Biomedical subjects
Publications and source records attributed to D San Román.
We report the case of a 62-year-old patient with a mitral prosthesis hospitalized with an anterior acute myocardial infarction who was treated with r-tPA. Some days later, the patient had mitral thrombosis with heart failure. Because of the high risk of surgical intervention, he was successfully treated with a new dose of r-tPA.
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OBJECTIVES: This study sought to assess the diagnostic implications of the flow dependence of Doppler echocardiographic indexes of aortic valve stenosis. BACKGROUND: Although valve area has been shown to change with alterations in flow rate, the diagnostic consequences of this phenomenon remain unknown. Valve resistance has been suggested as a more stable index for evaluating aortic stenosis. METHODS: A low dose dobutamine protocol was performed in 35 patients with aortic stenosis. Hemodynamic indexes were obtained by Doppler echocardiography at baseline and at each dobutamine dose. RESULTS: As a result of the shortening of the systolic ejection period, flow increased from (mean +/- SD) 164 +/- 48 to 229 +/- 102 ml/s (p < 0.0001). At peak flow, valve area increased by 28% (from 0.5 +/- 0.2 to 0.6 +/- 0.3 cm2, p < 0.0001), whereas valve resistance decreased by 4% (from 498 +/- 252 to 459 +/- 222 dynes.s.cm-5, p = 0.04). This observed change in resistance was smaller than that for valve area (p < 0.01). The flow dependence of valve area varied among individual patients (p < 0.0001). Multivariate analysis identified calcific degenerative etiology (beta 0.29, p = 0.002), left ventricular velocity of fiber shortening (beta 0.22, p = 0.01), baseline flow (beta -0.28, p = 0.04) and amount of flow increased induced by dobutamine (beta 0.90, p < 0.0001) as factors related to valve area flow dependence. CONCLUSIONS: Although all Doppler echocardiographic indexes of aortic stenosis are affected by flow, valve resistance is more stable than valve area under dobutamine-induced hemodynamic changes. Baseline valve area may be unreliable in patients with calcific degenerative aortic stenosis and low output states.
INTRODUCTION AND OBJECTIVES: We analyzed the characteristics of mitral valve apparatus by transesophageal echocardiography in a consecutive series of patients with hypertrophic cardiomyopathy. METHODS: We performed a transesophageal study in 60 patients; 35 of them had intraventricular obstruction at basal state. The following measurements and observations were made in the frontal long-axis transesophageal plane: a) length of both mitral leaflets and dimensions of left ventricular outflow tract that were compared with those obtained from 25 normal subjects; b) structure involved in the systolic anterior mitral motion; c) mechanism of mitral regurgitation, and d) sequence of systolic events. RESULTS: Compared with control subjects (anterior mitral leaflet: 2.86 +/- 0.3 cm, posterior mitral leaflet: 1.62 +/- 0.2 and 1.7 +/- 0.2 cm, respectively; the mitral leaflets were longer in patients with and without subaortic obstruction (anterior leaflet: 2.3 +/- 0.1; posterior leaflet: 1.07 both, p < 0.01). Systolic anterior motion was observed in 49 patients, with mitral leaflet-septal contact in 87% of patients with obstruction and in 11% of nonobstructive patients (p < 0.01). Structures participating in this phenomenon were: distal portion of the anterior mitral leaflet (77.5%), of both mitral leaflets (18.4%) and anomalous chordae (4.1%); in 5 patients the obstruction was located at a more distal level. Mitral regurgitation was observed in 43 patients; in 37 of them the jet was posteriorly directed in late systole. Patients with hypertrophic cardiomyopathy have longer mitral leaflets with frequent associated abnormalities suggesting that this disease is not confined to myocardium and that leaflet length is not the sole determinant of the obstruction; 2) in almost 80% of patients the systolic anterior motion was produced by the distal anterior mitral leaflet resulting in incomplete coaptation in mid-systole; 3) the sequence of systolic events was ejection/obstruction/leak.
