Biventricular Pacing Mode Research Articles

B-PO03-190 COMPARISON OF ADAPTIVE AND NON-ADAPTIVE PACING MODES WITH BIVENTRICULAR STIMULATION ON TIME-TO-PEAK DERIVATIVE OF LEFT VENTRICULAR PRESSURE

Time-to-peak dP/dt (Td) is marker of mechanical resynchronization. Td links the time domain (dyssynchrony) to the mechanical domain (pressure) as the dyssynergic muscular contractions resulting from electrical dyssynchrony delays pressure development and hence the timing Td. Td shortens with resynchronization. In this study we investigated the acute changes in Td with standard BIVP and fusion with intrinsic conduction, single or multiple LV electrodes and different VV-intervals. 19 patients with sinus rhythm and LBBB undergoing CRT implantation were studied. We measured pressures with an indwelling LV pressure sensor catheter. Td was calculated as the time from onset of pacing to peak dP/dt and averaged in 10 subsequent beats at each stage of pacing. We used quadripolar LV pacing leads positioned in what was considered an optimal mid/basal posterolateral/ lateral branch of the coronary sinus and sequential pacing (DDD) was performed; Adaptive (A) and Non-Adaptive (NA) BIVP was performed at LV distal [LVdist], proximal electrode [LVprox] and at both electrodes as multipoint pacing [MPP]. VV-timing: LV pacing was performed relative to QRS onset (either as a result of intrinsic activation or RV pace, mean±SD): 1. LV only 76±21ms before QRS activation with minimal fusion with RV activation (LVonly); 2. 28±14ms before QRS activation (Pre); 3. 12±15ms after (Post) QRS activation. Average Td (data pooled) with RVP was 173±2ms, MPP 144±0.4ms and BIVP 150±0.4ms. Analyzing pacingmode (A,NA), VV-timing (LVonly,Pre,Post) and electrode (LVdist,LVprox,MPP) we found that Td was shorter (p<0.01) with A(Post) for all electrode combinations [LVdist] 143±4ms, [LVprox] 140±4ms and [MPP] 134±4ms, while Td with A(Pre) was shorter with [MPP] 139±4ms only. NA(Post)[MPP] at 145±4ms and NA(Post)[LVdist] at 146±4ms provided the shortest Td (p<0.01) of the NA pacing modes, and Td with NA(Post)[MPP] was shorter (p<0.01) than all NA pacing modes. A(post)[MPP] provided the shortest Td of all (134±4ms, p<0.01). Td shortens the most with LV MPP timed to near simultaneous intrinsic RV activation, indicating a beneficial mechanical effect from Adaptive MPP compared to standard biventricular pacing modes.

Association Between Subcutaneous Implantable Cardioverter Defibrillator Preimplantation Screening and the Response to Cardiac Resynchronization Therapy.

Background and ObjectivesPreimplantation QRS-T morphology screening (TMS) is a composite tool for selecting subcutaneous implantable cardioverter defibrillator (S-ICD) candidates. However, its role in predicting the patient's response to cardiac resynchronization therapy (CRT) is uncertain.MethodsA total of 55 consecutive de novo CRT candidates were enrolled between January 2016 and March 2017. Electrocardiogram (ECG) and TMS were performed before and soon after implantation. The ECG parameters were recorded, including QRS duration and morphology (such as ΔQRS_Index, QTc during biventricular pacing mode [BiV pacing QTc], and QRS/T ratio during biventricular pacing mode [BiV pacing QRS/T ratio]). TMS monitored three sensory vectors of the S-ICD. Six months after implantation, the responses to CRT were evaluated.ResultsThirty-nine patients (70.9%) passed the TMS during biventricular pacing mode. At the six-month follow-up, the number of responders and super-responders was significantly higher in the passing group than in the non-passing group (responders: 31/39 [79.5%] vs. 5/16 [31.3%], p<0.001; super-responders: 9/39 [23.1%] vs. 1/16 [6.3%], p=0.020). The super-response rate was higher among patients who passed all three vectors than among those who passed 1 or 2 vectors (3 vs. 2 vectors, p=0.018; 3 vs. 1 vector, p=0.003). A smaller left atrial diameter, vectors that passed TMS during biventricular pacing mode, and larger ΔQRS_Index values were independently associated with good CRT response.ConclusionsOur study demonstrated that patients on CRT who pass the TMS during biventricular pacing mode are more likely to respond and super-respond to CRT.

