Jan Bogaert

Exercise-induced right ventricular dysfunction and structural remodelling in endurance athletes

AIMS Endurance training may be associated with arrhythmogenic cardiac remodelling of the right ventricle (RV). We examined whether myocardial dysfunction following intense endurance exercise affects the RV more than the left ventricle (LV) and whether cumulative exposure to endurance competition influences cardiac remodelling (including fibrosis) in well-trained athletes. METHODS AND RESULTS Forty athletes were studied at baseline, immediately following an endurance race (3-11 h duration) and 1-week post-race. Evaluation included cardiac troponin (cTnI), B-type natriuretic peptide, and echocardiography [including three-dimensional volumes, ejection fraction (EF), and systolic strain rate]. Delayed gadolinium enhancement (DGE) on cardiac magnetic resonance imaging (CMR) was assessed as a marker of myocardial fibrosis. Relative to baseline, RV volumes increased and all functional measures decreased post-race, whereas LV volumes reduced and function was preserved. B-type natriuretic peptide (13.1 ± 14.0 vs. 25.4 ± 21.4 ng/L, P = 0.003) and cTnI (0.01 ± .03 vs. 0.14 ± .17 μg/L, P < 0.0001) increased post-race and correlated with reductions in RVEF (r = 0.52, P = 0.001 and r = 0.49, P = 0.002, respectively), but not LVEF. Right ventricular ejection fraction decreased with increasing race duration (r = -0.501, P < 0.0001) and VO(2)max (r = -0.359, P = 0.011). Right ventricular function mostly recovered by 1 week. On CMR, DGE localized to the interventricular septum was identified in 5 of 39 athletes who had greater cumulative exercise exposure and lower RVEF (47.1 ± 5.9 vs. 51.1 ± 3.7%, P = 0.042) than those with normal CMR. CONCLUSION Intense endurance exercise causes acute dysfunction of the RV, but not the LV. Although short-term recovery appears complete, chronic structural changes and reduced RV function are evident in some of the most practiced athletes, the long-term clinical significance of which warrants further study.

A clinical prediction rule for the diagnosis of coronary artery disease: validation, updating, and extension

AIMS The aim was to validate, update, and extend the Diamond-Forrester model for estimating the probability of obstructive coronary artery disease (CAD) in a contemporary cohort. METHODS AND RESULTS Prospectively collected data from 14 hospitals on patients with chest pain without a history of CAD and referred for conventional coronary angiography (CCA) were used. Primary outcome was obstructive CAD, defined as ≥ 50% stenosis in one or more vessels on CCA. The validity of the Diamond-Forrester model was assessed using calibration plots, calibration-in-the-large, and recalibration in logistic regression. The model was subsequently updated and extended by revising the predictive value of age, sex, and type of chest pain. Diagnostic performance was assessed by calculating the area under the receiver operating characteristic curve (c-statistic) and reclassification was determined. We included 2260 patients, of whom 1319 had obstructive CAD on CCA. Validation demonstrated an overestimation of the CAD probability, especially in women. The updated and extended models demonstrated a c-statistic of 0.79 (95% CI 0.77-0.81) and 0.82 (95% CI 0.80-0.84), respectively. Sixteen per cent of men and 64% of women were correctly reclassified. The predicted probability of obstructive CAD ranged from 10% for 50-year-old females with non-specific chest pain to 91% for 80-year-old males with typical chest pain. Predictions varied across hospitals due to differences in disease prevalence. CONCLUSION Our results suggest that the Diamond-Forrester model overestimates the probability of CAD especially in women. We updated the predictive effects of age, sex, type of chest pain, and hospital setting which improved model performance and we extended it to include patients of 70 years and older.

