Bifocal Right Ventricular Pacing Research Articles

Bifocal Right Ventricular Pacing: Alternative to Biventricular Pacing for Cardiac Resynchronization Therapy?

A 59-year-old patient with dilated cardiomyopathy, severe systolic left ventricular dysfunction and drug-refractory advanced heart failure (New York Heart Association-NYHA class III-IV symptoms) and prior history of mitral valve replacement was scheduled for implantation of a biventricular pacing system (cardiac resynchronization therapy-defibrillator or CRT-D device). The coronary sinus was cannulated after some effort and a venous coronary angiogram was performed. Although a posterolateral cardiac venous branch was identified to accommodate the left ventricular pacing lead, placement of the lead in this tributary was accompanied by phrenic nerve stimulation, which could not be remedied by moving to more proximal positions where the lead could not be stabilized. Having no other option except for sending the patient to surgery for epicardial lead placement, albeit most difficult and high-risk procedure due to prior history of cardiac surgery, we attempted bifocal right ventricular pacing by placing the composite pacing-defibrillating lead at a low septal position and the left ventricular lead at a very high right ventricular (RV) outflow tract position. The procedure was otherwise uncomplicated and the patient’s post-procedural course remained uneventful. The patient had a good clinical response to this type of bifocal RV pacing over the subsequent days and months with amelioration of his dyspneic symptoms and improvement of his quality of life. At the three-year follow-up he remains in NYHA class II category.

The role of real time three dimensional echocardiography to guide optimal lead positioning and improve response to cardiac resynchronization therapy: A prospective pilot study

Abstract Aims A non-optimal resynchronization lead (RL) position is a possible cause of poor CRT response. The study aims to test the value of real-time-three-dimensional-echocardiography (RT3DE) for individual assessment of LV dyssynchrony and prospective evaluation of CRT response after RL implantation at the pre-determined segment of maximal delay (SMMD) whatever the method of CRT used. Methods Seventeen HF patients were prospectively included in the study. RT3DE data were obtained before and after 1, 3, 6 months of CRT. Time/volume curves and parametric imaging were applied for pre-implant identification of SMMD and for individual assessment of CRT response. Delta-time delay (delta-t) and selective parameters between tmsv of the latest and earliest activated segments were calculated. Results All patients received CRT according to accessibility of the SMMD. We used bifocal right ventricular pacing (BFRVP) in 5 patients with septal SMMD; biventricular pacing (BVP) in 12 patients with LV SMMD. The RL was successfully implanted at the SMMD or nearest segment in 14 (82.4%) initial responders (5 BFRVP, 9 BVP). Twelve of them were still responders after 6 months. CRT response was comparable in BFRVP and BIVP. A moderate correlation was found between % change of EF and that of SDI ( r = −.406), delta-t (−.497). Baseline delta-t showed a stronger correlation with % change of EF ( r = −.718 ∗∗ , P = 0.009) than that of SDI ( r = −.509, P = 0.091). Conclusion The use of RT3DE for individual assessment of LV mechanical dyssynchrony and for optimal RL positioning at the pre-identified SMMD can provide more optimum CRT regardless the method of CRT.

Bifocal right ventricular pacing: an alternative way to achieve resynchronization when left ventricular lead insertion is unsuccessful

