Left ventricular remodeling in human heart failure: quantitative echocardiographic assessment of 1,794 patients.

BACKGROUND: The left ventricle (LV) undergoes significant architectural remodeling in heart failure (HF). However, the fundamental associations between cardiac function and LV size and performance have not been thoroughly characterized in this population. We sought to define the adaptive remodeling that occurs in chronic human HF through the detailed analyses of a large quantitative echocardiography database. METHODS: Baseline echocardiograms were performed in 1,794 patients with HF across a broad range of ejection fraction (EF), from less than 10% to greater than 70%. Core lab measurements of LV volumes and length were made, from which EF, mass, sphericity indices, stroke volume (SV), and stroke work were derived. Spearman correlation coefficients and linear regression methods were used to determine the relationships between remodeling parameters. RESULTS: The median EF was 28.6% (IQR 21.9-37.0). Across a multitude of parameters of cardiac structure and function, indexed end-systolic volumes (ESVs) explained the greatest proportion of the variance in EF (R =-0.87, P < 0.0001). Systolic sphericity index and LV mass were also strongly correlated with EF (R =-0.62 and -0.63, P < 0.0001), reflective of the alterations in LV shape and size that occur as EF declines. SV was rigorously maintained across a broad spectrum of EF, until the EF fell below 20%, at which point SV decreased significantly (P < 0.0001). CONCLUSIONS: In chronic HF, the LV undergoes extensive structural adaptive remodeling in order to maintain SV across a broad range of EF. However, when the EF falls below 20%, further modulation of SV is no longer possible through alterations in ventricular architecture.

The utility of prescreening transesophageal echocardiograms: a prospective study.

BACKGROUND: Recent emphasis on the judicious use of imaging prompted the publication of the 2007 ACC/ASE Appropriateness Use Criteria (AUC) for Echocardiography. However, the intersection of the AUC with the safety and clinical use of transesophageal echocardiography (TEE) is not well established. METHODS: We reviewed 490 consecutive orders for TEEs for appropriateness, significant findings, and reasons for cancellation. RESULTS: We found that 79% (389/490) of ordered studies were performed and 21% (101/490) were not. The number of TEEs cancelled for safety reasons (n = 29) was similar to that cancelled for inappropriateness (n = 36). Only 2% (6/389) of those performed were inappropriate vs. 16% of those that were cancelled. New or unsuspected findings were obtained in half of all performed TEEs; the majority of which were ordered to detect cardiac source of embolism (CSE). CONCLUSIONS: The AUC should specifically consider the utility of clinician-based prescreening of TEEs to encourage appropriate use and safety. Furthermore, given the incremental value of TEE over transthoracic echocardiography in detection of CSE, in some cases, TEE may be considered an appropriate initial test for this indication.

Time-varying myocardial stress and systolic pressure-stress relationship: role in myocardial-arterial coupling in hypertension.

BACKGROUND: Myocardial afterload depends on left ventricular (LV) cavity size, pressure, and wall thickness, all of which change markedly throughout ejection. We assessed the relationship between instantaneous ejection-phase pressure and myocardial stress and the effect of arterial wave reflections on myocardial stress in hypertensive and normotensive adults. METHODS AND RESULTS: We studied 42 untreated hypertensive, 42 treated hypertensive, and 42 normotensive adults with normal LV ejection fraction. Time-resolved central pressure, flow, and LV geometry were measured with carotid tonometry, Doppler, and speckle-tracking echocardiography for computation of arterial load and time-varying circumferential and longitudinal myocardial stress. In all 3 groups, peak myocardial stress typically occurred in early systole (within the first 100 milliseconds of ejection), followed by a marked midsystolic shift in the pressure-stress relationship, which favored lower late systolic stress values (P<0.001) relative to pressure. The mean magnitude of this midsystolic shift was quantitatively important in all 3 groups (circumferential stress, 144 to 148 kdynes/cm(2)) and was independently predicted by a higher LV ejection fraction and ratio of LV end-diastolic cavity to wall volume. Time of peak myocardial stress independently correlated with time of the first systolic but not with time of the second systolic central pressure peak. CONCLUSIONS: Peak myocardial stress occurs in early systole, before important contributions of reflected waves to central pressure. In the presence of normal LV ejection fraction, a midsystolic shift in the pressure-stress relationship protects cardiomyocytes against excessive late systolic stress (despite pressure augmentation associated with wave reflections), a coupling mechanism that may be altered in various disease states.

