New Clinical Classification for Ventricular Free Wall Rupture following Acute Myocardial Infarction

Ventricular free wall rupture (FWR) is a catastrophic complication after acute myocardial infarction (AMI). However, patients with FWR die of cardiac tamponade secondary to intrapericardial hemorrhage that can be treated if properly diagnosed. Unfortunately, FWR was still not diagnosed and classified quickly and accurately. The aim of this study was to present a new clinical classification for FWR. Seventy-eight patients with FWR after STEMI were enrolled in the study. We classified FWR, according to clinical situations after onset, into the cardiac arrest type, unstable type, and stable type. The cardiac arrest type was the most common type, accounting for about 83.3%. 90.8% of patients of this type were complicated with electromechanical dissociation at the time of FWR onset, and 100% of patients of this type died in the hospital. The unstable type was characterized by sudden clinical condition changes with moderate/massive pericardial effusion. In this study, 9.0% of patients were diagnosed as the unstable type. The average time from onset to death was 4.5 hours. This period was the “golden time” to rescue such patients. The stable types usually have stable hemodynamics, but may worsen, requiring rigorous detection of pericardial effusion and vital signs. In this study, 7.7% of patients were diagnosed as the stable type, and 83.5% of them survived in the hospital. The new clinical classification provides a basis for clinical diagnosis and treatment of FWR. The clinical application of the new classification is expected to improve the prognosis of FWR patients.

Fracturing curve and its corresponding gas productivity of coalbed methane wells in the Zhengzhuang block, southern Qinshui Basin, North China

Hydraulic fracturing has been widely used in low permeability coalbed methane reservoirs to enhance gas production. To better evaluate the hydraulic fracturing curve and its effect on gas productivity, geological and engineering data of 265 development coalbed methane wells and 14 appraisal coalbed methane wells in the Zhengzhuang block were investigated. Based on the regional geologic research and statistical analysis, the microseismic monitoring results, in-situ stress parameters, and gas productivity were synthetically evaluated. The results show that hydraulic fracturing curves can be divided into four types (descending type, stable type, wavy type, and ascending type) according to the fracturing pressure and fracture morphology, and the distributions of different type curves have direct relationship with geological structure. The vertical in-situ stress is greater than the closure stress in the Zhengzhuang block, but there is anomaly in the aggregation areas of the wavy and ascending fracturing curves, which is the main reason for the development of multi-directional propagated fractures. The fracture azimuth is consistent with the regional maximum principle in-situ stress direction (NE–NEE direction). Furthermore, the 265 fracturing curves indicate that the coalbed methane wells owned descending, and stable-type fracturing curves possibly have better fracturing effect considering the propagation pressure gradient (FP) and instantaneous shut-in pressure (PISI). Two fracturing-productivity patterns are summarized according to 61 continuous production wells with different fracturing type and their plane distribution, which indicates that the fracturing effect of different fracturing curve follows the pattern: descending type > stable type > wavy type > ascending type.

Gradient estimates for the fundamental solution of Lévy type operator

We prove a gradient estimate and the Hölder continuity of the gradient for the fundamental solution of a class of α-stable type operators with α ∈ (0, 1), which improve known results in the literature where the condition α > 1/2 is commonly assumed.