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Allan L Klein

Publications and source records attributed to Allan L Klein.

35 records · Page 2Linked to original sources
PubMed2004

Pericarditis.

Pericarditis is a common disorder that has multiple causes and presents in various primary-care and secondary-care settings. New diagnostic techniques have improved the sampling and analysis of pericardial fluid and allow comprehensive characterisation of cause. Despite this advance, pericarditis is most commonly idiopathic, and radiation therapy, cardiac surgery, and percutaneous procedures have become important causes. Pericarditis is frequently self-limiting, and non-steroidal anti-inflammatory agents remain the first-line treatment for uncomplicated cases. Integrated use of new imaging methods facilitates accurate detection and management of complications such as pericardial effusion or constriction. Differentiation of constrictive pericarditis from restrictive cardiomyopathy remains a clinical challenge but is facilitated by tissue doppler and colour M-mode echocardiography. Most pericardial effusions can be safely managed with an echo-guided percutaneous approach. Pericardiectomy remains the definitive treatment for constrictive pericarditis and provides symptomatic relief in most cases. In the future, the pericardial space might become a conduit for treatments directed at the pericardium and myocardium.

Acute Disease↗
PubMed2004

Plasma B-type natriuretic peptide levels in systolic heart failure: importance of left ventricular diastolic function and right ventricular systolic function.

OBJECTIVES: This study was designed to characterize the importance of echocardiographic indexes, including newer indexes of diastolic function, as determinants of plasma B-type natriuretic peptide (BNP) levels in patients with systolic heart failure (SHF). BACKGROUND: Plasma BNP levels have utility for diagnosing and managing heart failure. However, there is significant heterogeneity in BNP levels that is not explained by left ventricular size and function alone. METHODS: In 106 patients with symptomatic SHF (left ventricular ejection fraction [LVEF] <0.35), we measured plasma BNP levels and performed comprehensive echocardiography with assessment of left ventricular diastolic function, including color M-mode (CMM) and tissue Doppler imaging (TDI), and of right ventricular (RV) function. RESULTS: Median plasma BNP levels were elevated and increased with greater severity of diastolic dysfunction. We found significant correlations (p < 0.001 for all) between BNP and indexes of myocardial relaxation (early diastolic velocity: r = -0.26), compliance (deceleration time: r = -0.55), and filling pressure (early transmitral to early annular diastolic velocity ratio: r = 0.51; early transmitral flow to the velocity of early left ventricular flow propagation ratio: r = 0.41). In multivariate analysis, overall diastolic stage, LVEF, RV systolic dysfunction, mitral regurgitation (MR) severity, age and creatinine clearance were independent predictors of BNP levels (model fit r = 0.8, p < 0.001). CONCLUSIONS: Plasma BNP levels are significantly related to newer diastolic indexes measured from TDI and CMM in SHF. Heterogeneity of BNP levels in patients with SHF reflects the severity of diastolic abnormality, RV dysfunction, and MR in addition to LVEF, age, and renal function. These findings may explain the powerful relationship of BNP to symptoms and prognosis in SHF.

Aged↗
PubMed2004

Tissue Doppler imaging in the evaluation of patients with cardiac amyloidosis.

PURPOSE OF REVIEW: Although two-dimensional, M-mode, and Doppler echocardiography have played a major role in the assessment of amyloid deposition in the heart, diagnosis of cardiac amyloidosis (CA) based on these conventional techniques is often only possible once the disease is in a relatively advanced stage. To optimize survival, early diagnosis and institution of therapy are essential. Recently, tissue Doppler imaging (TDI) and myocardial strain rate (SR) have emerged as important clinical tools in the assessment of CA. RECENT FINDINGS: Tissue Doppler imaging-derived modalities including TDI velocities, strain, and SR are currently being used in the early diagnosis and evaluation of patients with CA. Although these new indices have been examined in relatively few patients, findings suggest an important and expanding role of TDI in amyloid infiltration of the heart. SUMMARY: This review summarizes the recent literature addressing the role of TDI velocities, strain, and SR in the diagnosis and assessment of CA.

Amyloidosis↗
PubMed2003

Spontaneous conversion of patients with atrial fibrillation scheduled for electrical cardioversion: an ACUTE trial ancillary study.

