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PubMed1996

[Multiple dural arteriovenous fistulas following extensive sinus thrombosis: a case report].

A 43-year-old man suffered generalized convulsions following severe headache. Initial angiography showed a dural arteriovenous fistula (DAVF) involving the right transverse-sigmoid sinus, and no contrast filling of the superior sagittal sinus, bilateral transverse sinuses, the left sigmoid sinus and the straight sinus. The diagnosis was extensive sinus thrombosis associated with DAVF. Transarterial embolization was performed for the DAVF. The follow-up angiography at 7 days postembolization showed no contrast filling of the DAVF. But the follow-up angiography at 6 months disclosed the appearance of multiple DAVF's involving the superior sagittal sinus, the left transverse sinus and the straight sinus. Each DAVF was supplied by different dural arteries. Coagulation tests revealed deficiency of plasma protein S. The pathogenesis of DAVF is controversial. But our case suggests that multiple isolated lesions indicated the presence of a congenital dural vascular abnormality, which was transformed to multiple DAVF's by sinus thrombosis.

Adult↗
PubMed1997

[Use of long-acting drainage (sino-ject) in treatment of chronic maxillary sinusitis].

The authors present the results of treatment of chronic maxillary sinusitis with punctures and with permanent drainage (sino-ject). The use of permanent drainage shortened the time of treatment and increased percentage of very good results of treatment. Presented method of permanent drainage of maxillary sinus avoid many punctures of sinus. The drainage of sinus allow for each day rinsing of sinus with physiological saline and with drugs (mucolitic, antibiotic) and also for bacteriological examination of sinus secretion. As in classical puncture of maxillary sinus the permanent drainage play a diagnostic and therapeutic roles. The permanent drainage of maxillary sinus allow for inflow of oxygen into sinus and protect from anaerobic infection. The fact that puncture needle is pushed to a depth of only 1 cm greatly reduces the risk of injuring neighbouring structures. This method enables puncture of maxillary sinus with minimum trauma and hardly any pain.

Adult↗
PubMed1995

Eosinophilia in chronic childhood sinusitis.

OBJECTIVES: To quantify eosinophilia in sinus tissues obtained from children with chronic sinusitis and to correlate the degree of eosinophilia with history of asthma, allergy, cystic fibrosis, and preoperative computed tomographic (CT) scans. DESIGN: Examination of surgical specimens from children who underwent functional endoscopic sinus surgery and controls. SETTING: Tertiary care medical center. PATIENTS: Thirty-four children who underwent functional endoscopic sinus surgery for chronic sinusitis refractory to medical treatment were divided into three groups: 13 with asthma, 11 without asthma, and 10 with cystic fibrosis. Normal sphenoid sinus mucosa was also obtained from six adults undergoing transsphenoidal hypophysectomies. MAIN OUTCOME MEASURES: Number of lamina propria and intraepithelial eosinophils in surgical specimens, allergic status, presence or absence of asthma, and CT scans obtained preoperatively. RESULTS: There were significantly more lamina propria and intraepithelial eosinophils in the tissue of children with chronic sinusitis compared with normal sphenoid sinus mucosa. More eosinophils were counted in the tissues of patients with asthma and cystic fibrosis compared with patients without concomitant disease, but this did not reach statistical significance. Allergy status did not affect the degree of tissue eosinophilia. Eosinophilia did not correlate with severity of mucosal disease as assessed by CT scans. CONCLUSIONS: Tissue eosinophilia is a characteristic histologic feature of chronic sinusitis in children, especially those with asthma. The presence of allergy does not predict tissue eosinophilia. Furthermore, the degree of tissue eosinophilia does not correlate with the severity of mucosal thickening seen on CT scans.

Adolescent↗
PubMed1996

Cavernous sinus thrombophlebitis: case report.

OBJECTIVE AND IMPORTANCE: Cavernous sinus thrombophlebitis is a rare, dangerous, and historically difficult condition to diagnose and treat. Knowledge of the imaging findings and the importance of early diagnosis and treatment are emphasized. CLINICAL PRESENTATION: We present a case of cavernous sinus thrombo-phlebitis caused by sphenoid sinusitis. Previously undescribed magnetic resonance imaging findings of cavernous sinus thrombophlebitis include enlargement of the cavernous sinus, abnormal enhancement and increased T2 signal of the petrous apex and clivus, and marked narrowing of the cavernous portion of the internal carotid artery. Resolution of cavernous sinus thrombophlebitis is also documented by magnetic resonance imaging. INTERVENTION: The anatomy of the cavernous sinus dictates the natural history and diagnosis of cavernous sinus thrombophlebitis. We review the literature regarding the clinical diagnosis, differential diagnosis, and treatment of cavernous sinus thrombophlebitis. CONCLUSION: We emphasize the importance of a high index of suspicion, the potentially rapid and fatal course of the disease process, and the subsequent need for antibiotic therapy and selective surgery.

