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Introduction: Elite breath-hold divers (BHD) possess several oxygen conserving adaptations to endure long dives similar to diving mammals. During dives, Bottlenose Dolphins may increase the alveolar ventilation (V A ) to perfusion (Q) ratio to increase alveolar oxygen delivery. We hypothesized that BHD possess similar adaptive mechanisms during apnea., Methods and Results: Pulmonary blood volume (PBV) was determined by echocardiography, 15 O-H 2 O PET/CT, and cardiac MRi, (n = 6) during and after maximum apneas. Pulmonary function was determined by body box spirometry and compared to matched controls. After 2 min of apnea, the PBV determined by echocardiography and 15 O-H 2 O-PET/CT decreased by 26% and 41%, respectively. After 4 min of apnea, the PBV assessed by echocardiography and cardiac MRi decreased by 48% and 67%, respectively (n = 6). Fractional saturation (F)O 2 Hb determined by arterial blood-gas-analyses collected after warm-up and a 5-minute pool-apnea (n = 9) decreased by 43%. Compared to matched controls (n = 8), spirometry revealed a higher total and alveolar-lung-capacity in BHD (n = 9), but a lower diffusion-constant., Conclusion: Our results contrast with previous studies, that demonstrated similar lung gas transfer in BHD and matched controls. We conclude that elite BHD 1) have a lower diffusion constant than matched controls, and 2) gradually decrease PBV during apnea and in turn increase V A /Q to increase alveolar oxygen delivery during maximum apnea. We suggest that BHD possess pulmonary adaptations similar to diving mammals to tolerate decreasing tissue oxygenation., New and Noteworthy: This manuscript addresses novel knowledge on tolerance to hypoxia during diving, which is shared by elite breath-hold divers and adult diving mammals: Our study indicates that elite breath-hold divers gradually decrease pulmonary blood volume and in turn increase VA/Q, to increase alveolar oxygen delivery during maximum apnea to tolerate decreasing oxygen levels similar to the Bottlenose Dolphin., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Kjeld, Isbrand, Arendrup, Højberg, Bejder, Krag, Vissing, Tolbod, Harms, Gormsen, Fuglø and Hansen.)

Introduction: Elite breath-hold divers (BHD) enduring apneas of more than 5 min are characterized by tolerance to arterial blood oxygen levels of 4.3 kPa and low oxygen-consumption in their hearts and skeletal muscles, similar to adult seals. Adult seals possess an adaptive higher hemoglobin-concentration and Bohr effect than pups, and when sedated, adult seals demonstrate a blood shift from the spleen towards the brain, lungs, and heart during apnea. We hypothesized these observations to be similar in human BHD. Therefore, we measured hemoglobin- and 2,3-biphosphoglycerate-concentrations in BHD ( n = 11) and matched controls ( n = 11) at rest, while myocardial mass, spleen and lower extremity volumes were assessed at rest and during apnea in BHD., Methods and Results: After 4 min of apnea, left ventricular myocardial mass (LVMM) determined by 15 O-H 2 O-PET/CT ( n = 6) and cardiac MRI ( n = 6), was unaltered compared to rest. During maximum apnea (∼6 min), lower extremity volume assessed by DXA-scan revealed a ∼268 mL decrease, and spleen volume, assessed by ultrasonography, decreased ∼102 mL. Compared to age, BMI and VO 2 max matched controls ( n = 11), BHD had similar spleen sizes and 2,3- biphosphoglycerate-concentrations, but higher total hemoglobin-concentrations., Conclusion: Our results indicate: 1) Apnea training in BHD may increase hemoglobin concentration as an oxygen conserving adaptation similar to adult diving mammals. 2) The blood shift during dry apnea in BHD is 162% more from the lower extremities than from the spleen. 3) In contrast to the previous theory of the blood shift demonstrated in sedated adult seals, blood shift is not towards the heart during dry apnea in humans., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Kjeld, Krag, Brenøe, Møller, Arendrup, Højberg, Fuglø, Hancke, Tolbod, Gormsen, Vissing and Hansen.)

