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Risk factors for post-stem cell transplant sinusitis.

An understanding of the factors that place the post-transplant patient at increased risk for sinusitis would help identify patients likely to develop disease and possibly allow for interventions that would decrease the incidence or severity of sinus disease. This retrospective study investigates the ability of screening paranasal sinus computed tomographic scans (CTs), clinical history, and potential risk factors for sinusitis, including history of tobacco use, history of allergies or asthma, IgG level, history of sinusitis, remission status and acute graft-versus-host disease (GVHD) to predict post-transplant sinusitis. Medical records and sinus CTs of 100 allogeneic bone marrow recipients were reviewed. There was no increased risk of developing sinusitis post SCT for patients with significant disease on screening CT, symptoms at time of transplant, a history of tobacco use, asthma or allergies, low IgG level, history of sinusitis or for patients at high risk of relapse. Patients with GVHD were 4.3 times more likely than patients without GVHD to develop sinusitis post transplant (95% CI: 1.7-11.0, P = 0.002). Acute GVHD places patients at greater risk of developing sinus infections.

Adult↗

Benign expansile lesions of the sphenoid sinus: differentiation from normal asymmetry of the lateral recesses.

BACKGROUND AND PURPOSE: There is a wide range of normal variation is sphenoid sinus development, especially in the size of the lateral recesses. The purpose of this study was to determine imaging characteristics that may help differentiate between opacification of a developmentally asymmetric lateral recess and a true expansile lesion of the sphenoid sinus. METHODS: Coronal CT was performed in seven patients with expansile or erosive benign lesions of the sphenoid sinus, and results were compared to a control population of 72 subjects with unopacified sphenoid sinuses. The degree of asymmetry of lateral recess development was assessed with particular attention to the separation of vidian's canal and the foramen rotundum (vidian-rotundum distance). The images were also examined for evidence of: erosion, defined as loss of the normal thin bony margin on at least two contiguous sections; apparent thinning of the sinus wall, defined as a focal apparent decrease in thickness again on at least two contiguous sections; and for vidian's canal or foramen rotundum rim erosion or flattening. RESULTS: Of the seven patients with expansile lesions, vidian's canal margin erosion was present in seven, unequivocal sinus expansion in three, wall erosion in three, wall thinning in three, erosion of the foramen rotundum in two, and flattening in the foramen rotundum in four. Forty-one of the 72 controls had lateral recess formation, 28 of which were asymmetric. The distance between vidian's canal and the foramen rotundum (vidian-rotundum distance) relied on the presence or absence of pneumatization, with a significantly larger distance in the presence of greater wing pneumatization. Examination of 24 controls revealed apparent thinning of the sinus wall, typically at the carotid groove, but no flattening, thinning, or erosion of the vidian canal or of the foramen rotundum. CONCLUSION: Examination of controls and patients with expansile or erosive lesions of the sphenoid sinus revealed side-to-side asymmetry in the development of the sinus and lateral recess, making subtle expansion difficult to assess. Furthermore, variability in the vidian-rotundum distance correlated with degree of pneumatization, and did not necessarily reflect expansion. Thus, in the absence of gross sinus wall erosion, flattening or erosion of the rims of vidian's canal or the foramen rotundum provides the most specific evidence of an expansile or erosive process within the sinus.

Adolescent↗

B-mode ultrasonography of the paranasal sinuses compared with CT findings.

Ultrasound as a diagnostic aid in the evaluation of the sinuses has been a controversial issue. Sensitivities have been reported from 29% to 100% and specificities from 55% to 99%. These wide variations in results from previous studies may have resulted from technical differences. However, the "gold standard" most often used for comparison has been a Water's view radiograph, which has been shown to correlate poorly with intraoperative and CT scan findings. To our knowledge, no one in the English language literature has evaluated sonography of the sinuses with computed tomography as the gold standard. In addition, evaluation of the ethmoid sinus has been neglected by previous studies that have primarily assessed the maxillary sinus. We report the results of a blinded, prospective trial comprised of 41 patients examined by B-mode ultrasound with comparison to computed tomography. Frontal and maxillary sinuses were examined with traditional sonographic techniques and the ethmoid sinuses were scanned with a transglobe technique not previously evaluated in the English language literature. Excluding isolated mucous retention cysts and focal minimal mucosal thickening (defined as < 4 mm), sensitivities for ultrasound of the maxillary, frontal, and ethmoid sinuses were 100% each. Specificities were 98% for the maxillary sinus, 100% for the frontal sinus, and 94% for the ethmoid sinus. Technical aspects and implications of this and previous reports will be discussed.

