Subcutaneous air entrapment after subcutaneous implantable cardioverter defibrillator implantation evaluated by computed tomography.

BACKGROUND: Inappropriate shock (IAS) caused by subcutaneous air entrapment (AE) in an early period after subcutaneous implantable cardioverter defibrillator (S-ICD) implantation has been reported, however, no detailed data on air volume are available. We evaluated the subcutaneous air volume after implantation and its absorption rate one week after implantation. METHODS: Patients who underwent S-ICD implantation in our hospital received chest CT scans immediately after implantation and followed up 1 week later. The total subcutaneous air volume, air around the generator, the distal electrode, and the proximal electrode within 3 cm were calculated using a three-dimensional workstation. Fat areas at the level of the lower edge of the generator were also analyzed. RESULT: Fifteen patients received CT immediately after implantation. The mean age was 45.6 ± 17.9 (66.7% of men), and the mean body mass index was 24.3 ± 3.3. The three-incision technique was applied in seven patients and two-incision technique was in the latter eight patients. The mean total subcutaneous air volume was 18.54 ± 7.50 mL. Air volume around the generator, the distal electrode, and the proximal electrode were 11.05 ± 5.12, 0.72 ± 0.72, and 0.88 ± 0.87 mL, respectively. Twelve patients received a follow-up CT 1 week later. The mean total subcutaneous air was 0.25 ± 0.45 mL, showing a 98.7% absorption rate. CONCLUSION: Although subcutaneous air was observed in all patients after S-ICD implantation, most of the air was absorbed within 1 week, suggesting a low occurrence of AE-related IAS after a week postoperation.

Intra-atrial re-entrant tachycardia after percutaneous atrial septal defect closure: a case report.

We report a case of a 6-year-old boy who developed intra-atrial re-entrant tachycardia after percutaneous atrial septal defect closure. Ablation was performed, and the circuit of tachycardia was identified. This was a rare complication caused by right atrial enlargement due to an atrial septal defect closure device.

Dysbiosis of Gut Microbiome Is Associated With Rupture of Cerebral Aneurysms.

BACKGROUND AND PURPOSE: Environmental factors are important with respect to the rupture of cerebral aneurysms. However, the relationship between the gut microbiome, an environmental factor, and aneurysm rupture is unclear. Therefore, we compared the gut microbiome in patients with unruptured intracranial aneurysms (UIAs) and ruptured aneurysms (RAs) to identify the specific bacteria causing the rupture of cerebral aneurysms. METHODS: A multicenter, prospective case-control study was conducted over one year from 2019 to 2020. The fecal samples of patients with stable UIAs and RAs immediately after onset were collected. Their gut microbiomes were analyzed using 16S rRNA sequencing. Subsequently, a phylogenetic tree was constructed, and polymerase chain reaction was performed to identify the specific species. RESULTS: A total of 28 RAs and 33 UIAs were included in this study. There was no difference in patient characteristics between RAs and UIAs: age, sex, hypertension, dyslipidemia, diabetes status, body mass index, and smoking. No difference was observed in alpha diversity; however, beta diversity was significantly different in the unweighted UniFrac distances. At the phylum level, the relative abundance of Campylobacter in the RA group was larger than that in the UIA group. Furthermore, the gut microbiome in the RA and UIA groups exhibited significantly different taxonomies. However, Campylobacter was focused on because it is widely known as pathogenic among these bacteria. Then, a phylogenetic tree of operational taxonomic units related to Campylobacter was constructed and 4 species were identified. Polymerase chain reaction for these species identified that the abundance of the genus Campylobacter and Campylobacter ureolyticus was significantly higher in the RA group. CONCLUSIONS: The gut microbiome profile of patients with stable UIAs and RAs were significantly different. The genus Campylobacter and Campylobacter ureolyticus may be associated with the rupture of cerebral aneurysms.

Characteristics and Prognosis of Patients with Vasospastic Angina Diagnosed by a Provocation Test with Secondary Prevention Implantable Cardioverter Defibrillator.

