Dag Teien

Reassessment of valve area determinations in mitral stenosis by the pressure half-time method: Impact of left ventricular stiffness and peak diastolic pressure difference

Estimation of the orifice area is of major importance in the timing of valve dilation or surgery in patients with mitral stenosis. Determination of the area has traditionally been accomplished at cardiac catheterization by the Gorlin equation. The valve area can also be estimated noninvasively with Doppler echocardiographic measurements of the pressure half-time, which is inversely proportional to the area. This method has gained widespread acceptance, but its accuracy has recently been questioned and factors other than reduction of orifice area appear to modify the pressure half-time. In the present study, the influence of left ventricular stiffness (defined as diastolic pressure rise per milliliter of mitral flow) and peak atrioventricular pressure difference on the pressure half-time was examined both in a hydraulic model and by review of data from 35 patients with mitral stenosis. Left ventricular stiffness less than 0.13 mm Hg/ml was considered normal. In the model study, the orifice area correlated only moderately with inverted pressure half-time (1/PHT) (r = 0.67). By multiple linear regression, inverted pressure half-time was shown to be dependent on valve area, chamber stiffness and peak pressure difference (R = 0.89), area and stiffness being most important (R = 0.85). In the clinical study, an increased ventricular stiffness was found in 22 of the 35 patients. The pressure half-time method overestimated the Gorlin-derived area by an average of 72% in these patients compared with only 10% in 13 patients with normal stiffness (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative assessment of aortic regurgitation by combined two‐dimensional, continuous‐wave and colour flow Doppler measurements

The width of the regurgitant jet at the aortic valve plane, i.e. the core flow diameter, the ratio of the jet width to the left ventricular outflow diameter, the regurgitant volume and regurgitant fraction were determined using two‐dimensional, continuous wave and colour flow Doppler echocardiography. The relationship between the non‐invasive measurements and semiquantitative angiographic grading of the regurgitant flow (1 + to 4 +) was examined in a primary group of 20 patients with chronic aortic regurgitation. Cut‐off points for the non‐invasive measurements were selected so as to separate patients with mild or moderate regurgitation (1 + or 2 +) from patients with moderately severe or severe regurgitation (3 + or 4 +). These cut‐off points were prospectively applied in a new group of 35 patients with aortic regurgitation to predict the angiographic grading. Jet width correctly predicted the angiographic grading in 86% of cases, the ratio of the jet width to the outflow diameter in 83% of cases, the regurgitant volume in 86% of cases and the regurgitant fraction in 91% of cases. We conclude that the severity of aortic regurgitation as determined by angiographic grading can be estimated with reasonable accuracy by non‐invasive techniques based on colour flow imaging.

Doppler echocardiographic assessment of the valve area in patients with atrioventricular valve stenosis by application of the continuity equation.

Abstract. The orifice area was non‐invasively assessed in 19 patients with mitral or mitral and tricuspid stenosis by combined cross‐sectional and Doppler echocardiography. Stroke volume was calculated as the product of aortic or pulmonic cross‐sectional area and the time velocity integral of the flow across that valve, and the stenotic valve area was obtained as the stroke volume divided by the time velocity integral of the stenotic valve. In addition, the mitral valve area was estimated by the pressure half‐time method of Hatle et al. The non‐invasive determinations were compared with those calculated by the Gorlin formula at cardiac catheterization.

Heart Rate Variability in Children with Fontan Circulation

Heart rate variability (HRV) can be used to study cardiovascular autonomic control. This study examines HRV in children with Fontan circulation and its change over time. Thirty-four children in two groups were examined. Group A consisted of 10 patients who had undergone total cavopulmonary connection. Group B consisted of 24 healthy children/adolescents matched for gender, height, and weight. To analyze HRV parameters, all examinations included echocardiography and 24-hour ambulatory electrocardiogram. Comparing all patients and controls, there were no significant differences in HRV parameters. Analyzing subgroups of patients younger than 10 years old, two of the HRV parameters were significantly different compared to controls. For the group of patients older than 10 years, eight of the HRV parameters were significantly reduced. Most significant differences were found regarding low-frequency range (p < 0.008) and high-frequency range p < 0.008. This study confirms the finding of earlier studies that patients with Fontan circulation have a reduced HRV, and our findings indicate that there is a progressive reduction of HRV over time.

