Integrating Active Learning and Transfer Learning for Carotid Intima-Media Thickness Video Interpretation.

Cardiovascular disease (CVD) is the number one killer in the USA, yet it is largely preventable (World Health Organization 2011). To prevent CVD, carotid intima-media thickness (CIMT) imaging, a noninvasive ultrasonography method, has proven to be clinically valuable in identifying at-risk persons before adverse events. Researchers are developing systems to automate CIMT video interpretation based on deep learning, but such efforts are impeded by the lack of large annotated CIMT video datasets. CIMT video annotation is not only tedious, laborious, and time consuming, but also demanding of costly, specialty-oriented knowledge and skills, which are not easily accessible. To dramatically reduce the cost of CIMT video annotation, this paper makes three main contributions. Our first contribution is a new concept, called Annotation Unit (AU), which simplifies the entire CIMT video annotation process down to six simple mouse clicks. Our second contribution is a new algorithm, called AFT (active fine-tuning), which naturally integrates active learning and transfer learning (fine-tuning) into a single framework. AFT starts directly with a pre-trained convolutional neural network (CNN), focuses on selecting the most informative and representative AU s from the unannotated pool for annotation, and then fine-tunes the CNN by incorporating newly annotated AU s in each iteration to enhance the CNN's performance gradually. Our third contribution is a systematic evaluation, which shows that, in comparison with the state-of-the-art method (Tajbakhsh et al., IEEE Trans Med Imaging 35(5):1299-1312, 2016), our method can cut the annotation cost by >81% relative to their training from scratch and >50% relative to their random selection. This performance is attributed to the several advantages derived from the advanced active, continuous learning capability of our AFT method.

Carotid intima-media thickness measurements are not affected by the ultrasound frequency.

OBJECTIVE: Carotid intima-media thickness (IMT) is a B-mode ultrasound measure of subclinical atherosclerosis predictive of future cardiovascular risk. Carotid IMT measurements were historically obtained at an ultrasound frequency of 8 MHz or lower, but it is unknown whether measurements obtained at higher frequencies using newer, more advanced ultrasound technology allow for valid comparison to the older general population databases that are commonly used for the interpretation of carotid IMT results. METHODS: Carotid IMT studies were conducted in 35 consecutive patients at standard (8 MHz) and high (14 MHz) frequencies and measurements were performed by two independent expert readers. Systematic bias was assessed by using the paired t-test and agreement was analyzed with the Bland-Altman method. RESULTS: The sample mean carotid IMT obtained at 14 MHz was 0.006 mm lower than that obtained at 8 MHz. The 95% confidence interval (CI) for the mean difference between frequencies indicated that the population mean for 14 MHz is unlikely to be more than 0.02 mm lower than for 8 MHz (95% CI -0.017 to 0.004). The 95% reference range for the difference between the two transducer frequencies indicated that the thickness obtained at 14 MHz was within 0.05 mm of that obtained at 8 MHz for 95% of subjects. CONCLUSIONS: Carotid IMT measurements obtained at higher transducer frequencies are similar to those obtained at standard frequency. This finding has important clinical implications because it validates comparison of carotid IMT measurements obtained with newer, more advanced ultrasound technology with the landmark reference carotid IMT studies commonly used for interpretation of carotid IMT results.

Preoperative dobutamine stress echocardiographic findings and subsequent short-term adverse cardiac events after orthotopic liver transplantation.

Cardiovascular (CV) complications are the leading cause of non-graft-related death in orthotopic liver transplant (OLT) patients. Pretransplant cardiac evaluation using dobutamine stress echocardiography (DSE) is commonly utilized for risk stratification of OLT candidates. To determine if clinical and echocardiographic variables identify patients with increased CV risk, we performed a retrospective chart review of all 284 patients that underwent OLT at our institution between June 1999 and August 2005. Of these patients, 157 had a DSE prior to their OLT. Serious adverse CV events occurring during surgery and up to 4 months post-transplantation were defined as cardiac-related death, myocardial infarction (MI), new heart failure, or asystole or unstable ventricular arrhythmia requiring acute treatment. Sixteen of 157 patients (10%) had an adverse CV event with 2 deaths. These included ventricular tachycardia (n = 8), asystole (n = 2), MI (n = 5), and new heart failure (n = 1). Nine of the 16 CV events occurred at the time of surgery (including both deaths), 5 occurred postoperatively, and 3 occurred after hospital discharge. Variables that correlated with increased CV events were inability during DSE to achieve >82% of the maximum predicted heart rate (22% versus 6%, P = 0.01), a peak rate pressure product during DSE of <16,333 (17% versus 5%, P = 0.02), and a Model for End-Stage Liver Disease (MELD) score of >24 at the time of OLT. A multivariate model calculated from the DSE maximum achieved heart rate (MAHR) and MELD score (result = 3.78 + 0.07 MELD - 0.05 MAHR) identified a 47% risk for a value > 0 versus a 6% risk for a value < 0 (P < 0.001). In conclusion, the maximum heart rate achieved during DSE together with the MELD score may be a predictor of adverse CV events up to 4 months post-OLT. A large prospective study is needed to more decisively support this conclusion.

