Inadvertent QRS prolongation by an optimization device-based algorithm in patients with cardiac resynchronization therapy.

BACKGROUND: Device-based algorithms offer the potential for automated optimization of cardiac resynchronization therapy (CRT), but the process for accepting them into clinical use is currently still ad-hoc, rather than based on pre-clinical and clinical testing of specific features of validity. We investigated how the QuickOpt-guided VV delay (VVD) programming performs against the clinical and engineering heuristic of QRS complex shortening by CRT. METHODS: A prospective, 2-center study enrolled 37 consecutive patients with CRT. QRS complex duration (QRSd) was assessed during intrinsic atrioventricular conduction, synchronous biventricular pacing, and biventricular pacing with QuickOpt-proposed VVD. The measurements were done manually by electronic calipers in signal-averaged and magnified 12-lead QRS complexes. RESULTS: Native QRSd was 174 ± 22 ms. Biventricular pacing with empiric AVD and synchronous VVD resulted in QRSd 156 ± 20 ms, a significant narrowing from the baseline QRSd by 17 ± 27 ms, P = 0.0003. In 36 of 37 patients, the QuickOpt algorithm recommended left ventricular preexcitation with VVD of 42 ± 18 ms (median 40 ms; interquartile range 30-55 ms, P <0.00001). QRSd in biventricular pacing with QuickOpt-based VVD was significantly longer compared with synchronous biventricular pacing (168 ± 25 ms vs. 156 ± 20 ms; difference 12 ± 11ms; P <0.00001). This prolongation correlated with the absolute VVD value (R = 0.66, P <0.00001). CONCLUSIONS: QuickOpt algorithm systematically favours a left-preexcitation VVD which translates into a significant prolongation of the QRSd compared to synchronous biventricular pacing. There is no reason to believe that a manipulation that systematically widens QRSd should be considered to optimize physiology. Device-based CRT optimization algorithms should undergo systematic mechanistic pre-clinical evaluation in various scenarios before they are tested in large clinical studies.

Simple electrophysiological predictor of QRS change induced by cardiac resynchronization therapy: A novel marker of complete left bundle branch block.

BACKGROUND: QRS complex shortening by cardiac resynchronization therapy (CRT) has been associated with improved outcomes. OBJECTIVE: We hypothesized that the absence of QRS duration (QRSd) prolongation by right ventricular mid-septal pacing (RVP) may indicate complete left bundle branch block (cLBBB). METHODS: We prospectively collected 12-lead surface electrocardiograms (ECGs) and intracardiac electrograms during CRT implant procedures. Digital recordings were edited and manually measured. The outcome measure was a change in QRSd induced by CRT (delta CRT). Several outcome predictors were investigated: native QRSd, cLBBB (by using Strauss criteria), interval between the onset of the QRS complex and the local left ventricular electrogram (Q-LV), and a newly proposed index defined by the difference between RVP and native QRSd (delta RVP). RESULTS: One hundred thirty-three consecutive patients were included in the study. Delta RVP was 27 ± 25 ms, and delta CRT was -14 ± 28 ms. Delta CRT correlated with native QRSd (r = -0.65), with the presence of ECG-based cLBBB (r = -0.40), with Q-LV (r = -0.68), and with delta RVP (r = 0.72) (P < .00001 for all correlations). In multivariable analysis, delta CRT was most strongly associated with delta RVP (P < .00001), followed by native QRSd and Q-LV, while ECG-based cLBBB became a nonsignificant factor. CONCLUSION: Baseline QRSd, delta RVP, and LV electrical lead position (Q-LV) represent strong independent predictors of ECG response to CRT. The absence of QRSd prolongation by RVP may serve as an alternative and more specific marker of cLBBB. Delta RVP correlates strongly with the CRT effect on QRSd and outperforms the predictive value of ECG-based cLBBB.

Cardiac resynchronization therapy guided by cardiac magnetic resonance imaging: A prospective, single-centre randomized study (CMR-CRT).

