Aortic dissection: A "humerus" case.

Aortic dissection usually presents with acute onset of severe chest pain. Classically there is a pressure differential between the 2 arms and widening of the mediastinum. Echocardiography is considered the investigation of choice in many institutions. A case is presented in which the presentation and clinical signs are classical for dissection. Transthoracic echocardiography demonstrated "enlargement" of the descending aorta and a "flap." A surprise diagnosis was made by transesophageal echocardiography. Other vascular structures in the para-aortic regions should be considered when the diagnosis of aortic dissection is entertained.

Interaction between fenofibrate and warfarin.

OBJECTIVE: To determine whether the potentiation of warfarin's anticoagulation effect, which occurred in two patients, was due to an interaction with fenofibrate. CASE SUMMARY: Two patients developed significant potentiation of the anticoagulant effect of warfarin while receiving fenofibrate. In one patient we followed published guidelines to test the potential interaction, including rechallenge twice, and measurements of factors II, V, and VII and liver enzymes to ensure the authenticity of the interaction. We confirmed the interaction by noting that the international normalized ratio (INR) increased with rechallenge, the clotting factor concentrations decreased in concert with the INR, and no other laboratory or clinical factors accounted for this potentiation of the oral anticoagulant affect. DISCUSSION: We previously developed criteria specifically for determining the strength of inferred causation in reports of drug interactions with oral anticoagulants; these criteria were adapted from previously described principles of causality assessment. Our observations in two patients suggest a "highly probable" potentiating interaction between fenofibrate and warfarin. Our data do not allow us to draw definitive conclusions on a mechanism of interaction, but fenofibrate is an oral antilipemic agent, similar to clofibrate, that has been described as potentiating oral anticoagulants by affecting coagulation factor synthesis, likely by altering receptor synthesis. Our finding of lower concentrations of coagulation factors suggests a similar mechanism for fenofibrate. Recent data suggest that lipid lowering is effective for primary and secondary prevention of cardiac events. One might therefore expect to see an increase in the use of the various lipid-lowering agents in patients who receive long-term anticoagulation. Our results indicate that the potential for an exaggerated anticoagulant effect occurs within 5-10 days in patients treated with fenofibrate who are receiving long-term anticoagulation with warfarin. CONCLUSIONS: Fenofibrate potentiates the effect of warfarin. Serial monitoring of the INR, at least three times per week, is therefore strongly recommended when initiating fenofibrate therapy in patients receiving warfarin.

An unusual coronary vein lesion thrombus with calcification.

In this article, a patient with chronic renal failure and probable secondary hyperparathyroidism is described; calcification of a variety of cardiac and other structures complicated the latter. Calcification of an occlusive thrombus in the great cardiac vein and coronary sinus was identified by echocardiography, although not initially appreciated as such. The echocardiographic similarity of this lesion to mitral annular calcification is discussed.

Comparison of Tc-99m sestamibi perfusion imaging and echocardiography using an arbutamine infusion for the detection of coronary artery disease.

Arbutamine, a synthetic catecholamine, coupled with a closed-loop, computerized delivery system was evaluated in conjunction with technetium-99m sestamibi scintigraphy and echocardiography for the detection of coronary artery disease. Concordance between the imaging methods was 68%, with a similar sensitivity for coronary disease using echocardiography (78%) and technetium-99m sestamibi (76%), although more arbutamine-induced ischemia was noted with perfusion imaging.

Feasibility and complications of single-plane and biplane versus multiplane transesophageal imaging: a review of 2947 consecutive studies.

OBJECTIVE: To analyze and compare the incidence of procedural complications and failure of intubation with various sizes of probes used in transesophageal echocardiography. DESIGN: Retrospective chart review. SETTING: A Canadian, tertiary care hospital. PATIENTS: A total of 2947 consecutive transesophageal echocardiographic patient examinations between January 1992 and March 1996 at the University of Ottawa Heart Institute, Ottawa, Ontario. RESULTS: The multiplane probe (MP) was used in 1274 studies, biplane (BP) in 1642 and single plane (SP) in 31. Data for BP and SP were combined because of their similar size. Complications or failed intubation occurred in 86 studies (2.9%). There were 53 complications (1.8%) and 40 failed intubations (1.4%). Seven patients (0.3%) had both. Complications were death in one, tracheal intubation or bronchospasm in nine, bleeding in nine, angina in two, pulmonary edema in two, superficial thrombophlebitis in two, supraventricular tachycardia in one and minor adverse events in 27. Complications were unrelated to the choice of probe (MP 2%, BP and SP 1.7%, not significant). Failure of intubation (40 cases) was more common with MP than with BP and SP (2.3% versus 0.7%, P = 0.0003, OR 3.5, 95% CI 1.7 to 7.5). The main reasons for failure were cervical spondylosis in 16 patients and hypersensitive pharynx despite topical anesthesia and sedation in 13 patients. Of 21 cases of failed MP intubation, 16 (76%) were subsequently successful with BP. CONCLUSIONS: Serious complications with transesophageal echocardiography, although infrequent, do occur. The MP carries a 3.5-fold increased risk of failed intubation. In the majority of failures, successful intubation can be achieved with a smaller probe.