Introduction: The cardiac electrical conduction system is very sensitive to hypoglycemia and hypoxia, and the consequence may be brady-arrythmias. Weddell seals endure brady-arrythmias during their dives when desaturating to 3.2 kPa and elite breath-hold-divers (BHD), who share metabolic and cardiovascular adaptions including bradycardia with diving mammals, endure similar desaturation during maximum apnea. We hypothesized that hypoxia causes brady-arrythmias during maximum apnea in elite BHD. Hence, this study aimed to define the arterial blood glucose (Glu), peripheral saturation (SAT), heart rhythm (HR), and mean arterial blood pressure (MAP) of elite BHD during maximum apneas. Methods: HR was monitored with Direct-Current-Pads/ECG-lead-II and MAP and Glu from a radial arterial-catheter in nine BHD performing an immersed and head-down maximal static pool apnea after three warm-up apneas. SAT was monitored with a sensor on the neck of the subjects. On a separate day, a 12-lead-ECG-monitored maximum static apnea was repeated dry ( n = 6). Results: During pool apnea of maximum duration (385 ± 70 s), SAT decreased from 99.6 ± 0.5 to 58.5 ± 5.5% (∼PaO 2 4.8 ± 1.5 kPa, P < 0.001), while Glu increased from 5.8 ± 0.2 to 6.2 ± 0.2 mmol/l ( P = 0.009). MAP increased from 103 ± 4 to 155 ± 6 mm Hg ( P < 0.005). HR decreased to 46 ± 10 from 86 ± 14 beats/minute ( P < 0.001). HR and MAP were unchanged after 3-4 min of apnea. During dry apnea (378 ± 31 s), HR decreased from 55 ± 4 to 40 ± 3 beats/minute ( P = 0.031). Atrioventricular dissociation and junctional rhythm were observed both during pool and dry apneas. Conclusion: Our findings contrast with previous studies concluding that Glu decreases during apnea diving. We conclude during maximum apnea in elite BHD that (1) the diving reflex is maximized after 3-4 min, (2) increasing Glu may indicate lactate metabolism in accordance with our previous results, and (3) extreme hypoxia rather than hypoglycemia causes brady-arrythmias in elite BHD similar to diving mammals., Competing Interests: TKj was voluntary (unpaid) board member of the Danish National Diving Federation. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Kjeld, Isbrand, Linnet, Zerahn, Højberg, Hansen, Gormsen, Bejder, Krag, Vissing, Bøtker and Arendrup.)

Breath-hold divers (BHD) enduring apnea for more than 4 min are characterized by resistance to release of reactive oxygen species, reduced sensitivity to hypoxia, and low mitochondrial oxygen consumption in their skeletal muscles similar to northern elephant seals. The muscles and myocardium of harbor seals also exhibit metabolic adaptations including increased cardiac lactate-dehydrogenase-activity, exceeding their hypoxic limit. We hypothesized that the myocardium of BHD possesses similar adaptive mechanisms. During maximum apnea 15 O-H 2 O-PET/CT (n = 6) revealed no myocardial perfusion deficits but increased myocardial blood flow (MBF). Cardiac MRI determined blood oxygen level dependence oxygenation (n = 8) after 4 min of apnea was unaltered compared to rest, whereas cine-MRI demonstrated increased left ventricular wall thickness (LVWT). Arterial blood gases were collected after warm-up and maximum apnea in a pool. At the end of the maximum pool apnea (5 min), arterial saturation decreased to 52%, and lactate decreased 20%. Our findings contrast with previous MR studies of BHD, that reported elevated cardiac troponins and decreased myocardial perfusion after 4 min of apnea. In conclusion, we demonstrated for the first time with 15 O-H 2 O-PET/CT and MRI in elite BHD during maximum apnea, that MBF and LVWT increases while lactate decreases, indicating anaerobic/fat-based cardiac-metabolism similar to diving mammals.