The Abnormal Contralateral Atrioventricular Valve in Mitral and Tricuspid Atresia in Neonates: An Echocardiographic Study

Abstract.Abnormalities of the mitral valve (MV) or the tricuspid valve (TV) morphology and/or function in patients with functional single ventricle may result in early morbidity and death. The purpose of this study was to determine the incidence of contralateral atrioventricular valve (AVV) pathologies in mitral valve atresia (MA) and tricuspid valve atresia (TA). We retrospectively reviewed the echocardiographic data of 50 neonates with MV and 20 with TA. Appearance of the papillary muscles, chordae tendinae, and valve leaflets was assessed. AVV regurgitation was semiquantitated by color-flow Doppler and the AVV annulus diameter was measured and indexed to body surface area. MV abnormalities were found in 9 of 20 (45%) of patients with TA. The MV was myxomatous in 9 patients, the leaflets were redundant in 5 patients, and prolapsing occurred in 4 patients. Mild regurgitation was found in 2 patients. In 18 of 20 (90%) patients MV annulus size was larger than 95% of predicted normal values. TV abnormalities were found in 12 of 50 (24%) patients with MA. The TV was myxomatous in 4 patients, prolapsing in 2, and redundant in 3, and moderate TV regurgitation was found in 3 patients. In 29 of 50 (58%) patients TV annulus size was larger than 95% of predicted normal values. Contralateral AVV abnormalities in tricuspid and mitral valve atresia are common and should be assessed carefully before surgical procedures.

Quantification of Left to Right Shunts by Echo Doppler Cardiography in Patients with Ventricular Septal Defects

ABSTRACT. Thirty‐one patients with ventricular septal defect were evaluated with Echo Doppler cardiography and colour flow mapping. The ventricular septal defect area was estimated by measurement of the jet diameter by colour flow mapping. The ventricular septal defect flow was calculated as the product of the cross‐sectional area of the ventricular septal defect and the velocity time integral of flow through the defect. In ten patients the diameter obtained by colour flow mapping was compared with the diameter obtained at angiography, r= 0.88 (SD = 0.14 cm). The aortic flow was calculated as the product of left ventricular outflow tract cross‐sectional area and the corresponding velocity time integral. QP/QS ratio was estimated as (ventricular defect flow + aortic flow) / aortic flow and compared to estimates by a radionucleide or oximetric method. A correlation of r= 0.95 (SD = 0.23) was found.

Left ventricular thrombosis after anterior myocardial infarction with and without thrombolytic treatment

Abstract. Objectives. To examine the incidence of left ventricular thrombus in patients with anterior myocardial infarction, with and without streptokinase treatment. To identify predictors of thrombus development.

Rapid cardiovascular effects of growth hormone treatment in short prepubertal children: impact of treatment duration

Previous studies show that growth hormone (GH) treatment increases cardiac dimensions in short children with GH deficiency (GHD) and has diverse cardiac effects in children with idiopathic short stature (ISS). This study was performed to assess the effect of GH on the cardiovascular system in short children with a broad range of GH secretion and GH sensitivity/responsiveness.

Doppler echocardiographic and morphologic evaluation of patients following operative repair of aortic coarctation

Sixty‐six patients operated on previously for coarctation of the aorta were included in the study. There were 50 children and 16 adults. Invasive and non‐invasive gradients were recorded. Anatomical obstruction was evaluated by angiography in 54 patients and the numbers and size of collaterals were quantified. The closest correlation was found between Doppler‐estimated gradients and invasive peakinstantaneous gradients (r= 0.87). The relation between anatomical obstruction and invasive peak‐to‐peak gradients, Doppler gradients and diastolic flow were discouraging (r ‐ 0.64, 0.54 and 0.35). Liberal indications for angiography or magnetic resonance tomography are recommended.

Long-term follow-up of mitral valve regurgitation—Importance of mitral valve pathology and left ventricular function on survival

BACKGROUND Timing of surgery for mitral regurgitation (MR) is one of the more difficult decisions for the practicing cardiologist. METHODS AND RESULTS In order to determine useful clinical cut-offs, we investigated the influence of baseline echocardiographic predictors for survival in a long-time follow-up cohort. Data from 144 patients with MR were collected between 1989 and 1993. Five-year mortality for MR patients was 30% compared to 13% for age- and sex matched controls (p<0.001). Each mm increase in left ventricular end systolic diameter (LVESD increased mortality with 2.5% (p<0.05) and each percent decrease in ejection fraction (EF) increased mortality with 1.8% (p<0.05). These effects were not linear and this material suggests cut-off points for LVESD to be 40 mm and EF 50%. Degree of MR did not correlate with survival, but patients with severe MR were operated more often than those with moderate MR. Patients with functional MR had reduced survival compared to patients with structural MR (p<0.01). CONCLUSIONS MR is a disease with greatly increased mortality and these data suggest a more aggressive approach to surgery.