Changes in regional left atrial function with aging: evaluation by Doppler tissue imaging

AIMS

This study applies pulsed wave Doppler tissue imaging and colour Doppler tissue imaging to study changes in atrial function with ageing. We tested the following hypotheses: (1) pulsed wave Doppler tissue imaging can detect global changes of left atrial function associated with ageing similar to standard echocardiographic methods, (2) colour Doppler tissue imaging can reproducibly detect regional changes in atrial function (wall motion) of the normal young and normal aging atrium.

METHODS AND RESULT

We studied 92 healthy subjects, divided into Group B (>or=50 years) and Group A (<50 years). As a reference standard the conventional measures of atrial function were determined: peak mitral A wave velocity, A wave velocity time integral, atrial emptying fraction and atrial ejection force. Pulsed wave Doppler tissue imaging estimated atrial contraction velocity (A' velocity) in late diastolic and segmental atrial contraction was determined by colour Doppler tissue imaging. A' velocities were significantly higher in Group B vs Group A (9.8+/-1.8 vs 8.5+/-1.5cm/s; P=0.0005). A' velocity correlated with atrial fraction (r=0.28; P=0.007) and atrial ejection force (r=0.21; P=0.04). Age correlated significantly with atrial ejection force (r=0.47; P=0.0001), atrial fraction (r=0.61; P=0.0001) and A' velocity (r=0.4; P=0.0002). Longitudinal segmental atrial contraction using colour Doppler tissue imaging showed an annular to superior segment decremental gradient with contraction velocities higher in Group B vs Group A.

CONCLUSION

Pulsed wave Doppler tissue imaging and colour Doppler tissue imaging are reproducible and readily obtained parameters that provide unique data about global and segmental atrial contraction. In this study, changes in atrial contraction with aging were consistent with increased atrial contribution to filling accomplished by augmented atrial contractility.

Changes in regional left atrial function with aging: evaluation by Doppler tissue imaging

AIMS

This study applies pulsed wave Doppler tissue imaging and colour Doppler tissue imaging to study changes in atrial function with ageing. We tested the following hypotheses: (1) pulsed wave Doppler tissue imaging can detect global changes of left atrial function associated with ageing similar to standard echocardiographic methods, (2) colour Doppler tissue imaging can reproducibly detect regional changes in atrial function (wall motion) of the normal young and normal aging atrium.

METHODS AND RESULT

We studied 92 healthy subjects, divided into Group B (>or=50 years) and Group A (<50 years). As a reference standard the conventional measures of atrial function were determined: peak mitral A wave velocity, A wave velocity time integral, atrial emptying fraction and atrial ejection force. Pulsed wave Doppler tissue imaging estimated atrial contraction velocity (A' velocity) in late diastolic and segmental atrial contraction was determined by colour Doppler tissue imaging. A' velocities were significantly higher in Group B vs Group A (9.8+/-1.8 vs 8.5+/-1.5cm/s; P=0.0005). A' velocity correlated with atrial fraction (r=0.28; P=0.007) and atrial ejection force (r=0.21; P=0.04). Age correlated significantly with atrial ejection force (r=0.47; P=0.0001), atrial fraction (r=0.61; P=0.0001) and A' velocity (r=0.4; P=0.0002). Longitudinal segmental atrial contraction using colour Doppler tissue imaging showed an annular to superior segment decremental gradient with contraction velocities higher in Group B vs Group A.

CONCLUSION

Pulsed wave Doppler tissue imaging and colour Doppler tissue imaging are reproducible and readily obtained parameters that provide unique data about global and segmental atrial contraction. In this study, changes in atrial contraction with aging were consistent with increased atrial contribution to filling accomplished by augmented atrial contractility.

The adequacy of basic intraoperative transesophageal echocardiography performed by experienced anesthesiologists

Transesophageal echocardiography (TEE) may improve intraoperative decision-making and patient outcome if it is performed and interpreted correctly. After revising our TEE examination to fulfill the published guidelines for basic TEE practitioners, we prospectively evaluated the ability of our cardiac anesthesiologists (all very experienced with TEE) to record and interpret this revised examination. Educational aids and regular TEE performance feedback were provided to the anesthesiologists. Their interpretations were compared with the independently determined results of experts. Compared with their own historical controls (42% recording rate), all anesthesiologists showed significant improvement in their ability to record a basic intraoperative TEE examination resulting in 81% (P < 0.0001) of all required images being recorded: 88% before cardiopulmonary bypass, 77% immediately after bypass, and 64% after chest closure. Seventy-nine percent of the images recorded at baseline were correctly interpreted, 6% were incorrectly interpreted, and 15% were not evaluated. Our attempt to assess compliance with published guidelines for basic intraoperative TEE resulted in a marked improvement in our intraoperative TEE practice. Most, but not all, standard cross-sections are recorded or interpreted correctly, even by highly experienced and motivated practitioners.

IMPLICATIONS

Experienced cardiac anesthesiologists can obtain and correctly interpret most basic intraoperative transesophageal echocardiograms.

Usefulness of stroke distance by echocardiography as a surrogate marker of cardiac output that is independent of gender and size in a normal population

Left ventricular outflow tract stroke distance (SD) can be measured using pulsed-wave Doppler echocardiography, and is independent of body size. Moreover, persons with structurally normal hearts (heart rate < 55 beats/min) had SD > 0.18 m, and those with a heart rate > 95 beats/min had SD < 0.22 m; outside of these parameters, low- and high-output states are likely to exist, and suspicion of these can be confirmed by calculation of minute distance (normal range 9.7 to 20.5 m/min).

Cardiovascular effects of 3,4-methylenedioxymethamphetamine. A double-blind, placebo-controlled trial

BACKGROUND

The psychoactive stimulant 3, 4-methylenedioxymethamphetamine (MDMA), also known as "ecstasy," is widely used in nonmedical settings. Little is known about its cardiovascular effects.

OBJECTIVE

To evaluate the acute cardiovascular effects of MDMA by using transthoracic two-dimensional and Doppler echocardiography.

DESIGN

Four-session, ascending-dose, double-blind, placebo-controlled trial.

SETTING

Urban hospital.

PATIENTS

Eight healthy adults who self-reported MDMA use.

INTERVENTION

Echocardiographic effects of dobutamine (5, 20, and 40 microg/kg of body weight per minute) were measured in a preliminary session. Oral MDMA (0.5 and 1.5 mg/kg of body weight) or placebo was administered 1 hour before echocardiographic measurements in three weekly sessions.

MEASUREMENTS

Heart rate and blood pressure were measured at regular intervals before and after MDMA administration. Echocardiographic measures of stroke volume, ejection fraction, cardiac output, and meridional wall stress were obtained 1 hour after MDMA administration and during dobutamine infusions.

