3-Dimensional Modeling Guided Transcatheter Repair of Dehisced Pulmonary Venous Baffle With Gore ASD Device

A 38-year-old woman with sinus venosus atrial septal defect and partial anomalous return of the right upper pulmonary vein underwent a Warden procedure but experienced a large residual defect after patch dehiscence. Image-derived 3D modeling informed novel device closure with a Gore Cardioform atrial septal occluder. (Level of Difficulty: Advanced.).

Patients with Post-COVID-19 Vaccination Myocarditis Have More Favorable Strain in Cardiac Magnetic Resonance Than Those With Viral Myocarditis

There have been reports of myocarditis following vaccination against COVID-19. We sought to describe cardiac magnetic resonance (CMR) findings among pediatric patients. Retrospective review at a large academic center of patients clinically diagnosed with post-vaccine myocarditis (PVM) undergoing CMR. Data collected included parametric mapping, ventricular function, and degree of late gadolinium enhancement (LGE). Post-processing strain analysis was performed using feature tracking. Strain values, T1/T2 values, and ventricular function were compared to age- and gender-matched controls with viral myocarditis using a Wilcoxon Signed Rank test. Among 12 patients with presumed PVM, 11 were male and 11 presented after the second vaccination dose, typically within 4 days. All presented with chest pain and elevated troponin. 10 met MRI criteria for acute myocarditis. All had LGE typically seen in the lateral and inferior walls; only five had prolonged T1 values. 10 met criteria for edema based on skeletal muscle to myocardium signal intensity ratio and only 5 had prolonged T2 mapping values. Patients with PVM had greater short-axis global circumferential and radial strain, right ventricle function, and cardiac output when compared to those with viral myocarditis. Patients with PVM have greater short-axis global circumferential and radial strains compared to those with viral myocarditis. LGE was universal in our cohort. Signal intensity ratios between skeletal muscle and myocardium may be more sensitive in identifying edema than T2 mapping. Overall, the impact on myocardial strain by CMR is less significant in PVM compared to more classic viral myocarditis.

Longitudinal Trends of Vascular Flow and Growth in Patients Undergoing Fontan Operation

BACKGROUND

Single ventricle (SV) patients undergo multiple surgeries with subsequent changes in anatomy and hemodynamics. There is little cardiac magnetic resonance (CMR) data on serial changes in these patients. This study aimed to assess longitudinal changes of SV anatomy and hemodynamics in a large cohort.

METHODS

Anatomy and flow in SV patients with serial CMRs performed between 2008-2019 at a single institution were retrospectively reviewed. Mixed-effects linear regression was used to estimate changes over time at 3-9 months, 1-5 years, and >5 years after Fontan.

RESULTS

119 patients were included (51% with hypoplastic left heart;77% underwent extra-cardiac Fontan). 88 patients had 3 serial CMRs. Indexed right superior vena cava (RSVC), inferior vena cava (IVC), neo-aortic valve and descending aorta area decreased over time (beta -0.19,-0.44,-0.23 respectively;p<0.01) as did indexed RSVC, neo and native aorta and descending aorta flow (beta -0.49,-0.53,-0.59 respectively;p<0.0001). IVC flow and its contribution to total caval flow increased (beta 0.33;p<0.0001). Indexed right and left right pulmonary artery (LPA) flow did not change, however indexed LPA area decreased (beta -0.16;p=0.0014) with time. Systemic to pulmonary collateral flow remained unchanged prior to, and early after Fontan (beta -0.54;p=0.42) but decreased with time from Fontan (beta coefficient -0.22;p<0.0001).

CONCLUSIONS

In this cohort of longitudinally followed SV patients, there are significant trends in vascular size and flow over time from Fontan. These findings can be used as a framework to interpret serial CMR data in the SV, and non-invasively identify deviations from expected patterns prior to the development of clinical symptoms.

