Dopamine in the conscious dog with chronic heart-block

Summary The chronotropic effects of dopamine were studied in the conscious dog with chronic A-V block. Dopamine at 12.5–200 g/kg and 12.5–50 g/kg/min lowered atrial rate independently of dose. After blockade of muscarine receptors or alpha-adrenoceptors, it raised atrial rate. After blockade of dopamine receptors, dopamine still lowered atrial rate, and did so dose-relatedly after blockade of beta-adrenoceptors. It raised ventricular rate, and at high doses also induced ventricular rhythm disorders. Blockade of muscarine receptors enhanced the ventricular cardioaccelerator effect of dopamine (P<0.025) at 100 g/kg, while blockade of alpha-adrenoceptors reduced it (P<0.05). Blockade of dopamine receptors did not modify this effect, but blockade of beta-adrenoceptors reversed it. Dopamine at 25–200 g/kg raised mean blood pressure. This effect was enhanced by blockade of muscarine receptors, reversed by blockade of alpha-adrenoceptors, and was unaffected by blockade of beta-adrenoceptors or dopamine receptors. These results show that the atrial cardiomoderator effect of dopamine is a vagal reflex response to its hypertensive action, and that it is limited by its direct beta-adrenergic stimulating action. They also show that the ventricular cardioaccelerator effect of dopamine is attenuated by a reflex vagal depressor effect consequent to the induced hypertension. No evidence was found for the existence of positive chronotropic dopamine receptors in either atria or ventricles.A preliminary report of these findings was presented at the Symposium on Peripheral Dopaminergic Receptors, July 1978, in Strasbourg, France (Boucher et al. 1979b)     

Burden of Providing Informal Care for Patients with Atrial Fibrillation

ObjectivesPatients with atrial fibrillation (AF) have rapid and irregular heart rates, increasing the risk of comorbidities and mortality. Next to formal medical care, many patients receive informal care from their social environment. The objective of this study was to examine the well-being and economic burden of providing informal care to patients with AF in the UK, Italy, and Germany.MethodsCaregivers of patients with AF completed an online survey based on the iMTA Valuation of Informal Care Questionnaire, with questions about their caregiving situation, perceived burden of caregiving, and absence from work due to health problems resulting from caregiving. Care-related quality-of-life utilities were calculated using the Care-related Quality of Life instrument and associated tariffs. Societal costs of caregiving were calculated based on the proxy good method.ResultsA total of 585 caregivers participated in this study. On average, caregivers provided 33 hours of informal care per week to patients (SD 29 hours). On a scale from 0 to 10, their self-rated burden was 5.4. The average Care-related Quality of Life utility was 72. Caregivers primarily indicated problems with daily activities, mental health, and physical health. Still, the vast majority of caregivers (87%) derived fulfillment from providing care. Weekly societal costs of caregiving were on average €636. Comorbidities contributed substantially to the caregiver time and burden.ConclusionsCaring for a patient with AF is associated with substantial objective and subjective burden, but also provides fulfillment from being able to care for a loved one.     

急性心肌梗塞Q－T离散度分析－－附68例临床报告

目的：探讨急性心肌梗塞（AMI）患首次心电图Q－T离散度（Q－Td)及Q－Tc离散度（Q－Tcd）与严重室性心律失常发生的关系,对预后进行评估。方法：对68例AMI患首次心电图Q－Td及Q－Tcd进行测定。结果：18例AMI并室速室颤组患Q－Td,Q－Tcd显高于50例非室速室颤组患;结论：AMI患Q－Td及Q－Tcd值增大,室速室颤发生率增加,两呈正相关关系,易发生心源性猝死。故Q－Td及Q－Tcd可作为AMI病情危重预后差的标志,对判断预后有重要临床意义。     

心房颤动者并发脑梗死相关因素分析

目的 心房颤动是一种常见的心律失常,其并发症包括脑梗死等。国外 对此已经进行了广泛的研究。国内关于此方面的研究较少。本研究分析了心房颤动患者脑梗死发生的危险因素,筛选高危患者,指导临床干预。方法 结合186例慢性心房颤动患者的临床特点,分析不同性别、年龄、病因、并发高血压、糖尿病、心脏瓣膜钙化以及心房大小对房颤并发梗死的影响。结果本研究分析表明：风湿性心脏病（二尖瓣狭窄）、高血压、糖尿病、心脏瓣膜钙化是房颤并发脑梗死的高危因素,性别、年龄对房颤并发脑梗死无显著影响。结论 对于心房颤动并发风湿性心脏病（二尖瓣狭窄）、高血压、糖尿病、心脏瓣膜钙化的患者容易发生脑梗死,可能需要进行抗血栓治疗,预防脑梗死的发生。     

胺碘酮合用小剂量β受体阻滞剂治疗老年阵发房颤临床观察

目的 比较胺碘酮与小剂量β受体阻滞剂合用对老年阵发性房颤的疗效。方法 回顾分析30名老年阵发房颤患者,根据房颤复律后维持用药的不同,分为3组：单用胺碘酮组（n=11);单用β阻滞剂组（n=9);胺碘酮与小剂量β阻滞剂合用组（n=10)。比较3组患者用药后12个月中房颤控制情况及心室率、心脏传导情况。结果 单用胺碘酮组显效率54．5％,有效率45．5％,无效率0％;单用β受体阻滞剂组显效率22．2％,有效率44．5％,无效率33．3％;胺碘酮与小剂量β受体阻滞剂合用治疗房颤,显效率90％,有效率10％,其疗效明显优于单用胺碘酮（P＜0．05）或单用β阻滞剂（P＜0．01）组,且未见明显副作用：3组间心室率未见显著差别。结论 胺碘酮与小剂β受体阻滞剂合用可有效地控制老年阵发性心房纤颤的发作。     

