Quantitative relation between increased intrapericardial pressure and Doppler flow velocities during experimental cardiac tamponade.

To establish whether a quantitative relation exists between pericardial pressure and respiratory variation in intracardiac blood flow velocities, a spontaneously breathing closed chest canine model of pericardial tamponade was created. In seven dogs, pericardial pressure was sequentially increased in stages from a mean of -4 +/- 1 to 10 +/- 2 mm Hg while aortic and pulmonary Doppler flow velocities, pleural pressure changes (respiratory effort), blood pressure and cardiac output were measured. The variation in the Doppler-detected peak transaortic velocity (AV) during inspiration (IV) increased linearly from -5 +/- 3% at baseline (pericardial pressure -4 mm Hg) to -32 +/- 9% at a pericardial pressure of 10 mm Hg [IVAV = -2 (pericardial pressure)--13.1; r = 0.78, p less than 10(-6)]. The inspiratory variation in the peak transpulmonary velocity increased from 13 +/- 3% at baseline to 71 +/- 19% at a pericardial pressure of 10 mm Hg. The inspiratory variation in the pulmonary Doppler peak velocity (IVPV) was dependent on both pericardial pressure and degree of respiratory effort [IVPV = 3.8 (pericardial pressure) + 2.6 (respiratory effort) + 10.9; r = 0.88, p less than 10(-8)]. Thus, quantitative relations exist between increases in intrapericardial pressure and increases in inspiratory variation of peak aortic and pulmonary flow velocities. Additionally, pulmonary artery flow velocity is influenced more than aortic velocity by intrathoracic pressure.

Papillary muscle traction in mitral valve prolapse: quantitation by two-dimensional echocardiography.

Previous angiographic observations in patients with mitral valve prolapse have suggested that superior leaflet displacement results in abnormal superior tension on the papillary muscle tips that causes their superior traction or displacement. It has further been postulated that such tension can potentially affect the mechanical and electrophysiologic function of the left ventricle. The purpose of this study was to confirm and quantitate this phenomenon noninvasively by using two-dimensional echocardiography to determine whether superior displacement of the papillary muscle tips occurs and its relation to the degree of mitral leaflet displacement. Directed echocardiographic examination of the papillary muscles and mitral anulus was carried out in a series of patients with classic mitral valve prolapse and results were compared with those in a group of normal control subjects. Distance from the anulus to the papillary muscle tip was measured both in early and at peak ventricular systole. In normal subjects, this distance did not change significantly through systole, whereas in the patient group it decreased, corresponding to a superior displacement of the papillary muscle tips toward the anulus in systole (8.5 +/- 2.6 vs. 0.8 +/- 0.7 mm; p less than 0.0001). This superior papillary muscle motion paralleled the superior displacement of the leaflets in individual patients (y = 1.0x + 0.8; r = 0.93) and followed a similar time course.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic assessment of patients with infectious endocarditis: prediction of risk for complications.

To enhance the echocardiographic identification of high risk lesions in patients with infectious endocarditis, the medical records and two-dimensional echocardiograms of 204 patients with this condition were analyzed. The occurrence of specific clinical complications was recorded and vegetations were assessed with respect to predetermined morphologic characteristics. The overall complication rates were roughly equivalent for patients with mitral (53%), aortic (62%), tricuspid (77%) and prosthetic valve (61%) vegetations, as well as for those with nonspecific valvular changes but no discrete vegetations (57%), although the distribution of specific complications varied considerably among these groups. There were significantly fewer complications in patients without discernible valvular abnormalities (27%). In native left-sided valve endocarditis, vegetation size, extent, mobility and consistency were all found to be significant univariate predictors of complications. In multivariate analysis, vegetation size, extent and mobility emerged as optimal predictors and an echocardiographic score based on these factors predicted the occurrence of complications with 70% sensitivity and 92% specificity in mitral valve endocarditis and with 76% sensitivity and 62% specificity in aortic valve endocarditis.

Quantitation and significance of systolic mitral leaflet displacement in mitral valve prolapse.

