Subclinical Primary Aldosteronism and Cardiovascular Health: A Population-Based Cohort Study.

BACKGROUND: Primary aldosteronism, characterized by overt renin-independent aldosterone production, is a common but underrecognized form of hypertension and cardiovascular disease. Growing evidence suggests that milder and subclinical forms of primary aldosteronism are highly prevalent, yet their contribution to cardiovascular disease is not well characterized. METHODS: This prospective study included 1284 participants between the ages of 40 and 69 years from the randomly sampled population-based CARTaGENE cohort (Québec, Canada). Regression models were used to analyze associations of aldosterone, renin, and the aldosterone-to-renin ratio with the following measures of cardiovascular health: arterial stiffness, assessed by central blood pressure (BP) and pulse wave velocity; adverse cardiac remodeling, captured by cardiac magnetic resonance imaging, including indexed maximum left atrial volume, left ventricular mass index, left ventricular remodeling index, and left ventricular hypertrophy; and incident hypertension. RESULTS: The mean (SD) age of participants was 54 (8) years and 51% were men. The mean (SD) systolic and diastolic BP were 123 (15) and 72 (10) mm Hg, respectively. At baseline, 736 participants (57%) had normal BP and 548 (43%) had hypertension. Higher aldosterone-to-renin ratio, indicative of renin-independent aldosteronism (ie, subclinical primary aldosteronism), was associated with increased arterial stiffness, including increased central BP and pulse wave velocity, along with adverse cardiac remodeling, including increased indexed maximum left atrial volume, left ventricular mass index, and left ventricular remodeling index (all P<0.05). Higher aldosterone-to-renin ratio was also associated with higher odds of left ventricular hypertrophy (odds ratio, 1.32 [95% CI, 1.002-1.73]) and higher odds of developing incident hypertension (odds ratio, 1.29 [95% CI, 1.03-1.62]). All the associations were consistent when assessing participants with normal BP in isolation and were independent of brachial BP. CONCLUSIONS: Independent of brachial BP, a biochemical phenotype of subclinical primary aldosteronism is negatively associated with cardiovascular health, including greater arterial stiffness, adverse cardiac remodeling, and incident hypertension.

Myocardial flow reserve recovery in patients with Takotsubo syndrome: Insights from positron emission tomography.

BACKGROUND: Coronary microvascular dysfunction (CMD) has been implicated in the pathogenesis of Takotsubo syndrome (TTS). Positron emission tomography (PET) plays a key role in the assessment of CMD through myocardial flow reserve (MFR). However, there is limited information on the temporal progression of MFR and its relationship to coronary artery disease (CAD) in TTS patients. METHODS: This study evaluated patients with TTS who underwent cardiac catheterization and PET within one year of hospitalization. Patients were categorized into acute (≤10 days), subacute (11-30 days), and chronic (≥31 days) stages based on post-onset time of PET assessment. MFR values and prevalence of abnormal MFR (<2.0) were compared between stages. Temporal MFR changes in patients with obstructive CAD (≥70% stenosis by coronary angiography), non-obstructive CAD, and normal coronaries were compared. RESULTS: Of the 88 patients studied (mean age 70; 96% female), 52 (59%) were in the acute, 17 (19%) in the subacute, and 19 (22%) in the chronic stage. Median MFR in the acute stage was 2.0 (1.5-2.3), with 58% of patients showing abnormal MFR. A significant time-dependent improvement in MFR was observed (P = 0.002), accompanied by a decreased prevalence of abnormal MFR (P = 0.016). While patients with normal coronaries showed significant MFR improvement over time (P = 0.045), patients with obstructive or non-obstructive CAD demonstrated no improvement across three stages (P = 0.346 and 0.174, respectively). CONCLUSION: PET-derived MFR was impaired in TTS patients during the acute phase, with improvement suggesting potential recovery from CMD over time. The concurrent presence of obstructive CAD might impede this recovery process.

Myocardial strain assessment using cardiovascular magnetic resonance imaging in recipients of implantable cardioverter defibrillators.