Optimizing neonatal cardiac imaging (magnetic resonance/computed tomography)

Magnetic resonance imaging (MRI) and CT perform an important role in the evaluation of neonates with congenital heart disease (CHD) when echocardiography is not sufficient for surgical planning or postoperative follow-up. Cardiac MRI and cardiac CT have complementary applications in the evaluation of cardiovascular disease in neonates. This review focuses on the indications and technical aspects of these modalities and special considerations for imaging neonates with CHD.

Bleeding and thrombotic risk in pregnant women with Fontan physiology

BACKGROUND/OBJECTIVES

Pregnancy may potentiate the inherent hypercoagulability of the Fontan circulation, thereby amplifying adverse events. This study sought to evaluate thrombosis and bleeding risk in pregnant women with a Fontan.

METHODS

We performed a retrospective observational cohort study across 13 international centres and recorded data on thrombotic and bleeding events, antithrombotic therapies and pre-pregnancy thrombotic risk factors.

RESULTS

We analysed 84 women with Fontan physiology undergoing 108 pregnancies, average gestation 33±5 weeks. The most common antithrombotic therapy in pregnancy was aspirin (ASA, 47 pregnancies (43.5%)). Heparin (unfractionated (UFH) or low molecular weight (LMWH)) was prescribed in 32 pregnancies (30%) and vitamin K antagonist (VKA) in 10 pregnancies (9%). Three pregnancies were complicated by thrombotic events (2.8%). Thirty-eight pregnancies (35%) were complicated by bleeding, of which 5 (13%) were severe. Most bleeds were obstetric, occurring antepartum (45%) and postpartum (42%). The use of therapeutic heparin (OR 15.6, 95% CI 1.88 to 129, p=0.006), VKA (OR 11.7, 95% CI 1.06 to 130, p=0.032) or any combination of anticoagulation medication (OR 13.0, 95% CI 1.13 to 150, p=0.032) were significantly associated with bleeding events, while ASA (OR 5.41, 95% CI 0.73 to 40.4, p=0.067) and prophylactic heparin were not (OR 4.68, 95% CI 0.488 to 44.9, p=0.096).

CONCLUSIONS

Current antithrombotic strategies appear effective at attenuating thrombotic risk in pregnant women with a Fontan. However, this comes with high (>30%) bleeding risk, of which 13% are life threatening. Achieving haemostatic balance is challenging in pregnant women with a Fontan, necessitating individualised risk-adjusted counselling and therapeutic approaches that are monitored during the course of pregnancy.

Reducing radiation dose from myocardial perfusion imaging in subjects with complex congenital heart disease

INTRODUCTION

The prevalence of defects and effective radiation dose from various myocardial perfusion imaging (MPI) strategies in congenital heart disease (CHD) is unknown.

METHODS

We studied 75 subjects with complex CHD (ages 5 to 80 years) referred for MPI between 2002 and 2015. A rest and exercise or pharmacologic stress MPI was performed using 99mTechnetium sestamibi, 82rubidium or 13N-ammonia, and Sodium iodide SPECT (single-photon emission computed tomography), SPECT/CT or Cadmium zinc telluride (CZT) SPECT or PET (positron emission tomography)/CT scanners. Deidentified images were interpreted semi-quantitatively in three batches: stress only MPI, stress/rest MPI, and stress/rest MPI with taking into account a history of ventricular septal defect repair. Effective radiation dose was estimated for stress/rest MPI and predicted for 1-day stress-first (normal stress scans), and for 2-day stress/rest MPI (abnormal stress scans).

RESULTS

The median age was 18.6 years. The most common type of CHD was transposition of the great arteries (63%). Rest/stress MPI was abnormal in 43% of subjects and 25% of the abnormal scans demonstrated reversible defects. Of the subjects with abnormal MPI, 33% had significant underlying anatomic coronary artery obstruction. Estimated mean effective radiation dose ranged from 2.1 ± 0.6 mSv for 13N-ammonia PET/CT to 12.5 ± 0.9 mSv for SPECT/CT. Predicted effective radiation dose was significantly lower for stress-first MPI and for 2-day stress/rest protocols.