A fenestrated aortic valve contributing to iatrogenic aortic insufficiency post mitral valve replacement.

A case of an unusual local complication of cardiac valvular surgery is presented. Distortion of the geometry of the aortic valve base by a prosthetic mitral valve sewing ring allowed aortic insufficiency through the aortic valve's central orifice, as well as through an aortic valve cusp fenestration. During the 6 years after valve surgery, this patient developed chronic left heart failure contributed to by the aortic insufficiency and eventually, at age 65, required cardiac transplantation. Surgeons and pathologists should be aware of this unusual local complication of cardiac valve surgery, as it may have serious consequences.

Does septal position affect right ventricular function during left ventricular assist in an experimental porcine model?

Right ventricular (RV) failure has been a major problem with patients supported by left ventricular (LV) assist devices (LVADs). To assess the importance of interventricular septal (IVS) position as a mechanism of RV failure, 7 Yorkshire pigs underwent implantation of a Thoratec LVAD. RV function was assessed before and during LVAD operation under differing conditions: (1) with an LV intraventricular latex balloon inflated or deflated to alter IVS position and (2) with and without pulmonary artery (PA) constriction to assess the effect of changes in afterload. RV stroke work, RV dP/dt, and RV end-diastolic length did not change significantly with LVAD operation or with changing afterload conditions. Septal shift was documented as a change in LV shape index (LVSI) calculated using echocardiography. LVSI decreased by 11% when the LVAD was turned on, indicating leftward shifting of the IVS (P = .01). During LVAD support and increased RV afterload, the LVSI decreased by 14.8% (P = .02). RV cardiac output decreased somewhat during LVAD support. However, RV output was worst when the septal position was normalized using the inflated intraventricular balloon during increased RV afterload (P = .05). Unloading by the LVAD of the left ventricle results in a leftward shift of the interventricular septum, which does not appear to adversely affect RV function. However, during conditions of increased RV afterload, septal shifting may be beneficial to RV function.

Massive cardiac deposits of AL-amyloid in a patient with previous valve replacement.

A 78-year old male with AL-type cardiac amyloidosis is presented. Amyloidosis had not been diagnosed during life, as the patient's complaints had been incorrectly ascribed to failure of a Ionescu-Shiley bovine pericardial bioprosthesis inserted seven years previously. Technical considerations relevant to the correct interpretation of echocardiograms in this setting are reviewed. The unique observation of incidental involvement the bioprosthesis by deposits of the Al-amyloid is described.

Left atrial mass produced by extensive mitral annular calcification.

An unusual case of mitral annular calcification presenting as a left atrial mass is discussed. The differential diagnosis of left atrial masses with particular reference to their echocardiographic features is reviewed.

Atypical pseudoaneurysm after mitral valve replacement: Doppler echocardiographic diagnosis.

Ventricular pseudoaneurysm is a rare complication of mitral valve replacement or myocardial infarction. Typically, a ventricular pseudoaneurysm appears as an echocardiographic lucency posterior and lateral to the left ventricle and is best seen from the parasternal long axis and apical four-chamber views. We present an atypical case of left ventricular pseudoaneurysm that tracts posterior and lateral to the right ventricle that was best visualized from the subcostal and low parasternal windows with medial angulation. Doppler imaging confirmed the diagnosis by demonstrating to-and-fro flow between the left ventricle and the cavity located behind the right ventricle. This case emphasizes the importance of the use of multiple echocardiographic windows.

Spontaneous drainage of paravalvular abscess diagnosed by transesophageal echocardiography.

Paravalvular abscesses, which occur in up to 30% of cases of native valve endocarditis, are being detected with increasing frequency with the use of transesophageal echocardiography. Abscesses of the mitral aortic intervalvular fibrosa have been described but only in association with native or prosthetic aortic valve endocarditis. We describe a patient with native mitral valve endocarditis complicated by an abscess in the fibrosa. A 51-year-old diabetic man presented with Staphylococcus aureus mitral valve endocarditis. A transesophageal echocardiographic study done 8 days after admission revealed two large masses at the base of the anterior mitral leaflet with extension into the fibrosa consistent with a paravalvular abscess that was not detected by precordial echocardiography. A repeat transesophageal echocardiographic study done 20 days after admission showed spontaneous drainage of the abscess and a subsequent fistula between the left atrium and left ventricle. This case highlights the important role that transesophageal echocardiography has in suspected and known cases of endocarditis. Its major advantage of delineating posterior cardiac structures allowed accurate diagnosis and serial evaluation of this previously unreported complication of endocarditis.