Impact of Primary Coronary Angioplasty Delay on Myocardial Salvage, Infarct Size, and Microvascular Damage in Patients With ST-Segment Elevation Myocardial Infarction : Insight From Cardiovascular Magnetic Resonance

OBJECTIVES We investigated the extent and nature of myocardial damage by using cardiovascular magnetic resonance (CMR) in relation to different time-to-reperfusion intervals. BACKGROUND Previous studies evaluating the influence of time to reperfusion on infarct size (IS) and myocardial salvage in patients with ST-segment elevation myocardial infarction (STEMI) have yielded conflicting results. METHODS Seventy patients with STEMI successfully treated with primary percutaneous coronary intervention within 12 h from symptom onset underwent CMR 3 +/- 2 days after hospital admission. Patients were subcategorized into 4 time-to-reperfusion (symptom onset to balloon) quartiles: < or =90 min (group I, n = 19), >90 to 150 min (group II, n = 17), >150 to 360 min (group III, n = 17), and >360 min (group IV, n = 17). T2-weighted short tau inversion recovery and late gadolinium enhancement CMR were used to characterize reversible and irreversible myocardial injury (area at risk and IS, respectively); salvaged myocardium was defined as the normalized difference between extent of T2-weighted short tau inversion recovery and late gadolinium enhancement. RESULTS Shorter time-to-reperfusion (group I) was associated with smaller IS and microvascular obstruction and larger salvaged myocardium. Mean IS progressively increased overtime: 8% (group I), 11.7% (group II), 12.7% (group III), and 17.9% (group IV), p = 0.017; similarly, MVO was larger in patients reperfused later (0.5%, 1.5%, 3.7%, and 6.6%, respectively, p = 0.047). Accordingly, salvaged myocardium markedly decreased when reperfusion occurred >90 min of coronary occlusion (8.5%, 3.2%, 2.4%, and 2.1%, respectively, p = 0.004). CONCLUSIONS In patients with STEMI treated with primary percutaneous coronary intervention, time to reperfusion determines the extent of reversible and irreversible myocardial injury assessed by CMR. In particular, salvaged myocardium is markedly reduced when reperfusion occurs >90 min of coronary occlusion.

Expert Consensus for Multi-Modality Imaging Evaluation of Cardiovascular Complications of Radiotherapy in Adults: A Report from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

Cardiac toxicity is one of the most concerning side effects of anti-cancer therapy. The gain in life expectancy obtained with anti-cancer therapy can be compromised by increased morbidity and mortality associated with its cardiac complications. While radiosensitivity of the heart was initially recognized only in the early 1970s, the heart is regarded in the current era as one of the most critical dose-limiting organs in radiotherapy. Several clinical studies have identified adverse clinical consequences of radiation-induced heart disease (RIHD) on the outcome of long-term cancer survivors. A comprehensive review of potential cardiac complications related to radiotherapy is warranted. An evidence-based review of several imaging approaches used to detect, evaluate, and monitor RIHD is discussed. Recommendations for the early identification and monitoring of cardiovascular complications of radiotherapy by cardiac imaging are also proposed.

FDG-PET scan in potentially operable non-small cell lung cancer : Do anatometabolic PET-CT fusion images improve the localisation of regional lymph node metastases?

Abstract Exact localisation of thoracic lymph nodes (LNs) on fluorine-18 fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) can be hampered by the paucity of anatomical landmarks. In non-small cell lung cancer (NSCLC) patients referred for locoregional LN staging, we prospectively examined to what extent localisation of LNs at PET reading could be improved by visual correlation with computed tomography (CT), or by anatometabolic PET+CT fusion images. Fifty-six patients with potentially operable NSCLC underwent CT, PET and surgical staging. Prospective reading was performed for CT, PET without CT, PET+CT visual correlation and PET+CT fusion. Reading was blinded to surgical pathology data and noted on a standard LN map. Surgical staging was available for 493 LN stations. In the evaluation per individual LN station, CT was accurate in 87%, PET in 91% and visual correlation and fusion in 93%. In the identification of the nodal stage, CT was correct in 28/56 patients (50%), PET in 37/56 (66%), visual correlation in 40/56 (71%), and fusion in 41/56 (73%). It is concluded that in the exact localisation of metastatic thoracic LNs, the accuracy of reading of PET is increased if the PET images can be visually correlated with CT images. PET+CT anatometabolic fusion images add only a marginal benefit compared with visual correlation.