RESULTS

At a dose of 1.5 mg/kg, MDMA increased mean heart rate (by 28 beats/min), systolic blood pressure (by 25 mm Hg), diastolic blood pressure (by 7 mm Hg), and cardiac output (by 2 L/min). The effects of MDMA were similar to those of dobutamine, 20 and 40 microg/kg per minute. Inotropism, measured by using meridional wall stress corrected for ejection fraction, decreased after administration of dobutamine, 40 microg/kg per minute, but did not change after either dose of MDMA.

CONCLUSIONS

Modest oral doses of MDMA increase heart rate, blood pressure, and myocardial oxygen consumption in a magnitude similar to dobutamine, 20 to 40 microg/kg per minute. In contrast to dobutamine, MDMA has no measurable inotropic effects.

Hemodynamics derived from transesophageal echocardiography (TEE)

Table 1 lists the parameters that are sought routinely in developing a complete hemodynamic profile by TEE. The arterial blood pressure is an essential starting point. Knowledge of the cardiac output (flow velocity integral) allows placement of the other parameters in context by providing a notion of the status of the general circulation and of the level of pulmonary and systemic vascular resistance. The mitral inflow allows segregation of the diastolic function of the left ventricle into one of three categories: (1) normal, (2) restrictive, or (3) delayed relaxation. Pulmonary vein inflow is complementary to mitral inflow and further confirms the status of the filling pressure. The MR jet is another means of gauging the systemic blood pressure and the filling pressure but is more technically demanding than recording mitral valve and pulmonary valve inflows. Tricuspid regurgitation, also technically demanding, reliably provides peak pulmonary systolic pressure, and PR provides the end-diastolic pulmonary artery pressure. Doppler [table: see text] flow in the great veins is useful in estimating right atrial pressure; this information must be integrated with TR and PR velocities to estimate pulmonary artery pressure. Finally, the motion and curvature direction of the IAS allows identification of the atrium with the higher pressure. Using the dynamic behavior of this structure enables reconstructing of the pressure in one atrium from knowledge of pressure in the other. As the case example shows, using these techniques in a routine fashion enables an accurate, comprehensive, and reliable qualitative assay of hemodynamic status.

Introduction to transesophageal echocardiography (TEE) with a historical perspective

Since its introduction in the early 1980s, TEE has become an important standard clinical tool with greatly expanded applications. The technique continues to develop. We can expect the future to bring reliable imaging of myocardial perfusion and user-friendly three-dimensional applications.

Determinants of forward pulmonary vein flow: an open pericardium pig model

OBJECTIVE

To elucidate determinants of pulmonary venous (PV) flow.

BACKGROUND

Right ventricular (RV) systolic pressure (vis a tergo), left atrial (LA) relaxation and left ventricular (LV) systole and relaxation (vis a fronte) have been suggested as determinants of the pulmonary venous (PV) anterograde Doppler flow velocities, but their relative contributions to those flow velocities have not been quantified.

METHODS

We analyzed, by multiple regression analysis, the determinants of PV anterograde velocities in an open-pericardium, paced (70 and 90 beats/min) pig model in which LA afterload was modified by creating LV regional ischemia (left anterior descending coronary artery constriction). We measured high fidelity LA, LV and RV pressures and Doppler flow velocities (epicardial echocardiography). We calculated LV tau, LA relaxation (a through x pressure difference divided by time, normalized by a pressure), LA peak v through x and RV systolic through LA peak v (RVSP-v) pressure differences, LV ejection fraction, long-axis shortening, stroke volume (LV outflow integral x outflow area) and LA four-chamber dimensions, Doppler transmitral and PV flow velocities and velocity-time integrals.

RESULTS

Left ventricular regional ischemia increased mildly LA y trough pressure (8 +/- 1 vs. 6 +/- 1 mm Hg, p = 0.001). Left ventricular stroke volume (coefficient: 0.5 cm/ml, SE: 0.2, p = 0.005) and LA peak v pressure (coefficient: -0.8 cm/mm Hg, SE: 0.3, p = 0.008) determined the PV total systolic integral. Left atrial relaxation determined both PV early systolic peak velocity and integral (coefficient: -0.8 cm/mm Hg, SE: 0.3, p = 0.04). Left atrial maximum area (coefficient: 2 cm(-1) SE: 0.7, p = 0.01) and RVSP-v (coefficient: 0.1 cm/mm Hg, SE: 0.05, p = 0.03) determined the late systolic integral. The PV total systolic integral determined both PV early diastolic peak velocity and integral (coefficient: 1.2, SE: 0.2, p = 0.001).

CONCLUSIONS

In an experimental model of LV acute ischemia of limited duration, the main independent predictors of PV systolic anterograde flow velocities are LA relaxation and compliance (LA peak v pressure) and LV systole--all vis a fronte factors. In the setting of mildly increased LA pressures, PV systolic flow (LA reservoir filling) is an independent predictor of PV early diastolic flow (LA early conduit).

Fatigue, mood, and hemodynamic patterns after myocardial infarction

A descriptive design with repeated measures was used to describe patterns of fatigue, emotional stress, and left ventricular (LV) function among 22 patients with myocardial infarction (MI) from day 5 postadmission to day 21 postadmission for the MI. The severity of fatigue in patients with MI during the subacute period ranged from 32 to 44 on the 100-mm Visual Analogue Scale for Fatigue. Severity of fatigue and depression remained the same; however, LV function improved (p < .01) and patients experienced more energy (p < .01) and less anxiety (p < .01) in the third week following MI. Researchers observed five different fatigue patterns: decreasing fatigue, increasing fatigue, unchanged low fatigue, unchanged-high fatigue, and a curvilinear fatigue pattern. The finding of five different fatigue patterns after an MI suggests that all patients with MI should not be treated as a uniform group assumed to have decreasing fatigue with the passage of time.

The diagnostic validity of digitally captured intraoperative transesophageal echocardiography examinations compared with analog recordings: A pilot study

BACKGROUND

Digital acquisition and storage of echocardiographic studies offer many advantages over analog recordings, but the amount of computer memory required may be large. "Computer compression" of data is done by machines with various algorithms. "Clinical compression" involves limiting the recordings to 1-beat loops, and although it is commonly used, its diagnostic validity has not been demonstrated in the operating room.

METHODS

This prospective pilot study looked at 51 patients undergoing transesophageal echocardiography during cardiac surgery. During continuous videocassette recording, we captured digital loops to demonstrate wall motion abnormalities, ventricular systolic function, aortic insufficiency, and mitral regurgitation. Experts reviewed the loops and tapes. We then compared the diagnoses from the 2 methods.

RESULTS

There were major differences in the diagnosis of wall motion between loops and tapes in only 3.4% of myocardial segments. No major differences were seen in the diagnosis of systolic function, aortic insufficiency, or mitral regurgitation in any patients.

CONCLUSION

We conclude that clinical compression is a suitable method to compress data in the operating room. Large numbers of patients are required to definitively demonstrate the small differences.