Superior systolic displacement of the mitral leaflets is the echocardiographic finding generally used to diagnose mitral valve prolapse, but its clinical significance is not clearly established. This study was designed to determine if the presence of leaflet thickening, displacement in the multiple imaging planes or the quantitative degree of displacement could be used to identify clinically important valvular abnormality. To this end, these findings were prospectively assessed and correlated with the presence of mitral regurgitation and ventricular arrhythmia in 49 patients with displacement and in 49 age-matched control subjects with no identifiable displacement. Both ventricular arrhythmia and mitral regurgitation were found to occur with significantly greater frequency in patients with leaflet displacement than in control subjects. However, among the patients with leaflet displacement, both these complications occurred with greater frequency in subgroups characterized by the presence of leaflet thickening, quantitatively greater displacement and displacement evident in 2 orthogonal imaging planes. Logistic regression analysis demonstrated that the best echocardiographic predictor of either ventricular arrhythmia or mitral regurgitation was the quantitative degree of leaflet displacement. These results indicate that most patients with echocardiographic evidence of leaflet displacement had very low incidences of ventricular arrhythmia and mitral regurgitation. Subgroups, however, could be identified echocardiographically in which both complications occurred with significantly greater frequency.

Baroreflex function and cardiac structure with moderate endurance training in normotensive men.

Changes in arterial and cardiopulmonary baroreflex function and cardiac structure were followed throughout 10 wk of moderate endurance training [60 min of cycling, 3 days/wk, 60% maximal O2 uptake (VO2max)] in sedentary normotensive men (22-34 yr old). Subjects were randomly assigned to an exercise training group (ET; n = 9) or to a control group (UT; n = 4). Decreases in resting heart rate (8.9 +/- 2.6%, P < 0.01) and mean arterial pressure (7.0 +/- 2.3%, P < 0.05) and an increase in VO2max occurred after 10 wk in ET. An increase in the gain or slope of the spontaneous baroreflex response at rest was found after 10 wk in ET (50.1 +/- 6.3%, P < 0.01) but not in UT. An upward shift in the resting carotid-cardiac baroreflex response curve also occurred after 10 wk in ET, although the maximum range and gain of the response and the vagally mediated peak reflex sinus node responses were unchanged. Cardiopulmonary baroreflex function (reflex changes in forearm vascular conductance) and measured indexes of left ventricular structure were not altered in either ET or UT, although peak transmitral inflow velocity increased in ET (P < 0.05). These findings demonstrate that moderate exercise training results in an enhancement in the ability to reflexly adjust heart rate with spontaneous changes in arterial pressure within the operating range. This occurs independently of any changes in carotid-cardiac baroreflex function over the full response range in cardiopulmonary baroreflex function or in cardiac structure.

Early neonatal death due to an unusual pattern of total anomalous pulmonary venous drainage.

Total anomalous pulmonary venous drainage (TAPVD) is an uncommon congenital cardiovascular anomaly caused by failure of the common pulmonary vein to develop a connection with the common atrium in early ontogeny, resulting in persisting connections between pulmonary and systemic venous systems and a left-to-right shunt. This usually occurs via a single, enlarged, well-defined venous channel. The authors present an unusual case of TAPVD with venous obstruction with a profusely arborizing plexus of veins arising from the common pulmonary vein and forming multiple tiny anastomoses with the systemic venous system. This plexus may represent the persistence of an earlier, less involuted embryological form of the primitive pulmonary splanchnic plexus than those found in previously described patterns of TAPVD.

Aortic ring abscess and mitral valve aneurysm in aortic valvular endocarditis: enhanced diagnosis with transesophageal echocardiography.

Aortic ring abscess and mitral valve aneurysms complicating infective endocarditis have previously been described as surgical or autopsy findings. More recently, transesophageal echocardiography has been shown to be more sensitive than standard transthoracic echocardiography or other imaging modalities in detecting each of these complications. Since aortic ring abscess and mitral valve aneurysms virtually mandate surgical intervention, their early detection may be crucial. This report describes a 35-year-old male with congenitally abnormal aortic valve which became infected and in whom both an aortic ring abscess and mitral valve aneurysm occurred. These findings are discussed and the pertinent literature is reviewed.

Change in atrial volume following restoration of sinus rhythm in patients with atrial fibrillation: a prospective echocardiographic study.