PURPOSE: To assess the value of routine intraoperative transesophageal echocardiography (TEE) in unselected patients (P) undergoing cardiac surgery. DESIGN: Routine intraoperative TEE in unselected patients undergoing cardiac surgery and evaluation of its usefulness and contribute to a successful surgery. PATIENTS: In-hospital patients from cardiology, cardiac surgery and intensive care departments of a general hospital classified as a reference medical centre in cardiovascular pathology. MATERIAL AND METHODS: From February 1994 to May 1994 an intraoperative TEE was routinely performed in patients undergoing cardiac surgery. A total of 130 TEE studies were made corresponding to 128 patients, 69 males and 61 females, with a mean age of 49.4 +/- 12.1 years. Indications for surgery were as following: a) Coronary artery bypass grafting (C.A.B.G.)-39; b) Valvular surgery-76; c) C.A.B.G. and valvular surgery-5; d) Thoracic aorta pathology associated or not to aortic valve surgery and/or coronary arteries re-implantation-6; e) Other-4. TEE performed using either a monoplane, biplane or multiplane probe and the images acquisition was made before thoracotomy and cardiopulmonary bypass (CPB) and after CPB with hemodynamic stabilization. RESULTS: Pre CPB imaging yielded unsuspected findings in 11 P (8.5%) that changed the planned surgery in 7 cases (5.4%). Post CPB echo study, which was performed after hemodynamic stabilization, modified the surgical strategy in 13 cases (10.9%) avoiding 1 predetermined surgical procedure (tricuspid ring annuloplasty) and a new surgery in another case, leading to a 3 non-predetermined surgical procedures (by showing significative tricuspid regurgitation), to a further surgery in the same valve in 6 patients (mitral paravalvular leak with significative regurgitation in 1P, another mitral prosthesis dysfunction in 1P, residual mitral valve insufficiency after mitral valve repair in 3 P and aortic prosthesis dysfunction in 1 P), to a intraaortic counterpulsation balloon device in 1 P and to new CPB due to an insufficient extraction of calcified pericardium in one case of constrictive pericarditis. In 23 cases (17.7%) TEE has modified the anesthetic procedure by demonstrating signs of hemodynamic changes before Swan-Ganz catheter, thus prompting changes in the administrations of fluids and either in inotropic or vasodilator agents. In total, intraoperative TEE has changed the surgical and/or anesthetic plan in 43 cases (33.0%). There was no difficulties or complications related to the procedure. CONCLUSION: These data indicate that intraoperative TEE is useful in formulating the surgical plan and assessing immediate operative results as well as a guide to anesthetic procedures. Its high rentabillity in modifying the surgical and/or anesthetic plans lead us to believe that it must be used as a routine procedure in patients undergoing cardiac surgery.
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INTRODUCTION AND OBJECTIVES: Automated edge detection of endocardial borders is a new echo system that permits on-line delineation and tracking of blood-tissue interface and offers promise for measuring cyclic changes in cavity area and the assessment of left ventricular function on-line. Its accuracy has only been analyzed by linear regression and its applicability in unselected patients is not clearly established. METHODS: We analyzed the accuracy and clinical applicability of the system in 150 patients. Its accuracy was assessed not only by linear regression but also by bias analysis by comparing the results of the system with those obtained by manual tracing from parasternal short-axis and apical 4 chamber views. RESULTS: We obtained satisfactory studies with this system in at least one of the two echo views in 66% of patients: 47% from 4-chambers view, 43% from parasternal short-axis view and 24.6% from both echo views. A visual semiquantitative assessment of left ventricular function could be performed in 88.6% of patients (p < 0.001). On-line and hand-traced left ventricular areas there well correlated, but fractional area change values from both methods correlated less closely. 95% limits of agreement between both methods were: 2.8 +/- 5.5 cm2 (end-diastolic area), 1 +/- 4.4 cm2 (end-systolic area) and 1.2 +/- 23% (fractional area change) in short-axis parasternal view; in apical 4-chambers view these limits were: 1.16 +/- 6.4 cm2,--1.1 +/- 6 cm2 and 7.3 +/- 16%, respectively. CONCLUSIONS: Although the correlations between left ventricular areas from both methods were close the limits of agreement exceeded our acceptable range of reproducibility. Fractional area change showed only moderate correlations and a lack of agreement with off-line method. Poor image quality of the conventional echo still limits the clinical applicability of the current automated edge detection system.
