Second-Generation Visually Guided Laser Balloon Ablation System for Pulmonary Vein Isolation: Learning Curve, Safety and Efficacy　- The MERLIN Registry.

BACKGROUND: Radiofrequency (RF)-based pulmonary vein isolation (PVI) results in a favorable clinical outcome, although its complexity demands a long learning curve. Balloon-based systems have been developed to possibly solve these limitations. The 2nd-generation laser balloon (LB2) offers optimized features for improved tissue contact and visibility. We determined the safety, efficacy and learning curve of the LB2 for PVI.Methods and Results:A total of 45 consecutive patients (89% persistent AF) were prospectively enrolled and divided into 3 groups (T1, T2, T3) of n=15 patients per group. All patients underwent PVI by 2 operators using the LB2. The operators were experienced in RF and cryothermal procedures, but not in laser ablations. A total of 174/177 PVs (98%) were successfully isolated. The median procedure time significantly declined from 132 (114, 158) to 119 (102, 127) and 91 (86, 105) min in T1-3, respectively (P=0.0009). Similarly, the median fluoroscopy time significantly decreased from T1 to T3 (22 (17, 27) vs. 21 (16, 24) vs. 13 (10, 17) min, respectively, P=0.045). Adverse events occurred in 6.7%, with a trend towards a lower complication rate with increasing experience. CONCLUSIONS: The LB2 was safe and effective for PVI, even for operators without any previous experience in laser balloon-based PVI. Procedure time, left atrial dwelling time and fluoroscopy time decreased after a learning curve of 15 cases.

Evaluation of predictive scores for late and very late recurrence after cryoballoon-based ablation of atrial fibrillation.

PURPOSE: Studies on predictive scores for very late recurrence (VLR) (recurrence later than 12 months) after second-generation cryoballoon-based pulmonary vein isolation (CB2-PVI) are sparse. We aimed to evaluate the frequency of late recurrence (LR) (later than 3 months) and VLR, and to validate predictive scores for LR and VLR after initial CB2-PVI. METHODS: A total of 288 patients undergoing initial CB2-PVI (66 ± 11 years, 46% paroxysmal) were retrospectively enrolled in the LR cohort. In the VLR cohort, 83 patients with recurrence within 3-12 months or with < 12-month follow-up were excluded. The predictive scores of arrhythmia recurrence were assessed, including the APPLE, DR-FLASH, PLAAF, BASE-AF2, ATLAS, SCALE-CryoAF, and MB-LATER scores. RESULTS: During a mean follow-up of 15.3 ± 7.1 months, 188 of 288 (65.2%) patients remained in sinus rhythm without any recurrences. Thirty-two of 205 (15.6%) patients experienced VLR after a mean of 16.6 ± 5.6 months. Comparing the predictive values of these specific scores, the MB-LATER score showed a reliable trend toward greater risk of both LR and VLR (area under the curve in LR; 0.632, 0.637, 0.632, 0.637, 0.604, 0.725, and 0.691 (p = ns), VLR; 0.612, 0.636, 0.644, 0.586, 0.541, 0.633, and 0.680 (p = 0.038, vs. BASE-AF2, respectively)). Kaplan-Meier analysis estimated patients with higher MB-LATER scores which had favorable outcomes (24-month freedom from LR; 26.0% vs. 56.7%, p < 0.0001, VLR; 53.4% vs. 82.1%, p = 0.013). CONCLUSION: The MB-LATER score provided more reliable predictive value for both LR and VLR. Patients with higher MB-LATER scores may benefit from more intensive long-term follow-up.

Revisiting the optical properties of the FMO protein.

We review the optical properties of the FMO complex as found by spectroscopic studies of the Q ( y ) band over the last two decades. This article emphasizes the different methods used, both experimental and theoretical, to elucidate the excitonic structure and dynamics of this pigment-protein complex.

Rapid pulmonary vein isolation utilizing the third-generation laserballoon - The PhoeniX registry.