OBJECTIVES: To determine if restoration of sinus rhythm in patients with atrial fibrillation decreases atrial size, 16 patients undergoing elective cardioversion were prospectively studied. The frequent coexistence of atrial fibrillation and atrial dilation is well recognized. Recent data have demonstrated that atrial enlargement may be the result, rather than the cause, of atrial fibrillation. DESIGN: Echocardiographic examinations were performed before cardioversion, and at 24 h, three and six months of follow-up. Atrial dimensions were assessed in multiple orthogonal imaging planes and atrial volume was calculated using an ellipsoid formula. SETTING: A tertiary care university teaching hospital. PATIENTS: All patients admitted to hospital between June 1989 and June 1990 for elective cardioversion were considered for enrollment. Informed consent was obtained in all cases. Patients were excluded if echocardiographic images were technically inadequate or reversion to normal sinus rhythm was not achieved. Twenty-five patients were considered for inclusion. The final study population consisted of 16 patients. Complete follow-up data were obtained in 10 cases. MAIN RESULTS: Conversion to sinus rhythm resulted in a decrease in mean left atrial volume from 38.5 cm3 to 34.2 cm3 (P < 0.01) at 24 h, 21.7 cm3 (P < 0.02) at three months and 19.6 cm3 (P < 0.02) at six months. Mean right atrial volume decreased from 33.4 cm3 to 29.4 cm3 (P < 0.01) at 24 h, 19.1 cm3 (P < 0.02) at three months and 16.3 cm3 (P < 0.02) at six months of follow-up. CONCLUSIONS: Conversion from atrial fibrillation to sinus rhythm results in a significant decrease in both left and right atrial volumes.

Anterior wall myocardial infarction in a 15-year-old diabetic female associated with spontaneously resolving coronary thrombosis.

Myocardial infarction is an uncommon event in childhood and adolescence, and only rarely is found to be due to atherosclerotic disease. This report describes a 15-year-old diabetic female with an acute anterior wall myocardial infarction in whom initial coronary angiography showed a thrombus of the proximal anterior descending coronary artery which had resolved spontaneously by the time a follow-up study was carried out six weeks later. None of the usual precipitating causes of myocardial infarction in childhood were found, and repeat angiography did not demonstrate any fixed coronary artery disease. The relevant literature is reviewed and it is speculated that endothelial dysfunction, coronary spasm and altered coagulability may have contributed to the formation of intraluminal thrombus and subsequent infarction in this patient.

Cardiac tamponade secondary to haemophilus pericarditis: a case report.

Pyogenic pericarditis is encountered uncommonly in clinical practice. The majority of cases of clinically apparent pericarditis are viral in origin. When bacterial infection of the pericardial space does occur the causative organism is usually Staphylococcus or Streptococcus species. Isolation of an haemophilus organism from the pericardial space in this condition is distinctly unusual. There are only 10 previously reported cases in the literature of pericarditis secondary to Haemophilus influenzae. This report describes the case of a 36-year-old woman who presented with haemophilus empyema and purulent pericarditis progressing to cardiac tamponade. There are isolated reports of successful treatment of pyogenic pericarditis with closed drainage and antibiotics. In the absence of clear evidence demonstrating the efficacy of this approach the authors favour open exploration of the pericardial space.

Aortic dissection and use of the nicotine patch: a case involving a temporal relationship.

A 33-year-old woman presented with chest and abdominal pain shortly after first and second applications of the nicotine patch. Type A aortic dissection was diagnosed and repaired. Pathological examination revealed cystic medial necrosis, subacute and acute dissection, with no evidence of chronic aortic insufficiency. The close temporal relationship between applications of the nicotine patch and onset of symptoms compatible with dissection followed by extension raises the possibility that the nicotine patch was implicated in, or precipitated, this woman's aortic dissection.

In vitro analysis of colour Doppler flow with the use of proximal isovelocity surface area: improved flow estimates using a nonhemispherical model.

OBJECTIVE: To examine the geometry of the proximal isovelocity surface area (PISA) envelope and its associated isotach, and to evaluate the accuracy of two models of calculating volumetric flow by using the PISA technique. DESIGN: A new model for determining isotach geometry from the PISA envelope was developed and tested in an in vitro simulation. SETTING: Echocardiography Laboratory, Hotel Dieu Hospital, Kingston, Ontario. MATERIALS AND METHODS: PISA envelopes were visualized using an in vitro flow simulator with a series of sharp-edged orifices (2.5 to 16 mm diameter) at a range of flow rates (10 to 110 mL/s). INTERVENTIONS: Flow calculations based on the traditional hemispherical geometric assumption for the isotach and the new model were made and compared with measured flow rates. MAIN RESULTS: The hemispherical model systematically and significantly underestimated flow. The nonhemispherical model, which requires measurement of both the height (a) and lateral width (2d) of the PISA envelope, provided improved estimates of flow. CONCLUSIONS: The nonhemispherical model provides a better estimate of flow through an orifice. Flow rate Q can be calculated directly from the size of the PISA envelope and the aliasing velocity (VA) by using the relationship Q = (3.14d2 + 5.97da + 1.37a2)VA or can be read from a nomogram.