Three methods for evaluation of left atrial volume.

AIM: To compare and contrast 3 different echocardiographic methods used to measure left atrial (LA) volume: biplane area length (AL), biplane modified Simpson (SIMP), and prolate ellipse (PE) methods. METHODS AND RESULTS: A review of consecutive patients who presented to our outpatient echocardiography laboratory for a resting transthoracic study between April 2006 and May 2006 was performed. Echocardiograms were reexamined and LA volume measured using the AL, SIMP, and PE methods. Of 102 consecutive patients evaluated, 97 had a measure of LA volume using all 3 methods. A significant difference in the measurement of mean +/- SD LA volume was noted among the 3 different methods: 37 +/- 16 mL/m(2) for AL, 34 +/- 14 mL/m(2) for SIMP, and 27 +/- 12 mL/m(2) for PE. The PE method yielded routinely smaller values compared with either the AL or SIMP method (P < 0.001). Differences increased with increased LA volume. The SIMP method derived consistently smaller (<5 mL/m(2)) values than those of the AL method, consistent across the full range of LA volumes. CONCLUSION: Significant differences exist among these 3 commonly used methods for measuring LA volume. Standardization of the measurement of LA volume is recommended.

Isolated left ventricular basal ballooning phenotype of transient cardiomyopathy in young women.

This report describes a variant of transient regional left ventricular dysfunction in which isolated basal left ventricular akinesia with normal mid-ventricular (papillary-level) wall motion and apical hypercontractility were noted in young women (mean age 31 years). This finding was demonstrated in 3 consecutive patients; the first patient was experiencing emotional life-altering events, and the second presented with an acute flare of multiple sclerosis. The third patient presented < 24 hours after methamphetamine use. Coronary angiography demonstrated normal epicardial coronary arteries in all patients. Wall motion abnormalities resolved within 2 to 6 weeks. In conclusion, the entity described in this report is reminiscent of apical ballooning ("Tako-Tsubo"), mid-ventricular ballooning, and apical sparing syndromes; however, isolated basal left ventricular involvement has not been previously described and is a newer variant in the spectrum of transient cardiomyopathies. The pathophysiology of this entity has not been elucidated. A unifying feature between the transient cardiomyopathic syndromes most likely is in the concentration, distribution, and activity of cardiac adrenergic receptors.

Relation of electrocardiographic criteria for left atrial enlargement to two-dimensional echocardiographic left atrial volume measurements.

Left atrial (LA) enlargement by 2-dimensional (2-D) echocardiography predicts adverse cardiovascular outcomes. Electrocardiographic (ECG) criteria for LA enlargement are based on M-mode echocardiographic LA diameter, which is inferior to 2-D-derived LA volumes. This study compared established ECG criteria for LA enlargement with atrial volume obtained by 2-D echocardiography to determine if traditional ECG criteria accurately represent LA chamber enlargement, therefore offering a low-cost screening tool. A total of 261 randomly selected patients who underwent electrocardiography and 2-D echocardiography were enrolled. ECG parameters and electronically derived P-wave medians were analyzed with electronic calipers for maximal accuracy. LA volumes by 2-D echocardiography were measured with Simpson's method of discs, with enlargement defined as 32 ml/m(2). Sensitivity and specificity tables and receiver-operating characteristic curves were constructed for each criterion. Univariate and multivariate analyses were performed for predictors of 2-D echocardiographic LA enlargement. LA enlargement was present in 43% of patients. ECG P-wave duration was the most sensitive for the detection of LA enlargement (69%) but had low specificity (49%). Conversely, a biphasic P wave was the most specific (92%) but had low sensitivity (12%). The maximum area under the receiver-operating characteristic curve for any criterion was 0.64, too low to be of clinical utility. In conclusion, established ECG criteria for LA enlargement do not reliably reflect LA enlargement and lack sufficient predictive value to be useful clinically. These results suggest that P-wave abnormalities should be noted as nonspecific LA abnormalities, with the term "LA enlargement" no longer used.