OBJECTIVES: This study was designed to determine the characteristics and outcomes of spontaneous conversion (SC) to sinus rhythm (SR) in patients with atrial fibrillation (AF) of more than two days. BACKGROUND: The Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) multicenter study was a prospective trial in which transesophageal echocardiography (TEE)-guided treatment was compared with conventional anticoagulation treatment for the management of patients with AF >2 days undergoing direct current cardioversion (DCC). In an ancillary analysis, we evaluated the baseline and outcome data in patients who underwent SC to SR before scheduled DCC. METHODS: We identified 1,041 patients for this analysis after excluding patients on pre-existing antiarrhythmic agents. Patients with SC in the TEE-guided and conventional groups were first compared then pooled and compared with non-spontaneous conversion (No-SC) patients. RESULTS: Overall, 167 of 1,041 (16%) patients underwent SC, with twice as many in the conventional compared with the TEE-guided group (110/523 [21%] vs. 57/518 [11%]; p < 0.001). When compared with No-SC patients, a higher proportion of SC patients maintained SR at eight weeks (87.2% vs. 48.9%, p < 0.001), without statistically significant differences in bleeding, thromboembolism or mortality. Multivariate predictors of SC were shorter duration of AF, New York Heart Association (NYHA) functional class 1 or 2, smaller left atrial size, and absence of left atrial spontaneous echo contrast. CONCLUSIONS: Spontaneous conversion was associated with shorter duration of AF, lower NYHA class, smaller left atrial size, and absence of left atrial spontaneous echo contrast. There was a better SR outcome in the SR group, but no differences in the other clinical end points. The conventional treatment strategy allowed greater opportunity for SC. In the absence of favorable predictors of SC, the TEE-guided approach should be considered.

Atrial Fibrillation↗
PubMed2003

Bleeding complications in patients with atrial fibrillation undergoing cardioversion randomized to transesophageal echocardiographically guided and conventional anticoagulation therapies.

In a multicenter randomized trial, we studied a transesophageal echocardiography (TEE) guided strategy with short-term anticoagulation compared with a conventional strategy for patients with atrial fibrillation >2 days' duration and undergoing cardioversion. Composite major and minor bleeding was a predetermined secondary end point of the study. The objective of the study was to assess the incidence, location, and predictors of bleeding in the 2 treatment groups. A total of 1,222 patients were assigned to a TEE guided or conventional strategy and followed over 8 weeks. We present data on major and minor adjudicated bleeding complications for the 2 study groups during the 8-week study period. Composite major and minor bleeding complications occurred in 51 of 1,222 patients (4.2%) and were significantly lower in the TEE guided group compared with the conventional group (2.9 vs 5.5%, p = 0.025). The TEE group had fewer cancellations of cardioversion as a result of bleeding (0% vs 0.7%, p = 0.003). Major (n = 14) and minor (n = 38) bleeding complications were predominantly gastrointestinal (71.4% and 31.6%, respectively) and were associated with warfarin use. Predictors of bleeding included patient age, conventional group assignment, inpatient status, and functional status. Thus, composite major and minor bleeding complications occurred in 4.2% of the 1,222 patients and were significantly lower in the TEE guided group compared with the conventional group. Treatment variables affecting length of anticoagulant therapy in the conventional arm combined with advancing age and functional status are important concerns in patients who undergo cardioversion of atrial fibrillation.

Aged↗
PubMed2003

Pulmonary venous flow by doppler echocardiography: revisited 12 years later.

In 2003, pulmonary venous flow (PVF) evaluation by Doppler echocardiography is being used daily in clinical practice. Twelve years ago, we reviewed the potential uses of PVF in various conditions. Some of its important uses in cardiology have materialized, while others have not and have been supplanted by newer approaches. Current applications of measuring PVF have included: differentiating constrictive pericarditis from restriction, estimation of left ventricular (LV) filling pressures, evaluation of LV diastolic dysfunction and left atrial (LA) function, and grading the severity of mitral regurgitation (MR). However, there have been a number of controversies raised in the use of PVF profiles. Using transthoracic echocardiography, there may be technical issues in measuring the atrial reversal flow velocity. The use of PVF in the evaluation of the severity of MR is not always specific and can be affected by atrial fibrillation (AF) and elevated mean LA pressure. Mitral valvuloplasty and radiofrequency ablation for AF, which are the newer applications of PVF in monitoring invasive procedures, are mentioned. This article reviews the important clinical role of Doppler evaluation of PVF, discusses its limitations and pitfalls, and highlights its newer applications.

Catheter Ablation↗
PubMed2003

Transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation: ACUTE trial update.

The Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) trial was the first randomized prospective study to compare the conventional strategy of 3 weeks of anticoagulation before direct current cardioversion (DCC) for atrial fibrillation (AF) to a transesophageal echocardiography (TEE) guided approach with an expedited course of anticoagulation. This was a multicenter, international study with 70 sites enrolling 1222 patients between 1994-1999. The primary endpoint of composite embolic events and secondary endpoints including bleeding, functional status, prevalence of sinus rhythm, and death were assessed at 8 weeks following randomization. The ACUTE trial demonstrated that the TEE guided approach was safe and effective. There was no difference in the primary outcome of embolic events for the 2 strategies (0.8% TEE group vs. 0.5% conventional group, p =.50). There was a difference between the groups with respect to the number of bleeding events, with minor and major bleeding seen in 2.9% of patients in the TEE guided group and 5.5% in the conventional group (relative risk 0.53, 95% confidence interval 0.30-0.93, p = 0.03). The remaining secondary endpoints did not differ. Clinicians now have a viable alternative approach to cardioversion for patients with AF. Several factors influence the choice of strategies including (1) severity of symptoms and hemodynamic effect; (2) level and chronicity of anticoagulation; (3) risks of bleeding; (4) duration of AF and likelihood of reversion; and (5) risk and likelihood of left atrial thrombi. Future studies, such as ACUTE II are ongoing, with the aim of using low molecular weight heparin to further streamline the TEE guided approach to DCC and shorten hospital stay and costs.

Anticoagulants↗
PubMed2003

Transesophageal echocardiography in patients with atrial fibrillation.

Over the past decade transesophageal echocardiography (TEE) has become an integral tool in the management of patients with AF. Thrombi can be readily detected and the function of the left atrium and left atrial appendage (LAA) can be easily assessed by this modality. With this knowledge, informed decisions regarding anticoagulation, cardioversion, and the likelihood of restoring and maintaining sinus rhythm can be made. An alternative TEE-guided strategy for achieving sinus rhythm in patients with AF is now available with efficacy and safety similar to the conventional approach. Refinements of this strategy may include the use of low molecular weight heparin to avoid hospitalization in patients planned for cardioversion. Further uses of TEE in patients with AF are in their early stages including evaluation of patients following pulmonary vein radiofrequency ablation and those undergoing percutaneous or surgical closure of the LAA.

Atrial Fibrillation↗
PubMed2002

The role of contrast enhancement in echocardiographic assessment of left ventricular function.

With or without contrast, echocardiographic evaluation of left ventricular (LV) function is qualitative, subjective, and experience dependent, because it is mostly based on visual interpretation of gray-scale 2-dimensional images or, at best, relies on tedious and time-consuming manual tracing of the endocardial boundaries. Adequate endocardial visualization is essential for accurate interpretation of regional wall thickening abnormalities, which constitute the diagnostic hallmark of coronary artery disease, and for reproducible assessment of LV ejection fraction. Studies performed in the last decade have estimated the number of patients with suboptimal endocardial delineation by fundamental imaging at 30%. These studies have highlighted the problem of variable image quality as a major limitation of transthoracic echocardiography because failure to adequately visualize a segment, either at rest or during stress, may compromise the ability of this technique to identify areas of dysfunctional myocardium. Several remedies based on different technologic and methodologic approaches have been tested over the years with variable success. In this review we discuss the most recent techniques that have had a positive impact on endocardial visualization, as well as the potential benefits of these approaches.

Contrast Media↗
PubMed2002

Does rapid volume loading during transesophageal echocardiography differentiate constrictive pericarditis from restrictive cardiomyopathy?

BACKGROUND: Respiratory variation of the pulmonary venous (PV) peak flow velocities can be used to distinguish constrictive pericarditis (constriction) from restrictive cardiomyopathy (restriction). Rapid volume expansion has been used successfully to enhance diastolic pressure equalization in occult constriction. The effect of volume on the respiratory variation in constriction has not been studied previously. This study assessed the utility of volume in enhancing the PV respiratory variation of constriction to further separate it from restriction. METHODS: The study population consisted of 15 patients referred to the echocardiography laboratory for further evaluation of clinically suspected diastolic dysfunction. Pulsed-Doppler transesophageal echocardiography (TEE) of the left or right upper pulmonary vein and mitral inflow was performed with respiratory monitoring before and after infusion of 1 liter of normal saline over 5 to 10 minutes. The classification of patients as constriction (n = 8) or restriction (n = 7) was confirmed independently by cardiac catheterization or surgery. Peak velocities of the PV systolic and diastolic waves and the mitral inflow E were measured during inspiration and expiration. A mean of 3-6 respiratory cycles was obtained for each value before and after volume loading. The percent change from expiration to inspiration (%E) was calculated using the formula %E = expiration - inspiration / expiration. RESULTS: At baseline, patients with constrictive pericarditis can be separated reliably from those with restrictive cardiomyopathy based on a higher systolic/diastolic ratio and greater respiratory variation of their PV diastolic flow velocity. There were no complications in any patient due to volume expansion. Although the change from baseline to volume expansion was not statistically significant in either constriction or restriction, the %E of the PV diastolic wave became significantly higher in constriction than in restriction (P < 0.05). CONCLUSIONS: Rapid volume expansion is relatively safe during TEE and can be used for further separation of constrictive pericarditis from restrictive cardiomyopathy by significantly enhancing the respiratory variation of the PV diastolic flow velocity in constrictive pericarditis.

