Complicaciones mecánicas en el infarto agudo de miocardio. ¿Cuáles son, cuál es su tratamiento y qué papel tiene el intervencionismo percutáneo? / Mechanical complications of acute myocardial infarction. what are they? how are they treated and the role of percutaneous intervention?

Las complicaciones mecánicas son unos de los más indeseables contratiempos que pueden aparecer en el infarto agudo de miocardio (IAM) y, a pesar de su baja incidencia (en gran parte gracias a la aparición de tratamientos de revascularización precoz eficaces como la angioplastia primaria), la gravedad que confieren necesita un rápido y acertado diagnóstico y un tratamiento precoz. Las tres clases principales de complicaciones mecánicas son las comunicaciones interventriculares tras el IAM, la rotura libre de pared de ventrículo izquierdo y la insuficiencia mitral aguda severa secundaria a rotura de músculo papilar. Su aparición suele ser precoz, dentro de las primeras 48 h desde el inicio de los síntomas del infarto y, generalmente, se asocia a enfermedad coronaria oclusiva en ausencia de colaterales. Su pronóstico es malo, con mortalidades de más del 50% y el tratamiento de elección es la cirugía, a pesar de que en determinados casos, como la comunicación interventricular, se están desarrollando técnicas percutáneas con resultados prometedores (AU)

Mechanical complications are among the worst phenomena that can occur with acute myocardial infarction. Although they are not common (thanks largely to the introduction of effective early reperfusion therapy such as primary angioplasty), their seriousness means that they have to be quickly and accurately diagnosed and treated as soon as possible. The three main forms of mechanical complication are post-infarct ventricular septal rupture, rupture of the left ventricular free wall, and acute severe mitral regurgitation secondary to rupture of the papillary muscle. They usually appear early within the first 48 hours after symptom onset and are generally associated with occlusive coronary artery disease in the absence of collaterals. The prognosis is poor, mortality is greater than 50%, and surgery is the treatment of choice. However, a number of percutaneous techniques have been developed that show promising results in some cases, such as ventricular septal rupture (AU)

Signo de Brockembrough-Braunwald-Morrow / Brockembrough-Braunwald-Morrow sign

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Dispersión del intervalo QT y variabilidad de la frecuencia cardíaca postinfarto. evolución temporal y relaciones con la función ventricular izquierda / QT interval dispersion and heart rate variability following myicardial infarction. Time course and relations with the left ventricular function

Introducción y objetivos. Se investigaron los cambios precoces en la dispersión del intervalo QT y variabilidad de la frecuencia cardíaca en un grupo de pacientes consecutivos hospitalizados por infarto de miocardio de cara anterior, así como el curso evolutivo de estos indicadores pronósticos durante un período de 6 meses y la relación entre estas variables y los parámetros de función ventricular izquierda. Métodos. Se estudiaron 42 pacientes consecutivos ingresados por infarto de miocardio de cara anterior con onda Q. Se llevaron a cabo en la primera semana y a los 6 meses postinfarto un análisis de la variabilidad de la frecuencia cardíaca (Holter de 24 horas) empleando el método de la demodulación compleja, una medida de la dispersión del intervalo QT en el electrocardiograma (ECG) estándar de 12 derivaciones (QT máximo - QT mínimo) y se obtuvieron los parámetros de función ventricular izquierda a partir de la ventriculografía de contraste y la extensión de la disfunción regional ventricular izquierda. Resultados. La dispersión del QT disminuyó significativamente entre la primera semana (0,07s [0,050,08]) y los 6 meses (0,06s [0,04-0,08], p =0,029); la extensión de la anormalidad de la motilidad parietal mostró una tendencia similar (desde 51 por ciento [27-56] hasta 33 por ciento [11-46], p<0,00001). En cambio, la desviación estándar de los ciclos RR aumenta entre la 1ª semana (31 ms [22-44]) y los 6 meses (43 ms [32-58], p< 0,00001). Sin embargo, la fracción de eyección ventricular izquierda, volumen telediastólico, y volumen telesistólico (46 ml/m2 [31-67] no mostraron cambios significativos en este período de tiempo. En la 1ª semana, la desviación estándar (r = 0,46, p< 0,01) y el ciclo RR medio (r = 0,59, p < 0,0001) se relacionaron con la fracción de eyección, Sin embargo, la dispersión de QT no se correlacionó con la variabilidad de la frecuencia cardíaca o los parámetros de función ventricular en la primera semana o a los 6 meses de evolución. No existieron diferencias en los parámetros autonómicos o hemodinámicos entre los pacientes que presentaron unos valores de dispersión del QT < 0,08 (n=15) o 0,08 ( n=16) segundos. Conclusiones. a) La dispersión del QT disminuye y la variabilidad de la frecuencia cardíaca aumenta en los primeros meses postinfarto; b) la disminución de la variabilidad de la frecuencia cardíaca tiende a ser mayor cuanto mayor es el deterioro de la función ventricular secundario al infarto; y c) no se han encontrado relaciones entre la dispersión del QT y las características clínicas, variabilidad de la frecuencia cardíaca o parámetros de función ventricular izquierda en la primera semana o a los 6 meses postinfarto (AU)

