Prognostic significance of atrial fibrillation in acute decompensated heart failure with reduced versus preserved ejection fraction.

OBJECTIVE: The prognostic impact of atrial fibrillation (AF) in patients with acute decompensated heart failure (ADHF) has not been fully elucidated yet. Aim of the present study was thus to investigate the association of AF with all-cause mortality in patients with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). METHODS: We performed a retrospective single center study and analyzed data of 1286 patients admitted for ADHF. Patients were grouped according to AF status (i.e., "never AF", "history of AF", or "AF on admission") and type of heart failure. Patient and treatment characteristics were extracted by chart review. The primary outcome of all-cause mortality within 3 years following index hospitalization was determined by death registry linkage. RESULTS: In total, 529 (41.1%), 215 (16.7%), and 542 (42.1%) patients were grouped as "never AF", "history of AF", and "AF on admission", respectively. With regard to type of heart failure, 558 (43.4%) and 728 (56.6%) had HFrEF and HFpEF, respectively. Compared to "never AF", "AF on admission" was associated with increased all-cause mortality in an adjusted Cox regression model [hazard ratio, 1.64 (95% confidence interval 1.32-2.04); P < 0.001]. However, this association remained significant only for patients with HFpEF [2.16 (1.58-2.95)], but not for patients with HFrEF [1.18 (0.85-1.63)] in a subgroup analysis (P for effect modification = 0.020). CONCLUSIONS: AF is common in the setting of ADHF and is associated with increased all-cause mortality. However, this association remained significant only in patients with HFpEF, but not in patients with HFrEF.

Temporal and spatial effects inside a compact and CEP stabilized, few-cycle OPCPA system at high repetition rates.

We present a compact and ultra-stable few-cycle OPCPA system. In two non-collinear parametric amplification stages pulse energies up to 17 µJ at 200 kHz repetition rate are obtained. Recompression of the broadband pulses down to 6.3 fs is performed with chirped mirrors leading to peak powers above 800 MW. The parametric amplification processes were studied in detail employing (2 + 1) dimensional numerical simulations and compared to experimental observations in terms of spectral shapes, pulse energy, spatial effects as well as delay dependent nonlinear mixing products. This gives new insights into the parametric process and design guidelines for high repetition rate OPCPA systems.

Two-color pumped OPCPA system emitting spectra spanning 1.5 octaves from VIS to NIR.

We present a two-color pumped OPCPA system which delivers an ultra-broadband spectrum spanning from 430 nm to 1.3 µm with a Fourier limited pulse duration of sub-3 fs and 1 µJ of pulse energy at a repetition rate of 200 kHz. All frequency components propagate on a common path, thus the spectral phase along the whole spectrum is well-defined. The inner part of the spectrum has been compressed to sub-5 fs pulses.

Few-cycle oscillator pulse train with constant carrier-envelope- phase and 65 as jitter.

We report on an octave-spanning Ti:sapphire laser oscillator stabilized to carrier-envelope-offset frequency zero, generating a pulse train with constant field profile for every pulse. Stabilization is realized using an extended self-referenced locking scheme enabling to lock the carrier envelope-offset phase with less than 65 attosecond rms timing jitter. The stabilized system features a pulse repetition rate of 100 MHz with pulses as short as 4.5 fs and 220 mW average output power. With this laser system it was possible for the first time to demonstrate a spectral interference pattern of 1011 oscillator pulses in an out-of-loop f-to-2f-interferometer.

Microjoule pulse energy from a chirped-pulse Ti:sapphire oscillator with cavity dumping.

We demonstrate a chirped-pulse Ti:sapphire laser oscillator with both Kerr-lens and semiconductor- saturable-absorber-mirror-assisted mode locking generating 1.1 microJ pulses at 1 MHz pulse repetition rate. The pulses are coupled out of the laser cavity by means of an acousto-optical cavity dumper, have a spectral width that supports a Fourier limit of 74 fs, and currently have a chirped-pulse duration of 5 ps. After compressing the pulses, this laser will be an ideal tool for efficient high-harmonic generation directly from a laser oscillator.

Few-cycle femtosecond field synthesizer.

We report on an optical field synthesizer consisting of a CEO-phase stabilized octave-spanning Ti:sapphire laser oscillator, a double-LCD prism-based pulse shaper, and a SPIDER pulse characterization apparatus. This field synthesizer allows for generating pulses with durations as short as 3.6 fs and enables to control the electric field on a sub-cycle scale. Within the limits of the ultrabroad spectrum arbitrary spectral and temporal pulse shapes and pulse sequences can be realized. Together with the ability to stabilize the pulses with respect to their CEO-phase, this system forms a versatile tool for coherent control experiments of field sensitive processes and precision spectroscopy.

Controlled waveforms on the single-cycle scale from a femtosecond oscillator.

We present an octave-spanning Ti:sapphire oscillator supporting Fourier-limited pulses as short as 3.7 fs. This laser system can be directly CEO-phase stabilized delivering an average output power of about 90 mW with a pulse duration of 4.4 fs. The phase-stabilization is realized without additional spectral broadening using an f-2f interferometer approach allowing for full control of the electric pulse field on a sub-femtosecond time-scale.