Implantation of Left Ventricular Leads Using a Telescopic Catheter System

Left Ventricular Lead Placement Guided by Reduction in QRS Area

Background: Reduction in QRS area after cardiac resynchronization therapy (CRT) is associated with improved long-term clinical outcome. The aim of this study was to investigate whether the reduction in QRS area is associated with hemodynamic improvement by pacing different LV sites and can be used to guide LV lead placement. Methods: Patients with a class Ia/IIa CRT indication were prospectively included from three hospitals. Acute hemodynamic response was assessed as the relative change in maximum rate of rise of left ventricular (LV) pressure (%∆LVdP/dt_max). Change in QRS area (∆QRS area), in QRS duration (∆QRS duration), and %∆LVdP/dt_max were studied in relation to different LV pacing locations within a patient. Results: Data from 52 patients paced at 188 different LV pacing sites were investigated. Lateral LV pacing resulted in a larger %∆LVdP/dt_max than anterior or posterior pacing (p = 0.0007). A similar trend was found for ∆QRS area (p = 0.001) but not for ∆QRS duration (p = 0.23). Pacing from the proximal electrode pair resulted in a larger %∆LVdP/dt_max (p = 0.004), and ∆QRS area (p = 0.003) but not ∆QRS duration (p = 0.77). Within patients, correlation between ∆QRS area and %∆LVdP/dt_max was 0.76 (median, IQR 0.35; 0,89). Conclusion: Within patients, ∆QRS area is associated with %∆LVdP/dt_max at different LV pacing locations. Therefore, QRS area, which is an easily, noninvasively obtainable and objective parameter, may be useful to guide LV lead placement in CRT.

Novel two-lead cardiac resynchronization therapy system provides equivalent CRT responses with less complications than a conventional three-lead system: Results from the QP ExCELs lead registry

Introduction

The novel two‐lead cardiac resynchronization therapy (CRT)‐DX system utilizes a floating atrial dipole on the implantable cardioverter‐defibrillator lead, and when implanted with a left ventricular (LV) lead, offers a two‐lead CRT system with AV synchrony. This study compared complication rates and CRT response among subjects implanted with a two‐lead CRT‐DX system to those subjects implanted with a standard three‐lead CRT‐D system.

Methods and Results

A total of 240 subjects from the Sentus QP—Extended CRT Evaluation with Quadripolar Left Ventricular Leads postapproval study were selected to identify 120 matched pairs based on similar demographic characteristics using a Greedy algorithm. The complication‐free rate was evaluated as the primary endpoint. All‐cause mortality, heart failure hospitalizations, device diagnostic data, New York Heart Association (NYHA) class improvement, and defibrillator therapy were evaluated from clinical data, in‐office interrogations, and remote monitoring throughout the follow‐up period. Complication‐free survival favored the CRT‐DX group with 92.5% without a major complication compared to 85.0% in the CRT‐D cohort (P = .0495; 95% confidence interval: 0.1%‐14.9%) over a mean follow‐up of 1.3 and 1.4 years, respectively. Incidence of all‐cause mortality, heart failure hospitalizations, NYHA changes at 6 months postimplant, and percent of LV pacing during CRT therapy were similar in both device cohorts. Inappropriate shocks were more frequent in the CRT‐D cohort with 5.8% of subjects receiving an inappropriate shock vs 0.8% in the CRT‐DX cohort.

Conclusion

The results of this subanalysis demonstrate that the CRT‐DX system can provide similar CRT responses and significantly fewer complications when compared to a similar cohort with a conventional three‐lead CRT‐D system.

Hemodynamic comparison of different multisites and multipoint pacing strategies in cardiac resynchronization therapies

PURPOSE

In order to increase the responder rate to CRT, stimulation of the left ventricular (LV) from multiple sites has been suggested as a promising alternative to standard biventricular pacing (BIV). The aim of the study was to compare, in a group of candidates for CRT, the effects of different pacing configurations-BIV, triple ventricular (TRIV) by means of two LV leads, multipoint (MPP), and multipoint plus a second LV lead (MPP + TRIV) pacing-on both hemodynamics and QRS duration.