[The prognostic factors after an acute myocardial infarct treated with fibrinolytics]. / Factores pronósticos tras el infarto agudo de miocardio tratado con fibrinolíticos.

BACKGROUND: The usefulness of the exercise test in evaluating patients with an acute myocardial infarction treated with fibrinolytics is controversial. On the other hand, the prognostic value of a patent infarct-related artery has not been clearly established. The objectives of this study were to assess the validity of the exercise test and to study the prognostic value of the artery patency after a myocardial infarction. MATERIAL AND METHODS: We studied 99 patients with a myocardial infarction treated with fibrinolytics, non-complicated. An exercise test and a cardiac catheterization were performed in the first month. The patients were followed-up for 2 years, recording the major cardiac events (death and reinfarction) and the minor events (angina class (II, left cardiac failure class (II or maintained ventricular tachycardia). RESULTS: On multivariate analysis with Cox regression, a workload < 4 METS at the exercise test was the only independent prognostic factor of major events (RR 5.6; CI 95% 1.68-19). The independent prognostic factors of minor events were: multivessel disease (RR 3.36; CI 95% 1.56-7.24), anterior infarction (RR 3.15; CI 95% 1.3-7.6), abnormal exercise test (RR 2.98; CI 95% 1.46-6.09) and ejection fraction < or = 40% (RR 2.48; CI 95% 1.07-5.74). The patency of the infarct-related artery was not a predictor of events. CONCLUSIONS: The exercise test is useful in predicting the prognosis in patients treated with fibrinolytics. An occluded infarct-related artery was not an independent predictor of cardiac events in 2 years of follow-up.

[The single coronary artery arising from the sinus of Valsalva. A rare cause of myocardial ischemia]. / Arteria coronaria única desde seno de Valsalva derecho. Una causa poco frecuente de isquemia miocárdica.

The presence of a congenital anomaly in coronary arteries can be the cause of a defective coronary flow and ischaemic symptoms. Although they are rare, we must suspect them in the presence of major cardiac events in young people. A single coronary artery is present if the entire coronary system arises from a solitary ostium. Its presence is regarded as having little clinical significance and it is usually a fortuitous finding on coronary angiography. We report the case of a patient with effort anginal symptoms, with a single coronary artery arising from the right sinus of Valsalva without obstructive atherosclerotic lesions.

[Evolution of the filling pattern of the left ventricle during the first year after an acute myocardial infarct. The influence of the infarct size]. / Evolución del patrón de llenado del ventrículo izquierdo durante el primer año tras un infarto agudo de miocardio. Influencia del tamaño del infarto.

OBJECTIVES: Acute myocardial infarction induces diastolic dysfunction as a result of the alteration of left ventricular relaxation and stiffness caused by ischemia and fibrosis. This study analyzes the association of infarct size with the diastolic filling pattern and the evolution of the latter during the first postinfarction year. PATIENTS AND METHODS: The study group consisted of 68 patients with a first acute myocardial infarction treated with thrombolytic agents. A Doppler echocardiography was performed at 8 +/- 2, 32 +/- 7 and 370 +/- 23 days after infarction. Five measurements of the ratio between E and A waves peak velocities (E/A ratio) and of the E deceleration time (EDT, ms) were averaged in each echocardiographic study. The patients were divided according to infarct size into a large infarct group (creatine kinase > 1,000 U/ml; 1,913 +/- 883; n = 26) and a small infarct group (creatine kinase < 1,000 U/ml; 556 +/- 227; n = 42). RESULTS: The large infarct group exhibited a greater E/A ratio and shorter EDT than the small infarct group in the first week (E/A ratio: 1.4 +/- 0.7 vs 0.8 +/- 0.3; p = 0.0001; EDT: 159 +/- 49 vs 192 +/- 56; p = 0.02) and at one month (E/A ratio: 1.2 +/- 0.7 vs 0.9 +/- 0.3; p = 0.01; EDT: 170 +/- 55 vs 207 +/- 40; p = 0.004); however no differences were observed between either group at one year in either E/A ratio (0.8 +/- 0.2 vs 0.9 +/- 0.4; NS) or EDT (207 +/- 44 vs 219 +/- 54; NS). In the large infarct group, E/A ratio decreased and EDT increased at one year compared to the first week (E/A ratio: p = 0.0004; EDT: p = 0.0001) and the first month (E/A: p = 0.02; EDT: p = 0.003); in contrast, in the small infarct group there were no significant differences in E/A ratio nor EDT during the first year postinfarction. CONCLUSIONS: In the first month postinfarction, large infarcts exhibit a greater E/A ratio and shorter EDT than small infarcts. The evolution of large infarcts is characterized by an attenuation of this pattern, with a progressive reduction of E/A ratio and prolongation of EDT during the first year post-infarction.