Adolescent↗

The effects of negative chronotropic interventions on sinus node recovery time.

The effects of multiple increases in sinus cycle length on sinus node recovery time (SNRT) were examined in 5 dogs. Pacing was performed from the left atrial appendage for 30 and 60 seconds using at least 4 different pacing cycle lengths selected between 230 and 620 msec. Each dog received propranolol (1 mg/kg, IV) prior to any measurements. The effects of increases in sinus cycle length on SNRT were first assessed during 2 levels (4 and 8 Hz) of continuous vagal stimulation. From a control cycle length of 439 +/- 28 msec (mean +/- SE), the vagal stimulations lengthened the sinus cycle lengths to 604 +/- 10 msec and 758 +/- 16 msec respectively. Sinus cycle length was then prolonged by combined muscarinic and beta-receptor blockade resulting in a sinus cycle length of 549 +/- 9 msec. Autonomic blockade plus verapamil (3-10 mg IV) resulted in sinus cycle lengths of 612 +/- 14 and 721 +/- 18 msec respectively, which were not significantly different from those obtained with vagal stimulation. Data relating SNRT to the sinus cycle length, pacing cycle length, duration of pacing and the negative chronotropic interventions used to achieve the changes in the sinus cycle length were analyzed via covariance analysis. The results demonstrate that the single most important determinant of SNRT is the sinus cycle length. Furthermore, equivalent increases in sinus cycle length whether obtained by vagal stimulation, autonomic blockade or intravenous verapamil results in SNRTs that are not significantly different. Therefore, in the sinus node, changes in the rate of pacemaker activity, regardless of how they are achieved, will largely determine the changes in SNRT.

Adrenergic beta-Antagonists↗

Treatment of colorectal and ileoanal anastomotic sinuses.

PURPOSE: This study is designed to describe a technique and report results for treating low anastomotic sinuses. METHODS: Restorative proctocolectomy and complicated low anterior resections were protected with diverting loop ileostomy. Contrast enemas identified anastomotic problems before ileostomy closure. Pouch-anal or colorectal anastomotic sinuses that failed to resolve with observation were treated before intestinal continuity was restored. With the patient receiving regional or general anesthesia, a rigid proctoscope or anoscope was used to identify the sinus opening. The common wall between the sinus and the bowel lumen was divided under direct vision with laparoscopic cautery scissors, and the sinus cavity was debrided with a suction cautery wand placed through the scope. RESULTS: Six patients with anastomotic sinuses have received outpatient treatment in the described manner during the past two years. Four patients had restorative proctocolectomies for ulcerative colitis, and two had low anastomosis for rectal cancer. Three patients presented with pelvic sepsis before the contrast study; the remainder were asymptomatic. Division of anastomotic sinus was performed one to eight months after diagnosis of the sinus. Following division, anastomotic cavities resolved in five patients by 1 month and in one patient by 12 months. In these six patients, there was one dilatable anastomotic stricture but no other anastomotic complications at follow-up 5 to 16 (mean, 9.2) months after sinus division. CONCLUSION: When used in conjunction with fecal diversion, sinus unroofing by division of the common wall between the sinus and bowel lumen treats low pelvic sinuses.

Adolescent↗

Reproducibility of electrophysiological parameters of sinus node following autonomic blockade.