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BACKGROUND AND OBJECTIVES: It's well known the utility of transesophageal echocardiography in the evaluation of cardiological patients that are critically ill. However, there is less experience about this usefulness in non-cardiological critically ill patients. METHODS: To assess the utility and safety of the method we analyzed 51 correlative studies of patients admitted to our general Intensive Care Unit. Forty-seven patients (92%) were on mechanical ventilation and in 24 patients (47%) continuous assessment of the hemodynamic variables were available. RESULTS: The most frequent diagnoses on admission were sepsis (23.5%) and shock status (17.6%). The indications were: suspicion of endocarditis (15 patients), hemodynamic instability (11 cases), cardiac source of embolus (10), suspicion of cardiac tamponade (4), suspicion of aortic dissection (4) and other causes in 7. The study confirmed the clinical suspicion in 31 cases (60.8%), excluded it in 15 (29.4%) and established a new, non-suspected, diagnosis in 5 patients (9.8%). There were major diagnostic changes in 16 patients (31.6%) and minor changes in 17 (33.3%) comparing the results of the transesophageal and transthoracic approaches. It was also assessed the influence of the result on the clinical management of the patient: in 32 cases (62.8%) there were a significant change in the treatment; in 5 patients (9.8%) cardiac surgery was prompted by echocardiography. Only in 3 patients hypertensive reactions and tachycardia were detected, without posterior consequences. CONCLUSIONS: Transesophageal echocardiography can be safely performed and has a definite role in the diagnosis (showing sometimes non-suspected abnormalities) and management of non-cardiological critically ill patients.
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INTRODUCTION AND OBJECTIVES: We analyse the applicability and accuracy of the various Doppler methods for quantification of mitral stenosis as well as the value of combining measurements. PATIENTS AND METHODS: The study comprised 74 patients with reliable planimetry of mitral orifice. The following Doppler methods were tested: a) pressure half-time; b) color jet width at the mitral valve orifice in the apical long-axis view (short diameter) and its width in the 90 degree rotated view (long diameter), assuming an elliptic mitral orifice; c) proximal isovelocity surface area from the 4-chamber view assuming a hemispheric surface, and d) the continuity equation. The mean value of mitral valve area estimates from all applicable Doppler methods was calculated in each patient. RESULTS: The rates of applicability of each method were, respectively: 85, 97, 97 and 53% (p < 0.01). The correlations--r (SEE)--between each method and planimetry were: 0.86 (0.17 cm2), 0.81 (0.19 cm2), 0.74 (0.21 cm2) and 0.83 (0.18 cm2), respectively. The highest correlation was found with the mean value (r = 0.90; SEE = 0.14 cm2), and only this parameter was selected by stepwise multiple regression analysis (r = 0.93; SEE = 0.12 cm2). CONCLUSIONS: The continuity equation method has the lowest level of obtainable results owing to the high incidence of mitral regurgitation. The mean value of mitral area estimates from all applicable methods in each patient showed the closest correlation with planimetry, thus the performance of these Doppler methods provides improved accuracy in the quantification of mitral stenosis.