Best method in clinical practice and in research studies to determine left atrial size

Although the anteroposterior dimension of the left atrium is universally used in clinical practice and research, we hypothesized that it may be an inaccurate surrogate for volume because its use is based on the unlikely assumption that there is a constant relation among atrial dimensions. The following measurements of the left atrium were made at end ventricular systole: (1) M-mode-derived anteroposterior linear dimension from the parasternal long-axis view; (2) digitized planimetry of the left atrial (LA) cavity from the apical 4-chamber view; and (3) digitized planimetry of the LA cavity from the apical 2-chamber view. The following volume calculations were obtained from these digital measurements: (1) volume derived from the M-mode dimension assuming a spherical shape; (2) volume derived from the single plane area-length of apical 4-chamber view, which assumes that LA geometry can be generalized from a single 2-dimensional plane; and (3) volume derived from the biplane method of discs. The correlation coefficient between the M-mode and biplane methods of determining LA volume was r = 0.76. The mean difference (+/-2 SDs) between these methods is -25 +/- 33 ml. The correlation coefficient between the single plane apical 4-chamber and biplane methods of determining LA volume is r = 0.97. The mean difference (+/-2 SDs) between these methods was -5.0 +/- 12 ml, indicating good agreement. The M-mode measure of the left atrium is an inaccurate representation of its size. Two-dimensional-derived LA volumes provide a more accurate measure of the true size of the left atrium and are more sensitive to changes in LA size. When an echocardiographic measure of LA size is made either in an individual patient or as a variable in a research study, the M-mode measure should be avoided.

Echocardiography in patients with suspected endocarditis: a cost-effectiveness analysis

PURPOSE

We sought to determine the appropriate use of echocardiography for patients with suspected endocarditis.

PATIENTS AND METHODS

We constructed a decision tree and Markov model using published data to simulate the outcomes and costs of care for patients with suspected endocarditis.

RESULTS

Transesophageal imaging was optimal for patients who had a prior probability of endocarditis that is observed commonly in clinical practice (4% to 60%). In our base-case analysis (a 45-year-old man with a prior probability of endocarditis of 20%), use of transesophageal imaging improved quality-adjusted life expectancy (QALYs) by 9 days and reduced costs by $18 per person compared with the use of transthoracic echocardiography. Sequential test strategies that reserved the use of transesophageal echocardiography for patients who had an inadequate transthoracic study provided similar QALYs compared with the use of transesophageal echocardiography alone, but cost $230 to $250 more. For patients with prior probabilities of endocarditis greater than 60%, the optimal strategy is to treat for endocarditis without reliance on echocardiography for diagnosis. Patients with a prior probability of less than 2% should receive treatment for bacteremia without imaging. Transthoracic imaging was optimal for only a narrow range of prior probabilities (2% or 3%) of endocarditis.

CONCLUSION

The appropriate use of echocardiography depends on the prior probability of endocarditis. For patients whose prior probability of endocarditis is 4% to 60%, initial use of transesophageal echocardiography provides the greatest quality-adjusted survival at a cost that is within the range for commonly accepted health interventions.

Left atrial relaxation and left ventricular systolic function determine left atrial reservoir function

BACKGROUND

Determinants of left atrial (LA) reservoir function and its influence on left ventricular (LV) function have not been quantified.

METHODS AND RESULTS

In an open-pericardium, paced (70 and 90 bpm) pig model of LV regional ischemia (left anterior descending coronary constriction), with high-fidelity LV, LA, and RV pressure recordings, we obtained the LA area with 2D automated border detection echocardiography, LA pressure-area loops, and Doppler transmitral flow. We calculated LV tau, LA relaxation (a-x pressure difference divided by time, normalized by a pressure), and stiffness (slope between x and v pressure points of v loop). Determinants of total LA reservoir (maximum-minimum area, cm(2)) were identified by multiple regression analysis. Different mean rates of LA area increase identified 2 consecutive (early rapid and late slow) reservoir phases. During ischemia, LV long-axis shortening (LAS, LV base systolic descent) and LA reservoir area change decreased (7.3+/-0.3 [SEM] versus 5.6+/-0.3 cm(2), P<0.001) and LA stiffness increased (1.6+/-0.3 versus 3.1+/-0.3 mm Hg/cm(2), P=0.009). Early reservoir area change depended on LA mean ejection rate (LA area at ECG P wave minus minimum area divided by time; multiple regression coefficient=0.9; P<0.001) and relaxation (coefficient=4.9 cm(2)xms/s; P<0.001). Late reservoir area change depended on LAS (coefficient=8 cm/s; P<0.001). Total reservoir filling depended on LA stiffness (coefficient=-0.31 cm(4)/mm Hg; P=0. 001) and cardiac output (coefficient=0.001 cm(2)xmin/L; P=0.002). The strongest predictor of cardiac output was LA reservoir filling (coefficient=301 L/minxcm(2); P<0.001). The v loop area was determined by cardiac output, LV ejection time, tau, and early transmitral flow.

CONCLUSIONS

Two (early and late) reservoir phases are determined by LA contraction and relaxation and LV base descent. Acute LV regional ischemia increases LA stiffness and impairs LA reservoir function by reducing LV base descent.

Improved evaluation of the location and mechanism of mitral valve regurgitation with a systematic transesophageal echocardiography examination

Mitral regurgitation (MR) is a major determinant of outcome in cardiac surgery. The location and mechanism of mitral lesions determine the approach to various repairs and their feasibility. Because of incomplete evaluations or change in patient condition, detailed intraoperative transesophageal echocardiography (TEE) examination of the mitral valve may be required. We hypothesized that a systematic TEE mitral valve examination would allow precise identification of the anatomic location and mechanism of MR in patients undergoing mitral surgery. We designed a systematic mitral valve examination consisting of six views: five-chamber, four-chamber, two-chamber anterior, two-chamber mid, two-chamber posterior and short-axis. We used this examination prospectively in 13 patients undergoing mitral valve surgery for severe MR and compared the results with the surgical findings. We then retrospectively interpreted 11 similar patients who had undergone intraoperative TEE studies before this examination. TEE correctly diagnosed the mechanism and precise location of pathology in 12 of 13 patients in the prospective group, but in only 6 of 10 patients in the retrospective group. TEE also correctly identified 75 of 78 mitral segments (96%) as being normal or abnormal. In the retrospective group, only 42 of 60 segments (70%) were correctly identified (P < 0.001). We conclude that this systematic TEE mitral valve examination improves identification of mitral segments and precise localization of pathologies and may also improve the diagnosis of the mechanism of MR.

IMPLICATIONS

In this article, we describe how a systematic examination of the mitral valve by using transesophageal echocardiography allows identification of the different segments of the mitral valve, precise localization of pathology, and helps to diagnose the mechanism of mitral regurgitation. This is important in determining an approach to mitral valve repair and its feasibility.

The Mitral Regurgitation Index: an echocardiographic guide to severity

OBJECTIVES

The purpose of this study was to develop a semiquantitative index of mitral regurgitation severity suitable for use in daily clinical practice and research.