CONCLUSIONS

Due to the relatively high prevalence of abnormal stress MPI, tailored protocols with a stress-first MPI as well as the use of 2-day protocols and advanced imaging technologies including CZT SPECT, novel image reconstruction software, and PET MPI could substantially reduce radiation dose in complex CHD.

Successful in vitro fertilization in women with Fontan physiology

PURPOSE

Patients with single ventricle anatomy palliated with Fontan operation are at risk for thromboembolism, arrhythmia, and heart failure rendering pregnancy high risk or even contraindicated. Infertility and high rates of first trimester miscarriage are not uncommon. In vitro fertilization (IVF) with or without gestational surrogacy can be an option, but poses risks during ovarian stimulation, oocyte retrieval, and the post-procedural period. We present six cases of women with complex congenital heart disease status post Fontan operation who underwent successful IVF.

METHODS

Case series from a single-center tertiary care setting.

RESULTS

Indications for referral were cardiac or fertility concerns for pregnancy of the congenital cardiologist. One woman had mild volume overload after oocyte retrieval requiring furosemide and one experienced post-operative colitis. There were no thrombotic complications.

CONCLUSIONS

A multidisciplinary team-based approach can result in successful oocyte retrieval and IVF in women with complex congenital heart disease and Fontan physiology.

Improvement in ventricular function with rhythm control of atrial arrhythmias may delay the need for atrioventricular valve surgery in adults with congenital heart disease

OBJECTIVE

Atrial arrhythmias and atrioventricular valve regurgitation (AVVR) are common causes of morbidity among adults with congenital heart disease (ACHD). The impact of rhythm control on AVVR in this population is unknown. We sought to determine whether a rhythm control strategy is associated with greater freedom from AV valve surgery than a rate control strategy.

DESIGN

Patients evaluated by both ACHD and electrophysiology specialists at a single academic center were screened for atrial arrhythmias and at least moderate-severe AVVR. Clinical and electrographic data were abstracted. All echocardiograms were interpreted by a single echocardiographer blinded to treatment strategy. Patients were followed until AV valve surgery, heart transplantation, death, or last clinical follow-up.

RESULTS

Rhythm control was attempted in 9 of 24 identified patients. Among these nine patients, arrhythmias were eliminated in three and reduced from persistent to paroxysmal in another three. In the rhythm control group, mean left ventricular ejection fraction improved from 54.4 ± 12.4% to 60.0 ± 11.5% (P = .02) and mean right ventricular systolic function increased nearly one grade (P = .02). AVVR did not decrease significantly. No significant change in left or right ventricular systolic function, or AVVR was observed among the 15 patients treated with rate control. Four-year survival free of AV valve operation and heart transplant was 88% in the rhythm control group and 31% in the rate control group (P = .04).

CONCLUSIONS

In ACHD patients with atrial arrhythmias and at least moderate-severe AVVR, a rhythm control strategy was associated with improved biventricular systolic function. This improvement in ventricular function and symptoms may allow valve surgery to be deferred.

Relationship of Aortic Stiffness to Exercise and Ventricular Volumes in Single Ventricles

BACKGROUND

Patients with single ventricle (SV) may often undergo aortic reconstruction that creates a stiff large vessel, increasing afterload and affecting exercise performance. The objective of this study was to determine the relationship of pulse wave velocity (PWV) and distensibility in reconstructed and normal aortic arches after Fontan with exercise variables.

METHODS

PWV and distensibility of the descending aorta at the level of the diaphragm (DAo) were calculated with real-time exercise cardiac magnetic resonance in 48 patients with SV after Fontan (18 after aortic reconstruction; 30 without aortic reconstruction) and compared with metabolic exercise stress test variables.