The initial experience from electrophysiological studies showed that pacing induced termination of ventricular tachycardias is usually possible but requires a critical pacing sequence. Studies on the resetting phenomenon showed, in most instances of failure of termination, that the "limiting factor" to produce ventricular tachycardia termination is usually failure to produce block within the circuit rather than failure to access or interact with the ventricular tachycardia origin. The resetting response is related to tachycardia termination in a number of ways. Of note is that a steeply increasing resetting pattern usually predicts tachycardia termination. Between 50% and 90% of induced ventricular tachycardias will be terminated by trains of rapid ventricular pacing. The analysis of the pacing rate necessary for termination shows that it varies widely. Paced cycle lengths of < 80% of tachycardia cycle length are necessary in at least 20% of tachycardias. In contrast, the incidence of acceleration is closely related to the paced cycle length: it is negligible with paced cycle lengths over 80% of tachycardia cycle length and increases to 36% with paced cycle lengths below 76% of tachycardia cycle length. Present information about efficacy of antitachycardia pacing in spontaneous tachycardias suggests that it is extremely effective, with over 90% success. However, it is likely that these data correspond to a selected group of tachycardias.
Proximal coronary artery anatomy and coronary blood flow was evaluated by transesophageal echocardiography in 41 consecutive patients without coronary artery disease. The left main coronary artery was visualized in 37 patients (90%), the left anterior descending coronary artery in 20 (48%), the left circumflex artery in 16 (39%) and the right coronary artery in 7 (17%). The image quality was optimal in 58% of patients in left main coronary artery, 29% in left anterior descending coronary artery, 24% in left circumflex artery and 5% in right coronary artery. Transesophageal Pulsed Doppler echocardiography evaluation of blood flow velocity in the left coronary artery was obtained in 37% of patients. Velocity flow pattern was biphasic with greater diastolic component and smaller systolic one (average peak flow velocity of 47.5 +/- 16.6 cm/seg during diastole and 23.1 +/- 9.5 cm/seg during systole). Coronary blood flow was detected by transesophageal color Doppler echocardiography in 51% of patients in left main coronary artery, 24% in left anterior descending coronary artery, 19% in left circumflex artery and 2% in right coronary artery. We conclude that transesophageal echocardiography provides better and more accurate visualization of proximal coronary arteries than transthoracic echocardiography, but technical limitations still remain to detect and evaluate coronary artery anatomy and coronary blood flow in a large number of patients.
This study was performed to test the usefulness of transesophageal echocardiography in the diagnosis and assessment of pathological mitral regurgitation in patients with mitral valve prostheses. Doppler color flow imaging by transesophageal echocardiography was compared to the transthoracic echocardiography and angiographic and surgical assessment. We analyzed the influence of the spatial configuration of the jet on the semiquantitative assessment of mitral regurgitation. We studied 71 patients with prostheses in mitral position which were submitted for transesophageal echocardiography examination. 51 of these patients were found to have a pathological prosthetic regurgitation that was confirmed in 21 cases by left ventriculography and in 4 during cardiac surgery. Transesophageal echocardiography Doppler color flow imaging identified a regurgitant jet in 31 patients (60.7%). There was complete agreement with the quantitative assessment of regurgitation by angiography or surgery in 36% of the cases. All patients with prosthetic insufficiency observed by angiography or during cardiac surgery were confirmed by transesophageal echocardiography. Complete agreement in grade of severity by transthoracic echocardiography was found in 84% of cases. There was a difference in grade of severity of mitral regurgitation in only 4 patients. Regurgitant jets were classified by transesophageal echocardiography color Doppler in two groups: free jets and impinging wall jets. 21 cases presented a free jet and 31 excentrically directed impinging wall jet of mitral regurgitation. There was complete agreement with hemodynamic assessment of severity in all patients with regurgitant free jets (11/11). In presence of jet wall there was understimation of mitral regurgitation in 28.5% (4/13).(ABSTRACT TRUNCATED AT 250 WORDS)