Cavernous Sinus↗
PubMed1999

[The role of computed tomography after functional surgery on the paranasal sinuses. Normal findings and an assessment of the surgical failures].

INTRODUCTION: Functional endoscopic sinus surgery has become the technique of choice to treat benign or inflammatory diseases of paranasal sinuses resistant to medical therapy. The goal of this type of surgery is to open the obstructed sinus ostia and restore normal aeration and mucociliary clearance. Messerklinger's is the most widely used technique. PURPOSE: We investigated the role of CT after functional endoscopic sinus surgery and describe CT findings of postoperative anatomical changes together with frequent complications and surgical failures. METHODS AND MATERIALS: Twenty-seven patients with relapsing symptoms were examined with CT of paranasal sinuses 8-32 weeks after functional endoscopic sinus surgery. In all cases both preoperative CT and surgical reports were available: CT and surgical results were compared. RESULTS: In 21/27 patients nasosinusal changes were demonstrated with CT. Recurrent disease secondary to inflammation and/or fibrosis was observed in 14 cases. Residual disease was seen in 5 patients. A major orbital complication was found in 1 patient with diplopia. One patient exhibited a large interruption of cribriform plate with CSF fistula. CONCLUSION: CT permitted an accurate assessment of extension and results of functional endoscopic sinus surgery. CT is indicated in the postoperative study of the patients who a) present symptoms of cerebral and ocular complications (early after functional endoscopic sinus surgery); and b) do not respond to medical treatments 8-32 weeks after unsuccessful functional endoscopic sinus surgery. In these patients CT can demonstrate recurrent and/or residual nasosinusal disease and bony defects unintentionally caused by the surgeon during the procedure.

Endoscopy↗
PubMed1999

[Sinus mucoceles and surgery in iatrogenic diseases].

The increasing number of mucocele cases treated by the authors during the past ten years coincide with the expansion of functional endoscopic sinus surgery (FESS). The aim of this study is to evaluate the iatrogenic characteristics of this surgery by analysing the locations, time of development and the potential pathogenic factors of sinus mucoceles. Forty-two sinus mucoceles were operated in our department. These mucoceles were most frequently found in the anterior ethmoido-frontal system. Eleven patients had a history of endonasal ethmoidectomy mainly due to nasal polyposis. The time of mucocele formation after initial FESS (< 22 months) seems to be shorter than after exonasal sinus surgery or trauma (< 10 years). Endoscopic and CT-scan revealed different types of sinus obstruction findings: nasofrontal duct occlusion due to a fibrosis and osteogenic scar tissue process, or anterior ethmoid synechia in the case of ethmoido-frontal sinus mucocele, uncinate process fragment or scar tissue duct occlusion as far as maxillary sinus mucocele were concerned. We conclude that there seems to be a correlation between the expansion of FESS and the increasing number of mucocele cases. However, in this context it has to taken into consideration, that our department treats a considerable number of sinus pathology. Anterior ethmoid seems to be a favourable area for sinus mucocele formation. In order to prevent mucocele, it is essential to carry out FESS with great precaution. If endonasal surgery is performed, particularly in the anterior ethmoid, a close endoscopic follow-up, completed by radiological examinations, where necessary, must be ensured.

Adolescent↗
PubMed2000

Is there a correlation between radiographic and histologic findings in chronic sinusitis?

OBJECTIVE: To determine if the degree of radiologic changes noted on computed tomography (CT) scan correlate with the severity of histologic changes. DESIGN: Retrospective analysis. SETTING: Academic tertiary care centre. METHODS: Sixty consecutive patients undergoing endoscopic sinus surgery for chronic sinusitis, with complete data obtained for 131 sinuses. MAIN OUTCOME MEASURES: Paranasal sinus CT scans and pathologic reports were examined. Respective findings were graded as mild, moderate, or severe, and the results were analyzed for agreement. CT scan grading was based on the extent of sinus opacification and pathologic grading was determined by the number of inflammatory cells found in the sinus mucosa. RESULTS: Of the 51 ethmoid sinuses, agreement between the radiographic and histologic grading occurred in 32 or 62.7%. In the maxillary group, a 57.1% (24 of 42) correlation was noted. Of the 20 frontal sinuses, agreement occurred in 8 or 40%, whereas a 22.2% (4 of 18) correlation was present in the sphenoid group. CONCLUSION: This study suggests that the severity of sinus disease based on preoperative CT scan does not correlate with the histologic degree of disease.