This study aimed to evaluate the characteristics and prognosis of patients with vasospastic angina (VSA) diagnosed by a provocation test with a secondary prevention implantable cardioverter defibrillator (ICD), compared with patients with organic coronary stenosis. We retrospectively evaluated 309 consecutive patients who received an ICD implantation between January 2010 and March 2018 in our institutions. Of these patients, 206 were implanted with an ICD for secondary prevention. In these 206 patients, 40 with VSA and 72 with organic coronary stenosis were evaluated. Patients with VSA were characterized by younger age (56.1 ± 13.1 versus 69.2 ± 9.5 years, respectively), and a lower prevalence of diabetes (15.0% versus 40.3%, respectively) and heart failure (2.5% versus 26.4%, respectively) than patients with organic coronary stenosis (P < 0.001). Using the Kaplan-Meier analysis, with the VSA group as the reference, the incidence of appropriate ICD shock was similar between the two groups (hazard ratio, 0.85; 95% confidence interval, 0.341-2.109; P = 0.722). The incidence of ventricular fibrillation was significantly higher in the VSA group (hazard ratio, 0.22; 95% confidence interval, 0.057-0.814; P = 0.024), whereas the incidence of major adverse cardiac events, including cardiac death, nonfatal myocardial infarction, hospitalization for unstable angina pectoris, and heart failure, was significantly higher in the organic coronary stenosis group (hazard ratio, 13.1; 95% confidence interval, 1.756-98.17; P = 0.012). In conclusion, patients with VSA with an ICD implanted for secondary prevention have a higher risk of ventricular fibrillation and lower risk of major adverse cardiac events than patients with organic coronary stenosis.

Significance of Ventricular Arrhythmia Based on Stored Electrogram Analysis in a Pacemaker Population.

The incidence of ventricular arrhythmia in patients with an implanted pacemaker is not yet known. The aim of this study was to analyze non-sustained ventricular tachycardia (NSVT) episodes based on stored electrograms (EGM) and determine the occurrence rate and risk factors for NSVT in a pacemaker population.This study included 302 consecutive patients with a dual-chamber pacemaker. A total of 1024 EGMs stored in pacemakers as ventricular high-rate episodes were analyzed. The definition of NSVT was ≥ 5 consecutive ventricular beats at ≥ 150 bpm lasting < 30 seconds.In baseline, most patients (94.8%) had ≥ 60% left ventricular ejection fraction. Of 1024 EGMs, 420 (41.0%) showed appropriate NSVT episodes, as well as premature atrial contractions, atrial tachyarrhythmia, or atrial fibrillation with a rapid ventricular response, whereas other EGMs did not show an actual ventricular arrhythmia. On EGM analysis, during a mean follow-up period of 46.1 months, NSVT occurred one or more times in 82 patients (33.1%). On multivariate analysis, ≥ 50% right ventricular pacing was an independent risk factor for NSVT (odds ratios, 4.519; P < 0.001), but NSVT was not associated with increased all-cause mortality.Moreover, in the pacemaker population, ≥ 50% right ventricular pacing is an independent risk factor for NSVT; however, NSVT was not associated with increased all-cause mortality because of the preserved left ventricular function.

An Inappropriate Shock Case Early after Implantation of a Subcutaneous Cardiac Defibrillator by Subcutaneous Entrapped Air.

A 17-year-old woman was resuscitated from cardiac arrest due to ventricular fibrillation and was diagnosed with concealed long QT syndrome. She underwent subcutaneous implantable cardiac defibrillator (S-ICD) implantation at our hospital. The device electrogram immediately after implantation was normal. Four days after implantation, she received an inappropriate shock. The device interrogation revealed a continuous baseline shift and frequent oversensing for low amplitude signals, followed by a shock. A chest radiograph in the orthogonal view showed entrapped subcutaneous air surrounding the distal electrode. Entrapped subcutaneous air can cause inappropriate shocks in the early period after S-ICD implantation.

Characteristics and Prognosis of Pacemaker-Identified New-Onset Atrial Fibrillation in Japanese People.