Convolutional Neural Networks for Medical Image Analysis: Full Training or Fine Tuning?

Training a deep convolutional neural network (CNN) from scratch is difficult because it requires a large amount of labeled training data and a great deal of expertise to ensure proper convergence. A promising alternative is to fine-tune a CNN that has been pre-trained using, for instance, a large set of labeled natural images. However, the substantial differences between natural and medical images may advise against such knowledge transfer. In this paper, we seek to answer the following central question in the context of medical image analysis: Can the use of pre-trained deep CNNs with sufficient fine-tuning eliminate the need for training a deep CNN from scratch? To address this question, we considered four distinct medical imaging applications in three specialties (radiology, cardiology, and gastroenterology) involving classification, detection, and segmentation from three different imaging modalities, and investigated how the performance of deep CNNs trained from scratch compared with the pre-trained CNNs fine-tuned in a layer-wise manner. Our experiments consistently demonstrated that 1) the use of a pre-trained CNN with adequate fine-tuning outperformed or, in the worst case, performed as well as a CNN trained from scratch; 2) fine-tuned CNNs were more robust to the size of training sets than CNNs trained from scratch; 3) neither shallow tuning nor deep tuning was the optimal choice for a particular application; and 4) our layer-wise fine-tuning scheme could offer a practical way to reach the best performance for the application at hand based on the amount of available data.

Increased incidence of coronary atherosclerosis in type 2 diabetes mellitus: mechanisms and management.

Type 2 diabetes mellitus is a metabolic disease of carbohydrate metabolism. However, it should also be considered a vascular disease because diabetic patients have a strong predilection for atherosclerosis. With the increasing prevalence and earlier age at onset of diabetes, the projected effect of diabetes on cardiovascular health and resource utilization is sobering. The mechanisms of the high rate of atherosclerosis are multifactorial and give clinicians and researchers insights into potential preventive therapies. Effective pharmacologic and lifestyle interventions are available for primary and secondary prevention of cardiovascular complications. However, data show that these interventions continue to be underutilized. Treatment of patients with type 2 diabetes and coronary artery disease is similar to that of patients with coronary artery disease alone. However, patients with diabetes benefit more from treatments that reduce coronary artery disease risk.

Risk Stratification for Cardiovascular Disease in Women in the Primary Care Setting.

BACKGROUND: Traditional risk assessment tools classify the majority of middle-aged women at low risk despite cardiovascular (CV) disease's affecting >50% of women and remaining the leading cause of death. Ultrasound-determined carotid intima-media thickness (CIMT) and/or computed tomographic coronary artery calcium score (CACS) quantify subclinical atherosclerosis and add incremental prognostic value. The aim of this study was to assess the utility of CIMT and CACS to detect subclinical atherosclerosis in younger women. METHODS: Asymptomatic women aged 50 to 65 years with at least one CV risk factor and low Framingham risk scores were identified prospectively at primary care and cardiology clinics. Mean intimal thickness, plaque on CIMT, and Agatston calcium score for CACS were obtained. RESULTS: Of 86 women (mean age, 58 ± 4.6 years; mean Framingham risk score, 1.9 ± 1.2; mean low-density lipoprotein cholesterol level, 138.9 ± 37.0 mg/dL), 53 (62%) had high-risk CIMT (51% plaque, 11% CIMT > 75th percentile). In contrast, three women (3.5%) had CACS > 100, all of whom had plaque by CIMT. Of the 58 women with CACS of 0, 32 (55%) had high-risk CIMT (48% plaque, 7% CIMT > 75th percentile). CONCLUSIONS: In patients referred by their physicians for assessment of CV risk, CIMT in asymptomatic middle-aged women with at least one CV risk factor and low risk by the Framingham risk score identified a large number with advanced subclinical atherosclerosis despite low CACS. Our results suggest that CIMT may be a more sensitive method for CV risk assessment than CACS or traditional risk tools in this population. Further studies are needed to determine if earlier detection would be of clinical benefit.

Two cases of apical ballooning syndrome masking apical hypertrophic cardiomyopathy.