Chronic Disease↗
PubMed2004

The relationship between the sphenoid and the posterior ethmoid sinuses and the optic nerves in Turkish patients.

The sphenoid and the posterior ethmoid sinuses are surrounded by more vital structures than any other sinus. With the widespread acceptance and expanding role of endoscopic sinus surgery, a proper understanding of the anatomy of the sphenoid and the posterior ethmoid sinuses is achieved. We reviewed 100 CT studies of the paranasal sinuses belonging to patients examined for a chronic inflammatory disease of the nasal cavity and the paranasal sinuses. The relationship between the optic nerves and the paranasal sinuses is classified into four discrete categories. Type 1 with a proportion of 64% is observed to be the most often localized optic nerve. Type 2 is detected in 22% of the cases; types 3 and 4 are both 7% of the total number. A bony dehiscence was detected in 13.5% of the total cases, while it was observed in 39% of type 2 and 43% of type 3. We found a pneumatization of the anterior clinoid process in 11% of the patients. The proportion of pneumatization of the anterior clinoid process in type 3 configurations is found out to be as high as 86%. Optic nerve dehiscence was seen with a proportion of 23% in cases of pneumatization of the anterior clinoid process. Pneumatization of the posterior nasal septum was detected in 15% of the 100 cases. When the optic nerves were evaluated in these cases, mostly the type 1 configuration with a proportion of 63% was observed. An extensively pneumatized sphenoid sinus was detected in 4% of the 100 cases. Five of the investigated 8 optic nerves of these 4 cases were found out to be type 3 (62.5%). No significant optic nerve variations were met in patients with pneumatization of the posterior nasal septum. Nevertheless while performing surgery, it is important to bear in mind that there may be significant optic nerve variations with pneumatization of the anterior clinoid process and extensively pneumatized sphenoid sinuses.

Adolescent↗
PubMed2004

The incidence of anatomic variations and sinus opacities in pediatric patients with chronic sinonasal symptoms.

OBJECTIVES: In this study, our purpose was to determine the incidence of paranasal sinus anatomic variations and their relationship with sinus opacities in pediatric patients. PATIENTS AND METHODS: A total of 44 children (age range 3 to 16 years) unresponsive to maximum medical therapy were evaluated with coronal paranasal sinus computed tomography. RESULTS: Computed tomographic evaluations revealed that 70.5% (31/44) of the patients had at least one anatomic variation, the most common being septal deviation, followed by concha bullosa and agger nasi cells. Sinus opacities were found in 81.8% (36/44) of the patients, of whom 9 had single and 27 had multiple involvement of sinus groups. The most commonly involved sinuses were anterior ethmoids and maxillary sinuses, followed by posterior ethmoids, sphenoid and frontal sinuses. Patients with single, multiple, and no anatomic variations had 78.9% (15/19), 83.3% (10/12), and 84.6% (11/13) opacities, respectively. CONCLUSION: The incidence of anatomic variations was found to be similar to that reported for adults in the literature except for nasal septal deformity which was found lower. Our results showed no correlation between bony anatomic variations and sinus opacities in children.

Adolescent↗
PubMed2006

Antibiotic sensitivities of Streptococcus pneumoniae, viridans streptococci, and group A hemolytic streptococci isolated from the maxillary and ethmoid sinuses.