BACKGROUND

There is no simple method for quantification of mitral regurgitation (MR). The MR Index is a semiquantitative guide to MR severity. The MR Index is a composite of six echocardiographic variables: color Doppler regurgitant jet penetration and proximal isovelocity surface area, continuous wave Doppler characteristics of the regurgitant jet and tricuspid regurgitant jet-derived pulmonary artery pressure, pulse wave Doppler pulmonary venous flow pattern and two-dimensional echocardiographic estimation of left atrial size.

METHODS

Consecutive patients (n = 103) with varying grades of MR, seen in the Adult Echocardiography Laboratory at UCSF, were analyzed retrospectively. All patients were evaluated for the six variables, each variable being scored on a four point scale from 0 to 3. The reference standards for MR were qualitative echocardiographic evaluation by an expert and quantitation of regurgitant fraction using two-dimensional and Doppler echocardiography. A subgroup of patients with low ejection fraction (EF < 50%) were also analyzed.

RESULTS

The MR Index increased in proportion to MR severity with a significant difference among the three grades in both normal and low EF groups (F = 130 and F = 42, respectively, p < 0.0001). The MR Index correlated with regurgitant fraction (r = 0.76, p < 0.0001). An MR Index > or =2.2 identified 26/29 patients with severe MR (sensitivity = 90%, specificity = 88%, PPV = 79%). No patient with severe MR had an MR Index <1.8 and no patient with mild MR had an MR Index >1.7.

CONCLUSIONS

The MR Index is a simple semiquantitative estimate of MR severity, which seems to be useful in evaluating MR in patients with a low EF.

Demonstration of penetrating intramyocardial coronary arteries with high-frequency transthoracic echocardiography and Doppler in human subjects

Characterization of intramyocardial coronary artery flow may offer insight into the spectrum of coronary physiology. The purposes of this study were to test the feasibility of detection and measurement of intramyocardial coronary artery flow by using high-frequency transthoracic ultrasound and to evaluate the hemodynamic and morphologic differences in intramyocardial coronary arteries between patients with echocardiographically normal myocardium and patients with diseased myocardium. In 116 subjects (age 58 +/- 19 years; male:female 67:49; 58 normal [control subjects], 40 with left ventricular hypertrophy [LVH], 18 with systolic left ventricular dysfunction [cardiomyopathy, CM]), we examined the myocardium just beneath the apical impulse window at a depth of 3 to 5 cm by using a 6- or 7-MHz centerline frequency transducer. For color Doppler examination, a special preset coronary program with a low Nyquist limit (12 to 20 cm) was used. After obtaining linear color signals, the width and length, peak and mean diastolic pulsed Doppler flow velocities, diastolic velocity time integrals, and percent duration of diastolic Doppler flow were measured. The number of linear color flow signals per square centimeter was counted in 520 different cardiac cycles, and the angles formed by their inner curvature was measured with a graduated protractor. We identified color flow Doppler signals within the myocardium having a mean width of 1.1 +/- 0.4 mm and flow direction from epicardium to endocardium in 104 (89. 7%) subjects and spectral Doppler signals in 74 (63.8%) subjects. In 33 (45.8%) subjects, only diastolic flow was detected and in 39 (54. 2%) subjects, diastolic flow was predominant with systolic reversal. Peak and mean diastolic flow velocities and velocity time integrals of spectral Doppler signal in control subjects were 26.2 +/- 8.6 cm/s, 19.0 +/- 6.3 cm/s, and 9.5 +/- 2.7 cm, respectively. There were no significant differences in width and density of linear color flow signals among the 3 groups. The color flow signals in the LVH and CM groups had a narrower angle of inner curvature (P <.005 for LVH, P <.05 for CM, respectively), and their spectral Doppler signals showed significantly higher diastolic velocities and shorter diastolic flow duration (P <.005 for LVH, P <.05 for CM, respectively) than those of the control subjects. Detection and measurement of flow signals consistent with penetrating intramyocardial coronary arteries are feasible in a high percentage of subjects by use of high-frequency transthoracic ultrasound. The findings in patients with LVH and CM suggest that there are distinct hemodynamic and morphologic departures from those with normal left ventricles that may be a consequence of disordered myocardial perfusion in diseased myocardium.

Two-dimensional echocardiography with a 15-MHz transducer is a promising alternative for in vivo measurement of left ventricular mass in mice

Murine models of left ventricular (LV) hypertrophy recently have been developed. We tested the accuracy of 2-dimensional (2D) echocardiographic measurement of LV mass with high-frequency imaging in mice. Ten anesthetized mice (weight 20 to 31 g, aged 1 to 5 months) were examined with a 15-MHz transthoracic linear-array transducer. End-diastolic myocardial area (A)(epicardial - endocardial) from the parasternal short-axis view at the midpapillary level and LV length (L) from the parasternal long-axis view were measured to calculate LV mass with the area-length method (1.05 [5/6 x A x L]) and data were compared with LV-mass with the 2D guided M-mode method. Within 3 days of echocardiography, the hearts were removed and weighed after potassium-induced cardiac arrest. Two-dimensional echocardiographic measurement with a 15-MHz transducer was performed in all mice. LV chamber dimensions included end-diastolic septal (0.80 +/- 0.12 mm) and posterior wall thickness (0.76 +/- 0.13 mm), end-diastolic dimension (3.64 +/- 0.28 mm), and end-systolic dimension (2.34 +/- 0.32 mm). Echocardiographic LV mass with the area-length method, 2D guided M-mode method, and autopsy LV weight were 80.8 +/- 16.1 mg, 97.6 +/- 17.8 mg, and 78.8 +/- 13.2 mg, respectively. A strong correlation existed between LV weight (x ) and echocardiographic LV mass (y ) with the area-length method: y = 0.745x + 18.9, r =0.908, standard error of estimate (SEE) = 5.9 mg, P <.0005. This correlation was stronger than that of LV weight (x ) and echocardiographic LV mass (y ) with the 2D guided M-mode method: y = 0.577x + 22.6, r =0.779, SEE = 8.8 mg, P =.008. These data suggest that serial in vivo measurements of LV mass with the 2D area-length method may be more accurate than M-mode methods in experimental murine models of LV pathology.

Peak mitral inflow velocity predicts mitral regurgitation severity

OBJECTIVES

Mitral regurgitation (MR) is a common echocardiographic finding; however, there is no simple accurate method for quantification. The aim of this study was to develop an easily measured screening variable for hemodynamically significant MR.

BACKGROUND

The added regurgitant volume in MR increases the left atrial to left ventricular gradient, which then increases the peak mitral inflow or the peak E wave velocity. Our hypothesis was that peak E wave velocity and the E/A ratio increase in proportion to MR severity.

METHODS

We performed a retrospective analysis of 102 consecutive patients with varying grades of MR seen in the Adult Echocardiography Laboratory at the University of California, San Francisco. Peak E wave velocity, peak A wave velocity, E/A ratio and E wave deceleration time were measured in all patients. The reference standard for MR was qualitative echocardiographic evaluation by an expert and quantitation of regurgitant fraction using two-dimensional and Doppler echocardiography.