BACKGROUND: Cardiovascular magnetic resonance (CMR) is increasingly used in the evaluation of patients who are potential candidates for implantable cardioverter-defibrillator (ICD) therapy to assess left ventricular (LV) ejection fraction (LVEF), myocardial fibrosis, and etiology of cardiomyopathy. It is unclear whether CMR-derived strain measurements are predictive of appropriate shocks and death among patients who receive an ICD. We evaluated the prognostic value of LV strain parameters on feature-tracking (FT) CMR in patients who underwent subsequent ICD implant for primary or secondary prevention of sudden cardiac death. METHODS: Consecutive patients from 2 Canadian tertiary care hospitals who underwent ICD implant and had a pre-implant CMR scan were included. Using FT-CMR, a single, blinded, reader measured LV global longitudinal (GLS), circumferential (GCS), and radial (GRS) strain. Cox proportional hazards regression was performed to assess the associations between strain measurements and the primary composite endpoint of all-cause death or appropriate ICD shock that was independently ascertained. RESULTS: Of 364 patients (mean 61 years, mean LVEF 32%), 64(17.6%) died and 118(32.4%) reached the primary endpoint over a median follow-up of 62 months. Univariate analyses showed significant associations between GLS, GCS, and GRS and appropriate ICD shocks or death (all p < 0.01). In multivariable Cox models incorporating LVEF, GLS remained an independent predictor of both the primary endpoint (HR 1.05 per 1% higher GLS, 95% CI 1.01-1.09, p = 0.010) and death alone (HR 1.06 per 1% higher GLS, 95% CI 1.02-1.11, p = 0.003). There was no significant interaction between GLS and indication for ICD implant, presence of ischemic heart disease or late gadolinium enhancement (all p > 0.30). CONCLUSIONS: GLS by FT-CMR is an independent predictor of appropriate shocks or mortality in ICD patients, beyond conventional prognosticators including LVEF. Further study is needed to elucidate the role of LV strain analysis to refine risk stratification in routine assessment of ICD treatment benefit.

Noninvasive Imaging in Adult Congenital Heart Disease.

Multimodality cardiovascular imaging plays a central role in caring for patients with congenital heart disease (CHD). CHD clinicians and scientists are interested not only in cardiac morphology but also in the maladaptive ventricular responses and extracellular changes predisposing to adverse outcomes in this population. Expertise in the applications, strengths, and pitfalls of these cardiovascular imaging techniques as they relate to CHD is essential. The purpose of this article is to provide an overview of cardiovascular imaging in CHD. We focus on the role of 3 widely used noninvasive imaging techniques in CHD-echocardiography, cardiac magnetic resonance imaging, and cardiac computed tomography. Consideration is given to the common goals of cardiac imaging in CHD, including assessment of structural and residual heart disease before and after surgery, quantification of ventricular volume and function, stress imaging, shunt quantification, and tissue characterization. Extracardiac imaging is highlighted as an increasingly important aspect of CHD care.

Cardiovascular Magnetic Resonance Provides Evidence of Abnormal Myocardial Strain and Primary Cardiomyopathy in Marfan syndrome.

OBJECTIVE: Marfan syndrome is an autosomal-dominant genetic disorder caused by mutations in the fibrillin-1 gene. The condition is a connective tissue disease that frequently involves the cardiovascular system. The existence of a primary cardiomyopathy in Marfan syndrome, however, is controversial. The aims of this study were to investigate the prevalence of left ventricular dysfunction with both transthoracic echocardiography and cardiovascular magnetic resonance (CMR) in a cohort of Marfan syndrome patients and to investigate patterns of myocardial strain across the cohort. METHODS: We used an institutional database to identify all patients with a firm diagnosis of Marfan syndrome based on Ghent criteria. Inclusion required left ventricular ejection fraction (LVEF) to have been measured by both CMR and transthoracic echocardiography within 12 months of each other. Normal LVEF was defined as a value of >55% when measured by CMR. Velocity vector imaging was used to measure left ventricular longitudinal strain patterns by application of feature tracking to cine magnetic resonance images. Results were compared with data from 20 age-matched control subjects. RESULTS: Sixty-nine Marfan syndrome patients met the inclusion criteria. The mean age was 35.4 ± 15.0 years, and 56.5% were male. The mean LVEF was 59.0% ± 7.0% by CMR and 59.1% ± 5.8% by echo. One-fifth of Marfan syndrome patients (15/69; 21.7%) had reduced function with LVEF ≤55% by CMR, but only 5 of these were identified by echo. Furthermore, echo identified 5 Marfan syndrome patients as having reduced LVEF in the presence of a normal LVEF by CMR. Some Marfan syndrome patients had abnormal longitudinal strain patterns even with LVEF within the reference range. CONCLUSIONS: These data provide support for a primary cardiomyopathy in some Marfan syndrome patients. Cardiovascular magnetic resonance is more sensitive than echo for identifying cases with mild systolic dysfunction. Strain analysis may be more sensitive than simple LVEF assessment for identifying at-risk individuals.