Arterial pulsatile hemodynamic load induced by isometric exercise strongly predicts left ventricular mass in hypertension.

Although resting hemodynamic load has been extensively investigated as a determinant of left ventricular (LV) hypertrophy, little is known about the relationship between provoked hemodynamic load and the risk of LV hypertrophy. We studied central pressure-flow relations among 40 hypertensive and 19 normotensive adults using carotid applanation tonometry and Doppler echocardiography at rest and during a 40% maximal voluntary forearm contraction (handgrip) maneuver. Carotid-femoral pulse wave velocity (CF-PWV) was measured at rest. Hypertensive subjects demonstrated various abnormalities in resting and induced pulsatile load. Isometric exercise significantly increased systemic vascular resistance, aortic characteristic impedance (Zc), induced earlier wave reflections, increased augmentation index, and decreased total arterial compliance (TAC; all P < or = 0.01). In hypertensive subjects, CF-PWV was the strongest resting predictor of LV mass index (LVMI) and remained an independent predictor after adjustment for age, gender, systemic vascular resistance, reflection magnitude, aortic Zc, and TAC (beta = 2.52 m/s; P < 0.0001). Age, sex, CF-PWV, and resting hemodynamic indexes explained 48% of the interindividual variability in LVMI. In stepwise regression, TAC (beta = -17.85; P < 0.0001) during handgrip, Zc during handgrip (beta = -150; P < 0.0001), and the change in the timing of wave reflections during handgrip (beta = -0.63; P = 0.03) were independent predictors of LVMI. A model that included indexes of provoked hemodynamic load explained 68% of the interindividual variability in LVMI. Hemodynamic load provoked by isometric exercise strongly predicts LVMI in hypertension. The magnitude of this association is far greater than for resting hemodynamic load, suggesting that provoked testing captures important arterial properties that are not apparent at rest and is advantageous to assess dynamic arterial load in hypertension.

Preoperative Takotsubo cardiomyopathy identified in the operating room before induction of anesthesia.

We present a case of Takotsubo cardiomyopathy recognized in a patient just before induction of anesthesia. The patient's anxiety about surgery could have been an inciting factor. As the patient's surgery was cancelled and rescheduled for a later date, treatment and strategies to prevent recurrence of the syndrome are discussed.

Left ventricular assist devices and other devices for end-stage heart failure: utility of echocardiography.

The burgeoning ranks of patients with heart failure, the limited number of organs available for heart transplant, and technological improvements have made ventricular assist devices (VADs) important therapeutic options for patients with acute and chronic cardiac decompensation. The increased use of VADs is paralleled by an increased use of transthoracic and transesophageal echocardiography to 1) assist in the selection of patients for VAD therapy and VADs to meet patient needs; 2) identify important anatomic considerations prior to implant; 3) guide placement of VADs; 4) diagnose the etiology of VAD dysfunction; and 5) guide the weaning from VAD support and the optimization of VAD device settings. This review discusses types of VADs and the uses of echocardiography in the care of VAD patients.

ACCF/ASE/ACEP/AHA/ASNC/SCAI/SCCT/SCMR 2008 appropriateness criteria for stress echocardiography: a report of the American College of Cardiology Foundation Appropriateness Criteria Task Force, American Society of Echocardiography, American College of Emergency Physicians, American Heart Association, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and Society for Cardiovascular Magnetic Resonance: endorsed by the Heart Rhythm Society and the Society of Critical Care Medicine.

