The echocardiographic assessment of replacement heart valves: high time for a consensus view.
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Data Collection↗
Biomedical subjects
J B Chambers
Publications and source records attributed to J B Chambers.
Aorto-left atrial fistula in prosthetic aortic endocarditis.
Aortic valve endocarditis commonly leads to the formation of a root abscess, but fistulae are uncommon. The echocardiographic findings in a patient with Streptococcus viridans endocarditis of a prosthetic aortic valve associated with a fistula between the aorta and the left atrium are presented. The diagnosis was made by transthoracic echocardiography, although the transesophageal study gave higher resolution views and allowed a more confident exclusion of mitral valve involvement.
Abscess↗
Mitral pressure half-time: is it a valid measure of orifice area in artificial heart valves?
The Hatle orifice area formula was derived in patients with significant mitral stenosis and was not intended for use in other situations. Comparisons between it and other methods of estimating orifice area have shown variability in the slope of the regression lines with wide dispersal of data points. There is no relationship in prosthetic valves between pressure half-time and annulus diameter. Pressure half-time is determined by a number of factors other than orifice area, notably left ventricular compliance, the square root of the peak transmitral pressure drop at the start of diastole, and stroke volume. In normal prosthetic valves, therefore, pressure half-time reflects non-prosthetic factors more accurately than orifice area, and other formulae, such as the continuity equation, should be used to assess the latter. A pressure half-time prolonged beyond 200 ms remains a useful indication of obstruction, especially when the peak transmitral velocity is high.
Blood Pressure↗
Murmurs in pregnancy: an audit of echocardiography.
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Echocardiography↗
An uncommon cause of acute right ventricular failure and high mixed venous oxygen saturation.
Ruptured sinus of Valsalva aneurysms are rare. We report a case in which the usual clinical manifestations were not present and the patient was initially treated as an acute pulmonary embolus. Despite three negative echocardiograms an intra-cardiac shunt was suspected because of a persistently elevated mixed venous oxygen saturation. Cardiac catheterisation confirmed the diagnosis. Surgical repair was performed and post operative recovery was uneventful.
Aortic Rupture↗
Cardiac abnormalities in systemic lupus erythematosus: prevalence and relationship to disease activity.
We conducted a prospective longitudinal study to determine the nature and prevalence of cardiac abnormalities in systemic lupus erythematosus and to study their natural history and relationship with disease activity. Forty consecutive inpatients with systemic lupus erythematosus were studied during their admission and subsequently 6 to 12 months later. On each occasion a clinical cardiovascular examination was carried out, disease activity was scored using the "Lupus Activity Criteria Count" and a Doppler echocardiographic examination was carried out. 72.5% of patients had an abnormal echocardiogram in the first study while 51.7% were abnormal during the follow-up study. Valvar disease occurred in 37.5% of patients. The mitral valve was most commonly affected. Libman-Sacks endocarditis was rare (2.5%). Pericardial effusions were seen in 36.2% of echocardiograms. The majority (76.0%) of these were associated with hypoalbuminaemia. 80.0% of patients had active disease during the first examination and 41.4% at follow-up. There was no correlation between activity of disease and prevalence of cardiac abnormalities at either examination. We conclude that cardiac disease is common in systemic lupus erythematosus. Prevalence of cardiac abnormality did not correlate with disease activity.
Adolescent↗
Ventricular septal aneurysm in a case of Ehlers-Danlos syndrome.
Cardiac abnormalities are a recognised feature of connective tissue disorders. We report a case of Ehlers-Danlos syndrome associated with an aneurysm of the membranous ventricular septum and mitral valve prolapse. To our knowledge this is the first reported association of Ehlers-Danlos syndrome and ventricular septal aneurysm.
Adolescent↗
A study of the stability of orientation in the CarboMedics bileaflet heart valve prosthesis.
A total of 25 CarboMedics bileaflet prostheses was studied in the immediate postoperative period and at 1 week, 1 month and 3 months after surgery. No evidence of rotation was found on visual comparison of valve orientation and there were no significant differences between successive studies for the distance between the septum and either the anterior (P = 0.92) or posterior leaflet (P = 1.00) of valves in the mitral position. The possibility of spontaneous rotation is a potential drawback not only of the CarboMedics prosthesis, but also of designs currently being developed. This study suggests that major rotation does not occur commonly.
Adult↗
The effect of atrio-ventricular delay programming in patients with DDDR pacemakers.
