Pulmonary Venous Blood Research Articles

Balloon atrial septostomy: The oldest cardiac interventional procedure in Mansoura

Abstract Background Balloon atrial septostomy (BAS) was first described by Rashkind and Miller in 1966 and remains an important interventional procedure in the palliation of certain forms of congenital heart disease (CHD). Creating an atrial septa1 defect in patients with transposition of the great arteries (d-TGA) will enhance bidirectional mixing of the pulmonary and systemic venous blood, hence improving oxygen saturation. The aim of the work is to review and report our experience using balloon atrial septostomy in different CHD. Method We retrospectively reviewed the hospital records, echocardiographic and cardiac catheterization reports of patients subjected for BAS during the period from January 2001 till January 2010. One hundred and ninety two patients with CHD (78.5% d-TGA, 10% mitral atresia, 7.5% tricuspid atresia, and 4% hypoplastic left heart syndrome) underwent BAS. Their gestational age was 38.63 ± 1.48 weeks, postnatal age (median 3.5 days, range 1–54) and weight 3.08 ± 0.37 kg, 57.5% was male and 42.5% was female. All patients received PGE1 infusion before the procedure to maintain the ductal patency in a dose of 0.05–0.1 μg/kg/min. Results One hundred twenty two procedures (63.5%) were done in neonatal intensive care at bedside and 70 procedures (36.5%) in the catheterization laboratory. General anesthesia was used in 31.3% of patients whereas conscious sedation was used in 68.7% of patients. Femoral access in 78% while umbilical access in 22%. Seven F sheath was used in 100% of case. The Miller catheter was used in 75% and a Z-5 septostomy catheter in 25% of cases. The diameter of the atrial communication increased from 2.75 ± 0.97 mm to 7.07 ± 0.79 mm (p Conclusion BAS is safe and an effective palliative procedure for different CHD with good immediate results in our institution.

Assessment of operability in d-transposition of great arteries with ventricular septal defect: A practical method

Introduction:Pulmonary vascular disease is a risk factor in the surgical management of patients with d-transposition of great arteries (d-TGA) and a ventricular septal defect (VSD). In older infants or children with this physiology, the question of operability often arises. Cardiac catheterization in this condition can be fallacious. It is well known that oxygen reduces pulmonary arterial pressure and pulmonary vascular resistance especially where irreversible pulmonary vascular obstructive disease has still not set in. We tried to implement this effect of oxygen in correlation with echocardiography in patients with TGA-VSD physiology where operability was in question.Methods:Patients with d-TGA and a large post tricuspid shunt in whom operability was considered doubtful were selected for the study. We administered humidified oxygen at the rate of 10 litres/minute by mask for 48 hours in the ward or intensive care unit. After administration of oxygen we reassessed the child echocardiographically looking for signs of lowering of pulmonary vascular resistance which included increased pulmonary venous blood flow to the left atrium (LA) and right to left shunting across the VSD.Observation:We studied 1 patient with d-TGA and aortopulmonary window (APW), 4 patients with TGA / large VSD and 1 patient with Taussig-Bing anomaly. The age of the studied children ranged from 4 months to 3 years with a mean age of 1.1 years. After administering oxygen as described, echocardiogram showed an increase in pulmonary venous blood flow to the LA and right to left shunting across the VSD in 5 patients and increased flow reversal in aorta in presence of the APW.Conclusion:Patients with TGA/VSD physiology with doubtful operability can be subjected to this method of determining operability using echocardiography after administering oxygen. Although not 100% accurate in predicting long term postoperative pulmonary hypertension, this is a simple, noninvasive method that can aid in decision making in such a situation.

