Heart rate response to breathing: dependency upon breathing pattern

Summary. Heart rate responses to stepwise and periodic changes in lung volume were studied in seven young healthy males. Stepwise inspiration and expiration both resulted in an increase in heart rate followed by a rapid decrease in heart rate. The fastest heart rate was reached in 1·6 ± 0·5 s and in 3·6 ± 1·4 s in response to inspiration and expiration, respectively (P < 0·01). The slowest heart rate was reached in 4·8± 1·0 s and in 7·6± 1·9 s in response to inspiration and expiration, respectively (P < 0·01). Following this biphasic change the heart rate returned to a steady level. The difference between the fastest and the slowest heart rates was significantly larger in response to inspiration (21·7 ± 7·3 beats per minute) than in response to expiration (12·0±7·3 beats per minute; P < 0·01). Periodic changes in lung volume were performed with frequencies from 3·0 to 12·0 respirations per minute (r.p.m.). The changes in heart rate showed a constant amplitude in the frequency range below 5·5 r.p.m. Maximal heart rate changes were found at frequencies of 5·5 to 7·0 r.p.m. Changes in heart rate decreased in a linear manner on a log-log scale in the frequency range above 7·0 r.p.m. The relation between frequency and changes in heart rate is explained by interference between the transient changes in heart rate induced both by inspiration and by expiration. It is concluded that if heart rate changes in response to periodic changes in lung volume are to be used as a measure of vagal function a number of factors have to be taken into consideration and to simplify the analysis of heart rate responses to breathing we recommend, instead, the use of the transient changes in heart rate induced by stepwise changes in lung volume.     

Treatment Outcomes in Spontaneous Intracranial Hypotension: Do Epidural Blood Patches Stop the Leaks?

Abstract:   Spontaneous intracranial hypotension (SIH) is a postural headache syndrome unrelated to dural puncture. Because of the increasing failure of epidural blood patch (EBP) to relieve headache in SIH, we retrospectively investigated the epidemiological features and treatment outcomes in 55 cases of SIH. The study population was stratified by age and sex; continuous variables were compared for differences by t -tests; categorical variables were compared by Chi-squared analysis or Fisher exact tests. Significant differences were identified by P values of 0.05 or less. The mean age of the study population was 44 ± 12 years with a female to male ratio of 1.3:1.0. Men presented with subdural hematomas ( P  = 0.001) more often than women. Meningeal enhancement on contrast magnetic resonance imaging (MRI) was the most consistent radiographic finding. Radionuclide cisternography (RC) demonstrated thoracolumbar dural leaks in 16 of 22 patients. EBP failures were more common in patients aged 40 and younger than in older patients ( P  = 0.003). Postural headache from SIH was not uniformly responsive to EBP, and had significant comorbidities, especially in men. The management of postural headache in SIH by other techniques to restore brain position and cerebrospinal fluid dynamics should be investigated.     

Remote-controlled catheter ablation of accessory pathways: results from the magnetic laboratory.

AIMS: This study evaluates feasibility, safety, and efficacy of magnetic remote-controlled accessory pathway (AP) ablation. METHODS AND RESULTS: The novel magnetic navigation system (MNS) (Niobe, Stereotaxis) creates a steerable magnetic field (0.08 T) controlling the distal magnetic tip of an ablation catheter. In conjunction with a catheter advancer system (Cardiodrive, Stereotaxis) remote catheter ablation is enabled. Conventional electrophysiology study identified AP conduction in 59 patients (37 males, 36+/-14 years, 60 APs). First generation 1-magnet tip (1-M) (group I, n=18), second generation bipolar 3-magnet tip (3-M) (group II, n=27), and third generation quadripolar 3-magnet tip catheters (3-M quad.) (group III, n=14) were used for magnetic remote-controlled ablation. Successful AP ablation was achieved in 67% (group I), 85% (group II), and 92% (group III). A significant decrease of median [IQR: Q1-Q3] fluoroscopy time and dosage was observed: 21.2 [12.1-33.8] min, 1110 [395-3234] microGym2 (group I); 6.5 [4.4-15.4] min, 290 [129-489] microGym2 (group II), and 4.9 [3.4-8.0] min, 129 [74-270] microGym2 (group III). Mean procedure time (217+/-67 min; 182+/-68 min, and 172+/-90 min) significantly decreased in group III. Median number [Q1-Q3] of radiofrequency current applications in groups I, II, and III was 4 [2-9], 4 [2-6], and 2 [2-4], respectively. No complications occurred. CONCLUSION: Remote AP ablation is safe and feasible using the novel MNS. Introduction of the 3-magnet quadripolar ablation catheter significantly improved the efficacy of the procedure.     

房室结逆向传导电生理特点的观察

目的研究房室结逆向传导的电生理特点。方法分析在我院行电生理检查和／或射频消融的成年患者中电生理资料比较完整的300例患者的房室结逆传电生理特点。结果射频消融术后有161例（54％）有房室结逆传。有逆传患者的前传功能要好于无逆传的患者，对于术后存在室房逆传的患者，逆传功能均明显差于前传功能。射频消融术后有28例（17％）经房室结逆传最早激动冠状静脉窦口，其逆传功能较最早激动希氏束电图的病例相比要差，而两者的前传功能差异无统计学意义。结论射频消融术后54％的患者存在房室结逆传，可能是正常人群中室房逆传的真实反映。有室房逆传患者的房室结前传功能优于无室房逆传者，也优于其本身的逆传功能。房室结逆传冲动进入心房可能存在两条不同的通路。     

