口服胺碘酮治疗难治性室性期前收缩68例临床观察

目的评价口服胺碘酮治疗难治性室性期前收缩的疗效和安全性。方法入选68例难治性期前收缩患者接受胺碘酮治疗,胺碘酮先予负荷量200mg,3次／d,连用1周;200mg,2次／d,连用1周,再予小剂量100～200mg,1次／d维持。每周门诊或电话随访1次。结果随访0．4～2．8年。有效48例,无效16例,恶化4例,有效率达70．6％。毒副作用相对较少,停药率为8．8％。结论口服胺碘酮治疗难治性室性期前收缩的疗效显著,且安全性好。     

Visual quantitative estimation: semiquantitative wall motion scoring and determination of ejection fraction

Ejection fraction (EF) is the most commonly used parameter of left ventricular (LV) systolic function and can be assessed by echocardiography. Quantitative echocardiography is time consuming and is as accurate as visual estimation, which has significant variability. We hypothesized that each echocardiographer has developed a mental set of guidelines that relate to how much individual segment shortening constitutes normal function or hypokinesis of varying extents. We determined the accuracy of applying these guidelines to an accepted technique of EF determination using a retrospective analysis of consecutive two-dimensional echocardiographic studies performed on patients who had radioventriculography (RVG) within 48 hours. Using a 12 segment model, we scored each segment at the base and mid-ventricular level based on segmental excursion and thickening. The apex was scored similarly but with 1/3 of the value based on a cylinder-cone model. EF was determined from the sum of segment scores and was estimated visually. We termed this approach visual quantitative estimation (VQE). We correlated the EF derived from VQE and visual estimation with RVG EF. In the training set, VQE demonstrated a strong correlation with RVG (r = 0.969), which was significantly greater than visual estimation (r = 0.896, P < 0.01). The limits of agreement for VQE (+12% to -7%) were similar to the limits of RVG agreement with contrast ventriculography (+10% to -11%) with similar intraobserver and interobserver variabilities. Similar correlation was noted in the prediction set between VQE and RVG EF (r = 0.967, P < 0.001). We conclude that VQE provides highly correlated estimates of EF with RVG.     

Uncorrected pre-ejection period: A simple non-invasive measurement for pharmacodynamic screening of inotropic activity

Summary Since heart rate (HR) is an important determinant of the duration of systole, systolic time intervals (STI) from 8 healthy subjects were examined after infusion of atropine. As no overall correlation was found between HR and pre-ejection period (PEP), the results confirm the need for individual estimates of the correction of the left ventricular ejection time (LVET) and the total electromechanical systole (OS₂). In the same subjects the sensitivity of PEP to minor negative inotropic effects of mexiletine and disopyramide measured at C_max was confirmed. Thus, in addition to its simplicity and reliability, the sensitivity of the uncorrected PEP should encourage use of this technique as part of any screening system for the early detection of an inotropic effect of new chemical entities.     

The Heart in Scleroderma: Noninvasive assessment

Summary: Myocardial fibrosis is found at postmortem examination in up to 80% of patients with scleroderma, yet many such patients have an entirely normal cardiovascular examination. Isometric handgrip exercise is a useful provocative test for the detection of subclinical left ventricular abnormality. By this method 15 patients with scleroderma (American Heart Association criteria) were compared with 15 sex and age-matched normals. Results showed that scleroderma patients had a depressed heart rate response to handgrip (p<0.05) and abnormal systolic and diastolic time intervals. They showed a decreased shortening of the ratio pre-ejection period to ejection time (p<0.05) and a lengthening of the isovolumic relaxation time compared with the control group who steadily shortened this period (p<0.01). These findings indicate increased stiffness and impaired contractility of the left ventricle as would be caused by an underlying fibrotic process otherwise undetectable. Immunohistological studies give support to this concept. Staining with monospecific antibodies to collagens types I to V of cardiac muscle from patients who, in life, had no overt cardiac disease, showed an excess deposition of collagens type I, III, and IV. In conclusion isometric exercise may provide a noninvasive method of unmasking subclinical fibrosis of the left ventricle in scleroderma, and immunopathological studies support these findings.     

Automatic 3D+t four-chamber CMR quantification of the UK biobank: integrating imaging and non-imaging data priors at scale

Accurate 3D modelling of cardiac chambers is essential for clinical assessment of cardiac volume and function, including structural, and motion analysis. Furthermore, to study the correlation between cardiac morphology and other patient information within a large population, it is necessary to automatically generate cardiac mesh models of each subject within the population. In this study, we introduce MCSI-Net (Multi-Cue Shape Inference Network), where we embed a statistical shape model inside a convolutional neural network and leverage both phenotypic and demographic information from the cohort to infer subject-specific reconstructions of all four cardiac chambers in 3D. In this way, we leverage the ability of the network to learn the appearance of cardiac chambers in cine cardiac magnetic resonance (CMR) images, and generate plausible 3D cardiac shapes, by constraining the prediction using a shape prior, in the form of the statistical modes of shape variation learned a priori from a subset of the population. This, in turn, enables the network to generalise to samples across the entire population. To the best of our knowledge, this is the first work that uses such an approach for patient-specific cardiac shape generation. MCSI-Net is capable of producing accurate 3D shapes using just a fraction (about 23% to 46%) of the available image data, which is of significant importance to the community as it supports the acceleration of CMR scan acquisitions. Cardiac MR images from the UK Biobank were used to train and validate the proposed method. We also present the results from analysing 40,000 subjects of the UK Biobank at 50 time-frames, totalling two million image volumes. Our model can generate more globally consistent heart shape than that of manual annotations in the presence of inter-slice motion and shows strong agreement with the reference ranges for cardiac structure and function across cardiac ventricles and atria.