Background: Acute kidney injury after cardiac surgery is common and associated with increased mortality. It is unknown whether an intended higher arterial pressure during cardiopulmonary bypass reduces the incidence of acute and chronic kidney injury., Methods: Patients were randomised either to a control group or a high pressure group (arterial pressure > 60 mmHg). The inclusion criteria were age > 70 years, combined cardiac surgery and serum creatinine < 200 μmol/L. Glomerular filtration rate using the Cr-EDTA clearance method was measured the day before surgery and 4 months postoperatively. The RIFLE criteria were used to define the presence of acute kidney injury. In addition, the ratio between urinary Neutrophil Gelatinase-Associated Lipocalin (NGAL) and creatinine was measured., Results: Ninety patients were included. Mean age was 76 ± 4 years and 76% were male. Mean arterial pressure was 47 ± 5 mmHg in the control group and 61 ± 4 mmHg in the high pressure group (p < 0.0001). The change in glomerular filtration rate at follow-up was - 9 ± 12 ml/min in the control group and - 5 ± 16 ml/min in the high pressure group (p = 0.288, 95% CI - 13 to 4). According to the RIFLE criteria 38% in the control group and 46% in the high pressure group developed acute kidney injury (p = 0.447). The postoperative urinary NGAL/creatinine ratio was comparable between the groups., Conclusions: An intended increase in arterial pressure during cardiopulmonary bypass to > 60 mmHg did not decrease the incidence of acute or chronic kidney injury after cardiac surgery., Trial Registration: Clinicaltrials.gov, identifier: NCT01408420 . Registered 3rd of August 2011.

Background: The performance of elite breath hold divers (BHD) includes static breath hold for more than 11 minutes, swimming as far as 300 m, or going below 250 m in depth, all on a single breath of air. Diving mammals are adapted to sustain oxidative metabolism in hypoxic conditions through several metabolic adaptations, including improved capacity for oxygen transport and mitochondrial oxidative phosphorylation in skeletal muscle. It was hypothesized that similar adaptations characterized human BHD. Hence, the purpose of this study was to examine the capacity for oxidative metabolism in skeletal muscle of BHD compared to matched controls., Methods: Biopsies were obtained from the lateral vastus of the femoral muscle from 8 Danish BHD and 8 non-diving controls (Judo athletes) matched for morphometry and whole body VO2max. High resolution respirometry was used to determine mitochondrial respiratory capacity and leak respiration with simultaneous measurement of mitochondrial H2O2 emission. Maximal citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HAD) activity were measured in muscle tissue homogenates. Western Blotting was used to determine protein contents of respiratory complex I-V subunits and myoglobin in muscle tissue lysates., Results: Muscle biopsies of BHD revealed lower mitochondrial leak respiration and electron transfer system (ETS) capacity and higher H2O2 emission during leak respiration than controls, with no differences in enzyme activities (CS and HAD) or protein content of mitochondrial complex subunits myoglobin, myosin heavy chain isoforms, markers of glucose metabolism and antioxidant enzymes., Conclusion: We demonstrated for the first time in humans, that the skeletal muscles of BHD are characterized by lower mitochondrial oxygen consumption both during low leak and high (ETS) respiration than matched controls. This supports previous observations of diving mammals demonstrating a lower aerobic mitochondrial capacity of the skeletal muscles as an oxygen conserving adaptation during prolonged dives., Competing Interests: The authors have declared that no competing interests exist.

Closure of persistent foramen ovale (PFO) to avoid cryptogenic strokes is performed globally with enthusiasm but lacks prove of efficacy. We present a 79-year-old man who had had a PFO device introduced nine years previously because of cryptogenic strokes presenting as syncopes. The patient was referred from his general practitioner with two new syncopes. Transthoracic echocardiography revealed no cardiac causes of embolism. Transesophageal echocardiography (TEE) revealed a misplaced device like an umbrella in a storm, but no septum defects. Holter revealed seconds-long episodes of atrial fibrillation (AF). The patient was successfully treated with anticoagulation. A literature review showed that: (i) the efficacy of PFO closure devices has not been proven in any trial, but was demonstrated in a meta-analysis comparing three different devices; (ii) PFO devices are rarely controlled by TEE during or after insertion; (iii) residual shunts are detected in up to 45% of cases; (iv) there is an increased rate of post-arrhythmic complications; (v) the risk of AF in congenital heart disease increases with increasing age, with a 13% risk of transient ischemic attacks and stroke; and (vi) surgical treatment of PFO was found to have a 4.1% risk of complications including stroke. The question to be asked is whether device closure of PFO should be avoided, considering that PFO is a congenital heart defect with risks of AF and (cryptogenic) stroke? Heart surgery should be a treatment option for symptomatic PFO.