Time-resolved magnetic resonance angiography: Evaluation of intrapulmonary circulation parameters in pulmonary arterial hypertension

To determine whether pulmonary arterial and venous transit times measured by time-resolved magnetic resonance angiography (MRA) can be used as a diagnostic tool for pulmonary arterial hypertension (PAH). Twelve patients with confirmed PAH and 10 healthy volunteers were scanned with Institutional Review Board (IRB) approval. Time-resolved MRA and 2D phase contrast flow images of the pulmonary vasculature were acquired. Pulmonary arterial and venous transit times (PaTT and PvTT) and pulmonary valve flow (PVF) were obtained. Pulmonary arterial and pulmonary venous blood volumes (PaBV and PvBV) were calculated as the product of flow and transit time. Patients with PAH showed statistically significant increases in PaTT and PvTT (P < 0.0004, P < 0.05, respectively) compared to controls. PaBV (165.2 ± 92.0 mL) was significantly higher in PAH subjects than controls (97.0 ± 47.1 mL) (P < 0.04), whereas PvBV (127.9 ± 148.9 mL) of PAH subjects had no significant increase from those of healthy controls (142.5 ± 104.1 mL) (P < 0.38). Pulmonary arterial transit times measured using time-resolved MRA can be used as a simple, noninvasive metric for detection of altered hemodynamics in PAH.

Pulmonary vein endothelial cells (PVECs) exhibit characteristics of multiple lung endothelial cell phenotypes

Endothelial cells lining the lungs' pulmonary artery, capillary, and venous blood vessels exhibit vastly different morphologies and functions. We have previously shown that segment specific attributes of pulmonary artery endothelial cells (PAECs) and pulmonary microvascular endothelial cells (PMVECs) are retained in culture. However, fundamental information regarding the characteristics of endothelial cells obtained from the pulmonary vein is lacking. PMVECs are known to possess a higher growth rate than PAECs. We determined that PVECs have a growth rate (doubling time) that is only slightly higher than PAECs (29hrs vs. 33 hrs). PMVECs develop a tighter barrier than do PAECs (2000 ohms vs. 1100 ohms, respectively). Interestingly, PVEC barrier resistance is only slightly less than PMVECs (1800 ohms). All three phenotypes express typical endothelial markers, yet display distinct lectin binding patterns as determined by Fluorescence Activated Cell Sorting (FACS) and immunocytochemical analysis. Taken together these data demonstrate functional heterogeneity among lung endothelial cell phenotypes including those derived from the pulmonary vein. Supported by HL66299.

A mathematical model of pulmonary gas exchange under inflammatory stress

During a severe local or systemic inflammatory response, immune mediators target lung tissue. This process may lead to acute lung injury and impaired diffusion of gas molecules. Although several mathematical models of gas exchange have been described, none simulate acute lung injury following inflammatory stress. In view of recent laboratory and clinical progress in the understanding of the pathophysiology of acute lung injury, such a mathematical model would be useful. We first derived a partial differential equations model of gas exchange on a small physiological unit of the lung (≈25 alveoli), which we refer to as a respiratory unit (RU). We next developed a simple model of the acute inflammatory response and implemented its effects within a RU, creating a single RU model. Linking multiple RUs with various ventilation/perfusion ratios and taking into account pulmonary venous blood remixing yielded our lung-scale model. Using the lung-scale model, we explored the predicted effects of inflammation on ventilation/perfusion distribution and the resulting pulmonary venous partial pressure oxygen level during systemic inflammatory stresses. This model represents a first step towards the development of anatomically faithful models of gas exchange and ventilation under a broad range of local and systemic inflammatory stimuli resulting in acute lung injury, such as infection and mechanical strain of lung tissue.

Transpulmonary B-Type Natriuretic Peptide Uptake and Cyclic Guanosine Monophosphate Release in Heart Failure and Pulmonary Hypertension: The Effects of Sildenafil