We investigated the reproducibility of sinus node cycle length (SCL), corrected sinus node recovery time (CSRT) and sino-atrial conduction time (SACT) during the control state and following autonomic blockade in 25 patients (mean age: 56.9 +/- 13.8 years). Autonomic blockade was induced by i.v. administration of propranolol (0.2 mg/kg) and atropine (0.04 mg/kg). The electrophysiological study was repeated after 24 hr and the results were compared. The patients were divided into two groups: Group 1 (15) with normal and Group 2 (10) with abnormal intrinsic sinus node function. Following autonomic blockade in Group 1 the daily variations in SCL, CSRT and SACT were very slight whereas in Group 2 there was far greater variability in these parameters. However, in the latter group there were no patients who changed their status from prolonged to normal intrinsic CSRT on the second study, whereas SACT changed its status in 2 patients. In Group 1 the daily variations in sinus node parameters were much slighter following autonomic blockade than during the control state. In Group 2 the variations were very similar during control and following autonomic blockade. These data suggest that: (1) following autonomic blockade the reproducibility of sinus node parameters is very good in Group 1, whereas in Group 2 several patients show marked daily variations in sinus node parameters; (2) following autonomic blockade the sinus node electrophysiological parameters are meaningful in diagnosing an involvement of intrinsic sinus node function; and (3) in patients with abnormal sinus node parameters during control state, but with normal intrinsic sinus node function, the daily variations are mainly due to change in autonomic tone, whereas when the intrinsic sinus node function is abnormal, the day to day variations during control state appear due predominantly to intrinsic sinus node abnormalities.

Adolescent↗

Coronary sinus sampling of cytokines after heart transplantation: evidence for macrophage activation and interleukin-4 production within the graft.

OBJECTIVES: This study was undertaken to evaluate the organ-specific release of cytokines after heart transplantation and to assess any correlation with transplant rejection. This cytokine profile should document the relative activation of mononuclear cell subsets within the graft. BACKGROUND: Up to 60% of mononuclear cells infiltrating the cardiac allograft during rejection are macrophages, but their role is undetermined. The T lymphocytes are activated, but the activity of specific T cell subsets is not known. We sought to assess for the first time in humans the in vivo activation of mononuclear cell subsets by measuring coronary sinus cytokine levels after heart transplantation. METHODS: Paired superior vena cava and coronary sinus serum samples were assayed for interleukin (IL)-2, IL-4 and IL-6, soluble IL-2 receptors, tumor necrosis factor-alpha and neopterin in 10 patients at the time of 40 routine endomyocardial biopsy procedures. All cytokine measurements were made by using enzyme-linked immunosorbent assay; neopterin was measured by using radioimmunoassay. RESULTS: Interleukin-2 levels were not detectable (< 0.8 U/ml) in either the superior vena cava or the coronary sinus in the presence or absence of rejection. Interleukin-2 receptor levels were uniformly elevated to 1,283 U/ml in the superior vena cava and to 1,232 U/ml in the coronary sinus, with no correlation with rejection severity. Interleukin-4 levels were consistently higher in coronary sinus serum than in peripheral blood (229 vs. 61 pg/ml, p < 0.0005), but there was no relation with rejection. Interleukin-6 levels were higher in the coronary sinus than in the superior vena cava (200 vs. 120 pg/ml, p < 0.05). Tumor necrosis factor-alpha showed consistently elevated levels in coronary sinus serum (68 vs. 17 pg/ml, p < 0.0005), with no relation with rejection. Neopterin, which is produced only by activated macrophages, was also consistently elevated in the coronary sinus (2.5 vs. 2.2 nmol, p = 0.08). CONCLUSIONS: The cardiac allograft is a major source of cytokines after heart transplantation. The cytokine profile allows the activity of subsets of the mononuclear cell infiltrate to be investigated. Elevated coronary sinus activity of the macrophage-specific metabolite neopterin suggests macrophage activation within the allograft. This possibility is supported by elevated coronary sinus levels of tumor necrosis factor-alpha and IL-6. The T lymphocytes are activated, as evidenced by high soluble IL-2 receptor levels, but IL-2 production was suppressed by conventional immunosuppressive therapy. Coronary sinus IL-4 levels represent T helper-2 cell activation within the graft despite immunosuppression. We could find no temporal relation between the coronary sinus or superior vena cava cytokine concentration or profile and severity of rejection on concurrent biopsy studies.

Analysis of Variance↗

Coronary arteries in complete transposition: the significance of the sinus node artery.

Hearts from 29 children with complete transposition were examined postmortem to analyze the pattern of the coronary arteries and the origin of the sinus node artery. Four patterns of origin and distribution of the coronary arteries were found. In all, the coronary arteries arose from one or both of the facing sinuses, which were termed sinus 1 and sinus 2. The patterns were left coronary artery from sinus 1 and right coronary artery from sinus 2; anterior descending artery from sinus 1 and right coronary artery and circumflex artery from sinus 2; left coronary and right coronary from sinus 2; and circumflex artery from sinus 2 and right coronary artery from sinus 1. This study highlights the patterns of the coronary arteries in complete transposition and categorizes the variability using a simple classification. It also emphasizes the surgical significance of variations in distribution of the sinus node artery.