The quantification of mitral stenosis by pressure half-time method may be difficult in sinus rhythm with short deceleration slopes. To evaluate the usefulness of carotid sinus massage (CSM) for measuring mitral valve area by pressure half-time, 80 consecutive patients with mitral stenosis in sinus rhythm underwent a echo-Doppler study at basal heart rate and during right CSM. In both situations we measured: heart rate, mitral area by pressure half-time and E-F interval (time from E peak velocity to onset of atrial contraction). In 38 consecutive patients we also determined the mitral area by planimetry. The study group was divided into patients with basal E-F interval < or = 150 ms and a HR > or = 75 bpm (group A, 28 patients [35%]) and those with a basal E-F interval > 150 ms who showed a heart rate < 75 bpm (group B, 52 patients). In the group A, the values obtained at basal heart rate vs after CSM were: heart rate, 86 +/- 9 vs 61.6 +/- 10.5 lpm; E-F interval, 109 +/- 33 vs 372 +/- 136 ms; mitral area, 1.88 +/- 0.5 vs 1.23 +/- 0.29 cm2 (p < 0.001). In the group B, these values were: 69.7 +/- 6.6 vs 53 +/- 11 bpm, 253 +/- 60 vs 510 +/- 212 ms y 1.34 +/- 0.3 vs 1.18 +/- 0.32 cm2, respectively (p < 0.01). Mean differences in Doppler mitral areas between both situations for groups A and B were: 0.63 +/- 0.3 cm2 and 0.17 +/- 0.1 cm2, respectively (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Thirty-three patients (24 with typical and 9 with atypical flutter-wave morphology) were studied to evaluate the incidence and implications of resetting and entrainment of atrial flutter with right atrial stimulation. Resetting with single extrastimulus was present in 23 cases (group A) and absent in 10 (group B). Most cases of reset flutter were typical (20 of 23). Fixed fusion indicative of entrainment was observed in all 29 cases with pacing trains. Groups A and B did not differ significantly in flutter cycle length (230 +/- 20 vs 223 +/- 19 ms), atrial functional refractory period (165 +/- 18 vs 167 +/- 22 ms) or longest paced cycle length producing entrainment (213 +/- 19 vs 210 +/- 19 ms). In contrast, the return cycle after the longest paced cycle length producing entrainment was significantly shorter in group A (228 +/- 27 vs 284 +/- 56 ms; p = 0.001). The return cycle in group A was virtually identical to the flutter cycle length, whereas in group B it was greater (p = 0.002 compared with group A). Resetting was more frequent in typical than atypical flutter (20 of 24 vs 3 of 9; p = 0.01). Both typical and atypical flutter can be transiently entrained by right atrial pacing. Lack of resetting and longer return cycle, suggesting a longer conduction time between the reentrant circuit and the stimulation site, were mostly observed in atypical flutter. The data suggest a different location for both types of flutter, and may have implications for ablation techniques. A more cautious approach, with more extensive mapping, appears appropriate for ablation attempts of atypical flutter.
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The characteristics and clinical implications of left atrial appendage (LAA) flow have not been clearly analyzed. Thirty-nine consecutive patients underwent a transesophageal echocardiographic (TEE) color Doppler study to correlate the LAA pulsed Doppler flow pattern with echocardiographic variables and the cardiac rhythm of each patient. Three different LAA flow patterns were identified. Type I flow, characterized by a biphasic pattern (waves of filling and emptying), was found in 17 patients, all in sinus rhythm; it was not associated with LAA spontaneous contrast or thrombus. Mean peak velocities of the filling and emptying waves were, respectively: 28 +/- 12 cm/sec and 31 +/- 9 cm/sec. Type II sawtooth active flow (eight patients) (mean peak velocity: 49 +/- 12 cm/sec) was only detected in atrial fibrillation (AF) and dilated LAA (LAA area: 421 +/- 40 mm2) but without thrombus or significant LAA spontaneous echocardiographic contrast. Type III flow pattern was noted in 14 patients with AF and a very dilated LAA (LAA area: 619 +/- 96 mm2). This flow pattern was characterized by the absence of identifiable flow waves and was associated with the presence of LAA spontaneous contrast; the majority (six of seven) had evidence of thrombus. We concluded that the LAA is a dynamic structure in which TEE study identified three flow patterns with different implications. AF is associated with two LAA flow types (II and III) with a larger LAA size as well as a higher incidence of LAA clots in type III flow.