We sought to identify factors that discriminate heart failure (HF) patients with normal and elevated pulmonary vascular resistance (PVR) and to elucidate the role of cyclic guanosine monophosphate (cGMP)-dependent vasodilation. Mechanisms of PVR increase in patients with chronic HF are incompletely understood. Twenty-two HF patients with high pulmonary vascular resistance (H-PVR) (>200 dyn.s.cm(-5)) were compared with 24 matched low pulmonary vascular resistance (L-PVR) patients of similar age, sex, body size, HF severity, and volume status who were undergoing invasive hemodynamic study. Pulmonary arterial (PA) and venous blood samples from a wedged PA catheter were used to calculate transpulmonary B-type natriuretic peptide (BNP) uptake and cGMP release. The H-PVR patients were re-examined 1 h after a 40-mg oral dose of sildenafil. Although transpulmonary BNP uptake was similar (p = 0.2), cGMP release was diminished in the H-PVR patients (-1.9 vs. 27.8 nmol.min(-1); p = 0.005). Transpulmonary BNP uptake and cGMP release correlated in the L-PVR patients (R = 0.6, p = 0.004) but not in the H-PVR. The H-PVR patients also had lower PA compliance, systemic arterial compliance (by 47% and 20%, p < 0.001 and p < 0.03), and cardiac index. Sildenafil reduced PVR (-47%), systemic resistance (-24%) and heart rate (-8%), increased cardiac index (+24%), and PA compliance (+87%, all p < 0.001), with a parallel increase of cGMP release (from -5.6 to 16.5 nmol.min(-1), p = 0.047), without affecting BNP uptake or norepinephrine(PA). The PVR response was not dependent on PA wedge pressure or pulmonary hypertension reversibility with prostaglandin E(1). The H-PVR patients have stiffening of both pulmonary and systemic arteries, preserved transpulmonary BNP uptake, but diminished cGMP release, which is reversible by the administration of sildenafil. This study provides in vivo evidence that phosphodiesterase 5A inhibition restores sensitivity of pulmonary vasculature to endogenous cGMP-dependent vasodilators.

First locus for primary pulmonary vein stenosis maps to chromosome 2q

Primary pulmonary vein stenosis (PVS) is a rare cardiac abnormality that exhibits a high morbidity and mortality rate. The disease is characterized by obstruction of the pulmonary venous blood flow owing to congenital hypoplasia of individual extra-pulmonary veins. We describe a consanguineous Turkish family with four affected siblings with primary PVS in association with prenatal lymphatic abnormalities. We aimed to map the first gene for primary PVS. Patients had extensive cardiological examinations including electrocardiograms, echocardiograms, ventilation-perfusion scans, and cardiac catheterizations. All patients died before the age of 16 months because of severe progressive primary PVS. Chromosomal analysis revealed normal karyotypes. We performed a genome-wide linkage analysis using 250 K single nucleotide polymorphism arrays and found the first locus for primary PVS on chromosome 2q35-2q36.1 [multipoint logarithms (base 10) of odds (LOD) scores 3.6]. By fine-mapping with microsatellite markers, we confirmed the homozygous region that extended 6.6 Mb (D2S164-D2S133). Sequencing 12 (188 exons) of the 88 genes from the region revealed no disease-causing sequence variations. Our findings open perspectives for the identification of the genetic cause(s) leading to PVS, which might contribute to elucidate the pathological mechanisms involved in this disorder.

Circulating Tumor Cells in Pulmonary Venous Blood of Primary Lung Cancer Patients

Circulating tumor cells in peripheral blood (CTC) is a potential surrogate of distant metastasis, which is the critical factor influencing decision making regarding therapy and prognosis of primary lung cancer patients. After our preliminary study showing that CTCs were detected in peripheral blood in 29.4% of resectable lung cancer patients, we conducted a prospective study on CTC in pulmonary vein (PV) blood because tumor cells apart from the primary tumor may circulate after passing through the drainage PV. A total of 30 consecutive lung cancer patients who underwent thoracotomy were included. The CTCs in peripheral blood and in PV blood from the primary tumor site were quantitatively examined with the CellSearch system, and the numbers of CTCs per 7.5 mL peripheral and PV blood in each patient were represented as periCTC count and pvCTC count, respectively. Circulating tumor cell was detected in peripheral blood in 5 patients (16.7%; the periCTC count was 1 in 2 patients; and 2, 3, and 16 in 1 patient each), and the incidence of positive periCTC was higher in squamous carcinoma patients than in adenocarcinoma patients (p = 0.028). Circulating tumor cell was detected in PV blood in most patients (29 of 30, 96.7%), and the mean and median pvCTC counts were 1,195 and 81, respectively (range, 0 to 10,034). There was no significant correlation between pvCTC count and any other patient characteristic, including periCTC count. In resectable lung cancer, CTC was positive in peripheral blood of some patients and in PV blood of most patients. A long-term follow-up study to clarify the clinical significance of pvCTC status is warranted.