Autopsy↗

Anatomical and physiological studies on the aqueous sinus artery of the pigeon eye.

PURPOSE: To test the hypothesis that ischemia of the Schlemm's canal endothelium is involved in the control of intraocular pressure (IOP). METHODS: Experiments were conducted on pigeons. The course of the aqueous sinus and the aqueous sinus artery was determined by examining serial sections and the distribution of polymerized resin in the limbal region of the pigeon eye. Ischemia was produced by blocking two major arteries to the aqueous sinus artery and then determining the effect on the IOP. RESULTS: The anatomy and course of the pigeon aqueous sinus and aqueous sinus artery indicated that they are homologous to the human Schlemm's canal and Schlemm's canal artery, respectively. When the arterial inflow to the aqueous sinus artery was blocked by laser treatment, injected resin was absent in the artery but a small amount invaded the aqueous sinus. Blockage of the two major arteries to the aqueous sinus artery did not alter the IOP. CONCLUSIONS: The similarity of the pigeon aqueous sinus and aqueous sinus artery to the human Schlemm's canal and Schlemm's canal artery indicates that the pigeon eye can be used to study the relationship between ischemia of the endothelial meshwork cells and IOP. The lack of a change in IOP in pigeons after ischemia induction was probably the result of anastomotic arterial blood inflow to the aqueous sinus directly, and thus ischemia was not produced by blocking the two major arteries to the aqueous sinus artery.

Animals↗

The coronary sinus in the fetus.

INTRODUCTION: The normal coronary sinus drains venous blood from the cardiac veins to the right atrium. In some instances, the coronary sinus may be dilated due to volume or more rarely pressure overload. AIMS: To assess the feasibility of detecting the coronary sinus in the fetus and to establish the normal values of the coronary sinus dimensions throughout gestation. SUBJECTS AND METHODS: Fetal echocardiography was performed in 78 normal fetuses from the 16th to the 40th week of gestation (median 25 week). The coronary sinus was measured in four-chamber view (87% of cases) or in parasternal short axis view equivalent (13%). A second group of nine fetuses with a dilated coronary sinus was compared to the normal group. RESULTS: Adequate imaging of coronary sinus was obtained in 97.4% of the normal fetuses. The diameter of the coronary sinus ranged from 1 to 3.2 mm (2 mm +/- 0.13 mm, mean +/- 5% confidence interval) and correlated well with the age of pregnancy (r = 0.86). The length-to-diameter ratio of 24% (+/- 6%) did not vary throughout pregnancy. All nine fetuses with a dilated coronary sinus had a persistent left superior vena cava which drained into it. The diameter of the coronary sinus was approximately three times larger in the abnormal group with a diameter-to-length ratio of approximately 83% (P < 0.0001). CONCLUSION: The coronary sinus is readily identified in the fetus. It gradually increases during pregnancy. An abnormal coronary sinus is easily diagnosed and should prompt the sonographer to look for a persistent left superior vena cava.

Coronary Vessels↗

Modifications to the cavopulmonary anastomosis do not eliminate early sinus node dysfunction.

