ABSTRACT
INTRODUCTION: The prognostic value of myocardial deformation parameters in adults with repaired tetralogy of Fallot (rTOF) has not been well-elucidated. We therefore aimed to explore myocardial deformation parameters for outcome prediction in adults with rTOF using cardiovascular magnetic resonance imaging (CMR). METHODS: Adults with rTOF and at least moderate pulmonary regurgitation (PR) were identified from an institutional prospective CMR registry. Left (LV) and right ventricular (RV) global strain were recorded in longitudinal (GLS), circumferential (GCS) and radial (GRS) directions. Major adverse cardiovascular events (MACE) were defined as a composite of mortality, resuscitated sudden death, sustained ventricular tachycardia (>30seconds) or heart failure (hospital admission >24hours). In patients with pulmonary valve replacement (PVR), pre-and post-PVR CMR studies were analysed to assess for predictors of complete RV reverse remodelling, which we defined as RV end-diastolic volume indexed (RVEDVi) <110ml/m2. Logistic regression models were used to estimate the odds ratio (OR) per unit change in absolute strain value associated with clinical outcomes and receiver operator characteristic (ROC) curves were constructed with area under the curve (AUC) for select CMR variables. RESULTS: We included 307 patients (age 35±13 years, 59% male). During 6.1 years (3.3-8.8) of follow-up, pulmonary valve replacement (PVR) was performed in 142 (46%) and MACE occurred in 31 (10%). On univariate analysis, baseline biventricular ejection fraction (EF), mass and all strain parameters were associated with MACE. After adjustment for LVEF, only LVGLS remained independently predictive of MACE (OR 0.822 [0.693-0.976] p=0.025). Receiver operator curves identified an absolute LVGLS value less than 15 and LVEF <51% as thresholds for MACE prediction (AUC 0.759 [0.655-0.840] and 0.720 [0.608-0.810]). After adjusting for baseline RVEDVi, RVGCS (OR 1.323 [1.094-1.600] p=0.004), LVGCS (OR 1.276 [1.029-1.582] p=0.027) and LVGRS (OR 1.101 [1.0210-1.200], p=0.028) were independent predictors of complete remodelling post-PVR remodelling. CONCLUSIONS: Biventricular strain parameters predict clinical outcomes and post-PVR remodelling in rTOF. Further study will be necessary to establish the role of myocardial deformation parameters in clinical practice.
ABSTRACT
Background: Ambulatory surgeries are increasing all over. While searching for an ideal anesthetic, the use of lidocaine was linked to a greater rate of transitory neurological symptoms and bupivacaine delays discharge due to a longer duration of motor blockade. 2-chloroprocaine (2CP) with a shorter duration of action is gaining popularity. We aimed to compare intrathecal bupivacaine and 2CP for the subarachnoid block for elective ambulatory gynecological surgeries. Methods: A single-blind study was conducted on 90 patients comparing 40 mg 2CP and 10 mg 0.5% bupivacaine heavy measuring pinprick sensation, motor block, time to ambulation, and voiding of urine so as to get ready for discharge. Results: In both groups, the beginning of sensory blockage occurred at a similar time, while motor blockade achieved was faster in the 2CP group. The resolution of motor blockade was 1.7 times faster in the 2CP group than in the bupivacaine group. Time taken for ambulation was delayed significantly in the bupivacaine group, i.e., 263.04 ± 29.08 min compared to the 2CP group, i.e., 225.44 ± 29.48 min which was a delay of almost 38 min. Voiding of urine was also delayed in the bupivacaine group by 60 min compared to the 2CP group and was significant finding leading to delay of discharge of patients. Adverse effects were comparable in both groups. Conclusion: Intrathecal preservative-free 2CP provides satisfactory surgical block, and has a considerably faster rate of block regression, resulting in earlier ambulation and voiding, allowing the patient to be discharged from the hospital sooner as compared to intrathecal bupivacaine.
ABSTRACT
Aerosol indirect effects are one of the leading contributors to cloud radiative properties relevant to climate. Aerosol particles become cloud droplets when the ambient relative humidity (saturation ratio) exceeds a critical value, which depends on the particle size and chemical composition. In the traditional formulation of this problem, only average, uniform saturation ratios are considered. Using experiments and theory, we examine the effects of fluctuations, produced by turbulence. Our measurements, from a multiphase, turbulent cloud chamber, show a clear transition from a regime in which the mean saturation ratio dominates to one in which the fluctuations determine cloud properties. The laboratory measurements demonstrate cloud formation in mean-subsaturated conditions (i.e., relative humidity <100%) in the fluctuation-dominant activation regime. The theoretical framework developed to interpret these measurements predicts a transition from a mean- to a fluctuation-dominated regime, based on the relative values of the mean and standard deviation of the environmental saturation ratio and the critical saturation ratio at which aerosol particles activate or become droplets. The theory is similar to the concept of stochastic condensation and can be used in the context of the atmosphere to explore the conditions under which droplet activation is driven by fluctuations as opposed to mean supersaturation. It provides a basis for future development of cloud droplet activation parameterizations that go beyond the internally homogeneous parcel calculations that have been used in the past.