The monitoring of venous saturations of oxygen in children with congenitally malformed hearts

Mixed venous saturation of oxygen has for some time been used as a tool to assess the adequacy of systemic delivery of oxygen in intensive care. In the post-operative child with cardiac disease, it is increasingly being used to assess adequacy of cardiac output. In many of these patients, true sampling of mixed venous saturation of oxygen is not possible due to the infrequent use of pulmonary arterial catheters, or the presence of intra-cardiac left to right shunting leading to mixing of systemic and pulmonary venous blood. The use of saturation of oxygen in the central venous blood as a surrogate for mixed venous saturation of oxygen has been widely investigated in adults, but its use remains controversial. In this review, we discuss the theory behind the use of mixed venous saturation of oxygen in evaluating cardiac output, the problems pertinent to those patients with congenitally malformed hearts, and explore the evidence for central venous saturation of oxygen as a surrogate for mixed venous saturation of oxygen, and its use as a therapeutic target to improve outcomes in this population of patients.

Abstract 2597: Aortic Atresia Is Associated with an Inferior Postoperative Systemic, Cerebral and Splanchnic Oxygen Transport Status in Neonates with Hypoplastic Left Heart Syndrome after the Norwood Procedure

Aortic atresia (AA) has been identified as a risk factor for mortality after the Norwood procedure. We compared postoperative systemic and regional (cerebral and splanchnic) oxygen transport profiles in neonates with hypoplastic left heart syndrome with or without AA after the Norwood procedure. Systemic oxygen consumption (VO 2 ) was measured using respiratory mass spectrometry postoperatively for 72 hrs in 17 neonates (n=9 in AA group and 8 in non-AA group). Arterial, superior vena cava, and pulmonary venous blood gases and pressures were measured at 2– 4 hr intervals to calculate cardiac output (CO), systemic vascular resistance (SVR), oxygen delivery (DO 2 ) and oxygen extraction ratio (ERO 2 ). Cerebral (ScO 2 ) and splanchnic (SsO 2 ) oxygen saturations were measured using near infrared spectroscopy. The doses of dopamine, vasopressin (up to 0.0008 unit/kg/min), phenoxybenzamine and milrinone were noted. When compared to non-AA group, AA group had lower CO (p=0.03), higher systolic arterial blood pressure (p=0.01) and SVR (p=0.002), lower DO 2 (p=0.07), VO 2 (p=0.003) and ScO 2 during the first 30 to 40 hrs. There was no significant difference in SsO 2 (p=0.12, n=7 in AA group and 3 in non-AA group). Despite a similar ERO 2 (p=0.5), AA group had higher lactate over 72 hrs (p=0.01). AA group received higher doses of vasopressin (p=0.005) and milrinone (p&lt;0.0001), lower doses of dopamine (p=0.07), with similar use of phenoxybenzamine. Furthermore, VO 2 negatively correlated with vasopressin (p=0.05), positively correlated with milrinone (p=0.03) and dopamine (p&lt;0.0001). When including the drugs, the inferior status in all the oxygen transport variables remained, and additionally adversely correlated with vasopressin (p from &lt;0.0001 to 0.06), except for ScO 2 that positively correlated with dopamine, but not with other drugs. Aortic atresia is associated with an inferior status of systemic, cerebral and splanchnic oxygen transport in neonates after the Norwood procedure. Aggressive use of vasopressin worsens systemic and splanchnic oxygen transport status. Postoperative management strategies should be directed to improve both systemic and regional oxygen transport in this special group of patients.