OBJECTIVE: To determine whether operations that theoretically jeopardize the sinus node (hemi-Fontan and/or lateral tunnel Fontan procedures) are associated with a greater risk of sinus node dysfunction than those that theoretically spare the sinus node (bidirectional Glenn and/or extracardiac conduit). METHODS: Between January 1, 1996, and December 31, 1999, a prospective cohort study was conducted evaluating the incidence of sinus node dysfunction in patients undergoing a bidirectional Glenn or hemi-Fontan procedure and those in whom the Fontan repair was completed with either an extracardiac conduit or a lateral tunnel. Sinus node dysfunction was defined (1) as a heart rate more than 2 SD below age-adjusted norms or (2) as a predominant junctional rhythm and/or a sinus pause of more than 3 seconds as determined by the resting electrocardiogram and/or ambulatory monitoring at hospital discharge. RESULTS: Fifty-one patients had a bidirectional Glenn shunt (mean age 7.8 +/- 5.1 months) and 79 a hemi-Fontan procedure (mean age 6.9 +/- 2.8 months). The incidence of sinus node dysfunction on postoperative day 1 was significantly higher after the hemi-Fontan (36%) than after the bidirectional Glenn shunt (9.8%); however, by hospital discharge this difference was no longer apparent (hemi-Fontan [8%]; bidirectional Glenn [6%]; P = not significant). No difference in early sinus node dysfunction was discernible after the extracardiac conduit (4/30 [13%]) compared with the lateral tunnel Fontan procedure (6/46 [13%]) (P = not significant). No diagnostic or perioperative variables were predictive of sinus node dysfunction. CONCLUSIONS: Avoidance of surgery near the sinus node has no discernible effect on the development of early sinus node dysfunction. Thus, concerns about early sinus node dysfunction should not override patient anatomy or surgeon preference as determinants of which cavopulmonary anastomosis to perform.

Anastomosis, Surgical↗

Coronary sinus blood flow determination by the thermodilution technique: influence of catheter position and respiration.

By measuring the coronary sinus blood flow using the thermodilution technique the influence of "thermodilution catheter" withdrawal from the great cardiac vein to the ostium of the coronary sinus was investigated in 41 patients. In addition, the influence of normal and forced respiration on coronary sinus blood flow was measured in 16 of the patients. Mean great cardiac vein flow was measured to 54 +/- 25 ml X min-1. Catheter withdrawal revealed coronary sinus blood flows of 80 +/- 32, 103 +/- 35, 145 +/- 39 and 213 +/- 61 ml X min-1 when the catheter was moved by steps of 1 cm towards the coronary sinus ostium. The coronary sinus blood flow changed between 116 +/- 34 ml X min-1 and 128 +/- 41 ml X min-1 on expiration or inspiration during normal respiration, respectively, when the catheter was placed in a mid-coronary sinus position. Forced respiration changed the coronary sinus blood flow from 98 +/- 41 ml X min-1 during expiration to 196 +/- 76 ml X min-1 during inspiration. The data show that coronary sinus blood flow changes from 23 to 68 ml X min-1 per cm catheter movement, the nearer the ostium the greater the change. Therefore comparison of coronary sinus blood flow between groups of patients would be a comparison between different catheter positions. Normal respiration moves, as judged by the coronary sinus blood flow, the thermodilution catheter by less than 0.5 cm while forced respiration moves the catheter up to 2 cm within the coronary sinus.

Adult↗

The renal sinus is the principal invasive pathway: a prospective study of 100 renal cell carcinomas.

A total of 100 renal cell carcinomas were prospectively examined for renal sinus invasion, 74 clear cell renal cell carcinomas (CC), 3 renal cell carcinomas, unclassified (RUC), 16 papillary renal cell carcinomas (PapC), and 7 chromophobe renal cell carcinomas (ChC). Using the 2002 TNM staging formulation, 49 tumors were T1, 5 were T2, and 46 were T3 or T4. Renal sinus invasion occurred more often than renal capsule invasion. No tumor invaded the capsule that did not also invade the sinus. Renal sinus invasion correlated with Fuhrman grade; 17% of grades 1/2 tumors invaded the sinus, while 71% of grade 3/4 tumor invaded the sinus (P < 0.001). Sinus invasion correlated with tumor type; 2 of 23 PapC and ChC invaded the sinus compared with 44 of 77 CC and RUC. Sinus invasion occurred in approximately 16% of tumors 1 to 4 cm in size, then abruptly increased for larger tumors (P < 0.001). When tumors are staged by the 1997 and 2002 TNM formulation, renal sinus invasion upstaged 28% of cases stage T1 or T2 by the 1997 formulation, to T3 using the 2002 criteria. In conclusion, renal sinus invasion is the most common site of extrarenal extension of renal carcinoma and correlates with tumor type, grade and size. Appropriate evaluation for sinus invasion reduces the incidence of T1b and T2 CC tumors, limiting prognostic utility and suggesting reassessment of the T1 and T2 stage designations.

Carcinoma, Renal Cell↗

Sinus nodal function and risk for atrial fibrillation after coronary artery bypass graft surgery.