Modern DDDR (dual chamber universal, rate responsive) pacemakers are complex, hugely capable devices incorporating new features that theoretically should enhance haemodynamics and therefore quality of life. Ten patients (mean age 48 years) with chronotropic incompetence and high grade A-V block had activity sensing DDDR devices implanted and underwent a randomized double-blind crossover assessment of rate responsive and different fixed atrio-ventricular delay (AVD) settings during 2 weeks of out-of-hospital activity in DDDR mode. Subjective assessment showed improved 'general wellbeing' and preference for 175 ms rate responsive AVD (P less than 0.01) or 125 ms fixed AVD (P less than 0.05). The longest fixed AVD setting (250 ms) was least acceptable and had increased symptom prevalence (P less than 0.02). Perceived exercise capacity and exercise treadmill tolerance was not significantly different at any setting in DDDR mode but was less in DDD mode. Echocardiographically derived stroke distance was greater at 125 ms AVD than 250 ms at 100 b.min-1 (P less than 0.05) but did not differ at slower heart rates at any AVD. Colour Doppler assessed mitral and tricuspid regurgitation was greatest at 250 ms AVD at all heart rates but did not correlate with increased symptomatology. Stroke distance evaluated from the mitral inflow velocity profile allows improved AVD programming during DDDR pacing. Rate adaptive A-V delay is a useful feature during DDDR pacing.
Adolescent↗
Continuity equation and Gorlin formula compared with directly observed orifice area in native and prosthetic aortic valves.
Orifice areas calculated by the continuity and Gorlin equations have been shown to correlate well in vivo. The continuity equation, however, gives underestimates compared with the Gorlin formula and it is not clear which is the more accurate. Both equations have therefore been tested against maximal orifice area measured by planimetry in eight prepared native aortic valves and four bioprostheses. A computer controlled, ventricular flow simulator (cycled at 70 beats/min) was used at five different stroke volumes that gave cardiac outputs of 2.8 to 7.0 l/min. The mean difference between measured and estimated orifice area was zero for the continuity equation, but -0.14 cm2 for the conventional Gorlin formula. Thus the Gorlin formula tended to give overestimates compared with both measured area and area estimated by the continuity equation, probably because of the effect of pressure recovery. When predictive equations derived from these data were tested, residual standard deviations were around 0.3 cm2 at all stroke volumes for the continuity equation, around 0.2 cm2 for the invasive Gorlin formula, and between 0.2 and 0.4 cm2 for the modified Gorlin formula. These results suggest that estimates of orifice area in an individual valve as judged by any of the equations tested should be seen as a guide to rather than as a precise measure of actual orific area.
Anthropometry↗
The role of echocardiography in the diagnosis and management of infective endocarditis.
The echocardiographic appearance in suspected endocarditis must always be interpreted in the context of the clinical findings. Thus although echocardiography may contribute to the early diagnosis of infective endocarditis, it should rarely be used as a screening test. It is highly sensitive for the detection of complications such as abscesses or valvular regurgitation and can estimate their severity. Although transthoracic imaging will allow a complete study in many cases, the transoesophageal approach is superior for the detection of abscesses and the assessment of prosthetic mitral valves. Patients with large vegetations, particularly on the mitral valve, are at increased risk of embolism but there is no convincing evidence to support prophylactic surgery in these cases.
Echocardiography↗
Hyperventilation provocation in patients with chest pain and a negative treadmill exercise test.
Seventeen (39%) of 44 patients with chest pain but without significant ST depression on treadmill exercise had their usual chest pain reproduced during or after 3 min of voluntary hyperventilation (VHV) at rest. These patients with hyperventilation positive tests had not only significantly more hyperventilation-related symptoms and respiratory complaints but also shorter breath-holding times, lower mean resting end-tidal pCO2 and higher mean respiratory rates than those with negative tests and normal controls. Of the psychological variables, only phobic avoidance scores for agoraphobia were higher in patients with positive tests. These findings suggest that in two fifths of patients with exercise tests negative for ischaemia, chest pain is associated with HV, but abnormalities of breath control and relative hypocapnia are present even in the absence of chest pain. It is possible that a chronic abnormality of respiratory control may interact with attitudinal factors in the experience of non-cardiac chest pain.
Adult↗
Doppler echocardiography of double orifice of the left atrioventricular valve in atrioventricular septal defect.
A left atrioventricular valve having a double orifice is a rare congenital abnormality, and is most commonly described in association with atrioventricular septal defect. We report the Doppler echocardiographic findings of this abnormality and present a case where limited surgical repair has resulted in a favourable outcome.
Child, Preschool↗
Validation of the orifice formula for estimating effective heart valve opening area.