Effects of Shed Mediastinal Blood on Cardiovascular and Pulmonary Function: A Randomized, Double-Blind Study

Shed mediastinal blood during cardiopulmonary bypass (cardiotomy blood) contains fat, particulate matter, and vasoactive mediators that can adversely affect the pulmonary and systemic vasculature, as well as impair gas exchange. Our aim was to evaluate the effects of processing cardiotomy blood on cardiovascular and pulmonary function after cardiac surgery. Patients undergoing coronary artery bypass or aortic valve surgery, or both, using cardiopulmonary bypass were randomly allocated to receiving processed (treated, n = 132) or unprocessed shed blood (control, n = 134) In the treated group, shed blood was processed by centrifugation, washing, and additional filtration. Pulmonary function, arterial and venous blood gases, and hemodynamics were measured before, immediately after, and 2 hours after cardiopulmonary bypass in a consecutive subset of patients (n = 154). Patients and treating physicians were blinded to treatment assignment. Preoperative characteristics were similar between groups. There were no significant differences between groups in indexes of pulmonary mechanical function at any of the measured time points. Patients in the treated group demonstrated reduced pulmonary and systemic vascular resistance (both p < 0.01) as well as increased cardiac index in the perioperative period (2.6 +/- 0.07 versus 2.3 +/- 0.06 L . min(-1) . m(-2) at 2 hours after CPB, p = 0.004). Larger volumes of cardiotomy blood were associated with greater changes in systemic and pulmonary vascular resistance. Indicators of pulmonary gas exchange were similar between groups at all measured time points. Treated patients demonstrated a trend toward reduced length of ventilation (11.0 +/- 1.9 versus 13.9 +/- 2.4 hours, p = 0.12). Processing of shed mediastinal blood improves cardiopulmonary hemodynamics and may reduce ventilatory requirements after cardiac surgery.

Hypoxemia after an axial flow pump Jarvik-2000 implantation: Catheter induced

Hypoxemia after an axial flow pump Jarvik-2000 implantation: Catheter induced

Reference ranges for fetal pulmonary venous blood flow parameters and changes in hypoplastic left heard syndroms (HLHS)

Objectives Our main objectiv was to analyse changes in fetal pulmonary venous blood flow pattern in infants with hypoplastic left heart syndrome (HLHS). Furthermore, we aimed to establish reference ranges of the pulmonary venous blood flow pattern for the second half of pregnancy in healthy human fetuses. We contrasted these ranges with present normative data and with pulmonary venous Doppler parameters of fetuses with HLHS.

Significant correlation of comprehensive Aristotle score with total cardiac output during the early postoperative period after the Norwood procedure

The comprehensive Aristotle score has been proposed as an individualized measure of the complexity of a given surgical procedure and has been reported to significantly correlate with postoperative morbidity and mortality after the Norwood procedure. An important factor leading to postoperative morbidity and mortality is low cardiac output. We studied the correlation between the comprehensive Aristotle score and cardiac output (CO) in infants after the Norwood procedure. Respiratory mass spectrometry was used to continuously measure systemic oxygen consumption (VO(2)) in 22 infants for 72 hours postoperatively. Arterial, superior vena caval and pulmonary venous blood gases were measured at 2 to 4 hour intervals to calculate CO. The comprehensive Aristotle score was collected. Hospital mortality was 4.5%. The comprehensive Aristotle score ranged from 14.5 to 23.5 and negatively correlated with CO (P = 0.027). Among the patient-adjusted factors, myocardial dysfunction (n = 10), mechanical ventilation to treat cardiorespiratory failure (n = 9) and atrioventricular valve regurgitation (n = 4) (P = 0.01) negatively correlated with CO (P = 0.06 to 0.07). Aortic atresia (n = 9) was associated with a lower CO (P = 0.01) for the first 24 hours which linearly increased overtime (P = 0.0001). No correlation was found between CO and other factors (P > 0.3 for all). Comprehensive Aristotle score significantly negatively correlates with CO after the Norwood procedure. A preoperative estimation of the comprehensive Aristotle score, particularly in association with myocardial dysfunction, mechanical ventilation to treat cardiorespiratory failure, atrioventricular valve regurgitation and aortic atresia may help to anticipate a high postoperative morbidity with low cardiac output syndrome.