[Determination of ejection fraction and left ventricular fraction using isotopic ventriculography and bidimensional echocardiography. Comparison with contrast ventriculography]. / Determinación de la fracción de eyección y volúmenes del ventrículo izquierdo mediante ventriculografía isotópica y ecocardiografía bidimensional. Comparación con la ventriculografía de contraste.

OBJECTIVES: The aim of this study was to determine the correlation and agreement between the values of left ventricular ejection fraction and volumes assessed by echocardiography and radionuclide ventriculography with the results obtained by contrast angiography, as well as the variability of each method in these measurements. PATIENTS AND METHODS: In a group of 59 patients with a first acute myocardial infarction we have determined left ventricular ejection fraction and volumes by two-dimensional echocardiography, equilibrium radionuclide ventriculography and contrast angiography initially and six months after myocardial infarction. We also assess the variability in the determinations in these three methods. RESULTS: We found significant correlations in ejection fraction and volumes by radionuclide ventriculography and echocardiography with contrast angiography. The correlation was higher in ejection fraction and end-systolic volume by radionuclide ventriculography (r = 0.88 and r = 0.73) than by echocardiography (r = 0.55 and r = 0.63; p < 0.01), whereas the correlation of end-diastolic volume was moderate by both methods (r = 0.58 and r = 0.47), without significant differences. The agreement between contrast angiography and radionuclide ventriculography was higher, with narrower limits of agreement than between contrast angiography and echocardiography in ejection fraction as well as in ventricular volumes. We have found high and significant correlations between two determinations by each method in all parameters, although they were higher in ejection fraction by contrast angiography (r = 0.96) and radionuclide ventriculography (r = 0.98) than by echocardiography (r = 0.70; p < 0.01). The limits of agreement were always wider in echocardiography, narrower in contrast angiography and the narrowest in radionuclide ventriculography, showing its superior reproducibility. CONCLUSIONS: In this group of myocardial infarction patients, the variability in the measurements was lower by radionuclide ventriculography than by echocardiography, this could be the reason for overall better results found in correlation and agreement between radionuclide ventriculography and contrast angiography than between echocardiography and contrast angiography in the assessment of left ventricular ejection fraction and volumes.

[The significance of the elevation of basal and exercise segments on Q-leads after acute myocardial infarct]. / Significado de la elevación basal y al esfuerzo del segmento ST en derivaciones con onda Q tras un infarto agudo de miocardio.

INTRODUCTION: ST segment elevation on Q-leads has been related to a greater infarct size and to the existence of ventricular aneurysm. On the other hand, ST elevation during exercise testing has been related to the presence of myocardial viability. OBJECTIVES: In the present study we investigated the relation between ST segment elevation on infarct-related electrocardiographic leads at rest and during exercise with: a) the extension and severity of the regional dysfunction; b) the presence of myocardial viability (response to dobutamine), and c) the residual stenosis in the culprit artery. MATERIAL AND METHODS: The study group was composed of 51 patients; cardiac cathetherism (8 +/- 3 days) and exercise testing (8 +/- 2 days) were performed during the pre-discharge period. In contrast ventriculography (centerline method) we determined the circumferential extension (rads) and the severity (SD/rad) of the regional dysfunction at rest and after dobutamine (10 micrograms/kg/min). The minimal luminal diameter (MLD) in the culprit artery was also measured. Results are expressed as median [Q1-Q3] and the differences among the groups were assessed by Mann-Whitney U. RESULTS: Patients with ST segment elevation in two or more leads at rest (n = 36) showed a greater (41 [30-51] rads vs 20 [14-41] rads; p = 0.007) and more severe regional dysfunction (1.9 [1.5-2.5] SD/rad vs 0.6 [0.5-2.4] SD/rad; p = 0.01), less response to dobutamine (% of reduction of the dysfunction extension after dobutamine) (17 [0-42]% vs 50 [24-100]%; p = 0.004) and smaller MLD (0.5 [0-0.9] mm vs 0.8 [0.6-1.1] mm; p = 0.03). Likewise, patients with exercise-induced ST segment elevation (n = 28) showed less response to dobutamine (15 [0-45]% vs 40 [21-57]%; p = 0.03) and smaller MLD (0.5 [0-0.7] mm vs 0.9 [0.5-1] mm; p = 0.02). There were non significant differences between patients with and without ST elevation during exercise in the extension or severity of the regional dysfunction. ST segment elevation both at rest (RR 0.2; CI 95% 0.04-0.85) and during exercise (RR 0.19; CI 95%: 0.05-0.69) decreased the probability of improvement with dobutamine. CONCLUSIONS: We conclude that ST segment elevation on Q-leads at rest is related to a more extended and severe dysfunction. Patients with ST segment elevation (at rest or during exercise) show less response to dobutamine (myocardial viability less likely) and a more severe residual coronary stenosis.