Sarcoma of the inferior vena cava (IVC) is a rare clinical entity. Surgical treatment of IVC is associated with improved survival. This case report describes a 42-year-old woman with biopsy-proven leiomyosarcoma of the inferior vena cava with intracardial tumour growth. The primary tumour was only 1 x 1 cm in the wall of the vena cava while the intracaval tumour was 12 cm long with a diameter of 5 cm and 1.5 cm in the right atrium. Using venovenous bypass with circulatory support, the tumour was excised in toto and the caval vein closed with a pericardial patch. The patient was discharged in good condition after 19 days.

Introduction: To compare an invasive strategy employing percutaneous transluminal coronary angioplasty (PTCA) or coronary artery by-pass grafting (CABG) with a medical strategy in patients who had received thrombolytic treatment for first acute myocardial infarction (AMI), and with signs of inducible ischaemia., Methods: In a prospective study 1008 patients were randomized, 503 to invasive treatment, of whom 266 (52.9%) had PTCA, and 147 (29.2%) CABG, 505 to conservative treatment, of whom eight (1.6%) were revascularized within two months., Results: After a median follow-up of 2.4 years the mortality in the invasive group was 3.6% vs. 4.4% (p = 0.45) in the conservative group, re-infarction incidence was 5.6% vs. 10.5% (p = 0.0038) and percentage of admissions with unstable angina was 17.9% vs. 29.5% (p < 0.00001)., Discussion: We conclude that post-infarct patients with inducible ischaemia should be referred to coronary angiography and revascularised accordingly.

In carefully selected patients with end-stage heart failure heart transplantation has developed from an experimental procedure to standard therapy during the last 30 years. It is currently accepted as a procedure for prolonging life and also for improving quality of life. According to the Registry of the International Society for Heart and Lung Transplantation the overall one-year actuarial survival is 79% and 10-year survival barely 50%. Nine years after the start of the Heart Transplant Program at Rigshospitalet the overall actuarial survival of 157 consecutive patients is 66%. Due to the limited donor access a decline of heart transplant recipients has been recorded during the late nineties. Mechanical replacement of the heart may develop from technological advances and possibly this therapy may gain a complementary status in heart failure, however the human biological replacement is currently the standard.

Coronary complications caused by percutaneous transluminal coronary angioplasty (PTCA) may necessitate emergency coronary artery bypass grafting (CABG). In 1994-1998, 132 patients (1.5% of the patients registered in the Danish PTCA registry) underwent CABG within 24 h because of angioplasty complications. We reviewed the files of 86 patients who had emergency operations within 6 h and found that 35% suffered from 1-vessel disease. Fifty-eight percent were taken directly to the operating room from the cardiovascular laboratory, and 13% were given preoperative cardiovascular resuscitation. The vessels most frequently injured were the right coronary artery and the left anterior descending branch (LAD). The patients received a mean of 2.4 coronary bypasses each. Forty-three percent of the patients with lesions of the left main coronary artery and/or the LAD received a vein graft to the LAD. A perioperative Q-wave myocardial infarction developed in 51% of the patients. The in-hospital mortality rate was 12%. These results are inferior to those obtained after elective surgery. Local cardiothoracic backup is vital when PTCA is performed in an unselected patient group.

Unlabelled: Perioperative ischaemia and infarction after CABG are associated with increased morbidity and mortality., Objective: To study causes of perioperative ischaemia and infarction by acute re-angiography and to treat incomplete re-vascularization caused by graft failure or any other cause., Methods: Between 1990 and 1995, 2003 patients underwent an isolated CABG operation. Myocardial ischaemia was suspected if one or more of the following criteria were present: New changes in the ST-segment in the ECG; a CKMB value greater than 80 U/L; new Q-waves in the ECG; recurrent episodes of, or sustained ventricular tachyarrhythmia; ventricular fibrillation; haemodynamic deterioration and left ventricular failure. Acute coronary angiography was performed in stable patients, while haemodynamically severely compromised patients were rushed to the operating room., Results: A total of 71 (3.5%) patients of all CABGs with suspected graft failure were identified and included in the study. Patients were grouped according to whether they had an acute re-angiography (n = 59; group 1) or an immediate re-operation (n = 12; group 2) performed. In group 1, the acute re-angiography demonstrated graft failure/incomplete re-vascularization in 43 patients (73%). The angiographic findings were: Occluded vein graft(s) in 19 (32%); poor distal run-off to the grafted coronary artery in ten (17%); internal mammary artery stenosis in four (7%); internal mammary artery occlusion in three (5%); vein graft stenoses in three (5%); left mammary artery subclavian artery steal in two (3%); and the wrong coronary artery grafted in one (2%). Based on the angiography findings, 27 patients were re-operated and re-grafted. At the time of re-operation, 18 patients (67%) had evolving infarction documented by ECG or CKMB. Two patients (3%) experienced stroke in immediate relation to the re-angiography. The 30-day mortality was three (7%). In group 2, graft occlusions were found in 11 patients (92%). The 30-day mortality was six (50%)., Conclusion: An acute re-angiography demonstrated graft failure or incomplete re-vascularization in the majority of patients with myocardial ischaemia early after CABG. Re-operation for re-re-vascularization was performed with low risk. Few patients with circulatory collapse could be saved by an immediate re-operation without preceding angiography.

