Ingela Schnittger

Recommendations for quantitation of the left ventricle by two-dimensional echocardiography. American Society of Echocardiography Committee on Standards, Subcommittee on Quantitation of Two-Dimensional Echocardiograms.

We have presented recommendations for the optimum acquisition of quantitative two-dimensional data in the current echocardiographic environment. It is likely that advances in imaging may enhance or supplement these approaches. For example, three-dimensional reconstruction methods may greatly augment the accuracy of volume determination if they become more efficient. The development of three-dimensional methods will depend in turn on vastly improved transthoracic resolution similar to that now obtainable by transesophageal echocardiography. Better resolution will also make the use of more direct methods of measuring myocardial mass practical. For example, if the epicardium were well resolved in the long-axis apical views, the myocardial shell volume could be measured directly by the biplane method of discs rather than extrapolating myocardial thickness from a single short-axis view. At present, it is our opinion that current technology justifies the clinical use of the quantitative two-dimensional methods described in this article. When technically feasible, and if resources permit, we recommend the routine reporting of left ventricular ejection fraction, diastolic volume, mass, and wall motion score.

Asymptomatic cardiac disease following mediastinal irradiation

OBJECTIVES This study was designed to evaluate the potential benefit of screening previously irradiated patients with echocardiography. BACKGROUND Mediastinal irradiation is known to cause cardiac disease. However, the prevalence of asymptomatic cardiac disease and the potential for intervention before symptom development are unknown. METHODS We recruited 294 asymptomatic patients (mean age 42 +/- 9 years, 49% men, mean mantle irradiation dose 43 +/- 0.3 Gy) treated with at least 35 Gy to the mediastinum for Hodgkins disease. After providing written consent, each patient underwent electrocardiography and transthoracic echocardiography. Valvular disease was common and increased with time following irradiation. Patients who had received irradiation more than 20 years before evaluation had significantly more mild or greater aortic regurgitation (60% vs. 4%, p < 0.0001), moderate or greater tricuspid regurgitation (4% vs. 0%, p = 0.06), and aortic stenosis (16% vs. 0%, p = 0.0008) than those who had received irradiation within 10 years. The number needed to screen to detect one candidate for endocarditis prophylaxis was 13 (95% confidence interval [CI] 7 to 44) for patients treated within 10 years and 1.6 (95% CI 1.3 to 1.9) for those treated at least 20 years ago. Compared with the Framingham Heart Study population, mildly reduced left ventricular fractional shortening (<30%) was more common (36% vs. 3%), and age- and gender-adjusted left ventricular mass was lower (90 +/- 27 g/m vs. 117 g/m) in irradiated patients. CONCLUSIONS There is a high prevalence of asymptomatic heart disease in general, and aortic valvular disease in particular, following mediastinal irradiation. Screening echocardiography should be considered for patients with a history of mediastinal irradiation.

Enhanced detection of intracardiac sources of cerebral emboli by transesophageal echocardiography.

We performed transesophageal echocardiography in 50 consecutive hospitalized patients with recent transient ischemic attack or stroke of embolic origin to determine whether transesophageal echocardiography is more sensitive than transthoracic echocardiography in detection of possible intracardiac sources of embolism. Twenty-six of 50 patients with a negative transthoracic echocardiogram for potential source of emboli had a transesophageal echocardiography study that demonstrated at least one intracardiac abnormality. Abnormalities noted by transesophageal echocardiography included five of 50 patients with either a left atrial or left atrial appendage clot, four patients with a patent foramen ovale, and nine patients with spontaneous echocardiographic contrast. In 11 of 50 patients with no other source of embolism, we found highly mobile filamentous strands on the mitral valve, which have not been described previously. These mitral valve echo strands may represent a fissured surface or fibrosis that can serve as a nidus for thrombus formation. We detected no unexpected left ventricular thrombus or left atrial myxoma. Factors significantly associated with a greater likelihood of a positive transesophageal echocardiography study included left atrial enlargement, atrial fibrillation, and a calcified or thickened mitral valve. Our study suggests that transesophageal echocardiography is a valuable addition to transthoracic echocardiography in investigating potential intracardiac sources of embolism.