Dyspnea in a Pregnant 20-Year-Old Woman with Electrocardiographic Right Ventricular Enlargement

A 20-year-old woman, who was 2 months pregnant, came to the cardiology clinic complaining of exertional dyspnea of 6-months duration. Her chest was clear to auscultation, and the neck veins were modestly elevated. The second heart sound was single and loud. There was no cyanosis or clubbing. A midline sternal scar was noted and was described by the patient as the incision for a heart operation when she was 2 months old. An electrocardiogram showed sinus arrhythmia, marked right axis deviation (+135? as judged by equally positive QRS complexes in leads II and aVR), and right ventricular enlargement with a qR complex in lead V1 (Figure). Figure Electrocardiogram recorded when the patient came to the clinic. See text for description. Electrocardiograms with this extreme degree of right ventricular enlargement are rare in adults but may be seen in severe pulmonic stenosis with an intact ventricular septum, tetralogy of Fallot, the Eisenmenger reaction, primary pulmonary hypertension, and simple transposition of the great arteries with surgical redirection of the pulmonary and systemic venous blood at the atrial level via a baffle, i.e., the Albert-Senning-Mustard operation (1–3). The first two diagnoses are ruled out by the absence of a precordial murmur. The second and third are excluded by the lack of cyanosis. The heart operation at 2 months of age indicates a congenital malformation, thus excluding primary pulmonary hypertension. The absence of right bundle branch block strongly suggests that the operation did not include a right ventriculotomy. Thus, the only tenable diagnosis is transposition surgically corrected at the atrial level. The diagnosis was confirmed by echocardiography that revealed ventriculoarterial discordance (transposition of the great arteries), severe dilatation and hypokinesis of the systemic (anatomic right) ventricle, normal function of the pulmonary (anatomic left) ventricle, a normally functioning intraatrial baffle, mild regurgitation of both atrioventricular valves, a right atrial mean pressure of approximately 10 mm Hg, and a pulmonary arterial systolic pressure of approximately 30 mm Hg. Without intervention, 90% of infants with simple transposition die within a year of birth (4). With the Albert-Senning-Mustard operation, the majority become adults. Thus, it is a remarkably successful operation. A residuum of the operation, however, is an anatomic right ventricle serving as the systemic ventricle, which may fail after decades of pressure overload. One solution has been to do the Idriss-Jatene arterial-switch operation (5, 6) and undo the intraatrial baffle. In this patient with a left ventricular systolic pressure <70% of systemic arterial pressure, the arterial switch operation would have to be preceded by pulmonary arterial banding to prepare the currently low-pressure left ventricle for the high-pressure systemic arterial circulation. After several months, the band would be removed, the intraatrial baffle undone, and the great arteries switched. This two-stage operation has rarely been performed successfully in patients beyond their teens (7). Thus, cardiac transplantation will probably be this patient's best option when her cardiac failure worsens despite medications. A more immediate problem is the pregnancy. The patient is in New York Heart Association Class IIID: she has dyspnea with less than ordinary activity and has objective evidence of severe cardiovascular disease, i.e., a severely dilated and poorly contractile systemic ventricle (8). Thus, a good case can be made for terminating the pregnancy (9, 10). She wants to continue with the pregnancy, however, and will probably do so in spite of medical advice to the contrary.

Determination of the side-separated pulmonary right-to-left shunt volume

With the present method of intrapulmonary right-to-left shunt volume calculation, no differentiation can be made between the shunt volume shares of the right and left lungs. For a better understanding of pathophysiological processes during thorax surgery with side-separated ventilation, a side-separated shunt volume determination would be useful. In 14 young female pigs, catheters were implanted into the left atrium after left thoracotomy. After transient clamping of the ipsilateral pulmonary veins, pulmonary venous blood was selectively obtained from the right lung. Cardiac output (CO) and side-separated pulmonary perfusion were determined with flowprobes at the pulmonary trunk and the left pulmonary artery. The shunt volumes were determined before and after thoracotomy during two-lung ventilation (Two-LV), after one-lung (right) ventilation (One-LV) with a continuous positive airway pressure (CPAP) of +7.5, +5.0 cm H(2)O, and under atelectasis of the non-dependent left lung (NDL). After thoracotomy in lateral decubitus position and Two-LV, the shunt volumes of the two lungs differ. The right lung holds the major share (11.0 +/- 1.7% CO) [mean +/- SD]. The share of the left NDL is only 3.3 +/- 1.4. Under One-LV (right) and CPAP in the NDL, the total pulmonary shunt volume rises. This is caused by the increase in the NDL shunt volume share to 8.8 +/- 5.2 under CPAP +7.5 (p<0.05) and to 9.7 +/- 2.5 under CPAP +5.0 (p < 0.05). The new intraoperative method of side-separated arterial blood gas analysis in conjunction with side-separated perfusion measurement makes side- separated right-to-left shunt volume determination possible and may lead to interesting new pathophysiological insights.