RESULTS

Peak E wave velocity was seen to increase in proportion to MR severity, with a significant difference between the different groups (F = 37, p < 0.0001). Peak E wave velocity correlated with regurgitant fraction (r = 0.52, p < 0.001). Furthermore, an E wave velocity >1.2 m/s identified 24 of 27 patients with severe MR (sensitivity 86%, specificity 86%, positive predictive value 75%). An A wave dominant pattern excluded the presence of severe MR. The E/A ratio also increased in proportion to MR severity. Peak A wave velocity and E wave deceleration time showed no correlation with MR severity.

CONCLUSIONS

Peak E wave velocity is easy to obtain and is therefore widely applicable in clinical practice as a screening tool for evaluating MR severity.

Acute effects of intraoperative multisite ventricular pacing on left ventricular function and activation/contraction sequence in patients with depressed ventricular function

INTRODUCTION

We hypothesized that simultaneous right and left ventricular apical pacing would result in improvement in left ventricular function due to improved coordination of segmental ventricular contraction. Structural changes in ventricular muscle present in dilated cardiomyopathy compromise ventricular excitation and mechanical contraction.

METHODS AND RESULTS

Eleven patients with depressed left ventricular function having cardiac surgery underwent epicardial multisite pacing with continuous transesophageal echocardiographic imaging. Quantitative measurement of percent fractional area change was performed, and segmental changes in contraction sequence resulting from simultaneous right and left ventricular pacing were assessed by application of phase analysis to recorded transesophageal images. There was no statistically significant difference between the paced QRS duration achieved with simultaneous right and left ventricular apical pacing and the native QRS duration (139+/-39 msec vs 106+/-18 msec, P = NS), but all other paced modes resulted in longer QRS durations. Percent fractional area change improved with simultaneous right and left ventricular apical pacing but not with other paced modes (41.5+/-11.9 vs 34.3+/-9.7, P < 0.01). Phase analysis demonstrated a resequencing of segmental left ventricular activation/contraction when compared to baseline ventricular activation.

CONCLUSION

Simultaneous right and left ventricular apical pacing results in acute improvements in global ventricular performance in patients with depressed ventricular function. Improvements may result from pacing-induced global coordination through recruitment of left and right ventricular apical and septal segments critical to effective ventricular contraction.

Acute hypovolemia may cause segmental wall motion abnormalities in the absence of myocardial ischemia

New segmental wall motion abnormalities (SWMA) detected by echocardiography are considered sensitive and specific markers of myocardial ischemia. However, we have observed new SWMA during pacing-induced reductions in left ventricular filling, which resolved immediately with cessation of the atrial pacing and simultaneous restoration of filling. Therefore, we designed this study to determine whether acute reduction in filling can induce new SWMA in the absence of ischemia. Institution of cardiopulmonary bypass was used as a clinical model of acute reduction in filling, and a beat-by-beat analysis of left ventricular contraction, filling, blood pressures, and electrocardiogram was performed when the drainage of blood to the cardiopulmonary bypass machine rapidly emptied the heart. Acute reduction in filling induced new SWMA in 4 of 38 study patients. All 4 patients had preexisting abnormalities of left ventricular contraction, but translocation of these preexisting SWMA did not explain the new SWMA, nor did myocardial ischemia. We conclude that acute reduction in left ventricular filling can cause new SWMA in the absence of ischemia. This finding limits the usefulness of new SWMA as a marker of ischemia in the presence of acute reduction in filling, such as that secondary to severe hypovolemia.

IMPLICATIONS

This study documented that acute reduction in cardiac filling can be associated with new systolic wall motion abnormalities detected by transesophageal echocardiography in the absence of documented myocardial ischemia. These findings indicate that segmental wall motion may not be a valid marker for ischemia in the setting of acute hypovolemia.

Evaluation of acute dual-chamber pacing with a range of atrioventricular delays on cardiac performance in refractory heart failure

OBJECTIVES

This study evaluated how variations in atrioventricular (AV) delay affect hemodynamic function in patients with refractory heart failure being supported with intravenous inotropic and intravenous or oral inodilating agents.

BACKGROUND

Although preliminary data have suggested that dual-chamber pacing with short AV delays may improve cardiac function in patients with heart failure, detailed Doppler and invasive hemodynamic assessment of patients with refractory New York Heart Association class IV heart failure has not been performed.

METHODS

Nine patients with functional class IV clinical heart failure had Doppler assessment of transvalvular flow and right heart catheterization performed during pacing at AV delays of 200, 150, 100 and 50 to 75 ms.

RESULTS

Systemic arterial, pulmonary artery, right atrial and pulmonary capillary wedge pressures, cardiac index, systemic and pulmonary vascular resistances, stroke volume index, left ventricular stroke work index (SWI) and arteriovenous oxygen content difference demonstrated no significant changes during dual-chamber pacing with AV delays of 200 to 50 to 75 ms. There were also no changes in the Doppler echocardiographic indexes of systolic or diastolic ventricular function. The study was designed with SWI as the outcome variable. Assuming a clinically significant change in the SWI of 5 g/min per m2, a type I error of 0.05 and the observed standard deviation from our study, the observed power of our study is 85% (type II error of 15%).

CONCLUSIONS

Changes in AV delay between 200 and 50 ms during dual-chamber pacing do not significantly affect acute central hemodynamic data, including cardiac output and systolic or diastolic ventricular function in patients with severe refractory heart failure due to dilated cardiomyopathy.

Upper airway obstruction after transesophageal echocardiography

Although transesophageal echocardiography is considered a generally safe procedure, occasional complications have been reported. Serious esophageal trauma and Mallory Weiss tear have been described, as well as post-transesophageal echocardiography dysphagia. However, to our knowledge, upper airway and esophageal obstruction have not been previously cited. A case of upper airway obstruction resulting from a transesophageal echocardiography procedure is herein detailed.

Rapid atrial pacing for detecting provokable demand ischemia in anesthetized patients

A stress test that can be performed intraoperatively might be valuable for cardiac risk stratification in patients needing urgent noncardiac surgery and for early evaluation of coronary reserve in patients undergoing aortocoronary bypass surgery. Therefore, we evaluated the sensitivity and safety of rapid atrial pacing combined with electrocardiography and transesophageal echocardiography for inducing and detecting provokable demand ischemia in 20 anesthetized patients with multivessel coronary artery disease. Rapid atrial pacing induced ST segment changes or new segmental wall motion abnormalities (SWMA), which were defined as evidence of induced ischemia in 15 of the 20 patients. Unexpectedly, the new SWMA normalized during the first beat after abrupt cessation of pacing in three patients who did not show any ST segment changes. Simultaneously, left ventricular preload was severely decreased during pacing and recovered to baseline immediately when pacing was abruptly discontinued. Rapid atrial pacing was safe in all patients, but the target heart rate could not be achieved because of heart block or arterial hypotension in 4 of the 20 patients. These findings raise the question of whether rapid atrial pacing is the most appropriate approach for inducing provokable demand ischemia in anesthetized patients. However, its potential usefulness for predicting adverse cardiac outcomes has not been evaluated and would require larger studies. In addition, the immediate normalization of new SWMA after abrupt cessation of pacing in some patients calls into question the validity of new SWMA as evidence of myocardial ischemia when left ventricular preload is severely decreased.