BACKGROUND: Cardiac resynchronization therapy (CRT) improves symptoms of heart failure (HF), morbidity and mortality in selected population. The aim of the study was to investigate the impact of cardiac magnetic resonance (CMR)-guided left ventricular (LV) lead placement on clinical outcomes and LV reverse remodelling in CRT recipients. METHODS: Patients with CRT indication were randomized for CMR-guided (CMR group) or electrophysiologically guided (EP group) LV lead placement between 2011 and 2014. The target site in the CMR group was defined as the most delayed, scar-free, in the EP group as the site with the longest interval between the QRS onset and local electrogram. The primary endpoint was a combination of cardiovascular death or HF hospitalization. Secondary endpoints were New York Heart Association (NYHA) Class improvement ≥1, LV endsystolic diameter reduction >10%, B-type natriuretic peptide reduction by ≥30%. RESULTS: A total of 99 patients (47 in the CMR and 52 in the EP group) were enrolled. During a median follow-up of 47 months, primary composite endpoint occurred in 5 patients in the CMR group and 14 patients in the EP group (HR = 0.46; 95% CI: 0.16-1.32). Patients with left bundle branch block and NYHA Class >2 had better clinical outcome in the CMR group (HR = 0.09; 95% CI: 0.01-0.75). CONCLUSIONS: The use of CMR did not result in significant reduction of combined endpoint of cardiovascular death or HF hospitalization in the total study population. Significant clinical benefit from CMR-guided procedure was observed in a subgroup of optimum CRT candidates with advanced HF.

Ultrasound-guided versus conventional femoral venipuncture for catheter ablation of atrial fibrillation: a multicentre randomized efficacy and safety trial (ULTRA-FAST trial).

Aims: Complications of catheter ablation for atrial fibrillation (AF) are frequently related to vascular access. We hypothesized that ultrasound-guided (USG) venipuncture may facilitate the procedure and reduce complication rates. Methods and results: We conducted a multicentre, randomized trial in patients undergoing catheter ablation for AF on uninterrupted anticoagulation therapy. The study enrolled consecutive 320 patients (age: 63 ± 8 years; male: 62%) and were randomized to USG or conventional venipuncture in 1:1 fashion. It was prematurely terminated due to substantially lower-than-expected complication rates, which doubled the population size needed to maintain statistical power. While the complication rates did not differ between two study arms (0.6% vs. 1.9%, P = 0.62), intra-procedural outcome measures were in favour of the USG approach (puncture time, 288 vs. 369 s, P < 0.001; first pass success, 74% vs. 20%, P < 0.001; extra puncture attempts 0.5 vs. 2.1, P < 0.001; inadvertent arterial puncture 0.07 vs. 0.25, P < 0.001; unsuccessful cannulation 0.6% vs. 14%, P < 0.001). Though these measures varied between trainees (49% of procedures) and expert operators, between-arm differences (except for unsuccessful cannulation) were comparably significant in favour of USG approach for both subgroups. Conclusions: Ultrasound-guided puncture of femoral veins was associated with preferable intra-procedural outcomes, though the major complication rates were not reduced. Both trainees and expert operators benefited from the USG strategy. (www.clinicaltrials.gov ID: NCT02834221).

High-density epicardial activation mapping to optimize the site for video-thoracoscopic left ventricular lead implant.

BACKGROUND: The left ventricular (LV) lead local electrogram (EGM) delay from the beginning of the QRS complex (QLV) is considered a strong predictor of response to cardiac resynchronization therapy. We have developed a method for fast epicardial QLV mapping during video-thoracoscopic surgery to guide LV lead placement. METHODS: A three-port, video-thoracoscopic approach was used for LV free wall epicardial mapping and lead implantation. A decapolar electrophysiological catheter was introduced through one port and systematically attached to multiple accessible LV sites. The pacing lead was targeted to the site with maximum QLV. The LV free wall activation pattern was analyzed in 16 pre-specified anatomical segments. RESULTS: We implanted LV leads in 13 patients with LBBB or IVCD. The procedural and mapping times were 142 ± 39 minutes and 20 ± 9 minutes, respectively. A total of 15.0 ± 2.2 LV segments were mappable with variable spatial distribution of QLV-optimum. The QLV ratio (QLV/QRSd) at the optimum segment was significantly higher (by 0.17 ± 0.08, p < 0.00001) as compared to an empirical midventricular lateral segment. The LV lead was implanted at the optimum segment in 11 patients (at an adjacent segment in 2 patients) achieving a QLV ratio of 0.82 ± 0.09 (range 0.63-0.93) and 99.5 ± 0.6% match with intraprocedural mapping. CONCLUSION: Video-thoracoscopic LV lead implantation can be effectively and safely guided by epicardial QLV mapping. This strategy was highly successful in targeting the selected LV segment and resulted in significantly higher QLV ratios compared to an empirical midventricular lateral segment.