Interruption of cardiac resynchronization therapy triggered by the automatic right-ventricular pacing threshold test

We report on three patients with heart failure and left bundle branch block who received a BIOTRONIK implantable defibrillator with resynchronization therapy which manifested loss of resynchronization only at a specific time of the night. Desynchronization was sudden and repeatedly initiated by the daily automatic right ventricular pacing threshold test. Loss of resynchronization occurred after switching back from the temporary test mode to the permanent biventricular pacing mode due to the reactivation of the left ventricular (LV) control of the timing cycles. LV sensed events prevented the emission of an LV paced event by virtue of a realigned LV upper rate interval, thus inhibiting LV pacing.

Short‐Term Effects of Right Ventricular Pacing on Cardiorespiratory Function in Patients With a Biventricular Pacemaker

The intention of this study was to evaluate the short-term effect of right ventricular (RV) pacing on cardiorespiratory function in patients with a biventricular pacemaker. A group of 26 patients with a biventricular pacemaker was enrolled in this cross-over, single-blind study. All patients underwent spiroergometry and electrocardiography in RV and biventricular pacing mode. Peak work capacity (102+/-32 W and 107+/-34 W for RV and biventricular pacing mode, respectively; P<.01) and peak oxygen consumption (21.4+/-6.7 mL/min/kg and 22.6+/-7.0 mL/min/kg for RV and biventricular pacing mode, respectively; P<.01) were significantly lower in the RV pacing mode. Heart rate at rest was significantly higher with active RV pacing. Short-term RV pacing in patients with a biventricular pacemaker resulted in a higher heart rate at rest, a lower peak work capacity, and a lower peak oxygen consumption compared with that in the biventricular pacing mode.

Cardiac resynchronization therapy and adrenergic mechanisms

cardiac resynchronization therapy (CRT) is a major advance in the treatment of heart failure (HF), and thus far the most important HF therapeutic modality identified in the 21st century. When applied to patients with left ventricular dyssynchrony, CRT immediately improves chamber contractile

Is tailored lv only pacing inferior to biventricular pacing in cardiac resynchronization therapy?

Thirty percent of the typical patient (P) cohort undergoing cardiacresynchronization therapy (CRT) do not improve clinically in large randomizedtrials. All P were treated with biventricular pacing mode (BI). This study reportson the clinical follow-up in patients resynchronized with tailored LV only pacing. Methods: All P underwent preoperative hemodynamic testing with respect to pacing mode, AV delay and optimal pacing site. Response was defined as ≥10% pulsepressure (PP) increase. A difference of more than 3% PP increase between pacingmodes discriminated the best pacing mode. Ninety-one (23 female 46 P with DCM, 36 with CAD, 9 with other diseases, QRS 185±29 ms, NYHA 3, EF 25±7,2%) of 500 P, who had undergone CRT at our center between 1999 and 2004, showed a significantly higher response in acute testing with the LV pacing mode. Seventy-eight P received a unipolar, 13 a bipolar LV lead. The mean stimulated AV delay was 154±28 ms. During 6- and 9-month follow-up P with tailored LV pacing mode improved highly significantly in quality of life, functional objectives and LVEDD that is LV remodeling (Table).Only 8 P died or were referred to heart transplant during two years of follow-up! Despite historical pseudobipolar pacing in many P with unipolar LV lead tailored LV only pacing is significantly successful and superior to untailored BI pacing. Implantation of bipolar leads and careful tailoring of best chronic pacing mode is the clue to improve the success in CRT.