BACKGROUND: Balloon-based ablation systems for pulmonary vein isolation (PVI) are providing procedural safety and efficacy as well as favourable clinical outcome. Although second-generation laser balloon (LB2) based PVI has been shown safety and efficacy relatively long procedural duration was a strong limitation. The third-generation laser balloon (LB3) offers and automized ablation for rapid PVI. We determined safety, efficacy and procedural characteristics of this new promising ablation system. METHODS AND RESULTS: A total of 15 consecutive patients were prospectively enrolled. All patients underwent PVI using the LB3. A total 59/59 PVs (100%) were successfully isolated. Procedural data was compared to the last 15 consecutive patients treated by the LB2. The median procedure time significantly declined from LB2 (91 (86, 105) min) to LB3 (77 (68, 87) min), p < 0.001. Similarly, the median left atrial dwelling time significantly decreased from LB2 (72 (62, 84) min) to LB3 (45 (38, 52) min), p < 0.0001. The total laser time decreased from LB2 (1920 (1765, 2193) sec) to LB3 (1077 (896, 1165) sec), p < 0.00001. A pure single shot PVI was performed in 18/59 PVs (31%). For major adverse events no differences were detected between the groups (LB2 1/15 (6.7%) and LB3 1/15 (6.7%), p = 0.999). CONCLUSION: The LB3 was safe and effective for PVI. Procedure time, LA dwelling time and total laser time significantly decreased compared to LB2.

Biventricular Pacing Going Along with Acute Hemodynamic Response in a Patient with Huge Anterior Wall Aneurysm - Importance of Pacing Viable Myocardium.

BACKGROUND Response to cardiac resynchronization therapy (CRT) is variable among patients. Extensive scar tissue burden has been characterized as a negative predictor of significant response. Whereas mid-term and long-term response has been thoroughly investigated in randomized clinical trials; however, little is known about acute hemodynamic effects of biventricular pacing. CASE REPORT We report a case of an elderly female patient with severe ischemic cardiomyopathy and a large anterior wall aneurysm, who received right ventricular and biventricular pacing during ablation of incessant pleomorphic ventricular tachycardia. During the procedure, biventricular pacing was associated with a 20% acute increase in systolic blood pressure compared to right ventricular pacing, although there was no acute or long-term effect on left ventricular function. CONCLUSIONS The acute hemodynamic effect of CRT in our patient suggests an effect of CRT even in patients with negative predictors of CRT response such as severe ischemic cardiomyopathy with a large aneurysm. Although no marked increase in left ventricular function might be observed, the acute effect of CRT might contribute to stabilization of heart failure in these patients.

Safety and efficacy of persistent atrial fibrillation ablation using the second-generation cryoballoon.

BACKGROUND: The second-generation cryoballoon (CB) is increasingly used for treatment of persistent atrial fibrillation (AF). Data regarding the clinical outcome and mechanism of arrhythmia recurrence following persistent AF ablation using CB is sparse. In this study, we aimed to assess the efficacy of CB and mechanisms of atrial tachyarrhythmia (ATA) recurrence in patients with persistent AF. METHODS AND RESULTS: A total of 133 patients (66 ± 10 years, 60% male) with symptomatic persistent AF, who were scheduled for PVI using the second-generation CB were enrolled. Follow-up included 24 h Holter recording at 3, 6 and 12 months. Any documented episode of ATA lasting more than 30 s was considered as a recurrent arrhythmic event. All targeted veins were isolated (100%). Phrenic nerve palsy with recovery during follow-up occurred in six patients (4.5%), no patient experienced tamponade or a cerebrovascular event. During 12.6 ± 5.4 months of follow-up, 89/133 (67%) patients were free of ATA recurrences. Multivariable analysis revealed recurrence in the blanking period (HR 11.46, 0.95 CI 3.92-33.49, p < 0.001), presence of cardiomyopathy (HR 2.75, 0.95 CI 1.09-6.96, p = 0.032) and PV abnormality (HR 3.56, 0.95 CI 1.21-10.43, p = 0.021) as predictors for late recurrence. CONCLUSION: In patients with persistent AF, second-generation cryoballoon use is associated with an excellent safety profile and favorable outcomes. Arrhythmia recurrence during the blanking period, presence of cardiomyopathy and PV abnormality were independent predictors of long-term AF recurrence.

Pump-shaped dump optimal control reveals the nuclear reaction pathway of isomerization of a photoexcited cyanine dye.