The American College of Cardiology Foundation (ACCF) and the American Society of Echocardiography (ASE) together with key specialty and subspecialty societies, conducted an appropriateness review for stress echocardiography. The review assessed the risks and benefits of stress echocardiography for several indications or clinical scenarios and scored them on a scale of 1 to 9 (based upon methodology developed by the ACCF to assess imaging appropriateness). The upper range (7 to 9) implies that the test is generally acceptable and is a reasonable approach, and the lower range (1 to 3) implies that the test is generally not acceptable and is not a reasonable approach. The midrange (4 to 6) indicates a clinical scenario for which the indication for a stress echocardiogram is uncertain. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Use of stress echocardiography for risk assessment in patients with coronary artery disease (CAD) was viewed favorably, while routine repeat testing and general screening in certain clinical scenarios were viewed less favorably. It is anticipated that these results will have a significant impact on physician decision making and performance, reimbursement policy, and will help guide future research.

Imaging with (18)F-FDG-PET in infective endocarditis: promising role in difficult diagnosis and treatment monitoring.

Echocardiography (EC) plays a major role in diagnosing and monitoring the therapeutic response in infective endocarditis (IE) in routine practice. However in the setting of prosthetic valves or indwelling pacemakers, the EC findings are equivocal necessitating search for other diagnostic modalities. In these patients, (18)F-FDG/PET imaging may prove invaluable as evidenced by the presented case. We herein report a case of an 82 years old male with a mechanical aortic valve prosthesis who presented with a 10 days history of fever and malaise. Optimal interpretation of the EC results was difficult due to the presence of the prosthetic valve. However, (18)F-FDG-PET imaging findings were quite distinctive and revealed abnormally increased metabolic activity represented by two foci of increased (18)F-FDG uptake in the right and left borders of the heart that corresponded to areas of IE.

Clinical utility of automated assessment of left ventricular ejection fraction using artificial intelligence-assisted border detection.

BACKGROUND: Ejection fraction (EF) calculated from 2-dimensional echocardiography provides important prognostic and therapeutic information in patients with heart disease. However, quantification of EF requires planimetry and is time-consuming. As a result, visual assessment is frequently used but is subjective and requires extensive experience. New computer software to assess EF automatically is now available and could be used routinely in busy digital laboratories (>15,000 studies per year) and in core laboratories running large clinical trials. We tested Siemens AutoEF software (Siemens Medical Solutions, Erlangen, Germany) to determine whether it correlated with visual estimates of EF, manual planimetry, and cardiac magnetic resonance (CMR). METHODS: Siemens AutoEF is based on learned patterns and artificial intelligence. An expert and a novice reader assessed EF visually by reviewing transthoracic echocardiograms from consecutive patients. An experienced sonographer quantified EF in all studies using Simpson's method of disks. AutoEF results were compared to CMR. RESULTS: Ninety-two echocardiograms were analyzed. Visual assessment by the expert (R = 0.86) and the novice reader (R = 0.80) correlated more closely with manual planimetry using Simpson's method than did AutoEF (R = 0.64). The correlation between AutoEF and CMR was 0.63, 0.28, and 0.51 for EF, end-diastolic and end-systolic volumes, respectively. CONCLUSION: The discrepancies in EF estimates between AutoEF and manual tracing using Simpson's method and between AutoEF and CMR preclude routine clinical use of AutoEF until it has been validated in a number of large, busy echocardiographic laboratories. Visual assessment of EF, with its strong correlation with quantitative EF, underscores its continued clinical utility.

Failure of digital echocardiography to accurately diagnose intracardiac shunts.