Use of Myocardial T1 Mapping at 3.0 T to Differentiate Anderson-Fabry Disease from Hypertrophic Cardiomyopathy.

Purpose To compare left ventricular (LV) and right ventricular (RV) 3.0-T cardiac magnetic resonance (MR) imaging T1 values in Anderson-Fabry disease (AFD) and hypertrophic cardiomyopathy (HCM) and evaluate the diagnostic value of native T1 values beyond age, sex, and conventional imaging features. Materials and Methods For this prospective study, 30 patients with gene-positive AFD (37% male; mean age ± standard deviation, 45.0 years ± 14.1) and 30 patients with HCM (57% male; mean age, 49.3 years ± 13.5) were prospectively recruited between June 2016 and September 2017 to undergo cardiac MR imaging T1 mapping with a modified Look-Locker inversion recovery (MOLLI) acquisition scheme at 3.0 T (repetition time msec/echo time msec, 280/1.12; section thickness, 8 mm). LV and RV T1 values were evaluated. Statistical analysis included independent samples t test, receiver operating characteristic curve analysis, multivariable logistic regression, and likelihood ratio test. Results Septal LV, global LV, and RV native T1 values were significantly lower in AFD compared with those in HCM (1161 msec ± 47 vs 1296 msec ± 55, respectively [P < .001]; 1192 msec ± 52 vs 1268 msec ± 55 [P < .001]; and 1221 msec ± 54 vs 1271 msec ± 37 [P = .001], respectively). A septal LV native T1 cutoff point of 1220 msec or lower distinguished AFD from HCM with sensitivity of 97%, specificity of 93%, and accuracy of 95%. Septal LV native T1 values differentiated AFD from HCM after adjustment for age, sex, and conventional imaging features (odds ratio, 0.94; 95% confidence interval: 0.91, 0.98; P = < .001). In a nested logistic regression model with age, sex, and conventional imaging features, model fit was significantly improved by the addition of septal LV native T1 values (χ2 [df = 1] = 33.4; P < .001). Conclusion Cardiac MR imaging native T1 values at 3.0 T are significantly lower in patients with AFD compared with those with HCM and provide independent and incremental diagnostic value beyond age, sex, and conventional imaging features. © RSNA, 2018.

Noninvasive hematocrit assessment for cardiovascular magnetic resonance extracellular volume quantification using a point-of-care device and synthetic derivation.