鼻内镜鼻窦手术后应用香菊片对粘膜转归的影响

目的 观察内镜鼻窦手术后应用香菊片对术腔粘膜转归的影陶。方法 Ⅱ型鼻窦炎、鼻息肉患者180例作为治疗组，行内镜鼻窦手术后，在常规辅助治疗基础上加用香菊片口服，并设ll0例Ⅱ型鼻窦炎、鼻息肉患者作为对照组，对比观察术腔清洁时间、术腔上皮化时间及术后复发率。结果 治疗组术腔清洁时间平均为：Ⅰ期1．5周，Ⅱ期1．8周，Ⅲ期2．1周；对照组Ⅰ期2．0周，Ⅱ期2．5周，Ⅲ期3．3周，差异有显著性意义(P＜0．01)。治疗组术腔上皮化时间平均为：Ⅰ期7．0周，Ⅱ期7．5周，Ⅲ期7．8周；对照组Ⅰ期8．0周，Ⅱ期8．4周，Ⅲ期9．0周，差异有显著性意义(P＜0．01)。治疗组术后复发率为4．4％，明显少于对照组7．3％。结论 内镜鼻窦手术后，应用香菊片对鼻腔功能的恢复具有良好的疗效，并能减少复发率，可做为常规药物应用临床。     

国人上矢状窦窦腔内结构的内镜解剖

目的观察国人上矢状窦窦腔内结构，特别是纤维索和蛛网膜颗粒的完整解剖形态。方法成人头颅标本5具，去除颅盖，应用内镜观察研究上矢状窦窦腔内纤维索及蛛网膜颗粒的原始结构特征；并纵行剖开管腔，显微镜下观察纤维索、蛛网膜颗粒。结果内镜下观察上矢状窦管腔内纤维索大致分3种类型：瓣膜状（47．1％）、小梁状（30．6％）、板层状（22．3％）。蛛网膜颗粒多集中于上矢状窦中段侧壁及静脉隐窝处呈指状突起突入窦腔。结论内镜较常规解剖手段可以更直观地观察上矢状窦窦腔内结构的完整形态特征。     

阴道B超介导下后穹窿穿刺治疗盆腔囊肿

目的　介绍阴道B超介导下后穹窿穿刺治疗盆腔囊肿的方法和疗效。方法　 38例盆腔囊肿病人在阴道B超介导下行后穹窿穿刺术 ,并与 2 8例住院行经腹囊肿切除术病人进行对比。结果　阴道B超介导下后穹窿穿刺术治愈率 10 0 % ,复发率 2 6 %。与经腹囊肿切除术相比 ,手术时间短 ,术中出血少 ,病人可接受程度高 ,花费少 ,差异显著 (P <0 0 1)。结论　阴道B超介导下后穹窿穿刺治疗盆腔囊肿 ,方法简便、安全高效、创伤小、价廉 ,是一项理想的保守疗法 ,值得推广应用。     

左主干起源于右冠状动脉窦（附2例报告并文献复习）

目的:分析左主干起源于右冠状动脉窦的临床特征,提高对左主干起源于右冠状动脉窦的认识和诊断.方法:回顾分析2例左主干起源于右冠状动脉窦的临床病例并对文献进行回顾分析.结果:左主干起源于右冠状动脉窦是一种罕见的先天性冠脉畸形,这种畸形可分为良性或恶性,主要根据异常左冠状动脉与主动脉和肺动脉之间的关系.对于可能引起猝死或严重心肌缺血患者,应进行冠状动脉旁路移植术.2例患者左主干起源于右冠状动脉窦,其中1例左主干走行于主动脉与肺动脉之间,1例走行于主动脉前方,这2例未进行预防性外科手术,目前预后良好.结论:左主干起源于右冠状动脉窦是罕见的冠脉畸形,应注意鉴别是良性或是恶性,确定下一步治疗方案.     

Epidural blood patch illustrated by CT-epidurography

Four patients, who received epidural blood patch to treat postdural puncture headache, were examined with computed tomography in order to demonstrate the distribution of the injected blood. Blood alone could not be identified, but adding 2 ml contrast agent Iohexol 180 mg J/ ml (Omnipaque®, Nycomed Imaging) to 18 ml blood gave an excellent demonstration of the distribution of the blood in the epidural space, both cranio-caudally (7–14 segments) and spatially in relation to the epidural septae. The blood-contrast media had a strong affinity to the dural sac. There was no support of the spacefilling effect of blood patch.     

Coronary venous retroperfusion of arterial blood for the treatment of acute myocardial ischemia

Synchronized coronary venous retroperfusion of autologous arterial blood was offered to patients referred for medically refractory unstable angina or evolving myocardial infarction with contraindications to thrombolytic therapy. Primary endpoints of angina, ST segment deviation, and two-dimensional echocardiographic systolic wall motion were followed to determine the efficacy of retroperfusion in patients prior to and then during angioplasty, surgical intervention, or pharmacological management, as the clinical picture warranted. Over a 12 month period, 21 patients were referred and 15 received retroperfusion. All experienced full relief of angina (p = 0·008). ST segment deviations and systolic wall motion of ischemic zones were observed to improve (p = 0·06 ST changes; p = 0·0001 wall motion changes) with synchronized retrograde perfusion. During attempts to remove patients from retroperfusion, statistically significant (p < 0·01) reproducible changes in these same endpoints were documented. Retroperfusion appears to improve acute myocardial ischemia. This technique functions well in the intensive care unit environment with only fluoroscopy as technical imaging support.