Apical akinesis and dilation in the absence of obstructive coronary artery disease is a typical feature of stress-induced (takotsubo) cardiomyopathy, whereas apical hypertrophy is seen in apical-variant hypertrophic cardiomyopathy. We report the cases of 2 patients who presented with takotsubo cardiomyopathy and were subsequently found to have apical-variant hypertrophic cardiomyopathy, after the apical ballooning from the takotsubo cardiomyopathy had resolved. The first patient, a 43-year-old woman with a history of alcohol abuse, presented with shortness of breath, electrocardiographic and echocardiographic features consistent with takotsubo cardiomyopathy, and no significant coronary artery disease. An echocardiogram 2 weeks later revealed a normal left ventricular ejection fraction and newly apparent apical hypertrophy. The 2nd patient, a 70-year-old woman with pancreatitis, presented with chest pain, apical akinesis, and a left ventricular ejection fraction of 0.39, consistent with takotsubo cardiomyopathy. One month later, her left ventricular ejection fraction was normal; however, hypertrophy of the left ventricular apex was newly noted. To our knowledge, these are the first reported cases in which apical-variant hypertrophic cardiomyopathy was masked by apical ballooning from stress-induced cardiomyopathy.

A perspective on the New American College of Cardiology/American Heart Association guidelines for cardiovascular risk assessment.

The recently published American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for cardiovascular risk assessment provide equations to estimate the 10-year and lifetime atherosclerotic cardiovascular disease (ASCVD) risk in African Americans and non-Hispanic whites, include stroke as an adverse cardiovascular outcome, and emphasize shared decision making. The guidelines provide a valuable framework that can be adapted on the basis of clinical judgment and individual/institutional expertise. In this review, we provide a perspective on the new guidelines, highlighting what is new, what is controversial, and potential adaptations. We recommend obtaining family history of ASCVD at the time of estimating ASCVD risk and consideration of imaging to assess subclinical disease burden in patients at intermediate risk. In addition to the adjuncts for ASCVD risk estimation recommended in the guidelines, measures that may be useful in refining risk estimates include carotid ultrasonography, aortic pulse wave velocity, and serum lipoprotein(a) levels. Finally, we stress the need for research efforts to improve assessment of ASCVD risk given the suboptimal performance of available risk algorithms and suggest potential future directions in this regard.

A summary and critical assessment of the 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular disease risk in adults: filling the gaps.

The American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Practice Guidelines has recently released the new cholesterol treatment guideline. This update was based on a systematic review of the evidence and replaces the previous guidelines from 2002 that were widely accepted and implemented in clinical practice. The new cholesterol treatment guideline emphasizes matching the intensity of statin treatment to the level of atherosclerotic cardiovascular disease (ASCVD) risk and replaces the old paradigm of pursuing low-density lipoprotein cholesterol targets. The new guideline also emphasizes the primacy of the evidence base for statin therapy for ASCVD risk reduction and lists several patient groups that will not benefit from statin treatment despite their high cardiovascular risk, such as those with heart failure (New York Heart Association class II-IV) and patients undergoing hemodialysis. The guideline has been received with mixed reviews and significant controversy. Because of the evidence-based nature of the guideline, there is room for several questions and uncertainties on when and how to use lipid-lowering therapy in clinical practice. The goal of the Mayo Clinic Task Force in the assessment, interpretation, and expansion of the ACC/AHA cholesterol treatment guideline is to address gaps in information and some of the controversial aspects of the newly released cholesterol management guideline using additional sources of evidence and expert opinion as needed to guide clinicians on key aspects of ASCVD risk reduction.

Carotid intimal-medial thickness in active professional American football players aged 23 to 35 years.

Risk of cardiovascular disease and death in retired professional American football players may be higher than that in the general population. Previously published data have demonstrated that American football players have less glucose intolerance, less smoking, similar lipid profiles, and higher blood pressure despite a much larger body compared to the general population, although the presence of subclinical atherosclerosis in these subjects has not been evaluated. This study compared the prevalence of subclinical atherosclerosis in active professional American football players to that in age-, gender-, and race-matched controls derived from the Bogalusa Heart Study. Carotid intimal-medial thickness (CIMT) was used as an indicator of subclinical atherosclerosis in 75 active American football players (23 to 35 years old, 31 white, 44 African-American) as measured by B-mode ultrasonography at Mayo Clinic, Scottsdale, Arizona, on September 13 and 14, 2009. CIMT measurements of 75 athletes were compared to those of 518 matched controls who had CIMT determinations in 1995 and 1996. Two-group t tests determined population similarities between groups. In a generalized linear model, players (overall and by race) had lower CIMT values than controls after age and race adjustment (p <0.001 for all comparisons). Nonlinemen and linemen had lower CIMT values than controls (p < 0.001 and p = 0.004, respectively). In conclusion, active professional American football players, regardless of position, had mean CIMT values similar to or lower than those in a matched general population cohort, suggesting that if the prevalence of subclinical atherosclerosis is increased in retired professional American football players, this occurs after retirement.