肺静脉血流频谱评价高血压患者的左心室舒张功能

目的　探讨肺静脉血流频谱评价高血压患者左心室舒张功能的价值。　方法　选择 3 0例无心脏疾患者、3 0例高血压无左心房扩大者 ,2 5例高血压左心房扩大者共 85例为研究对象 ,用多普勒超声心动图检测各组肺静脉血流频谱 (PVFP)和二尖瓣血流频谱 (MVFP)参数并做比较。　结果　与正常对照组比较 ,高血压无左房扩大组PVFP中S峰速度加快 ,D峰速度减慢 ,S/D >1 ,AR峰明显加快 ,两组之间有明显差异 (P <0 .0 1 ) ;MVFP中E峰降低 ,A峰增加 ,E峰减速时间 (EDT)延长 ,E/A <1。与正常组对照 ,高血压左心房扩大组PVFP中的S峰降低 ,D峰降低 ,S/D <1 ,但AR峰明显的加速 ,两组之间也有明显的差异 (P <0 .0 1 ) ;MVFP中E峰、A峰、E/A比值和EDT两组近似 (P >0 .0 5 )。　结论　肺静脉血流频谱结合二尖瓣血流频谱能较全面地评价高血压患者的左心室舒张功能。     

Left atrial appendage perforation with Watchman device implantation: Strategies for surgical repair

Percutaneous occlusion of the left atrial appendage is increasingly being used as an alternative for stroke prevention in patients with non‐valvular atrial fibrillation at high risk of complications from long term anticoagulation. We describe a case of left atrial appendage perforation during Watchman device implantation requiring emergency repair of the left atrium using sternotomy and cardiopulmonary bypass. Technical considerations for surgical decision making are discussed; in hemodynamically unstable patients as well as those at high risk for embolization.     

Left ventricular mass index and ventricular contractility improvement in patients with severe obesity following rapid weight loss after bariatric surgery

BackgroundObesity is a well-known risk factor for heart disease, resulting in a broad spectrum of cardiovascular changes. Left ventricular mass (LVM) and contractility are recognized markers of cardiac function.ObjectivesTo determine the changes of LVM and contractility after bariatric surgery (BaS).SettingUniversity hospital, United StatesMethodsTo determine the cardiac changes in ventricular mass, ventricular contractility, and left ventricular shortening fraction (LVSF), we retrospectively reviewed the 2-dimensional echocardiographic parameters of patients with obesity who underwent BaS at our institution. We compared these results before and after BaS.ResultsA total of 40 patients met the inclusion criteria. The majority were females (57.5%; n = 23), with an average age of 63.5 ± 12.1. The excess body mass index (BMI) lost at 12 months was 48.9 ± 28.9%. The percent total weight loss after BaS was 16.46 ± 9.9%. The left ventricular mass was 234.9 ± 88.1 grams before and 181.5 ± 52.7 grams after BaS (P = .002). The LVM index was 101.3 ± 38.3 g/m² before versus 86.7 ± 26.6 g/m² after BaS (P = .005). The LVSF was 31% ± 8.8% before and 36.3% ± 8.2% after BaS (P = .007). We found a good correlation between the decrease in LVM index and the BMI after BaS (P = .03).ConclusionRapid weight loss results in a decrease of the LVM index, as well as improvement in the left ventricular muscle contractility. Our results suggest that there is left ventricular remodeling and an improvement of heart dynamics following bariatric surgery. Further studies are needed to better assess these findings.     

使用自相关和时间序列检测的方法检测心室纤颤信号

心室纤颤信号必须准确而及时地识别,如果不使用除颤器及时进行除颤,病人会迅速死亡。另一方面,如果心室纤颤信号没有发生,而误判为心室纤颤信号,给予电击,则病人的心脏受到不应有的损伤,这也属于严重的医疗事故。因此快速与准确的识别显得十分重要。自70年代以来,世界上许多科学家都在探讨各种方法,以期望使用计算机自动识别心室纤颤信号,但均因达不到实时判别的要求或准确率不够高而不能用于自动除颤器检测的设计方案。本文介绍了一种准确率高而又较简易的快速识别法。这一方法是取一秒心电信号,进行有限长度离散信号的自相关,然后对该自相关函数作零切割,让自相关函数变成一串二进制脉冲串,接着以一秒信号的脉冲串数作为特征参数,设计分类器。经证明,心室纤颤信号(VF信号)(Ventricular Fibrillation)和心动过速信号(VT信号)(Ventricular Tachycar-dia)的特征参数均属于高斯分布。因此可用Wald时间序列检测方法对VF信号和VT信号分类。这个算法可用于计算机进行实时处理和分析,同时此法与取样率无关,适用于各种取样系统,是一个较理想的方法。