The problem of echocardiographic detection of mitral valve prolapse and determination of its true prevalence.

The prevalence of mitral valve prolapse and the frequency of associated complications is currently still not known with certainty. In post-mortem studies, myxomatous changes of the mitral valve are found in less than 5%. The relationship between characteristic auscultatory findings, detectable in 6 to 18% of young asymptomatic subjects, and angiographic criteria for mitral valve prolapse, observed in up to 30% and more of those undergoing routine cardiac catheterization, is similarly unclear. Establishing the diagnosis based on M-mode echocardiographic criteria has yielded problems, in particular, a frequency too high for apparently healthy subjects. By means of two-dimensional echocardiography, displacement of a mitral leaflet could be detected more frequently in the four-chamber view than in the parasternal long-axis view, a finding which renders both the diagnostic comparability and the assumption of a planar mitral annulus questionable. Accordingly, a saddle-shaped mitral annulus has been postulated. The hypothesis of the saddle-shaped form has been repeatedly tested and confirmed: on a valve model, in patients without mitral valve disease by means of two-dimensional echocardiography as well as by means of three-dimensional reconstruction of two-dimensional echocardiographic images and, lastly, in animal experiments with surgical implantation of radioopaque markers with fluoroscopic observation. Patients can be divided into one of three categories according to the position of the leaflet with respect to the highest or lowest point of the mitral annulus: level of coaptation of the leaflets beneath, completely within or above the highest and lowest points of the annulus. A subgroup of patients in the latter category can be regarded as abnormal.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary left atrial leiomyosarcoma simulating pulmonary thromboembolism.

The authors describe a patient with primary left atrial leiomyosarcoma extending into the right pulmonary veins. The initial presentation and ventilation-perfusion scanning suggested pulmonary thromboembolism. The results of transthoracic echocardiography were nondiagnostic, and the diagnosis was eventually made on the basis of computed tomography (CT) and transesophageal echocardiography findings. The diagnosis was confirmed at surgery. This case demonstrates the complementary roles of CT and transesophageal echocardiography in the evaluation of intracardiac masses when transthoracic echocardiography is nondiagnostic. It also illustrates that cardiac tumours may present with nonspecific symptoms that mimic those of other disease.

[Echocardiographic diagnosis of angiosarcoma of the heart]. / Ehokardiografska dijagnostika angiosarkoma srca.

Cardiac angiosarcoma is the most common primary malignant tumour of the heart that is rarely diagnosed ante mortem. The authors present the case of a 73-year-old female with right atrial angiosarcoma that was followed-up echocardiographically for 20 months. Echocardiographic features suggestive of primary and metastatic malignant tumours of the right heart are discussed.

Clinical assessment of clonidine in the treatment of new-onset rapid atrial fibrillation: a prospective, randomized clinical trial.

PURPOSE: The role of digoxin and verapamil in the control of ventricular response in rapid atrial fibrillation is well established. This study investigates how clonidine compares with these standard therapies in rate control for new-onset rapid atrial fibrillation. We set out to test the hypothesis that clonidine effectively reduces heart rate in patients with new-onset rapid atrial fibrillation. SUBJECTS AND METHODS: Forty patients were seen in the emergency department with new-onset (< or =24 hours' duration), stable, rapid atrial fibrillation. Eligible patients were randomized to receive either clonidine, digoxin, or verapamil. Changes in heart rate and blood pressure over 6 hours, as well as frequency of conversion to sinus rhythm were recorded and analyzed. RESULTS: The mean reduction in heart rate over 6 hours was 44.4 beats/min (95% confidence interval [CI] 28.4-60.4 beats/min) in the clonidine group, 52.1 beats/min (95% CI 40.8-63.4 beats/min) in the digoxin group, and 41.8 beats/min (95% CI 22.5-61.0 beats/min) in the verapamil group. Analysis of variance of the heart rate changes in the 3 groups after 6 hours was not significant (P =.55). At 6 hours, 7 of 12 clonidine patients, 8 of 15 digoxin patients, and 7 of 13 verapamil patients remained in atrial fibrillation (P =.962 on chi(2)). CONCLUSION: Clonidine controls ventricular rate in new-onset atrial fibrillation with an efficacy comparable to that of standard agents.

Identification of high-risk and low-risk subgroups of patients with mitral-valve prolapse.