Echocardiographic measures of myocardial deformation by speckle-tracking technologies: the need for standardization?

BACKGROUND: Multiple vendor-specific two-dimensional speckle-tracking echocardiographic algorithms with which to characterize myocardial mechanics are commercially available. The purpose of this study was to compare global longitudinal strain (GLS) results between two independent software vendors using a neutral image platform. METHODS: A convenience sample of 100 prospectively collected patients was evaluated. Subjects with more than two left ventricular endocardial segments poorly delineated were excluded. GLS was obtained from the apical four-chamber, three-chamber, and two-chamber views using two independent speckle-tracking echocardiographic software packages (EchoInsight version 1.5.0 and Image-Arena version 4.5). Linear regression analysis and paired t tests were used to compare GLS results. Intraclass correlation coefficients and Bland-Altman plots were used for assessments of reliability. RESULTS: The "out-of-the-box" mean GLS was -12.99 ± 2.38% using EchoInsight and -16.87 ± 2.84% using Image-Arena (mean difference, 3.87 ± 2.42%; P = .0001). Agreement between the software packages was moderate (intraclass correlation coefficient, 0.43; 95% confidence interval, 0.32-0.55). Using uniform variables to derive GLS (Lagrangian strain measured in systole and diastole at the endocardium and averaging the peak segmental strain curves), EchoInsight GLS was -16.17 ± 2.90% and Image-Arena GLS was -16.87 ± 2.84% (mean difference, 0.70 ± 2.75%; P = .02), with an intraclass correlation coefficient of 0.70 (95% confidence interval, 0.52-0.79). CONCLUSIONS: Image-Arena GLS results were consistently different (more negative) than EchoInsight measures out of the box but became similar when information used to derive GLS was uniform. The evolution of measures of myocardial mechanics into routine clinical practice will require vigilance and standardization of the various techniques, necessitating independent validation of commercially available speckle-tracking echocardiographic products.

Coronary artery plaque burden does not affect left ventricular diastolic function in asymptomatic adults with normal ejection fraction.

BACKGROUND: Coronary artery disease (CAD) is commonly cited as a mechanism underlying diastolic dysfunction. However, the association of CAD without ischemia and left ventricular (LV) diastolic dysfunction has not been convincingly demonstrated in asymptomatic patients. The objective of this study was to determine if such a relation exists using coronary artery calcium score (CACS) as a surrogate for coronary atherosclerosis burden. METHODS: Consecutive eligible patients with normal ejection fraction who underwent CACS assessment, echocardiography, and stress testing with negative results for obstructive CAD between August 2006 and September 2007 were included in this retrospective study. Clinical variables were collected from the medical record. Diastolic function classification was based on established echocardiographic guidelines recommended by the American Society of Echocardiography. Statistical analysis was used to identify predictors of CACS. RESULTS: A total of 349 subjects (302 men) aged 58 ± 6 years were studied. Risk factors included hyperlipidemia (n = 202 [58%]), hypertension (n = 127 [36%]), impaired fasting glucose (n = 78 [22%]), and diabetes (n = 21 [6%]). Left atrial volume index was weakly correlated with CACS (r = 0.26, P < .001). There was no significant relationship between CACS and LV diastolic function grade in the entire group (P = .14) or in a subgroup of younger patients (n = 140) who matched the ages qualifying for premature CAD (P = .17). After stepwise elimination multivariate analysis, five variables independently predicted CACS: age (P < .001), hyperlipidemia (P < .001), LA volume index (P < .001), male gender (P = .01), and LV posterior wall thickness (P = .03). CONCLUSIONS: In asymptomatic patients with normal LV ejection fraction and negative cardiac stress test results, CACS does not correlate with LV diastolic function as defined by established Doppler echocardiographic criteria. In the absence of ischemia, postinfarction LV remodeling, or previous coronary artery bypass surgery, CAD does not appear be a cause of LV diastolic dysfunction in asymptomatic patients.

Usefulness of two-dimensional and speckle tracking echocardiography in "Gray Zone" left ventricular hypertrophy to differentiate professional football player's heart from hypertrophic cardiomyopathy.