Bifocal pacing in the right ventricle is an option for patients with end-stage heart failure in whom biventricular pacing is not possible, due to failure in left ventricular (LV) lead insertion. The purpose of this prospective study was to document the clinical response of these patients, after bifocal pacing. From the patients referred for cardiac resynchronization therapy (CRT), from 2009 to 2010, 13 cardiac CRT candidates who underwent unsuccessful LV lead implantation were included. The bifocal system's leads were implanted in the right atrium, the right ventricular (RV) apex, and the RV outflow tract. Initial patient assessment and follow-up evaluation after 6 months included clinical criteria, echocardiographic indices, and biochemical parameters. From 13 patients (age 68 ± 9 years, nine male), 10 improved clinically. New York Heart Association classification was reduced by one grade (from 3.6 ± 0.5 to 2.8 ± 0.8, p < 0.005 and respectively), while hospitalizations in 6-month time were reduced from three to one (p < 0.001). Six-minute walk test (in meters) increased from 176 ± 86 to 297 ± 91 (p < 0.001) and quality of life improved (EQ-VAS scale changed from 42 ± 12.5 % to 70.8 ± 20.3 %, p < 0.001). Mean shortening in QRS duration was 31.3 ms (from 165.1 ± 16.3 to 133.8 ± 12.7, p < 0.001) and B-type natriuretic peptide (in picograms per milliliter) dropped from 834 ± 350 to 621 ± 283 (p < 0.001). Ejection fraction (in percent) increased from 27.5 ± 4.6 to 33.3 ± 4.4 (p < 0.001), and mitral regurgitation severity decreased by one grade (from 2.7 ± 0.9 to 1.8 ± 0.7, p < 0.05). RV bifocal pacing seems to offer a substantial clinical benefit to heart failure patients with traditional CRT indications and could be an alternative option when LV access is unsuccessful.

Bifocal Right Ventricular Resynchronization for the Failing Right Ventricle

The present case illustrates that in patients with right ventricular (RV) failure and right bundle branch block it is possible to resynchronize the RV without further worsening RV or left ventricular (LV) pump function, even in cases with various degrees of atrioventricular block. The acute response to different pacing configurations was analyzed in terms of dP/dt variations. Bifocal RV pacing (His bundle plus RV outflow tract pacing) achieved the best acute results and was chosen for permanent pacing. This pacing configuration was associated to clinical and echocardiographic improvement.

Comparison of temporary bifocal right ventricular pacing and biventricular pacing for heart failure: evaluation by tissue Doppler imaging

Background:The complications and limitations of biventricular pacing largely relate to left ventricular (LV) pacing. An alternative approach was tested of simultaneously pacing the right ventricular (RV) apex and outflow tract...

Physiologic Pacing: New Modalities and Pacing Sites

Right ventricular (RV) apical pacing impairs left ventricular function by inducing dys-synchronous contraction and relaxation. Chronic RV apical pacing is associated with an increased risk of atrial fibrillation, morbidity, and even mortality. These observations have raised questions regarding the appropriate pacing mode and site, leading to the introduction of algorithms and new pacing modes to reduce the ventricular pacing burden in dual chamber devices, and a shift of the pacing site away from the RV apex. However, further investigations are required to assess the long-term results of pacing from alternative sites in the right ventricle, because long-term results so far are equivocal. The potential benefit of prophylactic biventricular, mono-chamber left ventricular, and bifocal RV pacing should be explored in selected patients with a narrow QRS complex, especially those with impaired left ventricular function. His bundle pacing is a promising and evolving technique that requires improvements in lead technology.

971 Biventricular and right-ventricular bifocal pacing improve severe heart failure by different mechanisms

971 Biventricular and right-ventricular bifocal pacing improve severe heart failure by different mechanisms

971 Biventricular and right-ventricular bifocal pacing improve severe heart failure by different mechanisms

971 Biventricular and right-ventricular bifocal pacing improve severe heart failure by different mechanisms

Assessment of regional wall motion during right-ventricular bifocal pacing in patients with severe congestive heart failure

Right-ventricular bifocal pacing (RVBF) was reported as a therapy of severe congestive heart failure. We evaluated regional wall motion by strain Doppler imaging in three patients with RVBF therapy who had conventional indication of pacemaker(70± 8 years old, mean ejection fraction 24±11%). Two dimensional SDI of the left ventricle were obtained from the apical four-chamber view during right ventricular apical pacing and RVBF pacing. Wall motion was assessed by strain of the myocardium and interval between Q-wave of surface ECG and peak of strain(QPSI) was measured in the three septal and lateral segments. Results were shown in table. RVBF pacing improves intra-ventricular contraction delay especially longitudinal dyssynchrony without improvement of left ventricle strain. View this table: