Long-term outcomes of mitral regurgitation by type and severity.

BACKGROUND: We aimed to determine the association of MR severity and type with all-cause death in a large, real-world, clinical setting. METHODS: We reviewed full echocardiography studies at Duke Echocardiography Laboratory (01/01/1995-12/31/2010), classifying MR based on valve morphology, presence of coronary artery disease, and left ventricular size and function. Survival was compared among patients stratified by MR type and baseline severity. RESULTS: Of 93,007 qualifying patients, 32,137 (34.6%) had ≥mild MR. A total of 8094 (8.7%) had moderate/severe MR, which was primary myxomatous (14.1%), primary non-myxomatous (6.2%), secondary non-ischemic (17.0%), and secondary ischemic (49.4%). At 10 years, patients with primary myxomatous MR or MR due to indeterminate cause had survival rates of >60%; primary non-myxomatous, secondary ischemic, and non-ischemic MR had survival rates <50%. While mild (HR 1.06, 95% CI 1.03-1.09), moderate (HR 1.31, 95% CI 1.27-1.37), and severe (HR 1.55, 95% CI 1.46-1.65) MR were independently associated with all-cause death, the relationship of increasing MR severity with mortality varied across MR types (P ≤ .001 for interaction); the highest risk associated with worsening severity was seen in primary myxomatous MR followed by secondary ischemic MR and primary non-myxomatous MR. CONCLUSIONS: Although MR severity is independently associated with increased all-cause death risk for most forms of MR, the absolute mortality rates associated with worse MR severity are much higher for primary myxomatous, non-myxomatous, and secondary ischemic MR. The findings from this study support carefully defining MR by type and severity.

Immersion-Induced Mitral Regurgitation: A Novel Risk Factor for Swimming-Induced Pulmonary Edema.

Immersion pulmonary edema, more commonly referred to as swimming-induced pulmonary edema (SIPE), is a well-documented condition believed to be a result of immersion physiologic condition that is characterized by a peripheral-to-central redistribution of blood volume. It disproportionally affects young, healthy athletes with no clinically overt cardiovascular or pulmonary conditions. We present four cases of healthy athletes with previously documented SIPE, who participated in Institutional Review Board-approved clinical studies that examined the pathophysiologic condition and prevention of SIPE. During standard recumbent echocardiography, trivial mitral regurgitation was observed in all four individuals. Acute exacerbation of their mitral regurgitation was observed during immersion with both immersed resting and immersed exercise echocardiography, contributing to the development of SIPE. These observations demonstrate that the occurrence of subclinical or trivial mitral valve regurgitation during dry rest is a novel risk factor for SIPE. We propose the use of immersion echocardiography as a useful investigative tool for otherwise healthy individuals with SIPE and no previously explainable cause.

Early cardiac dysfunction in children and young adults with perinatally acquired HIV.

OBJECTIVE: To define the prevalence of early cardiac dysfunction in children and young adults with perinatally acquired HIV and predictors of cardiac function. DESIGN: Cross-sectional design. METHODS: Early cardiac dysfunction was defined as left ventricular (LV) global longitudinal strain z-score less than -2 or myocardial performance index at least 0.5 with normal LV ejection fraction. Regression models were fitted to assess the relationship between measures of cardiac function and HIV RNA levels, clinical variables, and markers of inflammation. RESULTS: Six hundred and forty-three individuals (mean age 14.1 ±â€Š5.2 years) were enrolled. The average time on combination antiretroviral treatment was 6.8 ±â€Š3.6 years. Nearly 28% of individuals met criteria for early cardiac dysfunction. Individuals with early cardiac dysfunction were older (15.3 vs. 13.5 years, P < 0.001), had more frequently detectable HIV RNA (52.5 vs. 41.7%, P = 0.018), were more likely exposed to azidothymidine or zidovudine (ZDV) (55.6 vs. 41.2%, P = 0.002), and had higher median level of plasma IL-6 concentrations (1.00 vs. 0.88 pg/ml, P = 0.011). Multivariable models show LV ejection fraction negatively associated with HIV RNA levels [ß -0.18; 95% confidence interval (CI) -0.33, -0.03] and ZDV exposure (ß -1.75; 95% CI -2.62, -0.88) and positively associated with proportion of life on combination antiretroviral treatment (ß 2.65; 95% CI 0.90, 4.41). Higher myocardial performance index was positively associated with serum inflammation marker (IL-6 ß 0.01; 95% CI 0.0001, 0.001). Left ventricular global longitudinal strain was not significantly associated with clinical and laboratory variables of interest. CONCLUSION: Over one-quarter of children and young adults living with HIV demonstrated evidence of cardiac dysfunction, which may be associated with increasing levels of systemic inflammation.

Right Ventricular Longitudinal Strain Reproducibility Using Vendor-Dependent and Vendor-Independent Software.

BACKGROUND: Right ventricular peak systolic longitudinal strain (RVLS) has emerged as an approach for quantifying right ventricular function in diseases such as pulmonary hypertension and congenital heart disease. A major limitation in applying RVLS is that strain imaging and analysis are proprietary, which may result in systematic differences from vendor to vendor. The goal of this study was to test the reproducibility of right ventricular strain analysis among selected vendor-specific software (VSS) and vendor-independent software (VIS) on images obtained from different ultrasound scanners, as would be common in clinical practice or in a multicenter clinical trial. METHODS: In this prospective, single-center study, 35 patients (5 healthy subjects and 30 with pulmonary hypertension) each underwent two echocardiographic scans, one using GE (Vivid E9) and the other using Philips (iE33) ultrasound systems. Images were analyzed using both VSS and VIS (TomTec) software for determination of RVLS. A repeated-measures analysis of variance was used to assess for any systematic differences among methods, as well as effects of scanner and software and a possible interaction between scanner and software for each strain measurement. RESULTS: Differences for global strains were not statistically significant among VSS packages (P ≥ .05), but some differences were noted between VSS and VIS. Wide variability between regional peak strain measurements was noted, but no systematic differences were found. CONCLUSIONS: Global RVLS values between VSS systems are not significantly different but may differ slightly from VIS. When comparing regional strain between VSS and VIS analyses, there is widespread variability without clear systematic differences.

Crowdsourcing consensus: proposal of a novel method for assessing accuracy in echocardiography interpretation.

Quality in stress echocardiography interpretation is often gauged against coronary angiography (CA) data but anatomic obstructive coronary disease on CA is an imperfect gold standard for a stress induced wall motion abnormality. We examined the utility of crowd-sourcing a "majority-vote" consensus as an alternative 'gold standard' against which to evaluate the accuracy of an individual echocardiographer's interpretation of stress echocardiography studies. Participants independently interpreted baseline and post-exercise stress echocardiographic images of cases that had undergone follow up CA within 3 months of the stress echo in two surveys, 2 years apart. We examined the agreement of consensus on survey (survey participant response (> 60%) for one decision) with the stress echocardiography clinical read and with CA results. In the first survey, 29 participants reviewed and independently interpreted 14 stress echo cases. Consensus was reached in all 14 cases. There was good agreement between clinical and consensus (kappa = 0.57), survey participant response and consensus (kappa = 0.68) and consensus and CA results (kappa = 0.40). In the validation survey, the agreement between clinical reads and consensus (kappa = 0.75) and survey participant response and consensus (kappa = 0.81) remained excellent. Independent consensus is achievable and offers a fair comparison for stress echocardiographic interpretation. Future validation work, in other laboratories, and against hard outcomes, is necessary to test the feasibility and effectiveness of this approach.

Impaired Recovery of Left Ventricular Function in Patients With Cardiomyopathy and Left Bundle Branch Block.

BACKGROUND: Patients with left bundle branch block (LBBB) often respond to cardiac resynchronization therapy (CRT) with left ventricular ejection fraction (LVEF) improvement. Guideline-directed medical therapy (GDMT), not CRT, is first-line therapy for patients with reduced LVEF with LBBB. However, there are little data on how patients with reduced LVEF and LBBB respond to GDMT. OBJECTIVES: This study examined patients with cardiomyopathy and sought to assess rates of LVEF improvement for patients with LBBB compared to other QRS morphologies. METHODS: Using data from the Duke Echocardiography Laboratory Database, the study identified patients with baseline electrocardiography and LVEF ≤35% who had a follow-up LVEF 3 to 6 months later. The study excluded patients with severe valve disease, a cardiac device, left ventricular assist device, or heart transplant. QRS morphology was classified as LBBB, QRS duration <120 ms (narrow QRS duration), or a wide QRS duration ≥120 ms but not LBBB. Analysis of variance testing compared mean change in LVEF among the 3 groups with adjustment for significant comorbidities and GDMT. RESULTS: There were 659 patients that met the criteria: 111 LBBB (17%), 59 wide QRS duration ≥120 ms but not LBBB (9%), and 489 narrow QRS duration (74%). Adjusted mean increase in LVEF over 3 to 6 months in the 3 groups was 2.03%, 5.28%, and 8.00%, respectively (p < 0.0001). Results were similar when adjusted for interim revascularization and myocardial infarction. Comparison of mean LVEF improvement between patients with LBBB on GDMT and those not on GDMT showed virtually no difference (3.50% vs. 3.44%). The combined endpoint of heart failure hospitalization or mortality was highest for patients with LBBB. CONCLUSIONS: LBBB is associated with a smaller degree of LVEF improvement compared with other QRS morphologies, even with GDMT. Some patients with LBBB may benefit from CRT earlier than guidelines currently recommend.

Comparison of Incidence of Left Ventricular Systolic Dysfunction Among Patients With Left Bundle Branch Block Versus Those With Normal QRS Duration.