Adult↗
PubMed2002

Contrast and harmonic imaging improves accuracy and efficiency of novice readers for dobutamine stress echocardiography.

BACKGROUND: Newer contrast agents as well as tissue harmonic imaging enhance left ventricular (LV) endocardial border delineation, and therefore, improve LV wall-motion analysis. Interpretation of dobutamine stress echocardiography is observer-dependent and requires experience. This study was performed to evaluate whether these new imaging modalities would improve endocardial visualization and enhance accuracy and efficiency of the inexperienced reader interpreting dobutamine stress echocardiography. METHODS AND RESULTS: Twenty-nine consecutive patients with known or suspected coronary artery disease underwent dobutamine stress echocardiography. Both fundamental (2.5 MHZ) and harmonic (1.7 and 3.5 MHZ) mode images were obtained in four standard views at rest and at peak stress during a standard dobutamine infusion stress protocol. Following the noncontrast images, Optison was administered intravenously in bolus (0.5-3.0 ml), and fundamental and harmonic images were obtained. The dobutamine echocardiography studies were reviewed by one experienced and one inexperienced echocardiographer. LV segments were graded for image quality and function. Time for interpretation also was recorded. Contrast with harmonic imaging improved the diagnostic concordance of the novice reader to the expert reader by 7.1%, 7.5%, and 12.6% (P < 0.001) as compared with harmonic imaging, fundamental imaging, and fundamental imaging with contrast, respectively. For the novice reader, reading time was reduced by 47%, 55%, and 58% (P < 0.005) as compared with the time needed for fundamental, fundamental contrast, and harmonic modes, respectively. With harmonic imaging, the image quality score was 4.6% higher (P < 0.001) than for fundamental imaging. Image quality scores were not significantly different for noncontrast and contrast images. CONCLUSION: Harmonic imaging with contrast significantly improves the accuracy and efficiency of the novice dobutamine stress echocardiography reader. The use of harmonic imaging reduces the frequency of nondiagnostic wall segments.

Aged↗
PubMed2002

Prevalence of left ventricular diastolic dysfunction by Doppler echocardiography: clinical application of the Canadian consensus guidelines.

We evaluated diastolic filling patterns using Doppler echocardiography in 520 consecutive patients referred to our laboratory for transthoracic echocardiograms retrospectively and applied the standard guidelines used to characterize left ventricular (LV) diastolic function. Patients were classified by the Canadian consensus guidelines using transmitral and pulmonary venous Doppler echocardiographic parameters to have normal diastolic function or mild (abnormal relaxation), mild-to-moderate, moderate (pseudonormal), or severe (restrictive) diastolic dysfunction. LV diastolic dysfunction was present in 290 (56%) patients, whereas 167 (45%) patients with a normal LV ejection fraction had abnormal diastolic function. Patients with progressively more abnormal diastolic patterns had greater structural abnormalities with larger left atrial and LV size and lower LV ejection fractions. In the subset of patients with clinical evidence of congestive heart failure (99 patients), the prevalence of primary diastolic heart failure was 38% and most patients had underlying coronary or hypertensive heart disease. Standard guidelines of Doppler echocardiographic parameters allow semiquantitation of diastolic function and can be applied to studying large number of patients in a large clinical practice.

Adult↗
PubMed2002

The ACUTE trial. Transesophageal echocardiography to guide electrical cardioversion in atrial fibrillation. Assessment of Cardioversion Using Transesophageal Echocardiography.

The Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) trial compared cardioversion following transesophageal echocardiography (TEE) against conventional management of atrial fibrillation (ie, cardioversion following 3 weeks of anticoagulation) in patients scheduled to undergo electrical cardioversion.

Anticoagulants↗
PubMedDate not supplied

Diastolic heart failure: restrictive cardiomyopathy, constrictive pericarditis, and cardiac tamponade: clinical and echocardiographic evaluation.

An understanding of the basic principles of diastolic function is important in order to recognize diseases that may result in diastolic dysfunction and diastolic heart failure. Although uncommon, restrictive cardiomyopathy, constrictive pericarditis, and cardiac tamponade are among the disorders that may affect primarily diastolic function with preservation of systolic function. Diastolic heart failure may manifest with chronic nonspecific symptoms or may present with acute hemodynamic compromise. Echocardiography plays a vital role in the diagnosis of diastolic dysfunction and differentiation of these disease processes. It also provides a basis for clinical decisions regarding management and surgical referral. This review summarizes the clinical features, pathophysiology, and hemodynamic and echocardiographic signs of restrictive cardiomyopathy, constrictive pericarditis, and cardiac tamponade.

Cardiac Tamponade↗