Echocardiographic detection of pulmonary emboli-in-transit.

Echocardiography can detect pulmonary emboli-in-transit as mobile masses within the right heart. In this case report, a patient with biventricular failure had both transthoracic and transesophageal echocardiograms which revealed a thromboembolus entrapped within the right atrium. Surgery confirmed the echocardiographic findings.

Comparison of accuracy of transesophageal versus transthoracic echocardiography for the detection of mitral valve prolapse with ruptured chordae tendineae (flail mitral leaflet).

The accuracy of transesophageal echocardiography was compared with that of transthoracic echocardiography in the detection of ruptured chordae tendineae (flail mitral leaflet) in 27 patients with mitral valve prolapse (MVP) who underwent valve repair or replacement for mitral regurgitation. Confirmation of the presence of ruptured chordae resulting in a flail leaflet was available at surgery in all cases. The echocardiographic studies were read blindly by 2 independent observers with any differences resolved by a third. Mean (+/- standard deviation) age was 63 +/- 13 years. Men (n = 20) outnumbered women (n = 7) (p less than 0.02), and tended to be younger (p = 0.06). Flail leaflets were identified in 20 of 27 patients. In 1 patient, both leaflets were involved and in the remaining 19 patients posterior leaflets (15 patients) were more frequently affected than anterior leaflets (4 patients). Transesophageal echocardiography correctly identified all 20 patients with flail leaflets, but 1 false positive study occurred among the 7 patients without a flail leaflet. In contrast, transthoracic echocardiography identified only 12 of 20 patients with flail leaflets, with no false positive studies. Transesophageal echocardiography was more accurate, correctly classifying 26 of 27 (96%) cases versus 19 of 27 (70%) by the transthoracic approach (p less than 0.01). This study suggests a higher incidence of chordal rupture to the posterior leaflet in patients with MVP and demonstrates improved accuracy of transesophageal over transthoracic echocardiography in the detection of flail leaflets.

Hemodynamic effects of nasal CPAP examined by Doppler echocardiography.

The effects of incremental application of nasal continuous positive airway pressure (0 to 15 cm H2O) on heart rate, pulmonary artery pressure, and cardiac index were studied noninvasively by Doppler echocardiography. By two-way analysis of variance within two groups (19 normal volunteers and six sleep apnea patients), no significant effects on heart rate, pulmonary artery pressure, ventricular size, or cardiac index could be found with increasing positive intrathoracic pressures and consequent lung hyperinflation. In subjects with normal cardiac function, nasal CPAP is safe from a hemodynamic viewpoint. This simple, repeatable and noninvasive technique may be used to assess the clinical safety and efficacy of prescribed nasal CPAP on cardiac hemodynamics in individual patients.

The effects of right ventricular hemodynamics on left ventricular configuration.

While abnormalities of right ventricular hemodynamics are known to affect interventricular septal position and shape, their effect on left ventricular shape and possibly function have been less well studied. Accordingly, the two-dimensional echocardiographic appearance of the left ventricle was studied in 11 patients with right ventricular volume overload, 16 with right ventricular pressure overload, nine with combined pressure and volume loads of the right heart and 17 normal control subjects. An index of left ventricular shape (SI) was calculated from end diastolic, mid systolic and end systolic left ventricular short axis area (A) and circumference (C) taken at the level of the tips of the mitral leaflets, using the formula SI = 4 pi A/C2. The left ventricles of normal subjects had relatively round configurations throughout the entire cardiac cycle (SI = 0.86 at end diastole, mid and end systole). Pure right ventricular volume overload produced left ventricular deformity at end diastole only (SI at end diastole = 0.78), with a return to normal configuration during systole. Pure right ventricular pressure load resulted in left ventricular deformation throughout the cardiac cycle, with shape indices ranging between 0.77 and 0.80. Combined pressure and volume overload produced left ventricular deformation during the entire cycle which was of an order of magnitude more severe than any other group (SI = 0.69, 0.70 and 0.65, at end diastole, mid and end systole, respectively). The shape index at end systole showed an inverse correlation with the relative right-to-left ventricular systolic pressure ratio (P = 0.001, r = 0.76). It is concluded that left ventricular configuration is affected by right ventricular hemodynamics.(ABSTRACT TRUNCATED AT 250 WORDS)

Evolution of the temporal contraction sequence after acute experimental myocardial infarction.