RESULTS

PWV was greater in the reconstructed group than in the non-reconstructed group (median 4.4 m/s [range: 2.3 to 9.8 m/s] versus 3.6 [range: 2.6 to 6.3 m/s], respectively, p = 0.003). Statistically significant inverse correlations were found between PWV and end-diastolic, end-systolic, and stroke volumes at rest and at exercise in the reconstructed group. In addition, inverse correlations also existed in the reconstructed group between distensibility of the DAo and the exercise variables such as peak oxygen pulse (R = 0.56, p = 0.02), peak oxygen consumption (R = 0.63, p = 0.008), oxygen consumption at ventilatory anaerobic threshold (R = 0.48, p = 0.04), and peak work (R = 0.54, p = 0.02). Similar correlations were not seen in patients with non-reconstructed aortas.

CONCLUSIONS

Patients with SV with reconstructed aortas have increased aortic stiffness, increasing afterload on the ventricle. Native DAo stiffness distal to the reconstruction is inversely correlated with exercise performance, presumably to decrease impedance mismatch to maintain homogeneity of the aortic wall. This information suggests a possible mechanism for decreased exercise performance in patients with SV with aortic reconstructions.

MRI Evaluation of Lymphatic Abnormalities in the Neck and Thorax after Fontan Surgery: Relationship with Outcome

Background The Fontan operation is performed for surgical palliation of single ventricle physiology. This operation is usually preceded by a superior cavopulmonary connection (SCPC); lymphatic abnormalities after SCPC may be demonstrated at MRI and prior to the Fontan operation. Purpose To determine if the degree of neck and thoracic lymphatic abnormalities at T2-weighted MRI in patients after superior cavopulmonary connection (SCPC) correlated with surgical outcomes from the Fontan procedure. Materials and Methods Patients for whom SCPC was performed for palliation of single ventricle disease who underwent chest MRI between July 2012 and May 2015 at a single institution were retrospectively reviewed. T2-weighted images were scored as lymphatic type 1 (little or no T2 mediastinal and supraclavicular signal) to type 4 (T2 signal into both the mediastinum and the lung parenchyma). Fontan takedown, duration of post-Fontan hospitalization and pleural effusion, postoperative plastic bronchitis, need for transplant, and mortality were tabulated. The relationship between lymphatic type and clinical outcomes was evaluated by using analysis of variance (ANOVA), the Kruskal-Wallis H test, and the Fisher exact test. Results A total of 83 patients (mean age, 7.9 years ± 2.6) were evaluated. Among these 83 patients, 53 (64%) were classified with type 1 or 2 lymphatic abnormalities, 17 (20%) with type 3, and 12 (16%) with type 4. The rate of failure of Fontan completion was higher in patients with type 4 than in type 1 or 2 (54% vs 2%, respectively; P = .004). Need for cardiac transplant (one of 13 [8%]) and death (three of 13 [23%]) occurred only in type 4. Median postoperative length of stay was longer for patients with type 4 than for those with types 1 or 2 (29 days vs 9 days, respectively; P < .01). Conclusion Greater MRI-based severity of lymphatic abnormalities in patients prior to planned Fontan procedure was associated with failure of Fontan completion and longer postoperative stay. © RSNA, 2019 Online supplemental material is available for this article.

Cardiopulmonary Exercise Testing-A Valuable Tool, Not Gatekeeper When Referring Patients With Adult Congenital Heart Disease for Transplant Evaluation

INTRODUCTION

Treatment of patients with adult congenital heart disease (ACHD) with advanced therapies including heart transplant (HT) is often delayed due to paucity of objective prognostic markers for the severity of heart failure (HF). While the utility of Cardiopulmonary Exercise Testing (CPET) in non-ACHD patients has been well-defined as it relates to prognosis, CPET for this purpose in ACHD is still under investigation.

METHODS

We performed a retrospective cohort study of 20 consecutive patients with ACHD who underwent HT between March 2010 and February 2016. Only 12 of 20 patients underwent CPET prior to transplantation. Demographics, standard measures of CPET interpretation, and 30-day and 1-year post transplantation outcomes were collected.