BACKGROUND: Nonsurgical patients with sinus node dysfunction are at high risk for atrial tachyarrhythmias, but whether a similar relation exists for atrial fibrillation after coronary artery bypass graft surgery is not clear. The purpose of this study was to evaluate sinus nodal function before and after coronary artery bypass graft surgery and to evaluate its relation with the risk for postoperative atrial arrhythmias. METHODS: Sixty patients without complications having elective coronary artery bypass graft surgery underwent sinus nodal function testing by measurement of sinoatrial conduction time (SACT) and corrected sinus nodal recovery time (CSNRT). Patients were categorized based on whether postoperative atrial fibrillation developed. RESULTS: Twenty patients developed atrial fibrillation between postoperative days 1 through 3. For patients remaining in sinus rhythm (n = 40), sinoatrial conduction times were no different and corrected sinus nodal recovery times were shorter after surgery when compared with measurements obtained after anesthesia induction. Sinus node function test results before surgery were similar between the sinus rhythm and the atrial fibrillation groups. After surgery, patients who later developed atrial fibrillation had longer sinoatrial conduction times compared with the sinus rhythm group (P = 0.006), but corrected sinus nodal recover time was not different between these groups. A sinoatrial conduction time > 96 ms measured at this time point was associated with a 7.3-fold increased risk of postoperative atrial fibrillation (sensitivity, 62%; specificity, 81%; positive and negative predictive values, 56% and 85%, respectively; area under the receiver operator characteristic curve, 0.72). CONCLUSIONS: These data show that sinus nodal function is not adversely affected by uncomplicated coronary artery bypass surgery. Patients who later developed atrial fibrillation, however, had prolonged sinoatrial conduction immediately after surgery compared with patients remaining in sinus rhythm. These results suggest that injury to atrial conduction tissue at the time of surgery predisposes to postoperative atrial fibrillation and that assessment of sinoatrial conduction times could provide a means of identifying patients at high risk for postoperative atrial fibrillation.

Aged↗

Structural characteristic of splenic sinuses in idiopathic portal hypertension.

Splenic sinuses in idiopathic portal hypertension (IPH; 8 patients), liver cirrhosis (LC; 14 patients) and in regenerating autotransplanted spleens from 25 rats were compared with each other by scanning electron microscopy (SEM) and immunohistochemistry using antibodies against proliferating cell nuclear antigen (PCNA). Spleens obtained from six patients with gastric carcinoma and from five untreated adult rats were examined as controls. SEM of the sinuses showed that in IPH endothelial cells became irregular in shape, and the interendothelial slits of sinuses were irregularly enlarged. Sinus endothelial processes traversing the sinusal lumen were also found. The same changes were observed in the proliferating sinuses during regeneration of splenic tissue after autotransplantation in rats, but disappeared when the regeneration was completed. Irregular endothelial cells were few in LC. PCNA-positive sinus endothelial cells were increased in number in IPH as compared with those in LC; the mean number of PCNA-positive ones per cm2 was 45.4 in IPH and 8.2 in LC. It was suggested that, from SEM observation of sinus endothelial cells and counting PCNA-positive sinus endothelial cells, the sinuses of the spleen in IPH consist of proliferating endothelial cells or are in the state of increased proliferation. In conclusion, splenomegaly in IPH was presumed to be caused by proliferation of sinus endothelial cells, and by the increased splenic blood flow in the irregularly widened interendothelial slits of the sinuses.

Adult↗

Radiofrequency catheter modification of sinus pacemaker function guided by intracardiac echocardiography.