BACKGROUND: Calculation of cardiovascular magnetic resonance (CMR) extracellular volume (ECV) requires input of hematocrit, which may not be readily available. The purpose of this study was to evaluate the diagnostic accuracy of ECV calculated using various noninvasive measures of hematocrit compared to ECV calculated with input of laboratory hematocrit as the reference standard. METHODS: One hundred twenty three subjects (47.7 ± 14.1 years; 42% male) were prospectively recruited for CMR T1 mapping between August 2016 and April 2017. Laboratory hematocrit was assessed by venipuncture. Noninvasive hematocrit was assessed with a point-of-care (POC) device (Pronto-7® Pulse CO-Oximeter®, Masimo Personal Health, Irvine, California, USA) and by synthetic derivation based on the relationship with blood pool T1 values. Left ventricular ECV was calculated with input of laboratory hematocrit (Lab-ECV), POC hematocrit (POC-ECV), and synthetic hematocrit (synthetic-ECV), respectively. Statistical analysis included Wilcoxon signed-rank test, Bland-Altman analysis, receiver-operating curve analysis and intra-class correlation (ICC). RESULTS: There was no significant difference between Lab-ECV and POC-ECV (27.1 ± 4.7% vs. 27.3 ± 4.8%, p = 0.106), with minimal bias and modest precision (bias - 0.18%, 95%CI [- 2.85, 2.49]). There was no significant difference between Lab-ECV and synthetic-ECV (26.7 ± 4.4% vs. 26.5 ± 4.3%, p = 0.084) in subjects imaged at 1.5 T, although bias was slightly higher and limits of agreement were wider (bias 0.23%, 95%CI [- 2.82, 3.27]). For discrimination of abnormal Lab-ECV ≥30%, POC-ECV had good diagnostic performance (sensitivity 85%, specificity 96%, accuracy 94%, and AUC 0.902) and synthetic-ECV had moderate diagnostic performance (sensitivity 71%, specificity 98%, accuracy 93%, and AUC 0.849). POC-ECV had excellent test-retest (ICC 0.994, 95%CI[0.987, 0.997]) and inter-observer agreement (ICC 0.974, 95%CI[0.929, 0.991]). CONCLUSIONS: Myocardial ECV can be accurately and reproducibly calculated with input of hematocrit measured using a noninvasive POC device, potentially overcoming an important barrier to implementation of ECV. Further evaluation of synthetic ECV is required prior to clinical implementation.

Paediatric-onset coronary artery anomalies in pregnancy: a single-centre experience and systematic literature review.

OBJECTIVES: Individuals with childhood-onset coronary artery anomalies are at increased risk of lifelong complications. Although pregnancy is thought to confer additional risk, a few data are available regarding outcomes in this group of women. We sought to define outcomes of pregnancy in this unique population. METHODS: We performed a retrospective survey of women with paediatric-onset coronary anomalies and pregnancy in our institution, combined with a systematic review of published cases. We defined paediatric-onset coronary artery anomalies as congenital coronary anomalies and inflammatory arteriopathies of childhood that cause coronary aneurysms. Major cardiovascular events were defined as pulmonary oedema, sustained arrhythmia requiring treatment, stroke, myocardial infarction, cardiac arrest, or death. RESULTS: A total of 25 surveys were mailed, and 20 were returned (80% response rate). We included 46 articles from the literature, which described cardiovascular outcomes in 82 women (138 pregnancies). These data were amalgamated for a total of 102 women and 194 pregnancies; 59% of women were known to have paediatric-onset coronary artery anomalies before pregnancy. In 23%, the anomaly was unmasked during or shortly after pregnancy. The remainder, 18%, was diagnosed later in life. Major cardiovascular events occurred in 14 women (14%) and included heart failure (n=5, 5%), myocardial infarction (n=7, 7%), maternal death (n=2, 2%), cardiac arrest secondary to ventricular fibrillation (n=1, 1%), and stroke (n=1, 1%). The majority of maternal events (13/14, 93%) occurred in women with no previous diagnosis of coronary disease. CONCLUSIONS: Women with paediatric-onset coronary artery anomalies have a 14% risk of adverse cardiovascular events in pregnancy, indicating the need for careful assessment and close follow-up. Prospective, multicentre studies are required to better define risk and predictors of complications during pregnancy.