BACKGROUND: The characteristics and prognosis of implanted pacemaker-identified new-onset atrial fibrillation (AF) in Japanese people has not been well evaluated.Methods and Results:A total of 395 consecutive patients with newly implanted pacemakers were retrospectively analyzed between January 2010 and December 2015 at Yokohama City University Hospital. Patients with a prior history of AF, VVI mode pacemaker, congenital heart disease, severe valvular heart disease, and cardiovascular surgery before pacemaker implantation were excluded. Among the remaining patients, 44 (21.3%) developed new AF during follow-up (mean follow-up, 1,115±651 days; range, 9-2,176 days). Patients with new-onset AF had a significantly higher CHADS2score (2.09±1.27 vs. 1.31±1.08, P<0.001) and CHA2DS2-VASc score (3.00±1.39 vs. 2.26±1.19, P<0.001) compared with those without new-onset AF. On Cox regression analysis only age at implantation was significantly correlated with new-onset AF. Interestingly, the incidence of hospitalization due to heart failure was significantly higher in the new-onset AF than in the without new-onset AF group. CONCLUSIONS: A total of 21.3% of pacemaker-implanted patients with high CHADS2and CHA2DS2-VASc scores developed new-onset AF during a mean follow-up of 3.1 years; and pacemaker-identified AF was associated with an increased risk of worsening heart failure.

Performance of Leadless Pacemaker in Japanese Patients vs. Rest of the World　- Results From a Global Clinical Trial.

BACKGROUND: A global study designed to demonstrate the safety and efficacy of a transcatheter pacing system included 38 Japanese patients enrolled at 4 sites. Subgroup analysis to evaluate the performance of the leadless intracardiac transcatheter pacing system in Japanese patients was performed.Methods and Results:Safety and efficacy outcomes, patient and implant procedure characteristics, and patient and physician acceptability from the Japanese population were compared with those from outside Japan. Differences in patient characteristics, implant procedure characteristics and patient acceptability were observed. There were no major complications in Japanese patients and pacing thresholds remained low and stable throughout follow-up. There were no observable differences between Japanese patients and patients from outside Japan in the freedom from major complication rate at 12-months post-implant (100.0% vs. 95.7%, P=0.211) or physician acceptability. CONCLUSIONS: Although some differences in specific baseline characteristics, such as body size and pacing indication, and in implant procedure characteristics, including anticoagulation strategy and hospitalization period, were observed in the Japanese patients, transcatheter pacemaker performance was similar to that in the global trial. (Clinical Trial Registration: ClinicalTrials.gov ID NCT02004873.).

Development of Atrioventricular Block and Diagnostic Value of Stored Electrograms in Patients With Sick Sinus Syndrome and Implanted Pacemaker.

BACKGROUND: The incidence of atrioventricular block (AVB) in pacemaker patients with sick sinus syndrome (SSS) is not yet known. The aim of this study was to analyze AVB episodes in SafeR mode based on stored electrograms (EGM), and determine the occurrence rate and risk factors for advanced AVB in a pacemaker population with SSS. METHODS AND RESULTS: The study included 50 consecutive patients with SSS without a history of advanced AVB who had a dual-chamber pacemaker programmed in SafeR mode. A total of 377 EGM stored in the pacemakers as AVB episodes fulfilling the second- or third-degree criterion were analyzed. Of 377 EGM, 73 EGM (19.4%) were appropriate episodes, whereas the other EGM did not show actual AVB, and showed atrial tachyarrhythmia, ventricular event in the blanking period, or premature atrial contractions with block. On EGM analysis, advanced AVB occurred in 9 patients (18%), and the occurrence rate was 11.7% per year. Moreover, on multivariate analysis ß-blocker use was an independent risk factor for advanced AVB (OR, 9.10; P=0.004). CONCLUSIONS: The occurrence rate of advanced AVB in patients with SSS is much higher than previously reported, and ß-blocker use is an independent risk factor for advanced AVB. SafeR is useful to detect latent AVB. Stored EGM, however, sometimes include inaccurately classified events.

Clinical significance of collateral superficial vein across clavicle in patients with cardiovascular implantable electronic device.

BACKGROUND: Obstruction of the access vein is a well-known complication after cardiovascular implantable electronic device (CIED) implantation. In that case, well-developed collateral superficial veins are frequently observed on the skin surface around the CIED. The aim of this study was to clarify the relationship between venous obstruction and development of a superficial vein across the clavicle. METHODS AND RESULTS: A total of 107 patients scheduled for generator replacement, device upgrade, or lead extraction were enrolled. The skin surface around the device was photographed. A 20-ml bolus of contrast medium was injected into a peripheral arm vein on the side of CIED implantation, and contrast venography was performed. Venous obstruction was defined as luminal diameter narrowing >75%. Venography showed venous obstruction in 27 patients (25.2%). There were no statistically significant differences in patient characteristics between the venous obstruction and no venous obstruction group. Of 107 patients, 44 (41.1%) had a superficial vein across the clavicle on the side of CIED implantation. The sensitivity of the presence of a superficial vein across the clavicle in the diagnosis of venous obstruction was 96.3% and specificity was 77.5% (P<0.001). CONCLUSIONS: The presence of a superficial vein across the clavicle is useful for the prediction of venous obstruction in patients with CIED.