RESULTS

Patient Characteristics. Twenty patients with ACHD were transplanted at a median of 40 years of age (range: 23-57 years). Of the 12 patients who underwent CPET, 4 had undergone Fontan procedures, 4 had tetralogy of Fallot, 3 had d-transposition of the great arteries, and 1 had Ebstein anomaly. Thirty-day and one-year survival was 100%. All tests included in the analysis had a peak respiratory quotient _1.0. The median peak oxygen consumption per unit time (_VO2) for all diagnoses was 18.2 mL/kg/min (46% predicted), ranging from 12.2 to 22.6.

CONCLUSION

There is a paucity of data to support best practices for patients with ACHD requiring transplantation. While it cannot be proven based on available data, it could be inferred that outcomes would have been worse or perhaps life sustaining options unavailable if providers delayed referral because of the lack of attainment of CPET-specific thresholds.

Accuracy of risk prediction scores in pregnant women with congenital heart disease

OBJECTIVE

To assess performance of risk stratification schemes in predicting adverse cardiac outcomes in pregnant women with congenital heart disease (CHD) and to compare these schemes to clinical factors alone.

DESIGN

Single-center retrospective study.

SETTING

Tertiary care academic hospital.

PATIENTS

Women ≥18 years with International Classification of Diseases, Ninth Revision, Clinical Modification codes indicating CHD who delivered between 1998 and 2014. CARPREG I and ZAHARA risk scores and modified World Health Organization (WHO) criteria were applied to each woman.

OUTCOME MEASURES

The primary outcome was defined by ≥1 of the following: arrhythmia, heart failure/pulmonary edema, transient ischemic attack, stroke, dissection, myocardial infarction, cardiac arrest, death during gestation and up to 6 months postpartum.

RESULTS

Of 178 women, the most common CHD lesions were congenital aortic stenosis (15.2%), ventricular septal defect (13.5%), atrial septal defect (12.9%), and tetralogy of Fallot (12.9%). Thirty-five women (19.7%) sustained 39 cardiac events. Observed vs expected event rates were 9.9% vs 5% (P = .02) for CARPREG I score 0 and 26.1% vs 7.5% (P < .001) for ZAHARA scores 0.51-1.5. ZAHARA outperformed CARPREG I at predicting adverse cardiovascular outcomes (AUC 0.80 vs 0.72, P = .03) but was not significantly better than modified WHO. Clinical predictors of adverse cardiac event were symptoms (P = .002), systemic ventricular dysfunction (P < .001), and subpulmonary ventricular dysfunction (P = .03) with an AUC 0.83 comparable to ZAHARA (P = .66).

CONCLUSIONS

CARPREG I and ZAHARA scores underestimate cardiac risk for lower risk pregnancies in these women. Of the three risk schemes, CARPREG I performed least well in predictive capacity. Clinical factors specific to the population studied are comparable to stratification schemes.

A Comparison of Perioperative Management of Anomalous Aortic Origin of a Coronary Artery Between an Adult and Pediatric Cardiac Center

Background:

Anomalous aortic origin of a coronary artery (AAOCA) presents in varying age-groups. Assuming management algorithms differ between pediatric and adult institutions, we compared the perioperative management of patients with AAOCA at two such centers.

Methods:

A retrospective review was conducted at a pediatric and an adult institution of patients 14 years or older who underwent surgical repair of AAOCA between January 2000 and May 2014.

Results:

Twenty patients from the pediatric center (median age: 16.5 years, range: 14-18 years) and nine patients from the adult center (median age: 40 years, range: 37-52 years) were included. An anomalous aortic origin of a right coronary artery was the most frequent pathology at each institution. Chest pain was the most common presenting symptom at both institutions. Preoperative echocardiography was performed in 95% patients at the pediatric center and in 100% of patients at the adult center. Cardiac catheterization was utilized more frequently at the adult center, and cardiac magnetic resonance imaging more commonly employed at the pediatric center. Isolated coronary unroofing was performed in 19 of 20 cases at the pediatric center and in only 2 (22%) cases at the adult institution, both by congenitally trained cardiac surgeons. More concomitant cardiac procedures were performed at the adult center with associated longer operative times and hospital stays.