BACKGROUND: The sinus P wave arises from a pacemaker complex distributed along the crista terminalis. We investigated the feasibility of modification of sinus pacemaker function using graded applications of radiofrequency energy along the crista terminalis in dogs to achieve sinus rate control. METHODS AND RESULTS: Modification of sinus pacemaker function (30 +/- 5% reduction in intrinsic heart rate with retention of a normal P-wave axis) was performed in 11 dogs (group 1). Total sinus pacemaker ablation (> 50% reduction in intrinsic heart rate with development of a low ectopic atrial or a junctional rhythm) was performed in 4 dogs (group 2). Intracardiac echocardiography was used to identify the crista terminalis as an anatomic marker of sinus node location. Sinus pacemaker modification caused a significant decrease in intrinsic heart rate (31% reduction, P < .001), heart rate responsiveness to isoproterenol (30% reduction, P < .0001), and average (20% reduction, P = .0002) and maximal (22% reduction, P = .0007) heart rates during 24-hour Holter monitoring. In 6 of the 11 animals, the targeted rate reduction of 30 +/- 5% was accurately achieved (mean, 31.6 +/- 4.3%; P < .001), and in the other 5, significant reduction of intrinsic heart rate was achieved but with greater variation (28.0 +/- 17.3%, P < .005). Corrected sinus node recovery time was not prolonged. After modification, earliest activation was mapped to the crista terminalis inferior to the lesion in all animals. In long-term follow-up (3.7 +/- 1.0 months), effects were maintained. After total sinus pacemaker ablation, junctional and low atrial escape pacemakers were unstable. CONCLUSIONS: This study demonstrates the feasibility of modification of sinus pacemaker function for sinus rate control using catheter-based radiofrequency ablation guided by intracardiac echocardiography. This can be done while pacemaker stability and attenuated responsiveness to autonomic influences are preserved. Intracardiac echocardiography accurately defined the crista terminalis and provided a reliable means to anatomically localize catheter position in relation to the sinus node.

Animals↗

Fine structure of the sinus hair (pillus labialis maxillaris) and its microvascular architecture in the cat.

The hairs of the upper lip are designated as the sinus hairs morphologically and as the tactile hairs functionally. The characteristics of the sinus hair include the equipment of a follicular blood sinus, composed of cavernous and ring sinuses located between the external and internal radical dermal capsules. The present paper deals with microvascular architectures examined under SEM using plastic microvascular casts. The arterioles diverging from the superior labial artery divided into two groups near the external capsule. The radical arterioles passed through an opening at the bottom of the capsule and formed the capillary network of the hair papilla, in part communicating with the network of the radical dermal capsule. The subcapsular arteriole penetrated the external capsule and passed in the cavernous sinus up to the internal capsule, where the capillary network of the radical dermal capsule was formed. Its meshes appeared polygonal of the papilla site and elongated at the epithelial site. The follicular blood sinus extended between the sebaceous gland and the papilla radix of the sinus hair. In its papillary two-thirds, the cavernous sinus was formed by connective tissue trabeculae and in the epithelial one-third the ring sinus was formed in the shape of a doughnut without trabeculae. Locational differences in the meshes of both networks of the hair papilla and the radial dermal capsule were apparent according to the extent of the nutrient supply to the internal and external root sheathes. The follicular blood sinus acted as a reducing apparatus against the external forces pressing on the sinus hair and the cavernous sinus may serve to enhance the function of the tactile apparatus.

Animals↗

The anatomy of the tympanic sinus.

The tympanic sinus is one of the most important structures of the human temporal bone. Located in its vicinity are the round window, posterior semicircular canal and facial nerve. The study was performed on 30 temporal bones taken from adult cadavers of both sexes. After the tympanic sinus had been identified, its morphological features were evaluated. The sinus was then measured using a graticule with an accuracy of 0.05 mm. Also measured were the shortest distances from the tympanic sinus to the neighbouring structures (the lateral and posterior semicircular canal, the facial nerve canal and the jugular fossa). The measurements were performed under a surgical microscope with eye-piece graduation of 0.05 mm accuracy. Four main morphological types of fossa of the tympanic sinus and two main developmental forms, a deep sinus and a shallow sinus, were distinguished. The existence of a deep sinus was associated with absence of the bridge and the sinus was shallower when the bridge was prominent. The very deep sinuses were located close to the facial canal, in some cases penetrating deep in its vicinity (in some cases even going beyond two thirds of the canal's circumference), which poses a real risk of facial nerve damage during surgical removal of a lesion located in close proximity to the nerve. In most cases the tympanic sinus is elliptical in shape and its long diameter lies in the vertical plane (mean value: 2.73 x 2.23 mm). The mean distances from the tympanic sinus to the facial nerve canal, lateral semicircular canal, posterior semicircular canal and jugular fossa were 1.5 mm, 2.1 mm, 1.59 mm and 5.5 mm respectively. No correlation was observed between the measurement results and either sex or side.

Adult↗