Prognostic value of quantitative contrast-enhanced cardiovascular magnetic resonance for the evaluation of sudden death risk in patients with hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden death in the young, although not all patients eligible for sudden death prevention with an implantable cardioverter-defibrillator are identified. Contrast-enhanced cardiovascular magnetic resonance with late gadolinium enhancement (LGE) has emerged as an in vivo marker of myocardial fibrosis, although its role in stratifying sudden death risk in subgroups of HCM patients remains incompletely understood. METHODS AND RESULTS: We assessed the relation between LGE and cardiovascular outcomes in 1293 HCM patients referred for cardiovascular magnetic resonance and followed up for a median of 3.3 years. Sudden cardiac death (SCD) events (including appropriate defibrillator interventions) occurred in 37 patients (3%). A continuous relationship was evident between LGE by percent left ventricular mass and SCD event risk in HCM patients (P=0.001). Extent of LGE was associated with an increased risk of SCD events (adjusted hazard ratio, 1.46/10% increase in LGE; P=0.002), even after adjustment for other relevant disease variables. LGE of ≥15% of LV mass demonstrated a 2-fold increase in SCD event risk in those patients otherwise considered to be at lower risk, with an estimated likelihood for SCD events of 6% at 5 years. Performance of the SCD event risk model was enhanced by LGE (net reclassification index, 12.9%; 95% confidence interval, 0.3-38.3). Absence of LGE was associated with lower risk for SCD events (adjusted hazard ratio, 0.39; P=0.02). Extent of LGE also predicted the development of end-stage HCM with systolic dysfunction (adjusted hazard ratio, 1.80/10% increase in LGE; P<0.03). CONCLUSIONS: Extensive LGE measured by quantitative contrast enhanced CMR provides additional information for assessing SCD event risk among HCM patients, particularly patients otherwise judged to be at low risk.

Use of Cardiac Magnetic Resonance Imaging Based Measurements of Inferior Vena Cava Cross-Sectional Area in the Diagnosis of Pericardial Constriction.

PURPOSE: To evaluate the value of cardiac magnetic resonance imaging (MRI)-based measurements of inferior vena cava (IVC) cross-sectional area in the diagnosis of pericardial constriction. METHODS: Patients who had undergone cardiac MRI for evaluation of clinically suspected pericardial constriction were identified retrospectively. The diagnosis of pericardial constriction was established by clinical history, echocardiography, cardiac catheterization, intraoperative findings, and/or histopathology. Cross-sectional areas of the suprahepatic IVC and descending aorta were measured on a single axial steady-state free-precession (SSFP) image at the level of the esophageal hiatus in end-systole. Logistic regression and receiver-operating curve (ROC) analyses were performed. RESULTS: Thirty-six patients were included; 50% (n = 18) had pericardial constriction. Mean age was 53.9 ± 15.3 years, and 72% (n = 26) were male. IVC area, ratio of IVC to aortic area, pericardial thickness, and presence of respirophasic septal shift were all significantly different between patients with constriction and those without (P < .001 for all). IVC to aortic area ratio had the highest odds ratio for the prediction of constriction (1070, 95% confidence interval [8.0-143051], P = .005). ROC analysis illustrated that IVC to aortic area ratio discriminated between those with and without constriction with an area under the curve of 0.96 (95% confidence interval [0.91-1.00]). CONCLUSIONS: In patients referred for cardiac MRI assessment of suspected pericardial constriction, measurement of suprahepatic IVC cross-sectional area may be useful in confirming the diagnosis of constriction when used in combination with other imaging findings, including pericardial thickness and respirophasic septal shift.

Evaluation of a comprehensive cardiovascular magnetic resonance protocol in young adults late after the arterial switch operation for d-transposition of the great arteries.

BACKGROUND: In adults with prior arterial switch operation (ASO) for d-transposition of the great arteries, the need for routine coronary artery assessment and evaluation for silent myocardial ischemia is not well defined. In this observational study we aimed to determine the value of a comprehensive cardiovascular magnetic resonance (CMR) protocol for the detection of coronary problems in adults with prior ASO for d-transposition of the great arteries. METHODS: Adult ASO patients (≥18 years of age) were recruited consecutively. Patients underwent a comprehensive stress perfusion CMR protocol that included measurement of biventricular systolic function, myocardial scar burden, coronary ostial assessment and myocardial perfusion during vasodilator stress by perfusion CMR. Single photon emission computed tomography (SPECT) was performed on the same day as a confirmatory second imaging modality. Stress studies were visually assessed for perfusion defects (qualitative analysis). Additionally, myocardial blood flow was quantitatively analysed from mid-ventricular perfusion CMR images. In unclear cases, CT coronary angiography or conventional angiography was done. RESULTS: Twenty-seven adult ASO patients (mean age 23 years, 85% male, 67% with a usual coronary pattern; none with a prior coronary artery complication) were included in the study. CMR stress perfusion was normal in all 27 patients with no evidence of inducible perfusion defects. In 24 cases the coronary ostia could conclusively be demonstrated to be normal. There was disagreement between CMR and SPECT for visually-assessed perfusion defects in 54% of patients with most disagreement due to false positive SPECT. CONCLUSIONS: Adult ASO survivors in this study had no CMR evidence of myocardial ischemia, scar or coronary ostial abnormality. Compared to SPECT, CMR provides additional valuable information about the coronary artery anatomy. The data shows that the asymptomatic and clinically stable adult ASO patient has a low pre-test probability for inducible ischemia. In this situation it is likely that routine evaluation with stress CMR is unnecessary.

