Paaladinesh Thavendiranathan

Reproducibility of Echocardiographic Techniques for Sequential Assessment of Left Ventricular Ejection Fraction and Volumes Application to Patients Undergoing Cancer Chemotherapy

OBJECTIVESnThe aim of this study was to identify the best echocardiographic method for sequential quantification of left ventricular (LV) ejection fraction (EF) and volumes in patients undergoing cancer chemotherapy.nnnBACKGROUNDnDecisions regarding cancer therapy are based on temporal changes of EF. However the method for EF measurement with the lowest temporal variability is unknown.nnnMETHODSnWe selected patients in whom stable function in the face of chemotherapy for breast cancer was defined by stability of global longitudinal strain (GLS) at up to 5 time points (baseline, 3, 6, 9, and 12 months). In this way, changes in EF were considered to reflect temporal variability of measurements rather than cardiotoxicity. A comprehensive echocardiogram consisting of 2-dimensional (2D) and 3-dimensional (3D) acquisitions with and without contrast administration was performed at each time point. Stable LV function was defined as normal GLS (≤-16.0%) at each examination. The EF and volumes were measured with 2D-biplane Simpsons method, 2D-triplane, and 3-dimensional echocardiography (3DE) by 2 investigators blinded to any clinical data. Inter-, intra-, and test-retest variability were assessed in a subgroup. Variability was assessed by analysis of variance and compared with Levenes or t test.nnnRESULTSnAmong 56 patients (all female, 54 ± 13 years of age), noncontrast 3D EF, end-diastolic volume, and end-systolic volume had significantly lower temporal variability than all other methods. Contrast only decreased the temporal variability of LV end-diastolic volume measurements by the 2D biplane method. Our data suggest that a temporal variability in EF of 0.06 might occur with noncontrast 3DE due to physiological differences and measurement variability, whereas this might be >0.10 with 2D methods. Overall, 3DE also had the best intra- and inter-observer as well as test-retest variability.nnnCONCLUSIONSnNoncontrast 3DE was the most reproducible technique for LVEF and LV volume measurements over 1 year of follow-up.

Relative apical sparing of longitudinal strain using two-dimensional speckle-tracking echocardiography is both sensitive and specific for the diagnosis of cardiac amyloidosis

Background The diagnosis of cardiac amyloidosis (CA) is challenging owing to vague symptomatology and non-specific echocardiographic findings. Objective To describe regional patterns in longitudinal strain (LS) using two-dimensional speckle-tracking echocardiography in CA and to test the hypothesis that regional differences would help differentiate CA from other causes of increased left ventricular (LV) wall thickness. Methods and results 55 consecutive patients with CA were compared with 30 control patients with LV hypertrophy (n=15 with hypertrophic cardiomyopathy, n=15 with aortic stenosis). A relative apical LS of 1.0, defined using the equation (average apical LS/(average basal LS + mid-LS)), was sensitive (93%) and specific (82%) in differentiating CA from controls (area under the curve 0.94). In a logistic regression multivariate analysis, relative apical LS was the only parameter predictive of CA (p=0.004). Conclusions CA is characterised by regional variations in LS from base to apex. A relative ‘apical sparing’ pattern of LS is an easily recognisable, accurate and reproducible method of differentiating CA from other causes of LV hypertrophy.

Recommendations for Noninvasive Evaluation of Native Valvular Regurgitation: A Report from the American Society of Echocardiography Developed in Collaboration with the Society for Cardiovascular Magnetic Resonance

William A. Zoghbi, MD, FASE (Chair), David Adams, RCS, RDCS, FASE, Robert O. Bonow, MD, Maurice Enriquez-Sarano, MD, Elyse Foster, MD, FASE, Paul A. Grayburn, MD, FASE, Rebecca T. Hahn, MD, FASE, Yuchi Han, MD, MMSc,* Judy Hung, MD, FASE, Roberto M. Lang, MD, FASE, Stephen H. Little, MD, FASE, Dipan J. Shah, MD, MMSc,* Stanton Shernan, MD, FASE, Paaladinesh Thavendiranathan, MD, MSc, FASE,* James D. Thomas, MD, FASE, and Neil J. Weissman, MD, FASE, Houston and Dallas, Texas; Durham, North Carolina; Chicago, Illinois; Rochester, Minnesota; San Francisco, California; New York, New York; Philadelphia, Pennsylvania; Boston, Massachusetts; Toronto, Ontario, Canada; and Washington, DC