Conclusion:

Management strategies for AAOCA vary depending on both patient-specific factors and expertise of the managing team. Further studies are needed to optimally standardize diagnostic and treatment pathways regardless of location venue.

Clinical applications of radionuclide imaging in the evaluation and management of patients with congenital heart disease

Non-invasive testing of children with congenital heart disease (CHD) began in the 1950s with the introduction of radionuclide studies to assess shunt fractions, pulmonary blood flow, and ventricular contractile function. Echocardiography and cardiac magnetic resonance imaging have since replaced radionuclide imaging in many of these roles. Concurrently, percutaneous and surgical repairs of complex CHD evolved, creating new roles for radionuclide imaging. In this paper on applications of radionuclide imaging in CHD, we review the multiple mechanisms for myocardial ischemia in CHD. We critically compare optimal radionuclide imaging techniques to other imaging modalities for assessing ischemia in CHD. We present the current role of nuclear imaging for assessing viability and pulmonary blood flow. We highlight the value added by advances in dedicated cardiac SPECT scanners, novel reconstruction software, and cardiac PET in performing low-dose radionuclide imaging in CHD. Finally, we discuss the emerging clinical indications for radionuclide imaging in CHD including coronary flow reserve assessment and evaluation of cardiovascular prosthesis and device infections.

Cardiac magnetic resonance in adults with congenital heart disease

Increasing numbers of adults with congenital heart disease are referred for cardiac magnetic resonance imaging. Knowledge of the congenital heart anatomy, prior surgical interventions, and the development of an imaging focus for each individual patient plays a crucial role when performing a successful cardiac magnetic resonance imaging examination. The following manuscript focuses on cardiac magnetic resonance imaging considerations of three specific conotruncal congenital heart lesions: tetralogy of Fallot, transposition of the great arteries (TGA), and physiologically corrected TGA (c-TGA).

Safety and feasibility of regadenoson use for suboptimal heart rate response during symptom-limited standard Bruce exercise stress test

BACKGROUND

Regadenoson during exercise stress test (ETT) can provide maximal hyperemia for myocardial perfusion imaging (MPI), along with exercise information. Our aim was to study the feasibility and safety of regadenoson injection at peak ETT for submaximal heart rate (HR) response.

METHODS

Consecutive patients who underwent SPECT MPI with standard Bruce ETT or supine-regadenoson (Supine-Reg) were analyzed. ETT patients were grouped as ETT-Max [maximal HR > 0.85 * (220 - age), N = 1,522], ETT-Submax (submaximal HR no regadenoson, N = 504), ETT-Reg (submaximal HR and regadenoson, N = 211).

RESULTS

The HR during ETT was submaximal in 715 (32%) patients. Of these, 211 patients (30%) underwent ETT-Reg (mean exercise duration: 5.5 ± 2.5 minutes). ETT-Reg patients had a higher frequency of hypertension, diabetes, smoking and beta-blocker use, similar rest systolic blood pressure (SBP), but lower rest and peak HR and peak SBP compared to ETT-Max patients. There were no serious complications with regadenoson. Side effects (49% vs 6%, P < .0001) were fewer and aminophylline use was lower with ETT-Reg compared to Supine-Reg (0.5% vs 8.1%, P = .001).

CONCLUSIONS

Submaximal HR response to ETT is common. ETT-Reg is safe, feasible, and well-tolerated. ETT-Reg facilitates a diagnostic MPI with reporting of functional capacity, exercise ECG/hemodynamic changes and MPI at maximal hyperemia.