BACKGROUND: Intravenous agitated saline injection during transthoracic echocardiography assists in the detection of right to left intracardiac and intrapulmonary shunts. Whether digital echocardiography offers comparable sensitivity and specificity to analog tape recording to assess shunts is unknown. Technical differences between methods could lead to significant differences in shunt detection. METHODS: Agitated saline was injected intravenously at rest and with Valsalva in 189 consecutive patient studies (406 injections). Echocardiographers assessed presence and degree of left ventricle contrast on simultaneously recorded analog tape and digital echocardiography images in blinded fashion. RESULTS: Digital echocardiography had low overall sensitivity (rest 0.50, valsalva 0.63, late 0.39) compared to analog tape. Longer clip lengths improved sensitivity for detection of late contrast passage (rest 0.50, valsalva 0.67, late 0.46). CONCLUSION: Digital echocardiography saline contrast studies have poor sensitivity for assessment of intracardiac shunts versus analog tape, and increasing clip length only modestly increases sensitivity. Joint Photographic Experts Group digital compression losses may be an important cause of failure to detect intracardiac shunts, including patent foramen ovale.

Percutaneous transcatheter closure of patent foramen ovale with the Amplatzer Cribriform septal occluder.

OBJECTIVES: We tested the feasibility of percutaneous patent foramen ovale (PFO) closure utilizing the Amplatzer multifenestrated Cribriform atrial septal occluder device. BACKGROUND: This device recently became available and may offer unique advantages for closure of PFO. METHODS: Nineteen consecutive patients who underwent closure of PFO with the Cribriform device for a variety of indications under intracardiac echocardiographic and fluoroscopic guidance were studied. The degree of shunting was quantified pre- and postprocedure by echocardiography using both Doppler and agitated saline administration. The results with this device were compared to the prior 19 patients who underwent closure with a CardioSeal device. RESULTS: The mean age of patients was 52 years and 47% were female. Indications for closure were paradoxical embolism in 17 patients, and hypoxemia due to right to left shunt in 2 patients. The postprocedure bubble contrast study showed a marked improvement in right to left shunting with 13 patients (68%) demonstrating no shunt flow, 4 (21%) having trace shunting, and 2 (11%) mild shunting. There were no device-related complications. The mean procedure time was 28 +/- 10 min. In comparison to the CardioSeal device, a trend was apparent in terms of a greater percentage of patients with immediate closure with the Cribriform device, although a similar percentage of defect closure was seen at 6 months with both devices. Procedure time was shorter with the Cribriform device, related in part to the reduced need for balloon sizing. CONCLUSIONS: This initial experience suggests a number of favorable characteristics of the Amplatzer Cribriform device for PFO closure.

ACCF/ASE/ACEP/AHA/ASNC/SCAI/SCCT/SCMR 2008 Appropriateness Criteria for Stress Echocardiography. A report of the American College of Cardiology Foundation Appropriateness Criteria Task Force, American Society of Echocardiography, American College of Emergency Physicians, American Heart Association, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and Society for Cardiovascular Magnetic Resonance endorsed by the Heart Rhythm Society and the Society of Critical Care Medicine.

The American College of Cardiology Foundation (ACCF) and the American Society of Echocardiography (ASE) together with key specialty and subspecialty societies, conducted an appropriateness review for stress echocardiography. The review assessed the risks and benefits of stress echocardiography for several indications or clinical scenarios and scored them on a scale of 1 to 9 (based upon methodology developed by the ACCF to assess imaging appropriateness). The upper range (7 to 9) implies that the test is generally acceptable and is a reasonable approach, and the lower range (1 to 3) implies that the test is generally not acceptable and is not a reasonable approach. The midrange (4 to 6) indicates a clinical scenario for which the indication for a stress echocardiogram is uncertain. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Use of stress echocardiography for risk assessment in patients with coronary artery disease (CAD) was viewed favorably, while routine repeat testing and general screening in certain clinical scenarios were viewed less favorably. It is anticipated that these results will have a significant impact on physician decision making and performance, reimbursement policy, and will help guide future research.

Intracardiac Echocardiography in Structural Heart Disease Interventions.