Prevalence of cerebral aneurysm in patients with acromegaly.

The prevalence of cerebral aneurysm was retrospectively investigated in 208 patients with acromegaly relative to the rate of cerebral aneurysm in a group of control subjects. Neuroradiological examinations of the cerebral vascular system were conducted in 208 acromegaly patients (101 men; mean age, 48.8 years). The prevalence of cerebral aneurysm in the acromegaly patients was compared to that in a control group consisting of 7,390 subjects who underwent "brain checkup" between 2006 and 2008 (mean age, 51.6 years). In the acromegaly group, cerebral aneurysm was detected in 4.3 % of patients. By sex, the prevalence was 6.9 % in males, a significantly proportion than that in the control group with an odds ratio of 4.40. The prevalence in females did not differ between the two groups. In the acromegaly group, the rate of hypertension was significantly higher in the patients with aneurysm compared to those without aneurysm. Multiple logistic regression identified acromegaly as a significant factor related to the prevalence of cerebral aneurysm in all male subjects; other factors, such as age, hypertension and smoking, were not found to be significant. A significantly higher prevalence of cerebral aneurysm was detected in male patients with acromegaly. This finding indicates that excess growth hormone or insulin-like growth factor 1 affects the cerebral vascular wall, resulting in aneurysm formation. In addition to known systematic complications in the cardiovascular, respiratory, metabolic, and other systems, the risk of cerebral aneurysm should be considered in the management of acromegaly.

Does reducing unnecessary right ventricular pacing improve sympathetic activity and innervation of heart in sinus node disease patients? MVP and SafeR study.

Ventricular desynchronization imposed by ventricular pacing causes regional disturbances of adrenergic innervation in the left ventricular myocardium and increases the risk of heart failure and atrial fibrillation (AF) in patients with sinus node disease (SND). As a result, decreased iodine-123 metaiodobenzylguanidine (I-(123 )MIBG) uptake occurs in patients with an implanted permanent pacemaker. Fourteen SND patients with an implanted pacemaker equipped with an algorithm for reducing unnecessary right ventricular pacing (RURVP) were enrolled. Pacemakers were programmed to RURVP mode for the first 12 weeks, and then reprogrammed to DDD for the last 12 weeks. At the end of each mode, data on cumulative percent ventricular pacing (%Vp), atrial high rate episodes (%AHR), I-(123 )MIBG myocardial scintigraphy, brain natriuretic peptide (BNP), human atrial natriuretic peptide (hANP), and myocardial damage indices typified by troponin T and C-reactive protein (CRP) were collected. %Vp was lower in RURVP than in DDD (0.2% versus 95.7%, P = 0.00098). BNP, hANP, troponin T, and CRP did not differ significantly between the pacing modes. However, I-(123 )MIBG findings of patients with full ventricular pacing in DDD improved in RURVP. In contrast, among patients without full ventricular pacing in DDD, their I-(123 )MIBG findings did not differ significantly between the pacing modes. In SND patients with normal cardiac function and intact atrioventricular conduction, the reduction of %Vp in RURVP was due to the reduction of ineffective pacing and fusion pacing in DDD. Therefore, these 2 types of pacing do not affect cardiac pump function.

Diffuse Idiopathic Skeletal Hyperostosis with Severely Displaced Spine Fracture Managed with Posterior Approach Alone: Case Reports and Literature Review.

Diffuse idiopathic skeletal hyperostosis (DISH) is a condition in which minor trauma can cause extremely unstable vertebral fractures. Spinal fractures associated with DISH are prone to instability due to the large moment of lever arm and secondary neurological deterioration; hence, surgical internal fixation is considered necessary. On the other hand, some reports suggest that patients with DISH have a high osteogenic potential. In this report, we describe three patients with DISH. These patients had spinal injuries that resulted in a large gap, for which anterior fixation with bone graft would generally be considered due to comminuted fractures. However, we achieved good bony fusion with posterior fixation alone, without forcible correction.