Cardiac magnetic resonance imaging for stage B heart failure

Cardiac magnetic resonance imaging (CMR) can play a key role in the assessment and follow-up of patients with stage B heart failure. CMR currently serves as the reference standard for quantifying right and left ventricular size and ejection fraction. Technical advances have also enabled CMR to provide noninvasive tissue characterization and detailed assessments of myocardial performance. Thus, in addition to standard metrics of cardiac structure and function, CMR offers a variety of tools for determining cause, severity, and estimating the prognosis associated with an asymptomatic cardiomyopathy.

Multimodality imaging in the assessment of myocardial viability

The prevalence of heart failure due to coronary artery disease continues to increase, and it portends a worse prognosis than non-ischemic cardiomyopathy. Revascularization improves prognosis in these high-risk patients who have evidence of viability; therefore, optimal assessment of myocardial viability remains essential. Multiple imaging modalities exist for differentiating viable myocardium from scar in territories with contractile dysfunction. Given the multiple modalities available, choosing the best modality for a specific patient can be a daunting task. In this review, the physiology of myocardial hibernation and stunning will be reviewed. All the current methods available for assessing viability including echocardiography, cardiac magnetic resonance imaging, nuclear imaging with single photon emission tomography and positron emission tomography imaging and cardiac computed tomography will be reviewed. The effectiveness of the various techniques will be compared, and the limitations of the current literature will be discussed.

Cardiac magnetic resonance imaging as a prognostic tool in patients with nonischemic cardiomyopathy

Technical advancements have enabled cardiac magnetic resonance (CMR) imaging to provide a noninvasive assessment of cardiomyopathy. Cardiac magnetic resonance imaging acts as the reference standard for quantifying left and right ventricular function. It also assesses the etiology of cardiomyopathy by demonstrating the presence and size of myocardial scar and by detecting myocardial inflammation and interstitial infiltration. Cardiomyopathy can result in early mortality and arrhythmic risk, and CMR imaging aids in risk stratification among this group of patients. Left ventricular ejection fraction predicts which patients will benefit most from implantable cardioverter-defibrillators (ICDs), but this is not a perfect marker of arrhythmic risk. The etiology of cardiomyopathy, as assessed with CMR imaging, adds further prognostic information with infiltrative cardiomyopathies, resulting in higher mortality than idiopathic cardiomyopathies. Among patients with nonischemic cardiomyopathy (NICM), the degree of fibrosis as determined by the CMR imaging sequence of late gadolinium enhancement (LGE) imaging offers further prognostic information. Late gadolinium enhancement imaging in patients with NICM portends an approximately 3- to 8-fold greater risk of death or hospitalization than NICM without LGE imaging. Further research is needed to determine if the presence of LGE will be helpful in predicting which patients may benefit from ICD implantation.

Pulmonary vein stenosis following left pneumonectomy: a variant contributor to postpneumonectomy syndrome

Postpneumonectomy syndrome is a recognized complication following pneumonectomy, resulting from mediastinal displacement into the vacated pleural space. Mediastinal displacement causes bronchial compression and dyspnea. This report describes a 47-year-old woman who presented with shortness of breath 6 months after a left pneumonectomy. She was initially hypoxic and was found to have a patent foramen ovale. Following closure of the patent foramen ovale, she was no longer hypoxic, but she continued to have dyspnea with exertion and left lateral decubitus positioning. There was no evidence of bronchial compression, but MRI and transesophageal echocardiography suggested pulmonary vein compression due to mediastinal displacement. Transthoracic echocardiography confirmed functional pulmonary vein compression that was worse in the standing and in the left lateral positions. Her symptoms improved with mediastinal repositioning using a transesophageal echocardiography-guided approach. Positional pulmonary vein compression may be an underdiagnosed complication of pneumonectomy.

Pre-admission warfarin use in patients with acute ischemic stroke and atrial fibrillation: The appropriate use and barriers to oral anticoagulant therapy

INTRODUCTION

Warfarin reduces the risk of stroke in patients with atrial fibrillation. Despite strong guideline recommendations, studies continue to demonstrate the under-use of warfarin in clinical practice.