Do Blood Tests Cause Anemia in Hospitalized Patients?: The Effect of Diagnostic Phlebotomy on Hemoglobin and Hematocrit Levels

OBJECTIVE: To determine whether phlebotomy contributes to changes in hemoglobin and hematocrit levels in hospitalized general internal medicine patients.DESIGN: Retrospective cohort study.SETTING: General internal medicine inpatient service at a tertiary care hospital.PARTICIPANTS: All adult patients discharged from the Toronto General Hospital’s internal medicine service between January 1 and June 30, 2001. A total of 989 hospitalizations were reviewed and 404 hospitalizations were included in our analysis.MEASUREMENTS AND MAIN RESULTS: Mean (SD) hemoglobin and hematocrit changes during hospitalization were 7.9 (12.6) g/L (P<.0001) and 2.1% (3.8%) (P<.0001), respectively. The mean (SD) volume of phlebotomy during hospital stay was 74.6 (52.1) mL. On univariate analysis, changes in hemoglobin and hematocrit were predicted by the volume of phlebotomy, length of hospital stay, admission hemoglobin/hematocrit value, age, Charlson comorbidity index, and admission intravascular volume status. The volume of phlebotomy remained a strong predictor of drop in hemoglobin and hematocrit after adjusting for other predictors using multivariate analysis (P<.0001). On average, every 100mL of phlebotomy was associated with a decrease in hemoglobin and hematocrit of 7.0g/L and 1.9%, respectively.CONCLUSIONS: Phlebotomy is highly associated with changes in hemoglobin and hematocrit levels for patients admitted to an internal medicine service and can contribute to anemia. This anemia, in turn, may have significant consequences, especially for patients with cardiorespiratory diseases. Knowing the expected changes in hemoglobin and hematocrit due to diagnostic phlebotomy will help guide when to investigate anemia in hospitalized patients.

The MCT Ketogenic Diet: Effects on Animal Seizure Models

Male Wistar rat pups were weaned at 20 days of age and placed on either a control diet or a ketogenic diet containing medium-chain triglyceride (MCT) oil. After 10 days on the diets, they were subjected to one of four seizure tests-maximal electric shock, threshold electroconvulsive shock, threshold pentylenetetrazol, or maximal pentylenetetrazol. After testing, subjects were sacrificed and blood samples were analyzed for beta-hydroxybutyrate concentration. It was found that the MCT diet produced blood levels of beta-hydroxybutyrate that were comparable to or higher than those commonly reported in clinical studies. However, no anticonvulsant effects were seen in any of the seizure tests. In fact, the tests involving maximal seizures actually showed proconvulsant effects. It appears that clinical levels of ketones may be present in the bloodstream without suppressing seizures.

Quantitative Assessment of Mitral Regurgitation: How Best to Do It

Decisions regarding surgery for mitral regurgitation (MR) are predicated on the accurate quantification of MR severity. Quantitative parameters, including vena contracta width, regurgitant volume and fraction, and effective regurgitant orifice area have prognostic significance and are recommended to be obtained from patients with more than mild MR. New tools for MR quantification have been provided by 3-dimensional echocardiography, cardiac magnetic resonance, and cardiac computed tomography, but limited guidance on appropriate image acquisition and post-processing techniques has hindered their clinical application and reproducibility. This review describes optimal image acquisition and post-processing methods for quantification of MR.

Quantitative assessment of mitral regurgitation: validation of new methods.

Accurate assessment of mitral regurgitation (MR) severity is important for clinical decision making, prognostication, and decisions regarding timing of surgical intervention. The most common method for noninvasive assessment of MR has been with 2-dimensional transthoracic echocardiography, which is often used as a qualitative tool. Several newer noninvasive modalities including 3-dimensional echocardiography, cardiac magnetic resonance imaging, and cardiac computed tomography have also become available for this purpose; however, their role in routine clinical practice is not clearly defined. In this review, we provide an overview of these newer modalities for quantitative assessment of MR severity.

Isolated left ventricular non-compaction controversies in diagnostic criteria, adverse outcomes and management

Isolated left ventricular non-compaction (LVNC) is a morphological abnormality of excessive trabeculation of the LV, often complicated by ventricular dysfunction, arrhythmias and cardioembolism. Advances in cardiovascular imaging and widespread availability of imaging technology have led to an increase in the diagnosis of LVNC imposing a need for evidence-based imaging diagnostic criteria. Although recent studies have addressed the utility of newer diagnostic methodologies and the incidence of adverse events in this condition, the diagnosis and management remain controversial. In this review, we provide an overview of the current controversies in the clinical diagnosis of LVNC, and suggest a management approach.