Surgical epicardial left ventricular lead versus coronary sinus lead placement in biventricular pacing☆

Biventricular pacing has demonstrated improvement in cardiac function in treating congestive heart failure (CHF). Two different operative strategies (coronary sinus vs. epicardial stimulation) for left ventricular (LV) pacing were compared. Since April 1999, a total of 86 patients (pts, age: 63+/-10 years) with depressed systolic LV function (mean ejection fraction 24+/-9%), left bundle-branch-block (mean QRS 182+/-22 ms) and congestive heart failure NYHA III or higher were enrolled. For biventricular stimulation coronary sinus (CS) leads were placed in 79 pts. Nine of these devices were converted to surgical epicardial LV-leads, because of CS-lead failure. In 7 patients epicardial LV-leads were initially implanted surgically, accounting for a total of 16 pts with surgical placed epicardial steroid-eluting LV-leads. For these, a limited left-lateral thoracotomy (7+/-4 cm) was used. Thirty-three (38%) pts had an indication for a defibrillator. The mean follow-up time was 16.4+/-15.4 months (0.1-45 months), representing 107.1 patient-years. In the biventricular pacing mode, QRS duration decreased to 143+/-16 ms (P<0.001). Threshold capture of the CS-leads increased significantly compared to surgically placed epicardial leads (18 month control: 2.2+/-1.4V/0.5 ms vs. 0.7+/-0.3V/0.5 ms), which had no increase in threshold (P<0.001). At the 18 month follow-up 7 CS-leads had a threshold of >4V/0.5 ms vs. epicardial leads which were under 1.1V/0.5 ms, except for one (1.8V/0.5 ms). After CS-lead implantation 25 LV-lead related complications occurred, (failed implantation, CS-dissection, loss of pacing capture, diaphragm stimulation or lead dislodgment), vs. one dislodgement after surgical epicardial lead placement (P<0.05). Correct lead positioning (obtuse marginal branch area) was achieved in all surgical epicardial placements but only in 70% with CS-leads (P<0.03). In the follow up period, 9 pts died (4 cardiac related). Heart transplantation was necessary in 4 pts due to deterioration of the cardiomyopathy. Surgical epicardial lead placement revealed excellent long-term results and a lower LV-related complication rate compared to CS-leads. Although, the approach via limited thoracotomy for biventricular pacing is associated with 'more surgery', it is a safe and reliable technique and should be considered as an equal alternative.

Guiding and optimization of resynchronization therapy with dynamic three-dimensional echocardiography and segmental volume--time curves: a feasibility study.

To assess a new approach for guiding and hemodynamic optimization of resynchronization therapy, using three-dimensional (3D) transthoracic echocardiography. Resynchronization therapy for heart failure provides the greatest hemodynamic benefit when applied to the most delayed left ventricular (LV) site. Currently, the ideal LV pacing site is selected according to acute invasive hemodynamic assessment and/or tissue Doppler imaging. A total of 16 patients with advanced heart failure and an implanted biventricular pacemaker were included in this study. Transthoracic apical LV images at equidistant intervals were obtained using a prototype, fast-rotating second harmonic transducer to reconstruct 3D LV datasets during sinus rhythm (SR), right ventricular (RV) apical and biventricular pacing mode. A semi-automated contour analysis system (4D LV analysis, TomTec, Germany) was used for segmental wall motion analysis and identification of the most delayed contracting segment and calculation of global LV function. Data acquisition duration was 10 s and analyzable 3D images were obtained in 12 patients. Of these patients, data during SR were available in 9 and during biventricular pacing in 11. The greatest contraction delay during SR was found in the anterior and antero-septal segments in five of nine patients. Biventricular pacing resulted in reduction of the contraction delay in seven of eight patients. The global LV function did not change significantly. 3D echocardiography with appropriate analytic software allows detection of the most delayed LV contracting segment and can be used to select the optimal pacing site during resynchronization therapy.