Lateral Lumbar Interbody Fusion Using Bone Graft Substitute for Lumbar Vertebral Fracture Associated Radiculopathy.

This study aims to present our surgical technique of lateral lumbar interbody fusion (LLIF) without corpectomy for lumbar vertebral fracture (LVF) associated radiculopathy. This study includes three patients treated with LLIF (mean age of 77.3 years, Group L) and three patients treated with PLIF (mean age of 75.7 years, Group P) to compare the surgical outcomes. The cartilage on the fractured vertebrae was aggressively resected with attention to avoid injury to the ring apophysis. The central cavity of the fractured endplate was filled with a bone graft substitute made of hydroxyapatite and collagen composite, followed by interbody fusion achieved by utilizing of a cage with sufficient length spanning the bilateral edges of the fractured vertebra. PLIF was performed with a standard technique using two interbody cages, and vertebroplasty was combined in one patient. Comparing to PLIF, LLIF could be performed with less estimated blood loss in shorter surgical time. Local kyphotic angle improved in all cases of Group L immediately after the surgery, but correction loss was observed at the final examination. The lordotic angle was lost in Group P postoperatively. Arthrodesis was achieved in all the cases. The mean VAS score for leg pain was 85.3 mm in Group L and 82.0 mm in Group P at preoperation and decreased to 8.7 mm and 11.3 mm, respectively, at postoperation. LLIF is an effective surgical option that enables stabilization of the fractured vertebra and reduces radicular pain by indirect neural decompression.

Atlantoaxial Intradural Synovial Cyst Mimicking an Extradural Lesion Adjacent to a Retro-odontoid Pseudotumor: A Case Report.

Atlantoaxial synovial cysts can very rarely penetrate the dura mater into the thecal sac and cause direct neural compression. Several case reports have been available on "intradural synovial cysts" (IDSCs). In this study, we report on a case with an atlantoaxial IDSC mimicking an extradural lesion. A 90-year-old man was diagnosed with a cystic lesion located laterally to the atlantoaxial joint adjacent to the retro-odontoid pseudotumor (ROP) causing cervical spinal cord compression. Thus, surgical removal was planned. On preoperative examination, the cyst, which had a two-layer structure showing a T2-isointense small mass inside a T2-hyperintense lesion, was thought to be located in the extradural region. However, operative findings showed that the cyst was located inside the dura mater. Histopathological examination suggested a synovial cyst. No recurrence of the cyst was observed until the latest follow-up after 3 years, and the ROP decreased in size. Almost all IDSCs reported previously were observed in the medial site of the atlantoaxial joint. In our case, however, the cyst was observed adjacent to the posteromedial site of the right atlantoaxial joint and the ROP, mimicking an extradural lesion. We had no knowledge regarding the IDSC before the surgery and assumed an extradural lesion. Albeit rare, the existence of such a condition should be considered.

Vertebral Endplate Cyst Formation in Relation to Properties of Interbody Cages.

OBJECTIVE: This retrospective study aimed to compare vertebral endplate cyst formation (VECF), an early predictor for pseudoarthrosis, in different types of interbody cages. METHODS: We reviewed 84 cases treated with single-level posterior/transforaminal lumbar interbody fusion. We utilized a polyetheretherketone cage in 20 cases (group P), a titanium cage in 16 cases (group Ti), a titanium-coating polyetheretherketone cage in 13 cases (group TiP) and a porous tantalum cage in 35 cases (group Tn). VECF was evaluated comparing the computed tomography scans taken at day 0 and 6-month postoperation. We defined VECF (+) as enlargement of a pre-existing cyst or de novo formation of a cyst with the diameter over 2 mm. We calculated the adjusted odds ratio (OR) and 95% confidence intervals (CIs) as an indicator of association between different types of cages and VECF using a logistic regression model. RESULTS: VECF was observed in 13 (65%), 7 (44%), 9 (69%), and 8 (23%) cases in groups P, Ti, TiP and Tn, respectively. VECF correlated with the type of cage (p = 0.04). In comparison with group P, the proportion of VECF (+) cases was lower in group Tn (OR, 0.16; 95% CI, 0.04-0.60) but not different in group Ti (OR, 0.47; 95% CI, 0.10-2.20) and group TiP (OR, 1.06; 95% CI, 0.21-5.28). No patient underwent additional surgery for the fused spinal level during the follow-up periods (average, 37.9 months; range, 6-76 months). CONCLUSION: VECF was the least in the porous Tn cage, suggesting its potential superiority for initial stability.