Interest in the Gorlin formula for estimating heart valve effective orifice area (EOA) has recently been rekindled and the formula itself has been challenged. In this validation study, explanted native heart valves, unimplanted mechanical prostheses, unimplanted bioprostheses and explanted bioprostheses have been tested in vitro in a pulsatile flow simulator. Pressures have been measured 30 mm upstream and 100 mm downstream from the plane of the valve sewing ring (to give pressure drop, pd in kPa). Flow (Q in 1 min-1) has been measured directly by electromagnetic flowmeter and orifice areas have either been taken from manufacturer supplied data (mechanical valves) or have been digitised from video images at maximum orifice (biological valves). The formula EOA = Q/(6.96 x pd 1/2) - 0.7 fitted the data with good correlation, r = 0.96 (n = 179). The orifice assumption on which this formula is based (cf. Gorlin formula) is confirmed though it is recommended that the formula should be modified to account for (i) the pressure recovery phenomenon and (ii) the fact that forward flow through a valve only occurs over a portion of the cycle in pulsatile flow. Heart rates used in the study ranged from 40 to 140 min-1, stroke volumes ranged from 20 to 114.3 ml, cardiac outputs from 2.0 to 8.0 1 min-1 and peripheral resistance from 0.1 to 1.6 kPa 1-1 min (1 - 12 mmHg l-1 min). Application of the formula was independent of the flow conditions.
Adult↗
Chest pain with normal coronary anatomy: further out of the closet.
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Chest Pain↗
Single, total paracentesis for tense ascites: sequential hemodynamic changes and right atrial size.
Hemodynamic changes induced by a single, total paracentesis were evaluated in 21 patients with tense ascites from whom 4 to 16 L of ascites were drained over 2 to 8 hr with no serious complications. At 60 min, compared to baseline, there was an increase in cardiac output (7.7 +/- 0.5 to 8.5 +/- 0.6 L/min, p less than 0.02) and a tendency for right atrial pressure to decrease (9.3 +/- 0.8 to 7.50 +/- 0.8 mm Hg, NS), with no change in pulmonary capillary wedge pressure (10.9 +/- 0.9 to 10.7 +/- 0.9 mm Hg). Between 3 and 12 hr later, there was a drop in right atrial pressure, pulmonary capillary wedge pressure and cardiac output to 5.6 +/- 0.6 (p less than 0.02), 7.2 +/- 0.8 mm Hg (p less than 0.002) and 7.2 +/- 0.6 L/min (NS) respectively, indicative of the development of relative hypovolemia and suggesting that therapeutic plasma expansion is appropriate at this time. Two-dimensional echocardiography before paracentesis (n = 8) showed a reduction in the right to left atrium area ratio as compared with values in patients with minimal ascites (0.54 +/- 0.04 vs 0.82 +/- 0.02, p less than 0.0001). This technique may help in identifying patients with right atrial compression caused by tense ascites.
Adult↗
Ventricular stroke work loss: validation of a method of quantifying the severity of aortic stenosis and derivation of an orifice formula.
Because aortic stenosis results in the loss of left ventricular stroke work (due to resistance to flow through the valve and turbulence in the aorta), the percentage of stroke work that is lost may reflect the severity of stenosis. This index can be calculated from pressure data alone. The relation between percent stroke work loss and anatomic aortic valve orifice area (measured by planimetry from videotape) was investigated in a pulsatile flow model. Thirteen valves were studied (nine human aortic valves obtained at necropsy and four bioprosthetic valves) at stroke volumes of 40 to 100 ml, giving 57 data points. Valve area ranged from 0.3 to 2.8 cm2 and mean systolic pressure gradient from 3 to 84 mm Hg. Percent stroke work loss, calculated as mean systolic pressure gradient divided by mean ventricular systolic pressure x 100%, ranged from 7 to 68%. It was closely related to anatomic orifice area with an inverse exponential relation and was not significantly related to flow (r = -0.15). An orifice formula was derived that predicted anatomic orifice area with a 95% confidence interval of +/- 0.5 cm2 (orifice area [cm2] = 4.82 [2.39 x log percent stroke work loss], r = -0.94, SEE = 0.029). These results support the clinical use of percent stroke work loss as an easily obtained index of the severity of aortic stenosis.
Aortic Valve↗
QT prolongation on the electrocardiogram in diabetic autonomic neuropathy.
Patients with Type 1 diabetes and autonomic neuropathy have an increased risk of sudden death for which the mechanism remains obscure. Prolongation of the QT interval on the electrocardiogram may occur with sympathetic dysfunction and is also associated with ventricular arrhythmia and sudden death. We have therefore measured the QT interval in patients with Type 1 diabetes with normal, borderline, and definitely abnormal autonomic function tests and in non-diabetic control subjects. The maximum QT interval was measured on 12-lead electrocardiograms recorded at rest and then plotted against the RR interval. The QT interval was above the upper 95% limit for the non-diabetic control subjects in 5 diabetic patients with abnormal autonomic function tests (33%), but in no cases with normal or borderline tests. Multivariate analysis confirmed that autonomic score contributed significantly (p less than 0.025) to the variance in QT interval. The raw Valsalva ratio alone also contributed significantly to the variance in QT interval (p = 0.025). Heart rate variability, heart rate response to standing, age, sex, and the presence of symptoms of autonomic neuropathy did not contribute significantly.
Arrhythmias, Cardiac↗