PURPOSE

To determine the prevalence and predictors of warfarin use in patients presenting with atrial fibrillation and acute ischemic stroke who do not have a documented contraindication to anticoagulants.

METHODS

We conducted a retrospective chart review of all patients admitted to the Hamilton General Hospital with a primary diagnosis of ischemic stroke and a coded diagnosis of atrial fibrillation between 1999 and 2004. Using a standardized data abstraction form, the following variables were recorded: baseline demographics, past medical history including risk factors for stroke and major bleeding and known predictors of warfarin under-use. In cases where warfarin was not prescribed, charts were also reviewed for documented contraindications to warfarin use. The following were considered valid contraindications to warfarin: patient refusal, non-compliance with INR monitoring, bleeding diathesis, history of major bleeding or significant alcohol consumption.

RESULTS

In total, 196 patients with ischemic stroke and atrial fibrillation were identified. Of these patients, 106 were considered to be appropriate candidates for anticoagulation after excluding patients with no known diagnosis of atrial fibrillation prior to admission (N=59), a valid contraindication to warfarin use (N=18), a CHADS2 score <1 (N=6) or a competing diagnosis for warfarin use (N=7). Of the patients deemed to be suitable candidates for warfarin, 57 (54%) were receiving warfarin therapy on admission. On multivariable analyses, increasing age (OR 0.7; 95% CI 0.5-0.9) was associated with a reduced odds of warfarin use while a history of stroke or TIA (OR 2.6; 95% CI 1.1-6.5) and a history of congestive heart failure (OR 3.2; 95% CI 1.1-9.0) were associated with an increased odds of warfarin use in patients without a contraindication to warfarin. While 75% of patients <75 years old were anticoagulated, only 33% of those >85 years were prescribed warfarin on admission to hospital.

CONCLUSIONS

early half of all patients presenting with atrial fibrillation and acute ischemic stroke who were suitable candidates for anticoagulation were not prescribed warfarin. In patients not prescribed warfarin, very few had a documented contraindication. Advanced age appears to be the strongest predictor of warfarin non-use.

Substrate utilization during exercise performed with and without glucose ingestion in female and male endurance trained athletes

Compared to males, females oxidize proportionately more fat and less carbohydrate during endurance exercise performed in the fasted state. This study was designed to test the hypothesis that there may also be gender differences in exogenous carbohydrate (CHOexo) oxidation during exercise. Healthy, young males (n = 7) and females (n = 7) each completed 2 exercise trials (90 min cycle ergometry at 60% VO2peak), 1 week apart. Females were eumenorrheic and were tested in the midfollicular phase of their menstrual cycle. Subjects drank intermittently either 8% CHOexo (1 g glucose x kg x h(-1)) enriched with U-13C glucose or an artificially sweetened placebo during the trial. Whole-body substrate oxidation was determined from RER, urinary urea excretion, and the ratio of 13C:12C in expired gas during the final 60 min of exercise. During the placebo trial, fat oxidation was higher in females then in males (0.42 +/- 0.07 vs 0.32 +/- 0.09 g.min(-1).kg LBM(-1) x 10(2)) at 30 min of exercise (p < .05). When averaged over the final 60 min of exercise, the relative proportions of fat, total carbohydrate, and protein were all similar between groups. During CHOexo ingestion, both the ratio of 13C:12C in expired gas (p < .05) and the proportion of energy derived from CHOexo relative to LBM (p < .05) were higher in females compared to males at 75- and 90-min exercise. When averaged over the final 60 min of exercise, the percentage of CHOexo to the total energy contribution tended to be higher in females (14.3 +/- 1.2%) than in males (11.2 +/- 1.2%; p = .05). Compared to males, females may oxidize a greater relative proportion of CHOexo during endurance exercise which, in turn, may spare more endogenous fuel. Based on these observations, ingested carbohydrate may be a particularly beneficial source of fuel during endurance exercise for females.