Screening for Coronary Artery Disease After Mediastinal Irradiation for Hodgkin's Disease

PURPOSE Incidental cardiac irradiation during treatment of thoracic neoplasms has increased risks for subsequent acute myocardial infarction or sudden cardiac death. Identifying patients who have a high risk for a coronary event may decrease morbidity and mortality. The objective of this study was to evaluate whether stress imaging can identify severe, unsuspected coronary stenoses in patients who had prior mediastinal irradiation for Hodgkins disease. PATIENTS AND METHODS We enrolled 294 outpatients observed at a tertiary care cancer treatment center after mediastinal irradiation doses 35 Gy for Hodgkins disease who had no known ischemic cardiac disease. Patients underwent stress echocardiography and radionuclide perfusion imaging at one stress session. Coronary angiography was performed at the discretion of the physician. RESULTS Among the 294 participants, 63 (21.4%) had abnormal ventricular images at rest, suggesting prior myocardial injury. During stress testing, 42 patients (14%) developed perfusion defects (n = 26), impaired wall motion (n = 8), or both abnormalities (n = 8). Coronary angiography showed stenosis 50% in 22 patients (55%), less than 50% in nine patients (22.5%), and no stenosis in nine patients (22.5%). Screening led to bypass graft surgery in seven patients. Twenty-three patients developed coronary events during a median of 6.5 years of follow-up, with 10 acute myocardial infarctions (two fatal). CONCLUSION Stress-induced signs of ischemia and significant coronary artery disease are highly prevalent after mediastinal irradiation in young patients. Stress testing identifies asymptomatic individuals at high risk for acute myocardial infarction or sudden cardiac death.

Predictive Value of the Index of Microcirculatory Resistance in Patients With ST-Segment Elevation Myocardial Infarction

OBJECTIVES The objective of this study is to evaluate the predictive value of the index of microcirculatory resistance (IMR) in patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). BACKGROUND Despite adequate epicardial artery reperfusion, a number of patients with STEMI have a poor prognosis because of microvascular damage. Assessing the status of the microvasculature in this setting remains challenging. METHODS In 29 patients after primary PCI for STEMI, IMR was measured with a pressure sensor/thermistor-tipped guidewire. The Thrombolysis In Myocardial Infarction (TIMI) myocardial perfusion grade, TIMI frame count, coronary flow reserve, and ST-segment resolution were also recorded. RESULTS The IMR correlated significantly with the peak creatinine kinase (CK) (R = 0.61, p = 0.0005) while the other measures of microvascular dysfunction did not. In patients with an IMR greater than the median value of 32 U, the peak CK was significantly higher compared with those having values <or=32 U (3,128 +/- 1,634 ng/ml vs. 1,201 +/- 911 ng/ml, p = 0.002). The IMR correlated significantly with 3-month echocardiographic wall motion score (WMS) (R = 0.59, p = 0.002) while the other measures of microvascular function did not. The WMS at 3-month follow-up was significantly worse in the group with an IMR >32 U compared with <or=32 U (28 +/- 7 vs. 20 +/- 4, p = 0.001). On multivariate analysis, IMR was the strongest predictor of peak CK and 3-month WMS. The IMR was the only significant predictor of recovery of left ventricular function on the basis of the percent change in WMS (R = 0.50, p < 0.01). CONCLUSIONS Compared to standard measures, IMR appears to be a better predictor of microvascular damage after STEMI, both acutely and in short term follow-up.

Accuracy of biplane and multiplane transesophageal echocardiography in diagnosis of typical acute aortic dissection and intramural hematoma

OBJECTIVES The purpose of this study was to evaluate the diagnostic accuracy of biplane and multiplane transesophageal echocardiography in patients with suspected aortic dissection, including intramural hematoma. BACKGROUND Transesophageal echocardiography is a useful technique for rapid bedside evaluation of patients with suspected acute aortic dissection. The sensitivity of transesophageal echocardiography is high, but the diagnostic accuracy of biplane and multiplane transesophageal echocardiography for dissection and intramural hematoma is less well defined. METHODS We studied 112 consecutive patients at a major referral center who had undergone biplane or multiplane transesophageal echocardiography to identify aortic dissection. The presence, absence and type of aortic dissection (type A or B, typical dissection or intramural hematoma) were confirmed by operation or autopsy in 60 patients and by other imaging techniques in all. The accuracy of transesophageal echocardiography for ancillary findings of aortic dissection (intimal flap, fenestration and thrombosis) was assessed in the 60 patients with available surgical data. RESULTS Of the 112 patients, aortic dissection was present in 49 (44%); 10 of these had intramural hematoma (5 with and 5 without involvement of the ascending aorta). Of the remaining 63 patients without dissection, 33 (29%) had aortic aneurysm and 30 (27%) had neither dissection nor aneurysm. The overall sensitivity and specificity of transesophageal echocardiography for the presence of dissection were 98% and 95%, respectively. The specificity for type A and type B dissection was 97% and 99%, respectively. The sensitivity and specificity for intramural hematoma was 90% and 99%, respectively. The accuracy of transesophageal echocardiography for diagnosis of acute significant aortic regurgitation and pericardial tamponade was 100%. CONCLUSIONS Biplane and multiplane transesophageal echocardiography are highly accurate for prospective identification of the presence and site of aortic dissection, its ancillary findings and major complications in a large series of patients with varied aortic pathology. Intramural hematoma carries a high complication rate and should be treated identically with aortic dissection.

Transesophageal two-dimensional echocardiography and color Doppler flow velocity mapping in the evaluation of cardiac valve prostheses.

To determine the value of transesophageal ultrasound in the assessment of cardiac valve prostheses, 14 patients with clinically suspected mitral prosthesis malfunction were studied by transthoracic and transesophageal two-dimensional imaging as well as by color Doppler flow velocity mapping (color Doppler). Patients underwent left ventricular angiography (n = 13), surgery (n = 11), or both angiography and surgery (n = 10). Nine patients had only mitral valve replacement, four patients had both mitral and aortic valve replacement, and one patient had mitral, aortic, and tricuspid valve replacement. There were 16 biological and four mechanical prostheses. The degree of mitral regurgitation was graded by both transthoracic and transesophageal color Doppler according to the area of the regurgitant jet visualized and was compared with a three-point classification of mitral regurgitation by left ventricular angiography judged by observers blinded to the echocardiographic results. All transesophageal studies were performed without complication and were well tolerated. The pathological morphology of the mitral prosthesis was additionally or more clearly visualized by transesophageal two-dimensional imaging and subsequently proven at surgery in three patients with flail leaflets and one patient with a vegetation compared with images obtained by the transthoracic approach. Valvular regurgitation was graded by the transthoracic approach as absent in four patients, mild in two patients, moderate in five patients, and severe in only three patients. The transesophageal assessment showed absence of mitral regurgitation in two patients, moderate regurgitation in two patients, and severe regurgitation in 10 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonic tissue characterization of human hypertrophied hearts in vivo with cardiac cycle-dependent variation in integrated backscatter.

Integrated ultrasonic backscatter (IB) is a noninvasive measure of the acoustic properties of myocardium. Previous experimental studies have indicated that altered acoustic properties of the myocardium are reflected by the magnitude of variation of IB during the cardiac cycle. In our study, cardiac cycle-dependent variation of IB was noninvasively measured using a quantitative IB imaging system in 12 patients with uncomplicated pressure-overload hypertrophy and 13 patients with hypertrophic cardiomyopathy. Sixteen normal subjects served as a control. The magnitude of cardiac cycle-dependent variation of IB for the posterior wall was 6.0 +/- 0.9 dB in normal subjects, 5.7 +/- 0.8 dB in the patients with uncomplicated pressure-overload hypertrophy, and 6.7 +/- 2.1 dB in the patients with hypertrophic cardiomyopathy. There were no significant differences among any of these groups. In contrast, the magnitude of cardiac cycle-dependent variation of IB for the septum was significantly smaller in the patients with uncomplicated pressure-overload hypertrophy (2.8 +/- 1.3 dB) and in the patients with hypertrophic cardiomyopathy (3.1 +/- 2.3 dB) than in normal subjects (4.9 +/- 1.0 dB). The magnitude of cardiac cycle-dependent variation of IB was smaller as the wall-thickness index increased (r = -0.53, p less than 0.01, n = 82 for all data). This IB measure also correlated with percent-systolic thickening of the myocardium (r = 0.67, p less than 0.01, n = 82). Thus, alteration in the magnitude of cardiac cycle-dependent variation of IB was observed in hypertrophic hearts and showed apparent regional myocardial differences.

Standardized Intracardiac Measurements of Two-Dimensional Echocardiography

Thirty-five healthy adults were studied by two-dimensional echocardiography to attempt to standardize a simple method for measurement of intracardiac dimensions. Both ventricles and the atria and aorta were measured in five different views: parasternal long-axis, parasternal short-axis at the level of the aortic valve, the chordae tendineae and the papillary muscles and an apical four chamber view. The minor axis of each chamber was measured in all five views; the major axis in the apical four chamber view also was measured. All measurements are presented as a range of values (mean and 2 standard deviations about the mean); the mean value is given as well as the absolute range of values measured. Normalization according to body surface area is also presented. Data from these multiple views allow assessment of asymmetry of cardiac chambers in normal subjects. The mean minor axis dimension at end-diastole of the right ventricle in the parasternal long-axis view (1.9 to 3.8 cm) was 13.6% smaller than in the four chamber view (2.2 to 4.4 cm), whereas the minor axis dimension of the left ventricle in the parasternal long-axis view (3.5 to 6.0 cm) was only 1.1% larger than in the four chamber view (3.3 to 6.0 cm). Therefore, the right ventricular minor axis dimensions are not interchangeable. Reproducibility in 10 subjects for all dimensions showed a maximal variability of 4.8%. These values permit a standardized and expeditious method for measuring intracardiac dimensions by two-dimensional echocardiography.

Limitations of comparing left ventricular volumes by two dimensional echocardiography, myocardial markers and cineangiography

Abstract Measurement of left ventricular volume at end-diastole or end-systole with both two dimensional echocardiography and either Cineangiography or radionuclide scans, not recorded simultaneously, has shown large echocardiographic underestimation of volumes even in normal ventricles. In this study fluoroscopic and two dimensional echocardiographic recordings were obtained in 18 patients with abnormal wall motion and previously implanted myocardial markers. The echocardiographic values for volume and those derived from myocardial markers correlated well (r = 0.87), and there were no statistically significant differences in values obtained with the two methods at end-diastole or end-systole. The ejection fractions obtained with two dimensional echocardiography (mean ± standard deviation 46 ± 7 percent) and with fluoroscopic recording of the markers (41 ± 9 npercent) did not differ statistically. These results were compared with those in another 18 patients (nine with abnormal wall motion) having two dimensional echocardiography within 24 hours of a 30 ° right anterior oblique contrast left ventriculogram. Again, two dimensional echocardiographic ventricular volume correlated well with the angiographic volume (r = 0.85), although echocardiographic end-diastolic volume was consistently 20 percent less than angiographic end-diastolic volume (p Probable reasons for the lack of severe underestimation of volume with echocardiography even in very abnormal ventricles, relative to that demonstrated in prior reports, include improvements in ultrasonic beam width, tracing method, transducer position and scan plane orientation within the ventricle. In addition, the possible effects of angiographic dye in the ventricular trabeculae are discussed and the effect of simultaneous studies by two different methods are compared.