[The capacity of the rest-dobutamine gated SPECT protocol to predict contractile recovery after revascularization of myocardial dysinergic areas]. / Capacidad del protocolo de gated-SPECT reposo/dobutamina para predecir la recuperación contráctil posrevascularización de áreas miocárdicas disinérgicas.

INTRODUCTION AND AIM: Gated-SPECT is a promising method to analyze myocardial viability. We have assessed the accuracy of a new protocol of rest/Dobutamine gated-SPECT, based on the evaluation of contractile reserve induced by 10 microg/kg/min of Dobutamine, to predict contractile recovery after revascularization of dysinergic myocardial territories. PATIENTS AND METHODS: In a group of 36 patients submitted to percutaneous revascularization, we selected 40 vascular territories (21 left descending artery, 19 right coronary-circumflex) with severely depressed contractility (contrast ventriculography, center line method). Follow up evaluation at 6 months showed the absence of angiographic restenosis and control contrast ventriculography assessed the contractile changes of the selected territories, considering those with contractile restoration as viable. Before revascularization, rest/Dobutamine gated-SPECT study was applied and viability was defined as the presence of contractile reserve (positive or improvement [n = 21] and negative or impairment [n = 7]) with non viability being the absence of contractile reserve (n = 12). We analyzed the evolution of the ejection fraction in a group of 27 patients with impaired ventricular function and complete revascularization. RESULTS: Gated-SPECT showed a sensitivity of 0.96 (95% CI 0.78-0.99) and a specificity of 0.78 (95% CI 0.48-0.94) in the diagnosis of viability. The ejection fraction (median [interquartile range]) increased after revascularization: 0.42 (0.15) vs 0.55 (0.22), Z = -3.9; p < 0. 001. The diagnosis of viability by gated-SPECT (p < 0.001) and the extent of severely depressed myocardium (p = 0.04) independently predicted the increase of the ejection fraction after revascularization. CONCLUSIONS: The analysis of contractile reserve by rest/Dobutamine gated-SPECT is adequate to diagnose viability in territories with severely depressed contractility and independently predicts the increase of ejection fraction after revascularization.

[Validation of the three-dimensional method of sestamibi gated-SPECT in the calculation of the left ventricular ejection fraction in patients with ischemic heart disease. Comparison with contrast ventriculography]. / Validación del modelo tridimensional de gated-SPECT con sestamibi para el cálculo de la fracción de eyección ventricular izquierda en pacientes con cardiopatía isquémica. Comparación con la ventriculografía de contraste.

INTRODUCTION AND OBJECTIVE: Tomography with acquisition synchronized with electrocardiography, gated-tomography, allows the assessment of left ventricular contractile function. The accuracy of a new method of gated-tomography, based on the three dimensional representation of the left ventricle to calculate the ejection fraction was validated by means of comparison with contrast ventriculography. METHODS: We studied 85 patients with ischemic cardiopathy, and ejection fraction was calculated by contrast ventriculography and sestamibi-gated-tomography, at rest and throughout 10 micrograms/kg/min of dobutamine. Furthermore, we assessed the extent of perfusion defect, as well as the number of segments with activity below 50% of the total 13 segments in which the tomographic slices were divided. RESULTS: Gated-tomography was significantly correlated to contrast ventriculography in the calculation of ejection fraction, both with acquisition at rest (r = 0.80) and throughout Dobutamine (r = 0.82). The average underestimation of gated-tomography calculation of ejection fraction was significantly greater for the rest study (-0.12 [IC 95% 0.04, -0.30]) than the dobutamine study (-0.07 [IC 95% 0.09, -0.24]). Patients with greater perfusion defects (4 o more segments) had no differences in underestimation of ejection fraction (-0.13 [IC 95% 0.03, -0.30] versus -0.11 [IC 95% 0.07, -0.29]). CONCLUSIONS: The three-dimensional method of gated-tomography accurately assesses the ejection fraction. The underestimation determined by this method was lower in the study done with viable doses of dobutamine. The extent of perfusion defect had no deleterious effect on gated-tomography in the calculation of ejection fraction.

[Apical hypertrophic cardiomyopathy and coronary arteriovenous fistula]. / Miocardiopatía hipertrófica apical y fístula arteriovenosa coronaria.

We present a case of association of apical hypertrophic cardiomyopathy of the Japanese type and coronary arteriovenous fistula in a 56-year-old male who presented with anginal symptoms. Both cardiopathies can produce myocardial ischemia and angina, and their association could aggravate the ischemia. In our patient the symptoms were adequately controlled with Verapamil. The coexistence of these two rare entities in the same patient has recently been described in 2 other cases, allowing us to speculate on a possible etiological relation between the 2 abnormalities, probably both been originated in a common developmental error.

Intraoperative contrast two-dimensional echocardiography. Evaluation of the presence and severity of aortic and mitral regurgitation during cardiac operations.