Mechanisms of Periodic Breathing During Exercise in Patients With Chronic Heart Failure

Periodic breathing (PB) in heart failure (HF) is attributed to many factors, including low cardiac output delaying the time it takes pulmonary venous blood to reach the central and peripheral chemoreceptors, low lung volume, lung congestion, augmented chemoreceptor sensitivity, and the narrow difference between eupneic carbon dioxide tension and apneic/hypoventilatory threshold. We measured expired gases, ventilation, amplitude, and duration of PB in 23 patients with PB during progressive exercise tests done with 0 mL, 250 mL, or 500 mL of added dead space. Periodicity of PB remained constant despite heart rate, oxygen consumption, and minute ventilation increasing. Within each PB cycle, starting from the beginning of exercise, the largest (peak) tidal volume approached maximum observed tidal volume, while the smallest (nadir) tidal volume increased as exercise power output increased. PB ceased when nadir tidal volume reached peak tidal volume. End-tidal carbon dioxide increased with added dead space, and PB ceased progressively earlier during the exercise done with increased dead space. Circulatory delay does not contribute to the PB observed in exercising HF patients. The pattern of gradually increasing nadir tidal volume during exercise and the effect of dead space on both PB ceasing and end-tidal carbon dioxide suggest that low tidal volume and carbon dioxide apnea threshold are important contributors to PB that occurs during exercise in HF.

Fetal Atrial Septoplasty Is Performed for Left Atrial Decompression but not for Enhancing Preload to a Hypoplastic Left Heart

HomeCirculation ResearchVol. 101, No. 10Fetal Atrial Septoplasty Is Performed for Left Atrial Decompression but not for Enhancing Preload to a Hypoplastic Left Heart Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBFetal Atrial Septoplasty Is Performed for Left Atrial Decompression but not for Enhancing Preload to a Hypoplastic Left Heart Thomas Kohl Thomas KohlThomas Kohl German Center for Fetal Surgery & Minimally-Invasive Therapy, University of Bonn, Germany Search for more papers by this author Originally published9 Nov 2007https://doi.org/10.1161/CIRCRESAHA.107.164202Circulation Research. 2007;101:e113To the Editor:I thank Drs de Almeida, McQuinn, and Sedmera for demonstrating that an increase in ventricular preload is compensated by myocyte proliferation in normal and hypoplastic fetal chick left ventricle.1 The results of their study clearly provide further impetus to develop fetal cardiac interventions for hypoplastic left heart syndromes with intrinsically normal or only mildly stenotic mitral and aortic valves.The purpose of my letter is to point out an incorrect concept that the authors put forth in their discussion. Regarding the rationale behind percutaneous ultrasound-guided fetal atrial septoplasty, the authors state from clinical data collected by Marshall et al2 that “despite technical successful septoplasty the transseptal flow to the left atrium was minimal, pointing out the need of an additional procedure to force the blood into the left heart structures.” The opposite is the case: Atrial septoplasty in fetuses with hypoplastic left heart syndrome with intact or highly restrictive atrial septum is performed on one hand to enable pulmonary venous blood to reach the systemic circulation postnatally and on the other hand to alleviate severe pulmonary congestion by left atrial decompression toward the right side of the heart prenatally. The better outcomes in prenatally treated fetuses with this condition support the rationale that alleviation of pulmonary congestion improves abnormal muscularization of pulmonary veins and, by this mechanism, contributes to a lower risk of intractable pulmonary hypertension in these critically ill infants after birth.1 deAlmeida A, McQuinn T, Sedmera D. Increased ventricular preload is compensated by myocyte proliferation in normal and hypoplastic fetal chick left ventricle. Circ Res. 2007; 100: 1363–1370.LinkGoogle Scholar2 Marshall AC, van der Velde ME, Tworetzky W, Gomez CA, Wilkins-Haug L, Benson CB, Jennings RW, Lock JE. Creation of an atrial septal defect in utero for fetuses with hypoplastic left heart syndrome and intact or highly restrictive atrial septum. Circulation. 2004; 110: 253–258.LinkGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails November 9, 2007Vol 101, Issue 10 Advertisement Article InformationMetrics https://doi.org/10.1161/CIRCRESAHA.107.164202PMID: 17991886 Originally publishedNovember 9, 2007 Keywordspulmonary hypertensionpulmonary congestionfetal atrial septoplastyPDF download Advertisement