Intracardiac echocardiography has historically been used to guide a limited number of transcatheter cardiac interventions. However, the tremendous advances in structural heart disease interventions in the last decade led to a growing interest in intracardiac echocardiography as a potential alternative to transesophageal echocardiography that mitigates the need for endotracheal intubation. Nonetheless, the scarcity of data, the imperfection of the current probes, and the limited experience among operators prevented a wider adoption of this technology. This review summarizes the contemporary relevant evidence and provides the structural interventionalist with an illustrative guide on the use of intracardiac echocardiography to guide various structural heart interventions.

Quantitative assessment of severity of mitral regurgitation by serial echocardiography in a multicenter clinical trial of percutaneous mitral valve repair.

The aims of the echocardiographic substudy of this multicenter trial were to evaluate the use of quantitative assessment of mitral regurgitation (MR) severity using serial echocardiography and to assess the efficacy of percutaneous mitral valve repair. Previous surgical repair studies did not use quantitative echocardiographic methods. Results of a percutaneous mitral valve repair clip device in a core echocardiographic laboratory were evaluated. Published parameters for quantifying MR were used in a systematic protocol to qualify patients for study entry and evaluate treatment efficacy at discharge and 6 months after clip repair. Baseline results were presented for 55 patients, and follow-up results, for 49. Ninety-eight percent of required echocardiographic studies were submitted to the core laboratory, and >85% of required measurements were possible. At baseline, mean regurgitant volume was 54.8 +/- 24 ml, regurgitant fraction was 46.9 +/-16.2%, effective regurgitant orifice area was 0.71 +/- 0.40 cm(2), and vena contracta width was 0.66 +/- 0.20 cm. Based on a severity scale of 1 to 4, mean color flow grade was 3.4 +/- 0.7, and mean pulmonary vein flow was 2.8 +/- 1.2. In patients with a clip at 6 months, all measurements of MR severity were significantly decreased versus baseline, with mean regurgitant volume decreased from 50.3 to 27.5 ml (change -22.8 ml; p <0.0001), regurgitant fraction from 44.6% to 28.9% (change -15.7%; p <0.0001), color flow grade from an average of 3.4 to 1.8 (change -1.6; p <0.0001), and pulmonary vein flow from 2.8 to 1.8 (change -1.0; p <0.0018). In conclusion, quantitative assessment of MR is feasible in a multicenter trial, and percutaneous mitral repair with the MitraClip produces a sustained decrease in MR severity to moderate or less for > or =6 months.

Association of Liability Concerns with Decisions to Order Echocardiography and Cardiac Stress Tests with Imaging.

BACKGROUND: Professional societies have made efforts to curb overuse of cardiac imaging and decrease practice variation by publishing appropriate use criteria. However, little is known about the impact of physician-level determinants such as liability concerns and risk aversion on decisions to order testing. METHODS: A web-based survey was administered to cardiologists and general practice physicians affiliated with two academic institutions. The survey consisted of four clinical scenarios in which appropriate use criteria rated echocardiography or stress testing as "may be appropriate." Respondents' degree of liability concerns and risk aversion were measured using validated tools. The primary outcome variable was tendency to order imaging, calculated as the average likelihood to order an imaging test across the clinical scenarios (1 = very unlikely, 6 = very likely). Linear regression models were used to evaluate the association between tendency to order imaging and physician characteristics. RESULTS: From 420 physicians invited to participate, 108 complete responses were obtained (26% response rate, 54% cardiologists). There was no difference in tendency to order imaging between cardiologists and general practice physicians (3.46 [95% CI, 3.12-3.81] vs 3.15 [95% CI, 2.79-3.51], P = .22). On multivariate analysis, a higher degree of liability concerns was the only significant predictor of decisions to order imaging (mean difference in tendency to order imaging, 0.36; 95% CI, 0.09-0.62; P = .01). CONCLUSION: In clinical situations in which performance of cardiac imaging is rated as "may be appropriate" by appropriate use criteria, physicians with higher liability concerns ordered significantly more testing than physicians with lower concerns.