En-bloc double lung transplantation with tracheal anastomosis and direct revascularization of the bronchial arteries to the left internal mammary artery has been carried out in Denmark since June 1992. Forty-seven patients (32 with alfa-1 antitrypsin deficiency, 11 with chronic obstructive pulmonary disease, two with cystic fibrosis and two with primary pulmonary hypertension), 25 men and 22 women, average age 39 years (17-64 years), have received their first double-lung transplant with bronchial artery revascularization. Arteriography of the internal mammary artery and bronchial arteries was performed in 42 (89%) of the patients from 1-150 days after the operation. Successful bronchial artery revascularization was demonstrated arteriographically in 40 patients, in two patients the arteriography failed to show bronchial artery revascularization. Arteriography was not performed in five patients due to early complications and death. Bronchoscopy showed rapid, uncomplicated airway healing in 42 patients. Mucosal necrosis under the tracheal anastomosis was found in three patients, and severe obstructive endobronchial growth of the fungus Aspergillus fumigatus was diagnosed in the last two patients. The one- and two-year survival is 83% (Kaplan-Meier). Eleven patients are dead, five due to pulmonary causes and six due to extra-pulmonary causes. Pulmonary function became normal in nearly all surviving patients between three to six months after the transplantation. In conclusion, en-bloc double-lung transplantation with bronchial artery vascularization has shown good short-term results, and the one- and two-year survival gives hope that a successful bronchial artery revascularization will improve the long-term survival following lung transplantation.

During 1993-95 1000 consecutive patients were admitted for coronary bypass surgery. The total 30-day mortality of 1.9% was 0.9% for elective cases, 0.8% for reoperations and 0.2% for urgent cases. Perioperative myocardial infarction occurred in 44 patients of whom 25% had infarction at the start of the operation. Respiratory insufficiency occurred in 1.4% of the patients, 3.6% developed renal insufficiency and 1.8% had neurological defects postoperatively. Reoperation for bleeding occurred in 6%, and 0.2% developed sternal or mediastinal infection. This study demonstrates that the results of coronary bypass surgery at Rigshospitalet, Copenhagen are fully comparable to similar results in our neighbouring countries. The results can probably be further improved by more intensive treatment of perioperative ischaemia, especially in reoperations and urgent cases.

Thirty-six heart-lung and lung transplantations have been performed in Denmark from January 1992 to January 1994. Heart-lung transplantations was initially carried out in patients with pulmonary vascular diseases. Single lung, double lung and heart-lung transplantation have become therapeutical alternatives and the indications have been expanded to terminal patients with pulmonary diseases. Careful selection of patients and donors, careful surgical techniques and a stringent immunosuppressive treatment have minimized the perioperative mortality. Daily lung function measurements, transbronchial biopsies and bronchoalveolar lavage have created possibilities for an early and safe diagnosis of infections and rejections. A high frequency of obliterative bronchiolitis with loss of pulmonary function is still a serious and unsolved problem. Intensive investigations with the aim of understanding, preventing and treating obliterative bronchiolitis are going on.

When the criterion of brain-death was introduced in Denmark on 1.7.1990, the possibility for heart transplantation and other interventions was opened. The first heart transplantation was carried out 3.10.1990 and, during the first year, 28 transplantations were carried out on 27 patients. The therapeutic routines in the department are reviewed and the results obtained after the first year are presented. A total of 33 donors who fulfilled the donor criteria were available. Of these, 28 came to Rigshospitalet, two were sent abroad and suitable recipients could not be found for two. The recipient group consisted of four women and 23 men with an average of 46 years. At the time of writing, on an average 169 days after operation (13-330), 23 out of 27 patients survived in good health and with normal cardiac function. Three patients are still in hospital.