OBJECTIVES: To investigate antibiotic sensitivities of Streptococcus pneumoniae, viridans streptococci, and group A hemolytic streptococci isolated from the culture materials obtained from the sinuses of patients undergoing functional endoscopic sinus surgery due to chronic sinusitis. PATIENTS AND METHODS: We recruited 93 patients (63 males, 30 females; mean age 36+/-17.5; range 19 to 68 years) who underwent functional endoscopic sinus surgery due to chronic sinusitis. Before surgical intervention, in order to eliminate a possible contamination from the skin and neighboring structures, nasal mucosa was cleansed with povidone-iodine solution. Nasal smear samples were obtained from all the patients before and after applying povidone-iodine solution. Streptococcus pneumoniae, viridans streptococci and group A hemolytic streptococci that were isolated from the cultures were tested for antibiotic sensitivity. RESULTS: The number of anaerobic bacteria isolated from 58 patients (62.3%) before applying povidone-iodine was 72, following the application of povidone-iodine a total of 16 microorganisms were identified from 12 patients (12.9%). Microorganisms were isolated from 95.6% (89/93) of the samples obtained from the maxillary sinuses and 91.3% (85/93) of the samples obtained from the ethmoid sinuses. The most commonly identified microorganisms from both sinuses were coagulase negative staphylococcus followed by viridans streptococci, coagulase positive staphylococcus, Streptococcus pneumoniae and group A hemolytic streptococci. For viridans streptococcal strains that were isolated, 33.3% were resistant to tetracycline, 23.8% to chloramphenicol, and 19.04% to penicillin. Hemolytic streptococci strains were sensitive to penicillin, ofloxacin, ceftriaxone, and cefepime in all the groups; however, they had 50% resistance to erythromycin and chloramphenicol and 100% resistance to tetracycline. The resistance pattern of the isolated Streptococcus pneumoniae strains were as follows: 25% to penicillin, 66.6% to trimethoprim/sulfamethoxazole, 41.6% to erythromycin, 58.3% to tetracycline, 33.3% to chloramphenicol and 16.6% to rifampin. All of the isolated strains were sensitive to vancomycin. CONCLUSION: We suggest that identification of strains that are resistant to penicillin and other antibiotics is an important tool for choosing empirical treatment for Streptococcus pneumoniae, viridans streptococci, and group A hemolytic streptococci in clinical practice. Viridans streptococci which are frequently isolated from chronic sinusitis patients should be kept in mind.

Adult↗
PubMed1990

Sphenoidal and cavernous sinus resection for tumor.

Malignant neoplasms as well as those with an aggressive locally invasive character involving the sphenoid sinus have been considered heretofore to be inoperable and incurable. Because of fear of entering the cavernous sinus, the proximity of the internal carotid artery laterally and the optic chiasm superiorly as well as the middle fossa contents, these patients were relegated to palliative regimens of irradiation and chemotherapy. As methods have been developed of managing hemorrhage from the cavernous sinus, exposure and control or bypass of the internal carotid artery and combined subcranial and intracranial resection, the frontiers of surgery in the sphenoid sinus have been advanced. We have resected eight patients with tumors involving the sphenoid sinus in whom the walls of the sinus were exenterated, portions of the cavernous sinus removed, the internal carotid artery skeletonized, anterior and middle fossa dura resected, and in a few the temporal lobe was excised. Follow-up ranges from six years to 10 months. There have been no perioperative deaths; one patient succumbed to general inanition with locally recurrent tumor at four months; the rest are all alive and well without evidence of tumor, with the exception of one patient. This patient has a local recurrence anteriorly from an inadequate margin due to a technical error, but there is no recurrence in the sphenoid sinus, the cavernous sinus or the middle cranial fossa.

Cavernous Sinus↗
PubMed1998

[Traumatic intracerebral pneumocephalus communicating with two different paranasal sinuses: a case report].

We report a case of a 17-year-old male who had hit the front of his head in a traffic accident. CT scan revealed contusional hemorrhage and pneumocephalus of the left frontal lobe 10 hours after the accident. A month later he complained of rhinorrhea and CT scan revealed intracerebral pneumocephalus. One day he complained of headache and began to vomit after he sneezed. CT scan revealed that the pneumocephalus had become worse and air had spread throughout the subarachnoid space. Bone CT scan revealed the air communicated from the frontal sinus to the intracerebral air cavity. 3D-CT scan revealed bone defect in the roof of the ethmoid sinus. The intraoperative findings revealed that the intracerebral air cavity communicated with the frontal sinus and ethmoid sinus. Though the brain which dropped into the paranasal sinus, adhered to the dura mater around the bone defect, a part of the brain had come off from the dura mater around the frontal sinus. We suspected that the intracerebral air cavity communicated with the frontal sinus initially. When the air cavity communicated with the ethmoid sinus secondarily, intracranial pressure abated and air came into the subarachnoid space from the frontal sinus.

Accidents, Traffic↗
PubMed1977

Structure of sinuses in the human lymph node.