Echocardiographic evaluation of the severity of tricuspid valve regurgitation: 29 considerations useful in recognizing hemodynamically important lesions

Tricuspid regurgitation is a commonly encountered condition, but precise methods of measuring its severity await development. The purpose of this review is to propose 29 echocardiographic and Doppler considerations that can be applied to gain a qualitative impression of the "significance or severity" of this regurgitant lesion. These methods evaluate the right heart chambers, the morphology of the valve, regurgitant Doppler flow signals, and forward flow. The proposed methods are based on echocardiographic techniques for evaluating mitral regurgitation. However, the literature on directly applying these considerations to judging the severity of tricuspid regurgitation is scant and caution is urged in applying them. One intended consequence of this review is to identify understudied features of tricsupid regurgitation so that those engaged in echocardiographic clinical investigation may be stimulated to develop the tools needed for its ultimate quantitation.

The diagnosis of pericardial effusion and cardiac tamponade by 12-lead ECG. A technology assessment

OBJECTIVE

This study was designed to determine the diagnostic value of 12-lead ECG for pericardial effusion and cardiac tamponade.

DESIGN

Cross-sectional study.

SETTING

University hospital.

PATIENTS

Hospitalized patients with and without pericardial effusion and cardiac tamponade.

MEASUREMENTS AND RESULTS

In a blinded manner, we reviewed 12-lead ECGs from 136 patients with echocardiographically diagnosed pericardial effusions (12 of whom had cardiac tamponade) and from 19 control subjects without effusions. We examined the diagnostic value of three ECG signs: low voltage, PR segment depression, and electrical alternans. We found that all three ECG signs were specific but not sensitive for pericardial effusion (specificity, 89 to 100%; sensitivity, 1 to 17%) and cardiac tamponade (specificity, 86 to 99%; sensitivity, 0 to 42%). None of the ECG signs were associated with pericardial effusions of all sizes, but low voltage was associated with large and moderate pericardial effusions (odds ratio = 2.5; 95% confidence interval [CI] = 0.9 to 6.5; p = 0.06) and with cardiac tamponade (odds ratio = 4.7; 95% CI = 1.1 to 21.0; p = 0.004). In contrast, PR segment depression was associated only with cardiac tamponade (odds ratio = 2.0; 95% CI = 1.0 to 4.0; p = 0.05), while electrical alternans was not associated with either pericardial effusion or cardiac tamponade.

CONCLUSIONS

Low voltage and PR segment depression are ECG signs that are suggestive, but not diagnostic, of pericardial effusion and cardiac tamponade. Because these ECG findings cannot reliably identify these conditions, we conclude that 12-lead ECG is poorly diagnostic of pericardial effusion and cardiac tamponade.

Analysis of left ventricular systolic function

Images

Pericardial effusion in AIDS. Incidence and survival

BACKGROUND

Although pericardial effusion is known to be common among patients infected with HIV, the incidence of pericardial effusion and its relation to survival have never been described.

METHODS AND RESULTS

To evaluate the incidence of pericardial effusion and its relation to mortality in HIV-positive subjects, 601 echocardiograms were performed on 231 subjects recruited over a 5-year period (inception cohort: 59 subjects with asymptomatic HIV, 62 subjects with AIDS-related complex, and 74 subjects with AIDS; 21 HIV-negative healthy gay men; and 15 subjects with non-HIV end-stage medical illness). Echocardiograms were performed every 3 to 6 months (82% had follow-up studies). Sixteen subjects were diagnosed with effusions (prevalence of effusion for AIDS subjects entering the study was 5%). Thirteen subjects developed effusions during follow-up; 12 of these were subjects with AIDS (incidence, 11%/y). The majority of effusions (80%) were small and asymptomatic. The survival of AIDS subjects with effusions was significantly shorter (36% at 6 months) than survival for AIDS subjects without effusions (93% at 6 months). This shortened survival remained significant (relative risk, 2.2, P = .01) after adjustment for lead time bias and was independent of CD4 count and albumin level.

CONCLUSIONS

There is a high incidence of pericardial effusion in patients with AIDS, and the presence of an effusion is associated with shortened survival. The development of an effusion in the setting of HIV infection suggests end-stage HIV disease (AIDS).

Serial assessment of left ventricular function after myocardial infarction

Left ventricular (LV) function is an important predictor of morbidity and mortality after myocardial infarction (MI). Changes in LV function have been examined during the early and late phases after MI, but serial measurements of LV function during the subacute period have not been performed. To assess sequential changes in LV function during the subacute period after MI, we used quantitative two-dimensional echocardiography to examine 22 patients over a 1-year period. Twenty-one of the 22 patients had a Q-wave MI. Eleven had an anterior MI and 10 had an inferior MI; their peak creatine phosphokinase (CPK) was 1213 mIU/ml +/- 14. Three weeks after acute MI, LV ejection fraction (LVEF) had increased from 45% to 52%. Seven of 19 patients showed an LVEF < 43% at baseline. In five of these patients, LVEF improved, but in two patients, LVEF was still < 43% in week 3. There was a significant enlargement of LV end-diastolic volume (LVEDV) (94 ml to 112 ml, p < 0.05) across the four observations but no change in LV end-systolic volume (LVESV; 54 ml to 56 ml, p = n.s.). When two groups (G1 [depressed], LVEF < or = 43%; G2 [preserved], LVEF > 43%) were compared, the group with depressed LVEF demonstrated a higher probability of improvement in LVEF (34% to 47%, p < 0.001) and stroke volume (38 ml to 65 ml, p < 0.01).

Three-dimensional transabdominal ultrasound identification of aortic plaque

Tree-dimensional (3-D) reconstruction of acquired tomographic images in adults has recently been described. With an adaptation of this technique, we performed 3-D reconstruction of transabdominal images of the abdominal aorta to test the hypotheses that 3-D reconstruction of the abdominal aorta is feasible and that 3-D images have incremental value over 2-D in the detection of atheromatous plaque. Twenty-one patients undergoing contrast aortography (Aogram) for clinical indications (1 abdominal aorta (AA) aneurysm, 5 peripheral vascular disease, 1 renal artery stenosis, 14 renal donors) were studied using a 5-MHz annular array probe fitted to a mechanical registration device. In 13 of 21 patients, adequate 2-D ultrasound slices were acquired around a 180 degrees rotation and stored as a volumetric data set using a dedicated computer and 3-D images were reconstructed off-line. Three-dimensional and planar images were blindly compared with Aograms using the following scale: grade 1, normal; grade 2, increased echodensity of the intimal surface; grade 3, local intimal thickening and/or luminal irregularity; and grade 4, protruding mass. Analogous 3-D images were produced in all 13 patients with branching vessels visible in 3 of 13. In 10 patients, the Aogram was interpreted as normal. Compared with Aogram, blindly interpreted 3-D images were compared and correctly identified normal AA in 8 of 10 and atherosclerotic plaque (grade 3 or 4) in 2 of 3. Discordant results were present in 2 of 10 normal aortas and 1 of 3 disease aortas. When 2-D (planar) images were compared with Aograms, 8 of 10 identified normal AA and 3 of 3 aortas with grade 3 or 4 plaque. Thus, in 2 patients, 3-D and planar images suggested atherosclerotic changes not seen by Aogram. Transabdominal 3-D imaging of the abdominal aorta is a feasible technique. Early data suggest that 3-D imaging may distinguish normal from moderate to severe disease, but currently has no demonstrable incremental value over conventional 2-D images. These early results in a small number of patients suggest that this promising technique warrants further evaluation.

