Carving out configurable ultrafast pulses from a continuous wave source via the optical Kerr effect.

Wavelength-tunable, time-locked pairs of ultrafast pulses are crucial in modern-day time-resolved measurements. We demonstrate a simple means of generating configurable optical pulse sequences: sub-picosecond pulses are carved out from a continuous wave laser via pump-induced optical Kerr switching in 10 cm of a commercial single-mode fiber. By introducing dispersion to the pump, the near transform-limited switched pulse duration is tuned between 305-570 fs. Two- and four-pulse signal trains are also generated by adding birefringent α-BBO plates in the pump beam. These results highlight an ultrafast light source with intrinsic timing stability and pulse-to-pulse phase coherence, where pulse generation could be adapted to wavelengths ranging from ultraviolet to infrared.

3-Dimensional regional and global strain abnormalities in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is characterized by myocardial disarray, hypertrophy, and fibrosis. Reduced global longitudinal strain and presence of late gadolinium enhancement (LGE) by cardiac magnetic resonance imaging (CMR) have been associated with an adverse prognosis. This study evaluated 3D principal and conventional strain characteristics of non-enhanced myocardium in patients with HCM. 3D principal and conventional strain analysis was conducted in 51 HCM patients and 38 healthy controls. Principal strain was reduced within the non-enhanced myocardium of HCM as compared with controls (maximum principal: 51.5 ± 23.7 vs. 75.1 ± 21.4%, P < 0.0001; minimum principal: - 18.4 ± 4.0 vs. - 20.1 ± 2.9%, P < 0.05). Principal strain within the non-enhanced myocardium was incrementally reduced in HCM patients with extensive global LGE ( ≥ 15%) (maximum principal: 41.6 ± 17.5 vs. 56.9 ± 25.9%, P < 0.05; minimum principal: - 16.9 ± 3.9 vs. - 19.1 ± 4.0%, P = 0.1), as was longitudinal ( - 10.5 ± 2.6 vs. - 12.7 ± 2.6%, P < 0.05) and circumferential strain ( - 11.0 ± 2.7 vs. - 14.0 ± 2.9%, P < 0.01). Principal strain within non-enhanced myocardium was significantly correlated with indexed LV mass (P < 0.0001), maximum (P = 0.0008), and mean wall thickness (P < 0.0001), but not LGE (P = 0.0841). In adjusted analysis, all strain measures within non-enhanced myocardium were independently associated with indexed LV mass (maximum principal: P = 0.0003; minimum principal: P = 0.0039; longitudinal: P = 0.0015; circumferential: P = 0.0002; radial: P = 0.0023). 3D principal strain of non-enhanced myocardium was significantly reduced in HCM patients as compared with controls, and was incrementally reduced among patients with more extensive global LGE. Comprehensive strain assessment may be considered in routine CMR assessment of HCM patients.

Intra-thoracic adiposity is associated with impaired contractile function in patients with coronary artery disease: a cardiovascular magnetic resonance imaging study.

The influence of visceral adiposity on left ventricular remodeling following coronary artery disease (CAD)-related events has not been examined to date. Using magnetic resonance imaging (MRI) we explored intra-thoracic fat volume (ITFV) and strain-based markers of adverse remodeling in patients with CAD. Forty-seven patients with known CAD (25 with prior MI, 22 without prior MI) were studied. ITFV was quantified using previously validated imaging techniques. Myocardial strain was derived from cine MRI using a validated 3D feature-tracking (FT) software. Segmental LGE quantification was performed and was used to incrementally constrain strain analyses to non-infarcted (i.e. remote) segments. Remote myocardial strain was compared to the non-MI control cohort and was explored for associations with ITFV. Mean age was 57 ± 13 years with a mean BMI of 30.0 ± 6.2 kg/m2 (range 20.3-38.4 kg/m2). Patients with versus without prior MI had similar demographics and BMI (29.4 ± 4.4 vs. 30.4 ± 7.9 kg/m2, p = 0.62). Patients with prior MI had lower mean peak strain than non-MI patients (p = 0.02), consistent with remote tissue contractile dysfunction. Inverse associations were identified between ITFV and mean peak strain in both the MI group (circumferential: r = 0.43, p = 0.03; radial: - 0.41, p = 0.04; minimum principal: r = 0.41, p = 0.04; maximum principal: r = - 0.43, p = 0.03) and non-MI group (circumferential: r = 0.42, p = 0.05; minimum principal: r = 0.45, p = 0.03). In those with prior MI higher ITFV was associated with a greater reduction in remote tissue strain. ITFV is associated with contractile dysfunction in patients with CAD. This association is prominent in the post-MI setting suggesting relevant influence on remote tissue health following ischemic injury. Expanded study of intra-thoracic adiposity as a modulator of myocardial health in patients with CAD is warranted.