Implications of SENSE MR in routine clinical practice

Sensitivity encoding (SENSE) uses multiple MRI receive coil elements to encode spatial information in addition to traditional gradient encoding. Requiring less gradient encodings translates into shorter scan times, which is extremely beneficial in many clinical applications. SENSE is available to routine diagnostic imaging for the past 2 years. This paper highlights the use of SENSE with scan time reduction factors up to 6 in contrast-enhanced MRA, routine abdominal imaging, mammography, cardiac and neuro imaging. It is shown that SENSE has opened new horizons in both routine and advanced MR imaging.

Remote Myocardial Dysfunction After Acute Anterior Myocardial Infarction: Impact of Left Ventricular Shape on Regional Function A Magnetic Resonance Myocardial Tagging Study

OBJECTIVES We sought to evaluate regional morphology and function in patients in their first week after having a reperfused anterior myocardial infarction (MI) using magnetic resonance (MR) myocardial tagging. BACKGROUND The mechanism of myocardial dysfunction in the remote, noninfarct-related regions is an unresolved issue to date. METHODS Sixteen patients with a first reperfused transmural anterior MI were studied with MR tagging at 5 +/- 2 days after the event, and the results were compared with those of an age-matched control group regions. The left ventricle (LV) was divided into infarct, adjacent and remote regions. Magnetic resonance tagging provided information on the regional ventricular morphology and function. RESULTS Morphologically, an increase of the circumferential radius of curvature was found in the remote myocardium, whereas the longitudinal radius of curvature was increased in all regions of the LV. A significant increase in apical sphericity was also found. A significant reduction in strain and function was found not only in the infarct region, but also in the adjacent and remote myocardium. The loss in regional ejection fraction in the remote myocardium (61.4 +/- 11.7% in patients vs. 68.7 +/- 10.0% in control subjects, p < 0.0001) was related to a significant reduction of the longitudinal and circumferential strain, whereas systolic wall thickening was preserved. CONCLUSIONS Remote myocardial dysfunction contributes significantly to the loss in global ventricular function. This could be secondary to morphologic changes in the infarct region, leading to an increased systolic longitudinal wall stress without loss of intrinsic contractility in the remote regions.

Quantification of Myocardial Area at Risk With T2-Weighted CMR Comparison With Contrast-Enhanced CMR and Coronary Angiography

OBJECTIVES We sought to quantify the myocardium at risk in reperfused acute myocardial infarction (AMI) in man with T2-weighted (T2W) cardiac magnetic resonance (CMR). BACKGROUND The myocardial area at risk (AAR) is defined as the myocardial tissue within the perfusion bed distally to the culprit lesion of the infarct-related coronary artery. T2W CMR is appealing to retrospectively determine the myocardial AAR after reperfused AMI. Data on the utility of this technique in humans are limited. METHODS One hundred eight patients with successfully reperfused ST-segment elevation AMI were studied between 1 and 20 days after percutaneous coronary intervention (PCI). We compared the volume of hyperintense myocardium on T2W CMR with the myocardial AAR determined by contrast-enhanced CMR with infarct endocardial surface length (ESL) and AAR estimated by conventional coronary angiography with the BARI (Bypass Angioplasty Revascularization Investigation) risk score. RESULTS The volume of hyperintense myocardium on T2W CMR (mean 32 +/- 16%, range 3% to 67%) was consistently larger than the volume of myocardial infarction measured with contrast-enhanced images (mean 17 +/- 12%, range 0% to 55%) (p < 0.001). Myocardial salvage ranged from -4% to 45% of the left ventricular myocardium (mean 14 +/- 10%). The AAR determined by T2W CMR compared favorably with the infarct ESL (r = 0.77) with contrast-enhanced CMR, and there was moderate correlation between the BARI angiographic risk score and infarct ESL (r = 0.42). The time between PCI and CMR did not cause a significant difference in the volume of T2W hyperintense myocardium (r = 0.11, p = 0.27) or the calculated volume of salvaged myocardium (r = 0.12, p = 0.23). CONCLUSIONS T2W CMR performed early after successfully reperfused AMI in humans enables retrospective quantification of the myocardial AAR and salvaged myocardium.

