Slit-like Ostium Research Articles

Coronary Artery from the Wrong Sinus of Valsalva: A Physiologic Repair Strategy

The most commonly reported coronary artery malformation leading to sudden death in children and young athletes is an anomalous coronary origin from the wrong aortic sinus, with or without a proximal course of the coronary artery between the aorta and the pulmonary artery. Although the incidence is difficult to assess, there is a 0.17% incidence in autopsy series (all variants included) and a 0.1 to 0.3% in catheter-echo diagnostic series. There may be a regional variation. In a prospective study of 1950 consecutive patients undergoing coronary angiography, anomalous origin of the right coronary artery from the left aortic sinus was found in 0.92% of cases, whereas the incidence of left coronary artery arising from the right aortic sinus was 0.15%. 1 In a study of 2388 patients who had transthoracic echocardiographic examination of their proximal coronary anatomy as part of innocent murmur investigation and evaluation of performance status, four patients (0.2%) were found to have an anomalous origin of the coronary artery from the wrong sinus. 2 Whatever the true prevalence, this lesion predisposes to fatal episodes of myocardial ischemia that may occur during or shortly after strenuous exercise. 3-5 Timely diagnosis requires a high index of suspicion but is frequently impossible, as the majority of patients with the anomaly are asymptomatic and thus do not seek medical attention. Therefore, sudden death is frequently the first manifestation, especially in young athletes, with only 30% of patients reporting prodromal symptoms. 5,6 Screening young adults before participation in competitive sports has been unsuccessful. Stress testing is unreliable because of high false-positive and falsenegative results; echocardiogram, echocardiography, and stress testing all lack predictive value. 4,5 Finally, although the major association of sudden death is with young athletes, cases have also been reported in children under 1 year of age.

The coronary arteries of the C57BL/6 mouse strains: implications for comparison with mutant models

There are few detailed descriptions of the coronary arterial patterns in the mouse. Some recent reports on coronary anomalies in mutant mouse models have uncovered the importance of several genes (i.e. iv and connexin43) in coronary morphogenesis. These mutations spontaneously appeared (iv) or were generated (connexin43) in a C57BL/6 background, which is widely used for the development of mutant mice. We have studied the origin and course of the main coronary arteries of two C57BL/6 mouse strains. Unusual anatomical coronary arterial patterns were found, including: solitary ostium in aorta, accessory ostium, high take-off, aortic intramural course, slit-like ostium, sinus-like ostium and origin of a septal artery from the left coronary artery. In humans, some of these conditions are clinically relevant. Most of these patterns, which differ from those observed in wild mice and Swiss albino mice, coincide with those previously found in iv/iv and connexin43 knockout mice. The results indicate that there is variability in the coronary arterial arrangement of the laboratory mouse. Care should be taken when analysing coronary phenotypes of mutant mouse models.

Evaluation of rerouting surgery of a coronary artery anomaly by magnetic resonance angiography

A 25-year-old woman presented with episodes of palpitations, near-collapse, and chest pain. Physical examination revealed no abnormalities. Resting electrocardiogram showed sinus rhythm, normal heart axis without conduction abnormalities, and inverted T waves in leads V1 through V3. Laboratory tests and chest roentgenogram were normal. During exercise testing a nonsustained ventricular tachycardia (230 beats per minute) occurred. Coronary angiography showed an anomalous origin of the right coronary artery (RCA) from the left aortic sinus with a separate ostium. Atherosclerotic changes were not present. The coronary angiogram was inconclusive about the exact course of the RCA and therefore free-breathing, threedimensional coronary magnetic resonance angiography was performed using a 1.5 T MR scanner (Gyroscan ACSNT; Philips Medical Systems, Eindhoven, the Netherlands) [1]. Preoperative coronary magnetic resonance angiography revealed an interarterial course of the RCA between the aorta and pulmonary trunk (Fig 1; Ao aorta, PT pulmonary trunk). This malignant course is associated with an increased risk for myocardial infarction and sudden death, therefore surgical rerouting was planned. At inspection during surgery the ostium of the RCA was located above the commissure between the left and right coronary cusps and proximally coursing within the aortic wall. A small scar was observed in the inferior wall. The slit-like ostium was removed from the aorta and unroofing was performed. Then the ostium was reimplanted in the right coronary sinus. A xenopericard patch was used to close the aortic defect. Aortic regurgitation was excluded by intraoperative transesophageal echocardiography. Postoperative electrophysiological testing could not induce ventricular arrhythmias. After surgery coronary magnetic resonance angiography was repeated and evaluated the success of the rerouting procedure and postoperative course of the RCA (Fig 2; Ao aorta; LV left ventricle; PT pulmonary trunk; RV right ventricle). In our patient, the ventricular tachycardias most likely were caused by paroxysmal ischemia or infarction due to an anomalous RCA. Coronary magnetic resonance angiography can be used to identify the exact course of anomalous coronary arteries and in this case was also applied successfully to evaluate the course of the RCA after surgical rerouting.

THE RESPIRATORY SYSTEM OF THE EYED-TAMPAN TICK ORNITHODOROS SAVIGNYI AUDOUIN, 1827 (IXODOIDEA, ARGASIDAE)

In adult eyed-tampan tick there is only one pair of crescentic opening, one on either side of the body, dorsal to the fourth subcoxa (coxa of other authors) and above the supracoxal fold. Each spiracle consists of a pad-like macula, a crescentic spiracular plate and a slit-like ostium in between them. The spiracular plate and the macula are sclerotized structure and therefore differ from the idiosomal integument in its histological make up. The epicuticle of spiracular plate is supported internally by the pedicels which are solid structures and not hollow. The ostium continues into the atrium whence five main tracheal trunks run to various body regions. The two trunks, anterodorsal and the posterodorsal supply the dorsal body surface where as the remaining three-the anteroventral, ventral posteromedian and the posteroventral trunks supply the ventral body surface. The branches of anteroventral trunk go to the anterior body regions but most of the larger branches from both the sides unite below the central ganglionic mass and from the ventral tracheal sinus. This sinus is a peculiar feature in the eyed-tampan tick which has not been mentioned in any other tick. Probably, this sinus stores air which can be used by the tick when it conceals beneath the soil layers. A single muscle closes the ostium while it is opened by the elasticity of its own wall.