[E wave deceleration time predicts left ventricular telediastolic pressure in acute myocardial infarction in patients with systolic dysfunction]. / El tiempo de deceleración de la onda E predice la presión telediastólica del ventrículo izquierdo tras un infarto agudo de miocardio en pacientes con disfunción sistólica.

OBJECTIVES: Left ventricular end-diastolic pressure (LVEDP) is a useful parameter for the management of postinfarction patients. As the current methods of estimating LVEDP are invasive, the existence of non-invasive methods would be of great practical value. This study investigates the relation between LVEDP and Doppler parameters such as E wave deceleration time (EDT) and E/A ratio, at one month following an acute myocardial infarction. METHODS: Eighty-nine patients with a first acute myocardial infarction treated with thrombolytic agents were studied. Doppler-echocardiography at 29 +/- 3 days and cardiac catheterization at 30 +/- 4 days postinfarction were performed. According to the ejection fraction (EF), the patients were divided into group 1 (n = 17) with EF < 45%, and group 2 (n = 72) with EF > 45%. RESULTS: Overall, the E/A ratio showed a weak correlation with LVEDP (r = 0.32; p = 0.007), and EDT did not correlate with LVEDP. When patients from group 2 were analyzed, no correlation was found between LVEDP and either E/A or EDT. However, in patients from group 1, LVEDP strongly correlated with both EDT (r = -0.83; p = 0.00001) and E/A (r = 0.70; p = 0.003). Moreover, the sensitivity and specificity of an EDT of less than 150 ms in predicting a LVEDP > 20 mmHg was 100%. CONCLUSIONS: We conclude that at the first month after a myocardial infarction EDT provides a non-invasive and useful parameter for estimating LVEDP in patients with systolic dysfunction.

[The automatic, beat-to-beat determination of the QT interval and analysis of its spontaneous variability under basal conditions]. / Determinación automática, latido a latido, del intervalo QT y análisis de su variabilidad espontánea en condiciones basales.

OBJECTIVES: An analysis is made of the automatic beat-by-beat measurement of QT and other intervals related to ventricular repolarization. The variability pattern of these intervals is investigated in normal subjects at rest, along with their relation to RR cycle variability. MATERIAL AND METHODS: The electrocardiographic signals (LII) from 11 normal subjects (mean age 31 +/- 10 years) were recorded over 5 min and processed by applying specific algorithms to determine beat-by-beat the RR, QT, RT, QTm and RTm intervals (Tm = peak of T wave). An analysis was made of the variability of these intervals in the time (standard deviation, variation coefficient, difference between maximum and minimum values) and frequency domains (spectral analysis applying the Fourier transform). RESULTS: The differences between the automatic measurements and those performed by two observers (n = 110) were respectively -1.3 +/- 6.4 and -3.7 +/- 6.5 ms for QT, - 1.0 +/- 1.4 and -1.0 +/- 2.3 ms for QTm, -0.3 +/- 1.4 and -0.2 +/- 1.8 ms for RTm, and 0.7 +/- 6.5 and -2.8 +/- 10.3 ms for RT. The QT and RT intervals exhibited greater variability (SD = 6 +/- 1 ms) than QTm and RTm (SD = 3 +/- 1 ms, p < 0.0001). These differences persisted on comparing the corresponding variation coefficients. The differences between the maximum and minimum measurements were 45 +/- 24 ms for QT and RT, the values being significantly less in the case of QTm (21 +/- 26 ms, p < 0.05) and RTm (20 +/- 27 ms, p < 0.05). In the frequency domain, the high- (HF) and low-frequency (LF) band energies were low in the series formed by the ventricular repolarization intervals, and the LF band normalized amplitude was significantly lower than in the RR series. There were no significant differences in the frequencies of the maximum values of the LF and HF bands of the RR series with respect to the QT series. The correlations between the RR intervals and the subsequent repolarization intervals obtained in each subject were not significant in 7 of the 11 subjects studied. CONCLUSIONS: The automatic beat-by-beat determination of the ventricular repolarization intervals is precise, particularly when considering the intervals defined by the T wave peak. Repolarization variability during the sinus rhythm at rest is small, and is not linearly related to modifications of the previous RR interval. Neurovegetative and humoral influences are postulated to explain QT variations. The neurovegetative and humoral influences that regulate cardiac cycle and ventricular repolarization variability at rest, are found to be quantitatively different.