We compared the incidence of left ventricular systolic dysfunction (LVSD) among patients with left bundle branch block (LBBB) to a matched cohort of patients with a narrow QRS duration <120 ms (NQRS). We hypothesized patients with preserved ejection fraction (EF) ≥50% and LBBB would have higher incidence of LVSD compared with a matched population of NQRS patients. Patients with LBBB on electrocardiogram within 30 days of a baseline echocardiogram with EF ≥50%, who had at least 1 follow-up echocardiogram ≥6 months later, were matched 1:1 on risk factors for cardiomyopathy to patients with NQRS. Incident LVSD was defined as a decline in EF to ≤45% on follow-up echocardiogram, or heart transplant, receipt of a cardiac device for LVSD (defibrillator or biventricular pacemaker), or implantation of a left ventricular assist device ≥6 months post baseline echocardiogram. Relative risk was calculated using conditional Poisson regression techniques. The final study cohort consisted of 188 patients, 94 with LBBB and 94 with NQRS. On follow-up, progression to LVSD was noted in 36% of LBBB patients and 10% of NQRS patients. The relative risk for LVSD in patients with LBBB was 3.78 (95% confidence interval = 1.98 to 7.19). In conclusion, there is a strong association between LBBB and the subsequent development of LVSD independent of common risk factors for cardiomyopathy.

Feasibility of point-of-care echocardiography by internal medicine house staff.

OBJECTIVE: To determine whether internal medicine house staff with limited training in echocardiography can use point-of-care echocardiography to make simple, clinically important diagnoses. BACKGROUND: Availability of small, portable ultrasound devices could make point-of-care echocardiography widely available. The training required to perform point-of-care echocardiography has not been established. METHODS: Medical house staff participated in a 3-hour point-of-care echocardiography training program. Patients scheduled for standard echocardiography as part of clinical care underwent point-of-care echocardiography within 24 hours to assess four common clinically important diagnoses. Each standard echocardiogram was interpreted twice. Agreement (kappa) was calculated between point-of-care and standard echocardiography by using standard echocardiography as the gold standard and between the two interpretations of standard echocardiography. RESULTS: Agreement (kappa) between point-of-care echocardiography and standard echocardiography was 75% (0.51) for left ventricular dysfunction (ejection fraction <55%), 79% (0.31) for moderate or severe mitral regurgitation, 92% (0.32) for aortic valve thickening or immobility, and 98% (0.51) for moderate or large pericardial effusion. Agreement between the two interpretations of standard echocardiography was 83% (0.63) for left ventricular dysfunction, 92% (0.68) for moderate or severe mitral regurgitation, 95% (0.62) for aortic valve thickening or immobility, and 97% (0.53) for moderate or large pericardial effusion. CONCLUSIONS: Medical house staff with limited training in echocardiography can use point-of-care echocardiography to assess left ventricular function and pericardial effusion with moderate accuracy that is lower than that of standard echocardiography. Assessment of valvular disease and other diagnoses likely requires more training and/or experience in echocardiography.

Usefulness of myocardial viability or ischemia in predicting long-term survival for patients with severe left ventricular dysfunction undergoing revascularization.

In 107 patients with coronary disease and severe left ventricular dysfunction, we examined the prognostic power of viability identified by dobutamine stress echocardiography. At a mean follow-up of 27 months, patients with viable myocardium who underwent revascularization had a significant survival advantage over all other patients (2-year survival 83.5% vs 57.2%, p = 0.0037).

Short-lag spatial coherence imaging of cardiac ultrasound data: initial clinical results.

Short-lag spatial coherence (SLSC) imaging is a novel beamforming technique that reduces acoustic clutter in ultrasound images. A clinical study was conducted to investigate clutter reduction and endocardial border detection in cardiac SLSC images. Individual channel echo data were acquired from the left ventricle of 14 volunteers, after informed consent and institutional review board approval. Paired B-mode and SLSC images were created from these data. Contrast, contrast-to-noise, and signal-to-noise ratios were measured in paired images, and these metrics were improved with SLSC imaging in most cases. Three cardiology fellows rated the visibility of endocardial segments in randomly ordered B-mode and SLSC cine loops. SLSC imaging offered 22%-33% improvement (p < 0.05) in endocardial border visibility when B-mode image quality was poor (i.e., 80% or more of the endocardial segments could not be visualized by the three reviewers). The percentage of volunteers with poor-quality images was decreased from 21% to 7% with the SLSC beamformer. Results suggest that SLSC imaging has the potential to improve clinical cardiac assessments that are challenged by clutter.

Color Doppler imaging of cardiac catheters using vibrating motors.

A miniature motor rotating at 11,000 rpm was attached onto the proximal end of cardiac electrophysiological (EP) catheters in order to produce vibrations at the tip that were then visualized by color Doppler on ultrasound scanners. The catheter tip was imaged within a vascular graft submerged in a water tank using the Volumetrics Medical Imaging 3D scanner, the Siemens Sonoline Antares 2D scanner and the Philips ie33 3D ultrasound scanner with TEE probe. The vibrating catheter tip was visualized in each case, although results varied with the color Doppler properties of the individual scanner.