The value of stress perfusion cardiovascular magnetic resonance imaging for patients referred from the adult congenital heart disease clinic: 5-year experience at the Toronto General Hospital.

BACKGROUND: Vasodilator stress perfusion cardiovascular magnetic resonance imaging is a clinically useful tool for detection of clinically significant myocardial ischaemia in adults. We report our 5-year retrospective experience with perfusion cardiovascular magnetic resonance in a large, quarternary adult congenital heart disease centre. METHODS: We reviewed all cases of perfusion cardiovascular magnetic resonance in patients referred from the adult congenital heart disease service. Dipyridamole stress perfusion cardiovascular magnetic resonance was undertaken on commercially available 1.5 and 3 T cardiovascular magnetic resonance scanners. Late gadolinium enhancement imaging was performed 8-10 minutes after completion of the rest perfusion sequence. Navigator whole-heart coronary magnetic resonance angiography was also performed where feasible. RESULTS of stress cardiovascular magnetic resonance were correlated with complementary imaging studies, surgery, and clinical outcomes. RESULTS: Over 5 years, we performed 34 stress perfusion cardiovascular magnetic resonance examinations (11 positive). In all, 84% of patients had further investigations for ischaemia in addition to cardiovascular magnetic resonance. Within a subgroup of 19 patients who had definitive alternative assessment of their coronary arteries, stress perfusion cardiovascular magnetic resonance demonstrated a sensitivity of 82% and specificity of 100%. Of the 34 studies, two were false negatives, in which the aetiology of ischaemia was extrinsic arterial compression rather than intrinsic coronary luminal narrowing. Coronary abnormalities were identified in 71% of cases who had coronary magnetic resonance angiography. CONCLUSION: Stress perfusion cardiovascular magnetic resonance is a useful and accurate tool for investigation of myocardial ischaemia in an adult congenital heart disease population with suspected non-atherosclerotic coronary abnormalities.

Scanning the Imaging Horizon for Hypertrophic Cardiomyopathy.

In this article some of the recent advances in the use of noninvasive imaging applied to patients with hypertrophic cardiomyopathy (HCM) are discussed. Echocardiography and cardiac computed tomography are briefly discussed with respect to their power to detect apical aneurysmal disease. Echocardiographic phenotype-genotype correlations and the use of echocardiography to characterize myocardial work are reviewed. Positron emission tomography is reviewed in the context of ischemia imaging and also in the context of the use of a new tracer that might allow for recognition of early activation of the fibrosis pathway. Next, the technical capabilities of cardiovascular magnetic resonance to measure myocardial perfusion, oxygenation, and disarray are discussed as they apply to HCM. The application of radiomics to improve prediction of sudden cardiac death is touched upon. Finally, a deep learning approach to the recognition of HCM vs phenocopies is presented as a potential future diagnostic aid in the not-too-distant future.

Role of Nuclear Imaging in Cardiac Stereotactic Body Radiotherapy for Ablation of Ventricular Tachycardia.

