thus, finally, a CRT system was successfully established in 131 (94.9%) patients. There were 3 patients with CS dissection, of whom 1 was complicated by cardiac tamponade managed with pericardiocentesis. There were no perioperative deaths. During follow-up (31.0±21.2 months), clinical improvement was reported by 108 (82.4%) patients.

CONCLUSION

Routine use of an electrophysiology catheter greatly facilitated CS cannulation and successful LV lead placement in ∼95% of patients undergoing CRT system implantation.

Biventricular Pacemakers in Patients With Heart Failure

Patients with heart failure may benefit from implantation of a biventricular pacemaker. This article discusses the indications for biventricular pacemaker implantation and the assessment of patients with biventricular pacemakers. Biventricular pacemakers require more assessments than do traditional single- or dual-chamber pacemakers.

Improvement of left ventricular function under cardiac resynchronization therapy goes along with a reduced incidence of ventricular arrhythmia

Objectives

The beneficial effects of cardiac resynchronization therapy (CRT) are thought to result from favorable left ventricular (LV) reverse remodeling, however CRT is only successful in about 70% of patients. Whether response to CRT is associated with a decrease in ventricular arrhythmias (VA) is still discussed controversially. Therefore, we investigated the incidence of VA in CRT responders in comparison with non-responders.

Methods

In this nonrandomized, two-center, observational study patients with moderate-to-severe heart failure, LV ejection fraction (LVEF) ≤35%, and QRS duration >120 ms undergoing CRT were included. After 6 months patients were classified as CRT responders or non-responders. Incidence of VA was compared between both groups by Kaplan-Meier analysis and Cox regression analysis. ROC analysis was performed to determine the aptitude of LVEF cut-off values to predict VA.

Results

In total 126 consecutive patients (64±11years; 67%male) were included, 74 were classified as responders and 52 as non-responders. While the mean LVEF at baseline was comparable in both groups (25±7% vs. 24±8%; P = 0.4583) only the responder group showed an improvement of LVEF (36±6% vs. 24±7; p<0.0001) under CRT. In total in 56 patients VA were observed during a mean follow-up of 28±14 months, with CRT responders experiencing fewer VA than non-responders (35% vs. 58%, p<0.0061). Secondary preventive CRT implantation was associated with a higher likelihood of VA. As determined by ROC analysis an increase of LVEF by >7% was found to be a predictor of a significantly lower incidence of VA (AUC = 0.606).

Conclusions

Improvement of left ventricular function under cardiac resynchronization therapy goes along with a reduced incidence of ventricular arrhythmia.

Value of Cardiac CT in Patients With Heart Failure

Multidetector CT (MDCT) with 64-slice capability continues to gain momentum for cardiovascular imaging. Beyond images of coronary arteries, it also provides reliable information on left ventricular structure and function, cardiac venous anatomy, the pulmonary venous system, and right ventricular function-all aspects important in the management of heart failure patients. Potential unique applications in heart failure include cardiac dyssynchrony evaluation, assessing cardiomyopathies, and post-transplant annual follow-up. This review details the multiple applications and limitations of MDCT in the heart failure population, including comparison with other commonly used imaging modalities such as echocardiography and MRI.

Morphologic and Topologic Characteristics of Coronary Venous System Delineated by Noninvasive Multidetector Computed Tomography in Chronic Systolic Heart Failure Patients

BACKGROUND

Variations of coronary venous system in a dilated, failing heart may well be unpredictable. Noninvasive preview of coronary veins before left ventricular (LV) lead implantation for cardiac resynchronization therapy would facilitate successful procedure in chronic systolic heart failure (SHF) patients.