A casting technique has been employed to display in three dimensions, the lymphatic microcirculation within the human lymph node. The casting compound filled the marginal sinus, and diffusely permeated the cortical lymphoid parenchyma. However, deep within the lymph node in the medullary region, the medium remained within the limits of the sinus walls. The casts showed well-defined channels appearing similar to vessels. These converged into larger vessels, which drained into efferent lymphatics leaving the node at the hilus. Electron microscopic examination showed that the outer wall of the marginal sinus and the trabecular side of trabecular sinuses had an intact, continuous endothelium with a basement membrane. However, gaps were present in the inner wall of the marginal sinus, as well as in the parenchymal wall of the trabecular sinus. In the medulla, the sinuses were lined by endothelial cells which appeared similar to macrophages. The sinus lining was incomplete and possessed numerous perforations. These observations indicated that sinus walls adjacent to connective tissue served as a barrier to cell movement, but those adjacent to a large lymphoid cell population had gaps, with cells in apparent transit between sinus lumen and parenchyma.

Basement Membrane↗
PubMed1975

Sinus nodal function in the intact dog heart evaluated by premature atrial stimulation and atrial pacing.

Sinus nodal function was analyzed in 25 dogs by premature stimulation of the right atrium. The return (AT-AR) and post-return (AR-A) cycles were plotted as a function of the premature cycle, and four zones were identified. Zone I (compensatory zone) was observed during the last 4.8 percent (mean value) of the sinus cycle (A-A). Zone II was observed during 43.6 to 95.2 percent (mean value) of the sinus cycle. During the latter part of zone II, AT-AR was nearly constant and AR-A remained nearly equal to A-A during the last 29 percent (mean value) of the cycle. Earlier in zone II three distinct patterns of return cycle responses were observed whereas post-return cycles either remained nearly equal to A-A or showed progressive lengthening. Zone III (interpolation) was observed in 10 animals during 39.5 to 46.2 percent (mean value) of the sinus cycle. AR-A was nearly equal to A-A in zone III. Interpolation was incomplete late and complete early in the zone. Zone IV (echo zone) was seen in another 10 animals during 40.9 to 45.3 percent (mean value) of the sinus cycle and in this zone AR-A was greater than A-A. No significant difference in these zones was seen among the animals anesthetized with pentobarbital or alpha-chloralose, or given 6-OH-dopamine. The AR-A was important in the analysis of these zones and appears to be essential to the interpretation of data derived from premature atrial stimulation. Responses to premature atrial stimulation through a catheter electrode positioned against the sinus nodal region compared favorably with responses to direct epicardial stimulation. After periods of continuous right atrial pacing a vairety of patterns of sinus nodal depression were observed at different rates and durations of stimulation. The frequent occurrence of a short sinus escape cycle followed by the maximal pause observed during rapid pacing rates suggests sinus nodal entrance block. This may be an important factor to consider in determining an optimal pacing rate for assessing sinus nodal function.

Anesthesia, Intravenous↗
PubMed1989

Effects of verapamil, diltiazem and disopyramide on sinus function: a comparison with bepridil.

Cardiac drugs known to affect sinus function mostly exhibit negative chronotropic activity. However, impulse conduction within the sinus node can also be influenced. Recently we studied the direct effects of bepridil on rabbit sinus function. It appeared that sinoatrial impulse conduction was depressed markedly with drug concentrations that did not affect sinus automaticity. In the present study the direct effects of verapamil, diltiazem and disopyramide on rabbit sinus function and atrial conduction properties were studied. Verapamil (8.8 x 10(-8) M) reduced the sinoatrial impulse conduction velocity by 35% and prolonged sinoatrial refractoriness by 36%. On the other hand, the sinus rate and atrial conduction parameters were hardly affected. Diltiazem (5 x 10(-6) M) exerted similar actions on the sinoatrial impulse conduction velocity and caused a simultaneous reduction in the sinus rate of 48%. Atrial conduction remained unaffected. Disopyramide (5 x 10(-5) M) depressed both the atrial and nodal conduction properties markedly, whereas the sinus rate was reduced moderately, by almost 20%. Thus, verapamil, diltiazem and disopyramide act differently on sinus function and atrial conduction, whereby the predominant effect of verapamil and diltiazem on sinoatrial conduction properties favours the occurrence of a sinus exit block.

Animals↗
PubMed2003

The clinical anatomy of the sinus node artery.