The effect of the ‘classic’ ketogenic diet on animal seizure models

Bough et al. have recently demonstrated anticonvulsant effects of the classic ketogenic diet (KD) in the pentylenetetrazol infusion model in rats. Proconvulsant effects were seen, however, when the classic diet was tested against maximal electroshock (MES) seizures. These differing results may reflect the fact that the two models involve different kinds of epileptogenic stimulus, or, as Bough et al. note that the two tests involve different stimulation paradigms. The pentylenetetrazol infusion paradigm is a threshold test, whereas the MES test employs a stimulus which is well above threshold. The present experiments were designed to test the effects of the classic KD against seizures triggered in rats by both threshold and suprathreshold levels of electricity and pentylenetetrazol. The threshold tests employed were the pentylenetetrazol infusion test, and the threshold electroconvulsive shock (ECS) test. The subcutaneous pentylenetetrazol (scMET) test was also included, since it is sometimes considered to be a threshold test. The suprathreshold tests employed were the maximal pentylenetetrazol test (MMT) and the maximal electroshock test (MES). The KD failed to suppress seizures in either of the tests involving suprathreshold stimulation (MMT and MES), although there was a significant increase in latency in the MMT test. Small but significant threshold elevations (15-20%) were seen, however, in both the pentylenetetrazol infusion test and the ECS threshold test. No seizure suppression was seen in the scMET test, which actually employs a suprasthreshold stimulus. These data indicate that the KD has significant anticonvulsant effects against both chemically and electrically triggered seizures, but that they consist of small elevations in threshold which will be seen only when threshold measures are used.

Does This Patient With Palpitations Have a Cardiac Arrhythmia

CONTEXTnMany patients have palpitations and seek advice from general practitioners. Differentiating benign causes from those resulting from clinically significant cardiac arrhythmia can be challenging and the clinical examination may aid in this process.nnnOBJECTIVEnTo systematically review the accuracy of historical features, physical examination, and cardiac testing for the diagnosis of cardiac arrhythmia in patients with palpitations. Data Source, Study Selection, andnnnDATA EXTRACTIONnMEDLINE (1950 to August 25, 2009) and EMBASE (1947 to August 2009) searches of English-language articles that compared clinical features and diagnostic tests in patients with palpitations with a reference standard for cardiac arrhythmia. Of the 277 studies identified by the search strategy, 7 studies were used for accuracy analysis and 16 studies for diagnostic yield analysis. Two authors independently reviewed articles for study data and quality and a third author resolved disagreements.nnnDATA SYNTHESISnMost data were obtained from single studies with small sample sizes. A known history of cardiac disease (likelihood ratio [LR], 2.03; 95% confidence interval [CI], 1.33-3.11), having palpitations affected by sleeping (LR, 2.29; 95% CI, 1.33-3.94), or while the patient is at work (LR, 2.17; 95% CI, 1.19-3.96) slightly increase the likelihood of a cardiac arrhythmia. A known history of panic disorder (LR, 0.26; 95% CI, 0.07-1.01) or having palpitations lasting less than 5 minutes (LR, 0.38; 95% CI, 0.22-0.63) makes the diagnosis of cardiac arrhythmia slightly less likely. The presence of a regular rapid-pounding sensation in the neck (LR, 177; 95% CI, 25-1251) or visible neck pulsations (LR, 2.68; 95% CI, 1.25-5.78) in association with palpitations increases the likelihood of a specific type of arrhythmia (atrioventricular nodal reentry tachycardia). The absence of a regular rapid-pounding sensation in the neck makes detecting the same arrhythmia less likely (LR, 0.07; 95% CI, 0.03-0.19). No other features significantly alter the probability of clinically significant arrhythmia. Diagnostic tests for prolonged periods of electrocardiographic monitoring vary in their yield depending on the modality used, duration of monitoring, and occurrence of typical symptoms during monitoring. Loop monitors have the highest diagnostic yield (34%-84%) for identifying an arrhythmia.nnnCONCLUSIONSnWhile the presence of a regular rapid-pounding sensation in the neck or visible neck pulsations associated with palpitations makes the diagnosis of atrioventricular nodal reentry tachycardia likely, the reviewed studies suggest that the clinical examination is not sufficiently accurate to exclude clinically significant arrhythmias in most patients. Thus, prolonged electrocardiographic monitoring with demonstration of symptom-rhythm correlation is required to make the diagnosis of a cardiac arrhythmia for most patients with recurrent palpitations.