METHODS AND RESULTS

Multidetector computed tomography (MDCT) of the heart was investigated in 23 consecutive patients of chronic SHF with LV ejection fraction < or = 40%. Morphologic and topologic characteristics of coronary venous system were studied, and compared with 23 age-matched controls. All coronary veins including coronary sinus, posterior interventricular vein (PIV), LV posterior vein, left margin vein (LMV), and anterior interventricular vein (AIV) were clearly visible in all 23 SHF patients and 23 normal controls. Total coronary venous length (ie, from PIV to AIV) was directly correlated with LV volume (r = 0.65, P < .001). The main lengthened venous segment was between LMV and AIV. Ostial diameters of all coronary venous tributaries were larger in SHF patients, but the angle of branching was similar. However, the secondary angle of the coronary sinus relative to superior vena cava axis was more acute (30 +/- 7 degrees) in SHF patients than that in normal (44 +/- 8 degrees, P < .001). Local aneurysm locating at LV posterolateral wall could detour relevant coronary vein tributaries to the outer border of the aneurysm, compress venous dimensions throughout the cardiac cycle, and cause acute angulation of venous tributaries.

CONCLUSIONS

Coronary venous system shown by MDCT in SHF patients with low LV ejection fraction manifested longer venous length between LMV and AIV, acute secondary CS angle, and usually topologically distorted by posterolateral LV aneurysms. A panoramic delineation of all coronary venous tributaries could help effective venous intervention.

Initial Clinical Experience with Cardiac Resynchronization Therapy Utilizing a Magnetic Navigation System

INTRODUCTION

The placement of left ventricular (LV) leads during cardiac resynchronization therapy (CRT) involves many technical difficulties. These difficulties increase procedural times and decrease procedural success rates.

METHODS AND RESULTS

A total of 50 patients with severe cardiomyopathy (mean LV ejection fraction was 21 +/- 6%) and a wide QRS underwent CRT implantation. Magnetic navigation (Stereotaxis, Inc.) was used to position a magnet-tipped 0.014'' guidewire (Cronus guidewire) within the coronary sinus (CS) vasculature. LV leads were placed in a lateral CS branch, either using a standard CS delivery sheath or using a "bare-wire" approach without a CS delivery sheath. The mean total procedure time was 98.1 +/- 29.1 minutes with a mean fluoroscopy time of 22.7 +/- 15.1 minutes. The mean LV lead positioning time was 10.4 +/- 7.6 minutes. The use of a delivery sheath was associated with longer procedure times 98 +/- 32 minutes vs 80 +/- 18 minutes (P = 0.029), fluoroscopy times 23 +/- 15 minutes vs 13 +/- 4 minutes (P = 0.0007) and LV lead positioning times 10 +/- 6 minutes vs 4 +/- 2 minutes (P = 0.015) when compared to a "bare-wire" approach. When compared with 52 nonmagnetic-assisted control CRT cases, magnetic navigation reduced total LV lead positioning times (10.4 +/- 7.6 minutes vs 18.6 +/- 18.9 minutes; P = 0.005). If more than one CS branch vessel was tested, magnetic navigation was associated with significantly shorter times for LV lead placement (16.2 +/- 7.7 minutes vs 36.4 +/- 23.4 minutes; P = 0.004).

CONCLUSIONS

Magnetic navigation is a safe, feasible, and efficient tool for lateral LV lead placement during CRT. Magnetic navigation during CRT allows for control of the tip direction of the Cronus 0.014'' guidewire using either a standard CS delivery sheath or "bare-wire" approach. Although there are some important limitations to the 0.014'' Cronus magnetic navigation can decrease LV lead placement times compared with nonmagnetic-assisted control CRT cases, particularly if multiple CS branches are to be tested.

New tools for the effective delivery of cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) has been shown to provide symptom relief to many patients who have congestive heart failure (CHF). Still, there are technical concerns with implanting CRT systems, and these range from inadequate venous anatomy to a variety of left ventricular (LV) lead problems. Fortunately, there are several new implant tools to help physicians achieve a stable and adequate LV pacing site. There are a number of guiding catheter shapes to tailor the choice to specific anatomic abnormalities that may be encountered during implants. Key to success was the development of over-the-wire LV leads that are capable of maneuvering within complex venous anatomy. Improvements in LV leads have included increasing lead diameter and bipolar design. In some cases, epicardial LV lead placement may be necessary at surgery. The latest systems have begun to integrate disease management modalities, which hopefully will reduce the need for CHF hospitalizations.