Characteristics of patients with adult congenital heart disease treated by non-specialized doctors: The potential loss of follow-up.

BACKGROUND: In the treatment of adult congenital heart disease (ACHD), the transfer of patients from pediatric cardiologists to ACHD cardiologists is of relevance. However, little is known about the clinical courses of ACHD patients that have been referred by non-CHD-specialized doctors (n-CSDs). METHODS: This retrospective cohort study included 230 patients (average age: 37 ± 15.2 years, male: 97) who were referred to a single specialized ACHD center between April 2016 and July 2019. We compared the characteristics and clinical courses between patients referred by n-CSDs and those referred by CHD-specialized-doctors (CSDs). RESULTS: Overall, 121 (53%) patients were referred by n-CSDs. Among them, 91 (75%) patients were referred by adult cardiologists. Univariate analysis showed that the patients referred by n-CSDs were older than those referred by CSDs (41.6 ± 16.3 vs. 32.0 ± 12.0 years, p < 0.01), were more likely to have simple CHD, and less likely to have severe CHD (27.0% vs. 12.8% and 16.5% vs. 40.4%, respectively, p < 0.01). Patients referred by n-CSDs were also more likely to have a history of loss of follow-up (16.5% vs. 3.7%, p < 0.01) and to require invasive treatments after referral, including cardiac surgeries and transcatheter interventions (47.9% vs. 26.6 %, p < 0.01). Notably, unintended invasive treatments that were not designated by the referring doctors were more frequently required in patients with moderate complexity referred by n-CSDs (50.0% vs. 23.3%, p = 0.02). CONCLUSIONS: Patients with moderate CHD complexity referred by n-CSDs are more likely to require unintended invasive treatments. Referrals to specialized ACHD centers may be most beneficial for these patients.

A mechanism of a cardiac murmur with respiratory variation in a patient with straight back syndrome.

A 20-year-old male without any symptoms was referred for heart murmur on a medical examination. A thrill was palpable at the upper left sternal border. His cardiac murmur showed respiratory variation. The systolic murmur was louder (Levine grade IV/VI) during expiration and diminished during inspiration (Levine grade I/VI). He was thin and had a narrow thoracic cage in the anteroposterior direction due to straight back syndrome (SBS). An echocardiogram and a right ventriculogram showed changes in the diameter of the right ventricular outflow tract (RVOT) on respiration. During expiration, the RVOT was compressed and narrow, while it was expanded during inspiration. Cardiac catheterization demonstrated a 10-mmHg of pressure gradient across the RVOT during expiration but no pressure gradient during inspiration. Thus, respiratory compression to the RVOT by a narrow thoracic cage due to SBS was the cause of the cardiac murmur with respiratory alterations. Our case highlights the importance of physical examination, including an inspection of the patient's physique. .

Unusual double-chambered right ventricle induced by ruptured sinus of Valsalva aneurysm: A case report.

A 54-year-old male with a history of unrepaired ventricular septal defect (VSD) suffered from easy fatigability on exertion. A Levine grade V/VI continuous murmur was auscultated. Transthoracic echocardiogram showed a ruptured sinus of Valsalva aneurysm (SVA) and a significant left-to-right shunting from the ascending aorta to the right ventricle (RV). In addition, a 36 mmHg of pressure gradient was observed between the inflow and outflow tract in the RV, suggesting double-chambered RV (DCRV). Cardiac catheterization also revealed 33 mmHg of the pressure gradient in the mid-potion of the RV, which was coincident with DCRV. A calculated pulmonary-to-systemic flow ratio was 3.0. Therefore, the patient was offered surgical repair of the ruptured SVA and VSD, which was successfully performed. During the surgery, an anomalous muscle band, which is usually the cause of DCRV, was not found, instead, a thickened RV free-wall due to the exposure of the left-to-right shunt flow, so-named jet lesion, was found. Therefore, surgical resection of the anomalous muscle band was not required. The protruded SVA toward the RV, the jet lesion, and the increased RV stroke volume, which could induce relative stenosis, were the causes of the unusual DCRV. .