Using optimal control as a spectroscopic tool we decipher the details of the molecular dynamics of the essential multidimensional excited-state photoisomerization - a fundamental chemical reaction of key importance in biology. Two distinct nuclear motions are identified in addition to the overall bond-twisting motion: Initially, the reaction is dominated by motion perpendicular to the torsion coordinate. At later times, a second optically active vibration drives the system along the reaction path to the bottom of the excited-state potential. The time scales of the wavepacket motion on a different part of the excited-state potential are detailed by pump-shaped dump optimal control. This technique offers new means to control a chemical reaction far from the Franck-Condon point of absorption and to map details of excited-state reaction pathways revealing unique insights into the underlying reaction mechanism.

Structural induced control of energy transfer within Zn(II)-porphyrin dendrimers.

We report on a study of singlet-singlet annihilation kinetics in a series of Zn(II)-porphyrin-appended dendrimers, where the energy transfer efficiency is significantly improved by extending the molecular chain that connects the light-harvesting chromophores to the dendrimeric backbone with one additional carbon. For the largest dendrimer having 64 Zn(II)-porphyrins, only approximately 10% of the excitation intensity is needed in order to observe the same extent of annihilation in the dendrimers with the additional carbon in the connecting chain as compared to those without. Complete annihilation, until only one chromophore remains excited, now occurs within subunits of seven chromophores, when half of the chromophores are excited. The improvement of the annihilation efficiency in the largest dendrimer with 64 porphyrins can be explained by the presence of a the two-step delayed annihilation process, involving energy hopping from excited to nonexcited chromophores prior to annihilation. In the smallest dendrimer with only four chromophores, delayed annihilation is not present, since the direct annihilation process is more efficient than the two-step delayed annihilation process. As the dendrimer size increases and the chances of originally exciting two neighboring chromophores decreases, the delayed annihilation process becomes more visible. The additional carbon, added to the connecting chain, results in more favorable chromophore distances and orientations for energy hopping. Hence, the improved energy transfer properties makes the Zn(II)-porphyrin-appended dendrimers with the additional carbon promising candidates as light-harvesting antennas for artificial photosynthesis.

Mechanisms of molecular response in the optimal control of photoisomerization.

We report on adaptive feedback control of photoinduced barrierless isomerization of 1,1'-diethyl-2,2'-cyanine in solution. We compare the effect of different fitness parameters and show that optimal control of the absolute yield of isomerization (photoisomer concentration versus excitation photons) can be achieved, while the relative isomerization yield (photoisomer concentration versus number of relaxed excited-state molecules) is unaffected by adaptive feedback control. The temporal structure of the optimized excitation pulses allows one to draw clear mechanistic conclusions showing the critical importance of coherent nuclear motion for the control of isomerization.

Control of electron transfer pathways in a dye-sensitized solar cell.

Using shaped laser pulses, we increase the yield of ultrafast electron injection from the sensitizer to TiO2 nanocrystals in the core part of a dye-sensitized solar cell. The temporal structure of the optimized excitation pulse is in clear correlation with nuclear oscillations in the impulsively excited dye molecule. From DFT structure optimization and normal mode analyses we identified the modes which are responsible for the oscillations. The best pulse shape suggests Impulsive Stimulated (anti-Stokes) Raman scattering as a key process of optimization.

Energy transfer within Zn-porphyrin dendrimers: study of the singlet-singlet annihilation kinetics.

In this article, we explore energy transfer processes within a series of Zn-porphyrin-appended dendrimers by means of excitation intensity dependent transient absorption measurements. We report singlet-singlet annihilation on two distinct time scales of 18 +/- 5 ps and 130 +/- 10 ps in the dimer and the dendrimers. The two distinct processes reflect the presence of two structural conformer distributions. Analysis of the singlet-singlet annihilation transient kinetics shows that sequential annihilation occurs within subunits up to four Zn-porphyrins in the dendrimers. The onset of the singlet-singlet annihilation process depending on the size of the molecule reveals a difference in the number of communicating Zn-porphyrins. We further report a full characterization of the transient absorption kinetics of the monomer over a spectral range from 450 to 730 nm.