Ventricular tachycardia (VT) is a life-threatening arrhythmia common in patients with structural heart disease or nonischemic cardiomyopathy. Many VTs originate from regions of fibrotic scar tissue, where delayed electrical signals exit scar and re-enter viable myocardium. Cardiac stereotactic body radiotherapy (SBRT) has emerged as a completely noninvasive alternative to catheter ablation for the treatment of recurrent or refractory ventricular tachycardia. While there is no common consensus on the ideal imaging workflow, therapy planning for cardiac SBRT often combines information from a plurality of imaging modalities including MRI, CT, electroanatomic mapping and nuclear imaging. MRI and CT provide detailed anatomic information, and late enhancement contrast imaging can indicate regions of fibrosis. Electroanatomic maps indicate regions of heterogenous conduction voltage or early activation which are indicative of arrhythmogenic tissue. Some early clinical adopters performing cardiac SBRT report the use of myocardial perfusion and viability nuclear imaging to identify regions of scar. Nuclear imaging of hibernating myocardium, inflammation and sympathetic innervation have been studied for ventricular arrhythmia prognosis and in research relating to catheter ablation of VT but have yet to be studied in their potential applications for cardiac SBRT. The integration of information from these many imaging modalities to identify a target for ablation can be challenging. Multimodality image registration and dedicated therapy planning tools may enable higher target accuracy, accelerate therapy planning workflows and improve patient outcomes. Understanding the pathophysiology of ventricular arrhythmias, and localizing the arrhythmogenic tissues, is vital for successful ablation with cardiac SBRT. Nuclear imaging provides an arsenal of imaging strategies to identify regional scar, hibernation, inflammation, and sympathetic denervation with some advantages over alternative imaging strategies.

Canadian Cardiovascular Society Clinical Practice Update on Contemporary Management of the Patient with Hypertrophic Cardiomyopathy.

Numerous guidelines on the diagnosis and management of hypertrophic cardiomyopathy (HCM) have been published, by learned societies, over the last decade. While helpful they are often long and less adapted to non-experts. This writing panel was challenged to produce a document that grew as much from years of practical experience as it did from the peer-reviewed literature. As such, rather than produce yet another set of guidelines, we aim here to deliver a concentrate of our own experiential learning and distil for the reader the essence of effective and appropriate HCM care. This Clinical Practice Update on HCM is therefore aimed at general cardiologists and other cardiovascular practitioners rather than for HCM specialists. We set the stage with a description of the condition and its clinical presentation; discuss the central importance of 'obstruction' and how to look for it; review the role of cardiac magnetic resonance imaging; reflect on the appropriate use of genetic testing; review the treatment options for symptomatic HCM - crucially including cardiac myosin inhibitors; and deal concisely with practical issues surrounding risk assessment for sudden cardiac death, and management of the end-stage HCM patient. Uniquely, we have captured the pediatric experience on our panel to discuss appropriate differences in the management of younger patients with HCM. We ask the reader to remember that this document represents expert consensus opinion rather than dogma and to use their best judgement when dealing with the HCM patient in front of them.

High-resolution 3D scar imaging using a novel late iodine enhancement multidetector CT protocol to guide ventricular tachycardia catheter ablation.

Scar delineation with late gadolinium-enhanced MRI can direct VT substrate mapping and ablation, but imaging is poor and relatively contraindicated in the majority of patients with ICDs. We present a case of scar definition using late iodine-enhanced multidetector CT in a patient with ischemic cardiomyopathy and multiple ICD shocks for VT. CT images were acquired using a novel intracoronary contrast delivery protocol which provided high-resolution subendocardial scar visualization. The segmented scar images were subsequently imported into an electroanatomic mapping platform to guide successful VT ablation.

Coronary calcium scan acquisition before coronary CT angiography: limited benefit or useful addition?

OBJECTIVE: This article reviews the role of coronary calcium quantification in symptomatic patients and the pros and cons of acquiring an unenhanced coronary calcium scan in every patient with suspected coronary artery disease referred for coronary CT angiography. CONCLUSION: The acquisition of a coronary calcium scan in every symptomatic patient referred for coronary CT angiography requires a case-by-case approach.

Accuracy of right and left ventricular functional assessment by short-axis vs axial cine steady-state free-precession magnetic resonance imaging: intrapatient correlation with main pulmonary artery and ascending aorta phase-contrast flow measurements.