BACKGROUND: Our basic aim was to describe the topographic relation between the sinus node artery and the superior posterior border of the interatrial septum with regard to the sinus node dysfunction that follows the superior transseptal approach to the mitral valve. METHODS: During our study 50 human hearts without previous pathologic alterations were analyzed. The position of the sinus node and the course of the sinus node artery were investigated. For identification of the origin of the artery, selective coronary angiograms were performed. The course of sinus node artery and its topographic relation to the interatrial septum was identified by the dry dissections of the hearts. Based on histologic and dry dissected specimens the exact position of the sinus node was determined. RESULTS: We found that the sinus node artery originates from the right coronary artery in 66% of examined cases and from the left coronary artery in 34% of cases. The sinus node artery crosses the superior posterior border of the interatrial septum in 54% of cases. CONCLUSIONS: Our results were compared with clinical studies focusing the incidence of the sinus rhythm disturbance after the superior transseptal approach. The incidence of rhythm disturbance varies from 52% to 60% of cases. Comparing our morphologic and clinical results we can state that the risk for intraoperative damage to the sinus node artery during the superior transseptal approach to the mitral valve is high.

Adult↗
PubMed1985

Correlations of sinus, conical elevation, median depression of the lower lip and types of oral clefts.

The incidence of autosomal dominantly inherited Van der Woude's syndrome among Finnish patients with cleft lip and palate CL(P) and with isolated cleft palate (CP) is approximately 2.5%. The incidence of conical elevation of the lower lip (CE) is 39% in CP and 0.8% in CL(P) patients. A pathogenetic similarity of sinuses and CE's was noted. The following classification was used to study associations between sinuses and CE's: (1) sinus; bilateral, unilateral, atypical; (2) CE: bilateral, unilateral; (3) median depression of the lower lip (MD); (4) combined sinus and CE; (5) combined CE and MD. According to the classification developed, a group of 77 sinus patients and 156 CE and/or MD patients was classified in subgroups of CL(P), CP, Pierre Robin anomalad (PR) and non-cleft subjects. The findings were: the sinus was bilateral on 52%, unilateral in 34% and atypical in 14%; the CE without associated sinus was bilateral in all cases; the sinus was associated with CE in 77% of all sinus subjects. The highly increased incidence of the CE in the CP (92%) and in the CL(P) (61%) sinus groups compared to the incidences of CE in these groups in general (39% and 0.8%) shows a close relationship between these 2 disorders of the lower lip, but the similarity of the genetic etiology still remains unclear.

Child↗
PubMed1986

Differential modulation of autonomic activity by ethmozin and ethacizin (analog of ethmozin) on the canine sinus node and atrioventricular junction.

The chronotropic and dromotropic actions of ethmozin and its diethylamine analog ethacizin were studied in the presence and absence of combined muscarinic, beta- and alpha-adrenoreceptor blockade in the intact canine heart in situ (n = 38). Injections of ethacizin, 5, 10 and 25 micrograms/ml, into the sinus node artery caused an immediate and significant (p less than 0.001) sinus bradycardia of 2, 6 and 11%, respectively. Injection of 25 and 50 micrograms/ml of ethacizin into the atrioventricular (AV) node artery significantly (p less than 0.001) prolonged AV conduction time with occasional second degree heart block. Conduction delay was located exclusively during the AH interval of the His bundle electrogram. Autonomic blockade did not alter the negative chronotropic or negative dromotropic effects of ethacizin. Ethacizin, 25 micrograms/ml, injected into the sinus node artery immediately reduced the sinus node response to vagal stimulations by 30% and the effect of acetylcholine, 0.1 micrograms/ml, injected into the sinus node artery by 50%. Ethacizin, 25 micrograms/ml, injected into the AV node artery immediately reduced the duration of complete AV block elicited by vagal stimulation or intranodal acetylcholine, 0.5 micrograms/ml, by 90%. Ethacizin caused a minor reduction in sinus node response to right stellate stimulations without, however, altering the sinus node response to intranodal norepinephrine. Ethmozin injections of up to 50 micrograms/ml into the sinus and AV node arteries had no chronotropic or dromotropic effects. Ethmozin had a minor and variable vagolytic action but significantly (p less than 0.05) reduced the sinus node response to sympathetic nerve stimulation. Hence, ethacizin, in contrast to ethmozin, has a direct depressing action on both the sinus node and the AV junction.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