Mitral-valve prolapse is a common cardiac valvular disorder with a wide range of severity and diverse clinical outcomes. The lack of a standard definition of mitral-valve prolapse may explain the variation in reported complication rates. To identify high-risk and low-risk subgroups, we retrospectively analyzed clinical and two-dimensional echocardiographic data from 456 patients with mitral-valve prolapse. Mitral-valve prolapse was defined on the basis of echocardiographic findings as systolic displacement into the left atrium of one or both leaflets beyond the plane of the mitral annulus in the parasternal long-axis view. Two groups of patients were compared: those with thickening of the mitral-valve leaflets and redundancy (designated the classic form; n = 319) and those without leaflet thickening (designated the nonclassic form; n = 137). The two groups were similar in age and sex ratio. Complications or a history of complications was more prevalent in the classic than the nonclassic form: infective endocarditis, 3.5 percent and 0 percent, respectively (P less than 0.02); moderate-to-severe mitral regurgitation, 12 percent and 0 percent (P less than 0.001); and the need for mitral-valve replacement, 6.6 percent and 0.7 percent (P less than 0.02). However, the frequency of stroke was similar in the two groups: 7.5 percent and 5.8 percent (P not significant). We conclude that in a selected population of patients with mitral-valve prolapse, those with the classic form (leaflet thickening and redundancy) are at higher risk than those without these features for the infectious and hemodynamic complications of mitral-valve prolapse, but not for stroke.

Atrial enlargement as a consequence of atrial fibrillation. A prospective echocardiographic study.

To test the hypothesis that atrial enlargement can develop as a consequence of atrial fibrillation, left and right atrial dimensions were measured echocardiographically at two different time points in patients with atrial fibrillation. Patients were selected who initially had normal atrial sizes and who had no evidence of significant structural or functional cardiac abnormalities other than atrial fibrillation either by history or two-dimensional and Doppler echocardiography. Fifteen patients were studied (12 men and three women; mean age, 67.3 years). Average time between studies was 20.6 months. Three orthogonal left atrial dimensions and two right atrial dimensions were measured, and all were found to increase significantly between studies. Also, highly significant increases in calculated left atrial volume (from 45.2 to 64.1 cm3, p less than 0.001) and right atrial volume (from 49.2 to 66.2 cm3, p less than 0.001) were observed. The relative extents of left and right atrial volume increase did not differ, and left ventricular size did not change significantly between studies. These results indicate that atrial enlargement can occur as a consequence of atrial fibrillation. The maintenance of sinus rhythm, therefore, may prevent atrial enlargement and its adverse clinical effects.

Three-dimensional echocardiographic reconstruction of the mitral valve, with implications for the diagnosis of mitral valve prolapse.

Mitral valve prolapse has been diagnosed by two-dimensional echocardiographic criteria with surprising frequency in the general population, even when preselected normal subjects are examined. In most of these individuals, however, prolapse appears in the apical four-chamber view and is absent in roughly orthogonal long-axis views. Previous studies of in vitro models with nonplanar rings have shown that systolic mitral annular nonplanarity can potentially produce this discrepancy. However, to prove directly that apparent leaflet displacement in a two-dimensional view does not constitute true displacement above the three-dimensional annulus requires reconstruction of the entire mitral valve, including leaflets and annulus. Such reconstruction would also be necessary to explore the complex geometry of the valve and to derive volumetric measures of superior leaflet displacement. A technique was therefore developed and validated in vitro for three-dimensional reconstruction of the entire mitral valve. In this technique, simultaneous real-time acquisition of images and their spatial locations permits reconstruction of a localized structure by minimizing the effects of patient motion and respiration. By applying this method to 15 normal subjects, a coherent mitral valve surface could be reconstructed from intersecting scans. The results confirm mitral annular nonplanarity in systole, with a maximum deviation of 1.4 +/- 0.3 cm from planarity. They directly show that leaflets can appear to ascend above the mitral annulus in the apical four-chamber view, as they did in at least one view in all subjects, without actual leaflet displacement above the entire mitral valve in three dimensions, thereby challenging the diagnosis of prolapse by isolated four-chamber view displacement in otherwise normal individuals. This technique allows us to address a uniquely three-dimensional problem with high resolution and provide new information previously unavailable from the two-dimensional images. This new appreciation should enhance our ability to ask appropriate clinical questions relating mitral valve shape and leaflet displacement to clinical and pathologic consequences.