[Effect of the inhalation ++ anesthetic isoflurane on heart electrophysiology]. / Efecto del anestésico inhalatorio isoflurano sobre la electrofisiología cardíaca.

In two groups, A and B, both composed of 10 mongrel dogs, we studied the cardiac electrophysiologic effects of 1 and 1.5 MAC isoflurane administered by liquid injection in a closed circuit. In group B the study was done under pharmacological autonomic blockade (AB). With electrode catheters for programmed pacing and endocavitary potential recordings, we determined during the anesthesia with 1 and 1.5 MAC isoflurane: RR, spontaneous and paced AH, and HV intervals, corrected sinus recovery time (CSRT), Wenckebach point (WP), functional and effective refractory periods of atria (AFRP, AERP) and AV node (AVNFRP, AVNERP), and ventricular effective refractory period (VERP), these were compared to the ones obtained with a previous thiopental control. In group A, 1 MAC isoflurane increased over control: AERP and AH interval (p < 0.05), AFRP (p < 0.005), RR and AH paced intervals, WP, AVNFRP and VERP (p < 0.001), adding to these CSRT (p < 0.01) in 1.5 CAM. This level did not show differences with 1 MAC. In group B, 1 MAC isoflurane increased over control: AH (p < 0.05), RR, paced AH intervals, WP and AVNFRP (p < 0.001), adding to these AFRP and AERP (p < 0.05) in 1.5 MAC. This level increased with regard to 1 MAC: AFRP, AERP, AH paced interval and AVNERP (p < 0.05), and AVNFRP (p < 0.005). Isoflurane alone or with AB increased parameters of sinusal automaticity, atrial refractoriness, AV nodal conduction and refractoriness, increasing only without AB ventricular refractoriness and CSRT. With AB atrial and AV nodal refractoriness increased in an anesthetic depth dependent way.

[Anatomo-functional substrate of high risk arrhythmia after myocardial infarct]. / Sustrato anatomofuncional de las arritmias de alto riesgo tras el infarto de miocardio.

Ventricular arrhythmias detected in the late-hospital phase of myocardial infarction have been identified as a risk factor for sudden death, being their prognostic value independent of ventricular function. However, relations between both factors are not clarified. In order to study hypothetic associations between ventricular arrhythmias and some clinical, hemodynamic and angiographic variables, 60 patients (52 males, 8 females) underwent 24-hour Holter recordings and cardiac catheterization with left ventricular and coronary angiographies, 3-5 weeks after hospital admission. Past history data, acute phase complications and hemodynamic and angiographic results were compared between patients with and without significant ventricular arrhythmias during Holter monitoring (10 or more PVC's/hour and/or repetitive forms). No significant differences were found between both groups neither in mean age nor in the incidence of previous angina or infarction, cerebral ischemia, diabetes, lipid disorders or subjective feeling of being under psychological stress. Prior history of arterial hypertension was, however, significantly more frequent in patients with ventricular arrhythmias (53.3% vs 17.8%; p = 0.0183). No differences were observed in the localization of the infarct or in the complications during the acute phase (CPK peak, Killip's score, angina after 24 hours of evolution, intraventricular or A-V conduction disorders and supraventricular and ventricular arrhythmias). Among hemodynamic data, only left ventricular and aortic systolic pressures were different in both groups, being significantly higher in patients with ventricular arrhythmias. There were not differences in left ventricular segmentary contraction and in number of coronary vessels involved. To conclude, significant ventricular arrhythmias were recorded in 25% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)