Measurement of aortic blood flow by Doppler echocardiography: temporal, technician, and reader variability in normal subjects and the application of generalizability theory in clinical research

Although Doppler echocardiographic measurements of aortic flow have been found to correlate with stroke volume, the reliability of this technique is unknown. The purpose of this study was to measure the reliability of Doppler estimates of cardiac output by identifying and estimating the magnitude of different sources of error. We measured the reliability of Doppler estimates of cardiac output by identifying the magnitude of sources of error in 11 subjects with studies performed by two technicians and read by two readers. Analysis with generalizability theory demonstrated that the largest portion of the total variance was from differences among patients, with a smaller contribution due to day-to-day variability. Variability due to technician was low for continuous wave Doppler (2.0%), but high for pulsed wave (23.2%). Thus continuous wave, but not pulsed wave Doppler measurements, can be used to detect serial changes in cardiac output due to an intervention.

Screening for abdominal aortic aneurysms during transthoracic echocardiography

Patients undergoing transthoracic echocardiography often have atherosclerotic vascular disease and may be at risk for the development of abdominal aortic aneurysms. We therefore examined the abdominal aorta by ultrasound in 323 consecutive patients undergoing routine two-dimensional transthoracic echocardiography over a 6-month period. Measurements were made of aortic length (diaphragm to most caudal portion visualized) and maximum diameter. The study group comprised 169 men and 154 women with an average age of 57 +/- 19 years (range 13 to 94). The abdominal aorta was imaged in 265 (82%) patients. The average aortic length visualized was 13.0 +/- 4.6 cm, the average diameter 1.7 +/- 0.4 cm, and the time required for screening < 5 minutes. Seven (3%) patients were identified as having abdominal aortas > or = 2.5 cm in diameter: 1 with an aneurysm measuring 6.7 cm in diameter and 6 with mild dilatations measuring 2.5 to 3.0 cm in diameter. One of the patients with mild aortic dilatation was subsequently found to have an infrarenal aneurysm measuring 3.5 cm in diameter. Aortic dilatation was associated with male gender (p = 0.0006) and older age (p = 0.05) but was not associated with a history of ischemic heart disease (p = 0.16). From these results, we conclude that screening for abdominal aortic aneurysms in patients undergoing transthoracic echocardiography is practical and clinically useful. Only a small number of these patients are identified as having aneurysms, but the low cost and brief time required suggest that routine screening in this population may be worthwhile.

Transesophageal echocardiography predicts mortality in critically ill patients with unexplained hypotension

OBJECTIVES

This study sought to determine the prognostic yield and utility of transesophageal echocardiography in critically ill patients with unexplained hypotension.

BACKGROUND

Transesophageal echocardiography is increasingly utilized in the intensive care setting and is particularly suited for the evaluation of hypotension; however, the prognostic yield of transesophageal echocardiography in these patients is unknown.

METHODS

We prospectively studied 61 adult patients in the intensive care unit with sustained (> 60 min) unexplained hypotension. Both transthoracic and transesophageal echocardiography were performed, and results were immediately disclosed to the primary physician, who reported any resulting changes in management. Patients were classified on the basis of transesophageal echocardiographic findings into one of three prognostic groups: 1) nonventricular (valvular, pericardial) cardiac limitation to cardiac output; 2) ventricular failure; and 3) noncardiac systemic disease (hypovolemia or low systemic vascular resistance, or both). Primary end points were death or discharge from the intensive care unit.

RESULTS

A transesophageal echocardiographic diagnosis of nonventricular limitation to cardiac output was associated with improved survival to discharge from the intensive care unit (81%) versus a diagnosis of ventricular disease (41%) or hypovolemia/low systemic vascular resistance (44%, p = 0.03). Twenty-nine (64%) of 45 transthoracic echocardiographic studies were inadequate compared with 2 (3%) of 61 transesophageal echocardiographic studies (p < 0.001). Transesophageal echocardiography contributed new clinically significant diagnoses (not seen with transthoracic echocardiography) in 17 patients (28%), leading to operation in 12 (20%).

CONCLUSIONS

Transesophageal echocardiography makes a clinically important contribution to the diagnosis and management of unexplained hypotension and predicts prognosis in the critical care setting.

Abnormal pulmonary artery pressure profile after cardiac transplantation: an exercise Doppler echocardiographic study

This study was designed to test the hypothesis that pulmonary artery pressure at rest and during exercise differs between patients with a transplanted heart and normal subjects and to determine the mechanisms responsible for the difference. Twenty-one patients who had undergone heart transplantation 1.5 to 27 months earlier without current evidence of acute cardiac rejection and 25 normal subjects were studied by exercise Doppler echocardiography. Systolic pulmonary artery pressure was higher at baseline in heart transplant patients than in normal subjects, at 31.6 +/- 9 mm Hg (mean +/- SD) versus 22.5 +/- 4, respectively (p = 0.0001). The increase in systolic pulmonary artery pressure with exercise was 1.4 times higher in heart transplant patients and correlated with pretransplantation pulmonary vascular resistances (r = 0.55; p = 0.01). In contrast, cardiac index at baseline or during exercise did not differ between the two groups. Diastolic parameters and ejection fraction at baseline or during exercise did not correlate with systolic pulmonary artery pressure. In conclusion, Doppler exercise echocardiography offers an alternative, safe method hemodynamic study of the transplanted heart. Although an abnormal increase in left ventricular filling pressure with exercise has been well documented, further studies are needed to investigate and characterize potential abnormalities in pulmonary vascular tone in the transplanted heart.

Left ventricular morphologic features and function in nonhospitalized cocaine users: a quantitative two-dimensional echocardiographic study

To determine whether left ventricular (LV) hypertrophy or dysfunction is present in nonhospitalized cocaine users, we performed quantitative two-dimensional echocardiography in 20 intravenous cocaine users and 20 age- and sex-matched controls. Cocaine users were normotensive, had begun taking cocaine an average of 14 years earlier, and had used cocaine an average of 8 times/mo during the preceding year. There were no significant differences between cocaine users and control subjects for LV mass index (79 vs 74 gm/m2, respectively), mean wall thickness (0.95 vs 0.91 cm), end-diastolic volume index (55 vs 56 ml/m2), end-systolic volume index (17 vs 19 ml/m2), or ejection fraction (70 vs 66%; p > or = 0.09 for all comparisons). Moreover, none of the cocaine users or control subjects had significant regional wall motion abnormalities, and none of the subjects or controls had ejection fractions < 55%. Thus we found little evidence that significant LV hypertrophy or dysfunction is present in nonhospitalized cocaine users. From these results we speculate that cocaine-associated LV hypertrophy and dysfunction may be restricted to certain high-risk groups of chronic cocaine users.

Dyspnea in ambulatory patients with SLE: prevalence, severity, and correlation with incremental exercise testing

OBJECTIVE

We sought to determine the prevalence and severity of dyspnea, and to correlate dyspnea with clinical features and exercise limitation in ambulatory patients with systemic lupus erythematosus (SLE).

METHODS

Twenty-five consecutive patients were evaluated with a validated pulmonary questionnaire, chest radiograph, 2-dimensional echocardiography, resting pulmonary function tests, and incremental exercise testing.

RESULTS

Dyspnea was reported by 60% (95% CI 39-79) of patients; 20% (95% CI 7-40) had severe dyspnea (inability to dress without dyspnea) and 12% (95% CI 3-31) had moderate dyspnea (dyspnea after walking 100 yards). Compared to patients without dyspnea, patients with dyspnea were more likely to have had a history of clinical lupus involving the lung (80 vs 40%, p = 0.05), a lower total lung capacity (77.5 vs 94.8%, p = 0.002), and a reduced maximum oxygen consumption (VO2max of 53.4 vs 67.7%, p = 0.01). Patients with severe dyspnea and patients without dyspnea did not differ in duration of prednisone use, activity of disease, weight, or in frequency of Raynaud's phenomenon (p > 0.05). Only 4% of all patients had abnormal left ventricular motion on 2-dimensional echo; patients with moderate or severe dyspnea had normal left ventricular motion. Of the 5 patients with severe dyspnea, 4 (80%) had restrictive lung disease and 1 (20%) had an isolated diffusion defect. All patients with dyspnea had an abnormal exercise test, but so did 9/10 without dyspnea (p > 0.05). Severity of dyspnea correlated highly with maximum exercise tolerance measured by VO2max (R2 = 0.51, p = 0.0001).

CONCLUSION

In ambulatory patients with SLE, dyspnea is common, frequently disabling, associated with a history of lupus involvement of the lung, and correlates highly with objective measures of exercise limitation.

Five-year follow-up study of the prevalence and progression of pulmonary hypertension in systemic lupus erythematosus

The purpose of this study was to determine the prevalence and progression of pulmonary hypertension over a 5-year follow-up period in 28 patients with systemic lupus erythematosus (SLE) who were originally enrolled in an echocardiographic study of pulmonary hypertension in 1985 and 1986. Twenty healthy volunteers without cardiac or pulmonary disease participated as normal controls. Each patient and control underwent a complete Doppler echocardiographic study. Doppler echocardiographic recordings of tricuspid insufficiency, with saline contrast enhancement when necessary, were used to calculate pulmonary artery systolic pressure according to the modified Bernoulli equation. Doppler echocardiographic measurement of cardiac output was performed at rest for each subject, and pulmonary resistance was calculated by dividing the pulmonary artery systolic pressure by the cardiac output. These results were compared to results of the original studies to detect serial changes in pulmonary pressure and pulmonary resistance; results were also compared to the group of normal controls. The prevalence of pulmonary hypertension increased from 14% at the first study to 43% at follow-up. A significant increase in mean systolic pulmonary artery pressure was detected in the SLE patients during the follow-up period: 23.4 vs 27.5 mm Hg (p < 0.005). In addition, a significantly higher pulmonary artery pressure was detected in the SLE patients compared with the normal controls (p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Segmental analysis of resting echocardiographic function and stress scintigraphic perfusion: implications for myocardial viability

In 73 patients with coronary artery disease, we performed segmental analysis of resting two-dimensional echocardiography and stress thallium-201 single photon emission computed tomographic scintigraphy with 24-hour delayed imaging to test the hypotheses that (1) combined analysis of stress thallium-201 scintigraphy (with 24-hour redistribution) and echocardiography provides an evaluation of the viability of most myocardial segments; and (2) the severity of the scintigraphic perfusion abnormality in a given segment is equivalent to the severity of its echocardiographically determined functional impairment. Scintigraphy showed 14% of the 1168 segments analyzed to have fixed severe defects. Echocardiography showed 11% of the 1070 segments analyzed to be akinetic or dyskinetic. However, with combined analysis, only 62 (5%) segments showed no evidence of viability by either imaging technique. We conclude that in this group of patients, 95% of segments have evidence of viability by one of these two conventional imaging techniques.

Intracardiac echocardiography during radiofrequency catheter ablation of cardiac arrhythmias in humans

OBJECTIVES

The purpose of this study was to describe our preliminary experience using catheter-based intracardiac echocardiography as an adjunct to biplane fluoroscopy for guiding radiofrequency catheter ablation of atrial arrhythmias in the right side of the heart.

BACKGROUND

Catheter ablation requires precise positioning and stable ablation electrode-endocardial contact. This procedure is currently guided by an analysis of intracardiac electrograms and fluoroscopy. However, the use of fluoroscopy does not allow the endocardium and certain anatomic landmarks to be identified and is associated with the hazards of radiation exposure.

METHODS

Seventeen symptomatic patients were studied. A 10F 10-MHz intracardiac imaging catheter was used to visualize specific anatomic landmarks in the right atrium for directing the ablation electrode in 15 patients undergoing radiofrequency ablation of 19 arrhythmias and to assist with interatrial septal puncture in 3 patients.

RESULTS

Continuous intracardiac imaging was performed for a mean +/- SD of 63.6 +/- 39.2 min and demonstrated distal electrode-endocardial tissue contact in 81 (60%) of 134 radiofrequency applications. Movement of the catheter was demonstrated during 36 (44%), microcavitations during 39 (48%) and thrombus during 15 (19%) of the 81 imaged applications. In 7 of 10 procedures for atrial flutter, successful ablation was directed at anatomic corridors in the right atrium visualized with intracardiac echocardiography. During ablation of atrial tachycardia, imaging identified abnormal atrial anatomy related to previous surgery and guided successful ablation of a reentrant tachycardia circulating around these anatomic obstacles. In two procedures for slow pathway modification of atrioventricular node reentrant tachycardia, intracardiac echocardiography confirmed catheter stability at the tricuspid annulus anterior to the coronary sinus.

CONCLUSIONS

During catheter ablation, intracardiac echocardiography augments fluoroscopy by visualizing anatomic landmarks, ensuring stable endocardial contact and assisting in transseptal puncture. Ablation of typical atrial flutter can be successfully directed at anatomic corridors identified using intracardiac imaging.