METHODS

Fifteen patients (13 male) with permanent AF (mean age 76 ± 7 years; left ventricular ejection fraction 33 ± 7%; 7 with ischemic cardiomyopathy; mean QRS duration 178 ± 25 ms) were selected as candidates for CRT. Two LV leads were positioned in two different branches of the coronary sinus. Acute hemodynamic response was evaluated by means of a RADI pressure wire as the variation in LVdp/dtmax.

RESULTS

Per patient, 2.7 ± 0.7 veins and 5.2 ± 1.9 pacing sites were evaluated. From baseline values of 998 ± 186 mmHg/s, BIV, TRIV, MPP, and MPP-TRIV pacing increased LVdp/dtmax to 1200 ± 281 mmHg/s, 1226 ± 284 mmHg/s, 1274 ± 303 mmHg, and 1289 ± 298 mmHg, respectively (p < 0.001). Bonferroni post-hoc analysis showed significantly higher values during all pacing configurations in comparison with the baseline; moreover, higher values were recorded during MPP and MPP + TRIV than at the baseline or during BIV and also during MPP + TRIV than during TRIV. Mean QRS width decreased from 178 ± 25 ms at the baseline to 171 ± 21, 167 ± 20, 168 ± 20, and 164 ± 15 ms, during BIV, TRIV, MPP, and MPP-TRIV, respectively (p < 0.001).

CONCLUSIONS

In patients with AF, the acute response to CRT improves as the size of the early activated LV region increases.

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.

Determination of the longest intrapatient left ventricular electrical delay may predict acute hemodynamic improvement in patients after cardiac resynchronization therapy

BACKGROUND

One of the reasons for patient nonresponse to cardiac resynchronization therapy is a suboptimal left ventricular (LV) pacing site. LV electric delay (Q-LV interval) has been indicated as a prognostic parameter of cardiac resynchronization therapy response. This study evaluates the LV delay for the optimization of the LV pacing site.

METHODS AND RESULTS

Thirty-two consecutive patients (23 men; mean age, 71±11 years; LV ejection fraction, 30±6%; 18 with ischemic cardiomyopathy; QRS, 181±25 ms; all mean±SD) underwent cardiac resynchronization therapy device implantation. All available tributary veins of the coronary sinus were tested, and the Q-LV interval was measured at each pacing site. The hemodynamic effects of pacing at different sites were evaluated by invasive measurement of LV dP/dtmax at baseline and during pacing. Overall, 2.9±0.8 different veins and 6.4±2.3 pacing sites were tested. In 31 of 32 (96.8%) patients, the highest LV dP/dtmax coincided with the maximum Q-LV interval. Q-LV interval correlated with the increase in LV dP/dtmax in all patients at each site (AR1 ρ=0.98; P<0.001). A Q-LV value >95 ms corresponded to a >10% in LV dP/dtmax. An inverse correlation between paced QRS duration and improvement in LV dP/dtmax was seen in 24 patients (75%).

CONCLUSIONS

Pacing the LV at the latest activated site is highly predictive of the maximum increase in contractility, expressed as LV dP/dtmax. A positive correlation between Q-LV interval and hemodynamic improvement was found in all patients at every pacing site, a value of 95 ms corresponding to an increase in LV dP/dtmax of ≥10%.

[Current status of cardiac resynchronization therapy]

The present document reviews various aspects of the current status of cardiac resynchronization therapy: mechanisms of action, current indications and implantation technique.

[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.

Achievement of Right Ventricular Pacing by Use of a Long Guiding Catheter in a Hemodialysis Patient Presenting Significant Tortuosity of Vasculature

Increased vascular calcification and tortuosity are rather common in end-stage renal failure patients who are on hemodialysis. It renders manipulation of catheters and performance of percutaneous transluminal interventions more difficult than expected. Such vascular alterations may be evident in large veins and pose significant difficulties in placement of pacing leads as shown in our case. To overcome such difficulties, we demonstrated in this patient case that long guiding catheters may be of particular value.