Comparison of the Profiles of Postoperative Systemic Hemodynamics and Oxygen Transport in Neonates After the Hybrid or the Norwood Procedure

After the Norwood procedure, early postoperative neonatal physiology is characterized by hemodynamic instability and imbalance of oxygen transport that is commonly attributed to surgical myocardial injury and a systemic inflammatory response to cardiopulmonary bypass (CPB). Because the Hybrid procedure (arterial duct stenting and bilateral pulmonary artery banding) avoids CPB, cardioplegic arrest, and circulatory arrest, we hypothesized that the Hybrid procedure is associated with superior postoperative hemodynamics and oxygen transport. Oxygen consumption (VO2) was continuously measured using respiratory mass spectrometry for 72 hours after Hybrid (n=6) and Norwood (n=13) procedures. Arterial, superior vena cava, and pulmonary venous blood gases and pressures were measured at 2- to 4-hour intervals to calculate systemic and pulmonary blood flows (Qs, Qp), and systemic vascular resistance (SVR), total pulmonary vascular resistance including pulmonary arterial band or B-T shunt (tPVR), cardiac output (CO), oxygen delivery (DO2), and oxygen extraction ratio (ERO2). Rate-pressure product was calculated as heart rate x systolic arterial pressure. When compared with the Norwood procedure, the early postoperative Hybrid patients had lower CO, higher SVR, and higher Qp:Qs ratios. In addition, the DO2 and VO2 were both lower in the Hybrids with higher ERO2 and lactate levels. This early postoperative pattern reversed after 48 hours. Although Hybrid procedure avoids CPB and cardioplegic arrest, the early hemodynamic profile is not superior to the Norwood in terms of cardiac output and control of pulmonary blood flow. These data strongly suggest that a "hands off" approach to postoperative care in Hybrid patients may not be appropriate in patients with preoperative diminished myocardial function; and in such patients a Norwood-derived management strategy (afterload reduction and inotropic support) should be considered.

Ablation of Atrial Flutter in a Patient With Mustard Procedure Using Integration of Real-Time Electroanatomical Mapping With 3-Dimensional Computed Tomographic Imaging

A 24-year-old woman with a history of surgical palliation of d-transposition of the great arteries, a systemic ejection fraction of 66%, and symptomatic atrial flutter with rapid ventricular response was referred for an electrophysiological study and ablation procedure. At 6 months of age, she had undergone a Mustard (atrial switch) procedure, whereby a “baffle” was surgically constructed within her atria to direct systemic venous blood across the mitral valve into the left ventricle (systemic venous ventricle) and the pulmonary artery, and pulmonary venous blood across the tricuspid valve into the right ventricle (pulmonary venous ventricle) and the aorta. Her ECG, which shows atrial flutter with a ventricular rate of 262 beats per minute with 1:1 atrioventricular conduction, is illustrated in Figure 1. Figure 1. Patient’s ECG shows atrial flutter with 1:1 atrioventricular conduction with a ventricular rate of 262 beats per minute. The procedure was performed under the guidance of the CARTO-MERGE electroanatomical mapping system (Biosense Webster, Inc., Diamond Bar, Calif.). After creation of a 3-dimensional anatomic construct from a high-resolution contrast-enhanced cardiac computed tomography, the cardiac structures were segmented (Figure 2). Integration of the computed …