Functional Recovery of Subepicardial Myocardial Tissue in Transmural Myocardial Infarction After Successful Reperfusion: An Important Contribution to the Improvement of Regional and Global Left Ventricular Function

BACKGROUND The transmural extent of myocardial necrosis after an acute coronary artery occlusion can vary considerably. The contribution of residual subepicardial viable myocardium to global left ventricular function is largely unknown. METHODS AND RESULTS We studied 12 patients with single-vessel disease 1 week after successful reperfusion of a first transmural anterior myocardial infarction (MI). With PET, myocardial blood flow (MBF) and glucose metabolism were measured regionally, and the viability was graded as normal, mismatch, or match with severely (<50% of normal) or intermediately (50% to 80% of normal) impaired MBF. Magnetic resonance tagging was used to regionally quantify fiber strains, wall thickening, and ejection fraction in patients 1 week and 3 months after the MI and in age-matched healthy volunteers. From 1 week to 3 months, subepicardial fiber shortening improved significantly in the match region (MBF <50%, -5.1+/-7.0% to -9.9+/-8. 7%; MBF of 50% to 80%, -7.1+/-7.6% to -14.9+/-7.9%). This was associated with an improvement in regional ejection fraction in the infarcted myocardium (29.6+/-21.8% to 43.5+/-15.5%, P<0.0001) and in normal regions (54.3+/-15.1% to 56.5+/-13.1%, P=0.013), contributing to an increase in global ejection fraction from 44.2+/-22.2% to 49. 3+/-17.9% (P<0.0001). CONCLUSIONS Functional recovery of viable subepicardial regions is a mechanism of late improvement in regional and global ejection fraction after a so-called transmural MI.

Cardiac Three-Dimensional Magnetic Resonance Imaging and Fluoroscopy Merging A New Approach for Electroanatomic Mapping to Assist Catheter Ablation

Background— Modern nonfluoroscopic mapping systems construct 3D electroanatomic maps by tracking intracardiac catheters. They require specialized catheters and/or dedicated hardware. We developed a new method for electroanatomic mapping by merging detailed 3D models of the endocardial cavities with fluoroscopic images without the need for specialized hardware. This developmental work focused on the right atrium because of the difficulties in visualizing its anatomic landmarks in 3D with current approaches. Methods and Results— Cardiac MRI images were acquired in 39 patients referred for radiofrequency catheter ablation using balanced steady state free-precession sequences. We optimized acquisition and developed software for construction of detailed 3D models, after contouring of endocardial cavities with cross-checking of different imaging planes. 3D models were then merged with biplane fluoroscopic images by methods for image calibration and registration implemented in a custom software application. The feasibility and accuracy of this merging process were determined in heart-cast experiments and electroanatomic mapping in patients. Right atrial dimensions and relevant anatomic landmarks could be identified and measured in all 3D models. Cephalocaudal, posteroanterior, and lateroseptal diameters were, respectively, 65±11, 54±11, and 57±9 mm; posterior isthmus length was 26±6 mm; Eustachian valve height was 5±5 mm; and coronary sinus ostium height and width were 16±3 and 12±3 mm, respectively (n=39). The average alignment error was 0.2±0.3 mm in heart casts (n=40) and 1.9 to 2.5 mm in patient experiments (n=9), ie, acceptable for clinical use. In 11 patients, reliable catheter positioning and projection of activation times resulted in 3D electroanatomic maps with an unprecedented level of anatomic detail, which assisted ablation. Conclusions— This new approach allows activation visualization in a highly detailed 3D anatomic environment without the need for a specialized nonfluoroscopic mapping system.