The effect of infarct maturation on the temporal sequence of contraction within infarct zones has not previously been described. Accordingly, the time-varying pattern of contraction within ischemic/infarct zones was studied with use of cross-sectional echocardiography in 17 dogs at 10 min to 6 weeks after acute experimental myocardial infarction. Left ventricular short-axis images were digitized from end-diastole to end-systole and endocardial fractional radial change along 36 evenly spaced rays was calculated. The circumferential extent of dyskinesia and the number of rays that exhibited maximal dyskinesia were determined for each decile of the normalized contraction sequence. Between 10 min and 1 week after infarction, the greatest circumferential extent of dyskinesia occurred between the 3rd and 4th deciles of the normalized contraction sequence. However, as the infarct matured, the greatest spatial expanse of dyskinesia was noted to occur progressively earlier in the contraction sequence (second decile at 6 weeks), and the extent of mid- to late-systolic dyskinesia decreased markedly. Whereas end-systolic dyskinesia was present in 30% to 50% of ischemic/infarct zone rays from 10 min to 48 h, end-systolic dyskinesia was no longer observed at 6 weeks. Similarly, the maximal amplitude of dyskinesia was most commonly observed during midsystole from 10 min to 48 h, but occurred progressively earlier as the infarct matured, falling during the first decile at 6 weeks after infarction. These data suggest that maximal circumferential extent and amplitude of dyskinesia occur progressively earlier in the systolic contraction sequence as the infarct matures.(ABSTRACT TRUNCATED AT 250 WORDS)

Calculation of transmitral flow by Doppler echocardiography: a comparison of methods in a canine model.

Although several Doppler echocardiographic methods for measuring transmitral flow have been described, the optimal method for calculation of flow remains unclear. Seven time/shape combinations were tested in an experimental preparation in which mitral flow could be precisely controlled and measured. Annular shape was considered to be either circular or elliptical, and the mitral orifice area was calculated from the anteroposterior and/or the mediolateral dimension(s) recorded at early and middiastole. In addition the orifice area was calculated from the maximal mitral leaflet area corrected for diastolic variation. Transmitral flow ranged between 0.4 and 4.6 L/min. Good correlations with measured transmitral flow (r = 0.83 to 0.92) were observed for all methods of calculating the mitral orifice area. Methods that assumed a circular geometry and used the mediolateral annular diameter overestimated flow. Conversely, flows calculated by means of the anteroposterior diameter with the assumption of a circular anulus underestimated flow. The best approximations of transmitral flow were obtained with the assumption of an elliptical configuration that used measurements made in early diastole (Y = 1.04x + 0.2) and with the Fisher method (y = 0.94x + 0.08). Thus in the canine model approximation of the mitral orifice as an ellipse provides the most accurate measurement of transmitral flow.

Doppler-echocardiographic assessment of cardiac output.

Noninvasive Doppler-echocardiographic estimates of cardiac output correlate well with invasive measures of cardiac output, making Doppler echocardiography useful in clinical practice. The ability of Doppler echocardiography to measure flow at multiple sites within the heart makes calculation of intracardiac shunt flow ratios and regurgitant flow volume possible. Measurement of flows at stenotic and nonstenotic sites provides the potential for determining the area of a stenotic valve without cardiac catheterization. Although considerable work must be done before all of these methods can be applied routinely, Doppler echocardiography is clearly emerging as a powerful quantitative tool that greatly enhances the strength of noninvasive evaluation in cardiac diagnosis and management.

A Doppler-two-dimensional echocardiographic method for quantitation of mitral regurgitation.

A noninvasive method to accurately quantitate the severity of mitral insufficiency would be of major clinical value. In theory, in the absence of confounding variables, regurgitant mitral flow should represent the difference between forward mitral blood flow and aortic blood flow. Since Doppler-two-dimensional echocardiographic (D2DE) methods for measuring transvalvular mitral and aortic flow have been validated, it should be possible to use mitral and aortic flows derived by this method to calculate regurgitant mitral flow. To assess the validity and accuracy of this combined approach for quantitation of regurgitant flow, we developed an open-chest canine preparation in which we could simulate, vary, and accurately measure degrees of mitral regurgitation. Seven animals were anesthetized and prepared to allow controlled right heart output. Mitral regurgitation was than simulated by placing a flexible conduit incorporating a one-way valve and electromagnetic flowmeter between the left ventricular apex and left atrium. Flow through the tube (effective mitral regurgitation) was varied between 0.2 and 1.8 liters/min and forward cardiac output ranged between 0.5 and 4 liters/min. Transmitral and transaortic flows were calculated by previously reported Doppler methods. Doppler-derived estimates of forward flow through the aortic valve correlated well with the flow measured by flowmeter (r = .92), and regurgitant flow and regurgitant fraction calculated by the D2DE approach also compared well with those measured by flowmeter (r = .84 and .83, respectively). This study demonstrates that mitral regurgitant flow and regurgitant fraction calculated by the D2DE method provide an acceptable measure of both absolute regurgitant flow and the regurgitant fraction in the experimental setting.