OBJECTIVE: The left ventricle (LV) is routinely assessed with cardiac magnetic resonance imaging (MRI) by using short-axis orientation; it remains unclear whether the right ventricle (RV) can also be adequately assessed in this orientation or whether dedicated axial orientation is required. We used phase-contrast (PC) flow measurements in the main pulmonary artery (MPA) and the ascending aorta (Aorta) as nonvolumetric standard of reference and compared RV and LV volumes in short-axis and axial orientations. METHODS: A retrospective analysis identified 30 patients with cardiac MRI data sets. Patients underwent MRI (1.5 T or 3 T), with retrospectively gated cine steady-state free-precession in axial and short-axis orientations. PC flow analyses of MPA and Aorta were used as the reference measure of RV and LV output. RESULTS: There was a high linear correlation between MPA-PC flow and RV-stroke volume (SV) short axis (r = 0.9) and RV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 1.4 mL for RV axial and -2.3 mL for RV-short-axis vs MPA-PC flow. There was a high linear correlation between Aorta-PC flow and LV-SV short-axis (r = 0.9) and LV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 4.8 m for LV short axis and 7.0 mL for LV axial vs Aorta-PC flow. There was no significant difference (P = .6) between short-axis-LV SV and short-axis-RV SV. CONCLUSION: No significant impact of the slice acquisition orientation for determination of RV and LV stroke volumes was found. Therefore, cardiac magnetic resonance workflow does not need to be extended by an axial data set for patients without complex cardiac disease for assessment of biventricular function and volumes.

Essentials of Imaging the Repaired Tetralogy of Fallot Patient.

Tetralogy of Fallot is one of the commoner forms of congenital heart disease (CHD) with an incidence estimated at around 1 in 3000 live births. Its prevalence is roughly 5%-10% of all forms of CHD. Although it is a cyanotic disorder at presentation, early surgical repair has led to survival to adulthood in the overwhelming majority of cases. However-as with most repaired CHD-such patients are fixed, not cured, and will inevitably come to the attention of the imaging specialist. This article attempts to describe and summarize the main forms of repaired tetralogy that may be encountered in tertiary hospital imaging practice. The anatomy of different forms of tetralogy is reviewed, and relevant pathophysiology is discussed. Reference is made to 22q11 syndrome, which is often missed or not considered by even specialist congenital physicians, and the alerting features of this condition are reviewed. The benefits and challenges of computed tomography and magnetic resonance imaging in the congenital population are covered, and there is discussion regarding the various approaches to imaging available using these techniques.

La tétralogie de Fallot est l'une des formes plus courantes de cardiopathie congénitale, son incidence étant d'environ 1 naissance vivante sur 3000. Sa prévalence est d'approximativement 5 à 10 % de toutes les formes de cardiopathie congénitale. Bien qu'il s'agisse d'une maladie à présentation cyanogène, sa correction chirurgicale dans les premiers stades permet le prolongement de la survie jusqu'à l'âge adulte dans la très grande majorité des cas. Les patients qui bénéficient de ce traitement, comme c'est le cas de la plupart de ceux atteints d'une cardiopathie congénitale réparée chirurgicalement, sont cependant traités, et non guéris. Aussi, la maladie apparaîtra inévitablement à l'imagerie. Le présent article tente de décrire et de résumer les principales formes de tétralogie prises en charge par chirurgie qui pourraient ressortir dans le cadre d'examens d'imagerie en contexte de soins tertiaires. Il en examine les différentes particularités anatomiques et discute des aspects physiopathologiques pertinents. Il fait également référence au syndrome de délétion 22q11 qui est souvent négligé, même par les spécialistes en maladies congénitales, et explore les caractéristiques alarmantes de ce syndrome. Il passe en revue les bienfaits que la tomodensitométrie et l'imagerie par résonance magnétique peuvent offrir à la population de patients présentant une maladie congénitale ainsi que les difficultés qui peuvent survenir lors de ces examens. Enfin, il se penche sur les diverses méthodes d'imagerie qu'il est possible d'utiliser avec ces techniques.