We have used contrast two-dimensional echocardiography in the intraoperative evaluation of aortic and mitral regurgitation in 35 patients undergoing cardiac operations. All of them underwent previous cardiac catheterization in order to document the presence and severity of regurgitation. With the pericardium open, a catheter was introduced into the left ventricle (to document mitral regurgitation) or into the ascending aorta (to document aortic regurgitation). The two-dimensional echocardiographic probe was placed on the anterior surface of the right ventricle to obtain a basal image, equivalent to a conventional parasternal longitudinal view. Dextrose in water (5 ml) was rapidly hand-injected through the catheter, while echocardiograms were recorded on videotape. The observation of contrast medium (microbubbles) flowing in the retrograde direction through the incompetent valve was carefully evaluated with the same scoring system used in the hemodynamic laboratory. In 34 cases there was agreement between angiographic and echocardiographic evaluation of the presence and severity of mitral and aortic regurgitation. Only one case was evaluated as mild aortic regurgitation by angiography and moderate aortic regurgitation by echocardiography. There were no false positives or false negatives in the study. In view of the high degree of correlation between contrast two-dimensional echocardiography and hemodynamic data, we suggest that our method is an important tool for the cardiac surgeon. In addition, the present approach overcame the disadvantages of the conventional intraoperative methods, most of which are performed in a nonbeating or fibrillating heart.

Contrast bidimensional echocardiography in the morphologic and functional postoperative evaluation of the Senning technique for complete transposition of the great vessels.

Contrast bidimensional echocardiographic (2DE) studies were performed in eight patients with d-transposition of the great vessels in the postoperative period of the Senning technique. Contrast was injected into a peripheral vein of all patients, and into the arterial atrium in five in the postoperative period. The 2DE projections used were the four-chamber apical view and four-chamber subcostal view. In all patients it was possible to see and identify the new atrial cavities which greatly resembled the actual anatomy. Early postoperative alternating injections of contrast in both new atria not only achieved the main purpose of delineating the real anatomy, but also permitted more definitive identification of residual shunts.

Surgical treatment of primary malignant fibrous histiocytoma of the left atrium.

A 30-year-old patient was operated on as an emergency because of a left atrial tumor. Microscopic and electron microscopic examination of the tumor revealed it to be a myxoid variant of a malignant fibrous histiocytoma. The tumor subsequently recurred, and the recurrence was recognized by echocardiography. The patient died 21 months after initial operation.

Left ventricular function during haemofiltration and haemodialysis: a comparative study.

The relationship between systemic haemodynamics and left ventricular performance during HF and HD was evaluated by M-mode echocardiography. In patients with normal cardiac function and similar rates of fluid removal, special attention was paid to the effects of solute transport and buffer. Convective transport, independent of the replacement buffer, produces an increase in systemic vascular resistance with no changes in ventricular function. In contrast, a diffusive transport induces different effects depending on the dialysate buffer: acetate decreases vascular resistance and bicarbonate significantly improves myocardial contractility shifting the cardiac function curve to the left.

The ascending slope of the apexcardiogram. Its relationship with angiographic determination of left ventricular function.

The relationship between the ascending slope of the apexcardiogram (ACG) and direct determination of left ventricular (LV) performance as assessed angiographically by measurement of the ejection fraction (EF), mean velocity of circumferential fiber shortening (mVcF), mean normalized systolic ejection rate (MNSER), and percentage of the systolic shortening of ventricular long axis (%L), were studied in 40 patients with a wide variety of cardiac diseases. The ascending slope correlated closely and significantly (P less than 0.05) with all of them: (1) EF (r = 0.774), (2) mVcF (r = 0.776), (3) MNSER (r = 0.767) and (4) %L (r = 0.668). In a control group of 10 normal subjects, phi was determined and compared with that obtained in patients with depressed LV function, the difference being statistically significant (P less than 0.01). Other noninvasive indices derived from simultaneous phono-mechano-cardiographic readings were also studied. The calibrated ACG did not correlate with any of the hemodynamic indices; however the calibrated carotidogram did correlate with the peak systolic aortic pressure (r = 0.503). The ratio preejection period/left ventricular ejection time correlated significantly, but less than previously reported with the EF (r = 0.574). We conclude that the value of phi leads to additional evidence supporting the use of quantitative ACG as a noninvasive measure of LV performance in patients with cardiac disease.

Anterograde and retrograde bradycardiac block in the His-Purkinje system. Finding in a patient with acute myocardial infarction.

A patient with an acute inferior myocardial infarction developed a complete atrioventricular block and intermitent periods of atrioventricular conduction with QRS complexes showing right bundle branch block associated with left anterior hemiblock. Recordings of the His bundle electrogram showed that the atrioventricular block was infrahisian and that in periods of resumed atrioventricular conduction, the His-ventricle (H-V) interval was long. Ventricular escape beats showed concealed conduction to the atrioventricular node. Anterograde atrioventricular conduction was always resumed through the left posterior division when the preceding division when the preceding intervals between ventricular escape beats and the atrium (V-A intervals) were shorter than 580 msec. The same phenomenon occurred with right ventricular pacing. A retrograde His potential could be observed. Retrograde conduction of ventricular escape beats and ventricular paced beats was blocked if the H-V interval and the interval between the His bundle and the ventricular paced beat (H-V interval) were long (more than 600 msec and 550 msec, respectively). The existence of an intermittent anterograde and retrograde bradycardiac infrahisian block was inferred from the previously mentioned data; a fixed retrograde atrial nodal block was also present.