A retrospective investigation was undertaken of the mediastinal infections in patients submitted to cardiac surgery. A total of 1,763 patients participated in a period of 11 years from 1978 to 1988. All of the case records were reviewed for the occurrence of infections in the mediastinum and 24 patients (1.4%) were found to have had mediastinitis. Predisposing factors to mediastinal infections are reviewed. In all of the cases, treatment consisted re-thoracotomy with removal of all necrotic and infectious material. This was followed by primary closure over a retrosternal irrigation system which supplied an antibiotic solution for six days. In addition, oral antibiotics were administered on the basis of the findings on culture. The incidence of infection was found to be increased when the left internal mammary artery (LIMA) had been employed and in cases of combined cusp and coronary surgery. In 20 patients (83%), relevant culture findings were found from the mediastinal drain on an average of 2.5 days after the primary operation. These were reencountered in the mediastinum at rethoracotomy which was performed on an average of 15 days after the primary operation. This raises the question of the possibility of earlier intervention. The commonest microorganisms were micrococci and Staphylococcus aureus which together comprized approximately 83%. The antibiotic treatment routinely employed was 1 g meticillin four times daily. Five patients died (21%) and 19 patients were discharged. On follow-up examination, the sternum was stable and the scar healed. When infection in the mediastinum is suspected after cardiac surgery, early diagnosis and active surgical treatment are important. The closed method of irrigation drainage is recommended by the authors.

During the 16-year period from 1974 to 1989, coronary bypass operations were carried out on 938 patients. During the same period, 48 patients (5.1%) were submitted to reoperation on account of recurrent angina pectoris. Patients with early recurrence had more frequently graft-occlusion than patients with late recurrence in whom the main cause was progression of the arteriosclerotic cardiac condition. The actual rethoractomy was carried out without serious complications. The perioperative frequency of complications and the mortality correspond to the frequencies at the first operation. Follow-up control of these patients was undertaken after an average of 34 months (8-100) after reoperation. The results after reoperation as regards freedom from symptoms are not quite as good as the results after the primary operation but approximately 2/3 of the patients will benefit from reoperation.

The experience gained during a 16 year period from 27 patients with traumatic rupture of the diaphragm is reported upon. Automobile accidents were the most frequent cause of diaphragmatic rupture, and the left hemidiaphragm was that most often affected. The diagnosis is most frequently missed during the initial examination and treatment of such patients. The diagnosis was missed in the present material in 48 per cent of the patients during the first 24 hours. The preoperative diagnosis is based upon the suspicion that all patients with traumatic injuries to the thoracoabdominal region may have a rupture of the diaphragm. An ordinary roentgenogram of the chest gives rise to the diagnosis in 17 patients. Other diagnostic possibilities are nasogastric intubation and the demonstration of the passage of air or contrast medium from the abdominal cavity to the pleural cavity. Special attention should be paid to patients receiving artificial ventilation, in whom the positive airway pressure may keep the viscera in their correct position. Nine patients died during hospitalization of associated injuries, and no deaths were the direct result of the ruptured diaphragm. Follow-up time of one to 16 years, a mean of 5.1 years, showed that 15 patients had no pulmonary complaints, while three complained of minor respiratory or abdominal discomfort.

In the period 1965-1979, 26 patients underwent valvulotomy for congenital pulmonary valve stenosis without ventricular septal defect. Infundibular stenosis was additionally present in 14 of the patients, 12 children and 2 adults, but myocardial resection in the infundibular area was not performed. During the first postoperative year the right ventricular outflow tract underwent normalization in the 12 children and the right ventricular systolic pressure normalized in all 14 patients. No relationship could be demonstrated between the R wave in the precordial lead V1 and the systolic pressure in the right ventricle, the gradient to the pulmonary artery or the extent of subvalvular hypertrophy.

During a period of 17 months, four cases of lesions to the brachial plexus after cannulation of the internal jugular vein were observed in the Department of Thoracic Surgery in Odense Hospital. Other possible complications are mentioned and a method of catheterization with the fewest possible complications is reviewed. Patients who have been submitted to catheterization of the internal jugular vein should be observed with particular attention to nerve lesions. These symptoms usually regress within a relatively short period.