Distinguishing the pathologic hypertrophy of hypertrophic cardiomyopathy (HC) from the physiologic hypertrophy of professional football players (PFP) can be challenging when septal wall thickness falls within a "gray zone" between 12 and 16 mm. It was hypothesized that 2-dimensional and speckle-tracking strain (ε) echocardiography could differentiate the hearts of PFPs from those of patients with HC with similar wall thicknesses. Sixty-six subjects, including 28 professional American football players and 21 patients with HC, with septal wall thicknesses of 12 to 16 mm, along with 17 normal controls, were studied using 2-dimensional echocardiography. Echocardiographic parameters, including modified relative wall thickness (RWT; septal wall thickness + posterior wall thickness/left ventricular end-diastolic diameter) and early diastolic annular tissue velocity (e'), were measured. Two-dimensional ε was analyzed by speckle tracking to measure endocardial and epicardial longitudinal ε and circumferential ε and radial cardiac ε. Septal wall thickness was higher in patients with HC than in PFPs (14.7 ± 1.1 vs 12.9 ± 0.9 mm, respectively, p <0.001), while posterior wall thickness showed no difference. RWT was larger in patients with HC than in PFPs (0.68 ± 0.10 vs 0.48 ± 0.06, p <0.001). Longitudinal endocardial ε and radial cardiac ε were significantly higher in PFPs than in patients with HC, while circumferential endocardial ε was no different. RWT was the parameter that most accurately differentiated PFPs from patients with HC. An RWT cut point of 0.6 differentiated PFPs from patients with HC, with an area under the curve of 0.97. In conclusion, a 2-dimensional echocardiographic measure of RWT (septal wall + posterior wall thickness/left ventricular end-diastolic dimension) accurately differentiated PFPs' hearts from those of patients with HC when septal wall thickness was in the gray zone of 12 to 16 mm. Two-dimensional strain analysis identifies variations in myocardial deformation between PFPs and patients with HC with gray-zone hypertrophy.

Epicardial fat: an additional measurement for subclinical atherosclerosis and cardiovascular risk stratification?

BACKGROUND: The value of epicardial adipose tissue (EAT) thickness as determined by echocardiography in cardiovascular risk assessment is not well understood. The aim of this study was to determine the associations between EAT thickness and Framingham risk score, carotid intima media thickness, carotid artery plaque, and computed tomographic coronary calcium score in a primary prevention population. METHODS: Patients presenting for cardiovascular preventive care (n = 356) who underwent echocardiography as well as carotid artery ultrasound and/or coronary calcium scoring were included. RESULTS: EAT thickness was weakly correlated with Framingham risk score. The prevalence of carotid plaque was significantly greater in those with EAT thickness ≥ 5.0 mm who either had low Framingham risk scores or had body mass indexes ≥ 25 kg/m(2), compared with those with EAT thickness <5.0 mm. No significant association between EAT thickness and carotid intima-media thickness or coronary calcium score existed. CONCLUSION: EAT thickness ≥ 5.0 mm may identify an individual with a higher likelihood of having detectable carotid atherosclerosis.

Assessing individual cardiac risk using extra-cardiac arterial imaging.

Cardiovascular disease is the leading cause of death globally. Cardiovascular risk factors predict the risk of cardiovascular events in populations but have limitations in predicting individual risk. Emerging technologies that non-invasively measure carotid intima media thickness, aortic pressure and brachial artery reactivity may be useful in identifying the vulnerable patient who may benefit from more aggressive preventive therapy. These tests vary between each other in their reproducibility, cost, required operator skill, availability and patient preparation. However, all require further validation for clinical use as screening tests for cardiovascular disease.

Takotsubo cardiomyopathy: a unique cardiomyopathy with variable ventricular morphology.

Takotsubo cardiomyopathy is an important differential diagnosis of acute coronary syndrome. It is characterized by normal (or near-normal) coronary arteries, regional wall motion abnormalities that extend beyond a single coronary vascular bed, and often, a precipitating stressor. Variants of the classical left ventricular apical ballooning, including mid- or basal left ventricular wall motion abnormalities, are increasingly recognized. Takotsubo cardiomyopathy is not rare, and heightened awareness of this unique cardiomyopathy likely will lead to a higher reported incidence. Diagnosis of takotsubo cardiomyopathy has important implications for clinical management at presentation and afterward. The long-term prognosis is generally favorable; however, a small subset has potentially life-threatening complications during the initial presentation. The pathophysiologic mechanism is unknown, but catecholamine excess likely has a central role.