Influence of baseline QRS on the left ventricular ejection fraction recovery after frequent premature ventricular complex ablation.

AIMS: Frequent premature ventricular complexes (PVCs) can induce or worsen left ventricular systolic dysfunction. We aimed to investigate the influence of the baseline QRS in the response after PVC ablation in patients with depressed left ventricular ejection fraction (LVEF). METHODS AND RESULTS: Two hundred and fifteen [59 ± 13 years old, 152 (71%) men] consecutive patients with left ventricular (LV) systolic dysfunction and frequent PVCs referred for ablation were included and followed-up for 12 months. Echocardiographic response was defined as an improvement of at least five absolute points in LVEF. Clinical, electrocardiogram, and electrophysiological characteristics were analysed. Mean baseline QRS duration was 110 ms [97-140]. Premature ventricular complex burden significantly decreased after ablation from 23% [16-33] at baseline to 1% [0-8] at 12 months, P < 0.001. Mean PVC burden reduction was 18 [8-30] points. There was a significant improvement of LVEF from 35% [29-40] at baseline to 44% [35-55] at 12 months, P < 0.001. One hundred and thirty (61%) patients were considered as echocardiographic responders. Baseline QRS duration (ms) [odds ratio (OR) 0.98 (0.97-0.99), P = 0.01] was an independent predictor of echocardiographic response. Mean LVEF improvement was 16 [10-21] points when the baseline QRS duration was <90 ms; 12 [4-20] when it was 90-110 ms; 5 [0-15] when it was 110 ± 130 ms; and 0 [0-6] points when it was >130 ms. CONCLUSIONS: In patients with LV systolic dysfunction, intrinsic QRS duration is inversely related to the probability and the degree of echocardiographic response after frequent PVC ablation. Patients with a QRS duration >130 ms at baseline have the poorer response after ablation.

Yield of early rest and stress myocardial perfusion single-photon emission computed tomography and electrocardiographic exercise test in patients with atypical chest pain, nondiagnostic electrocardiogram, and negative biochemical markers in the emergency department.

There are no studies in which diagnostic yield of early rest myocardial perfusion gated single-photon emission computed tomography (SPECT), electrocardiographic exercise testing, and stress SPECT were compared in patients with atypical chest pain, nondiagnostic electrocardiograms (ECGs), and negative markers of myocardial damage in the emergency department. A prospective study of 96 patients who presented with atypical chest pain and nondiagnostic ECG, but without elevated markers of necrosis, was performed. All underwent rest gated SPECT using technetium-99m methoxyisobutyl isonitrile within 6 hours after pain subsided followed by an electrocardiographic exercise test to obtain stress-rest SPECT images. After 1 year, there were no deaths and coronary artery disease was confirmed in only 5 patients. Negative predictive values of the 3 techniques were high (99%, 96%, and 100%, respectively), but positive predictive values were low (27%, 22%, and 14%, respectively). Sensitivities of early SPECT (80%) and stress SPECT (100%) were higher than for the electrocardiographic exercise test (40%). In conclusion, in patients with atypical chest pain, nondiagnostic ECG, and negative biochemical markers, negative predictive values of the 3 tests analyzed are very high. The sensitivity of radionuclide tests is higher, but their widespread use does not appear warranted because their positive predictive value and incidence of complications is low.

[Myocardial perfusion SPECT in right bundle branch block and left anterior hemiblock]. / SPECT de perfusión miocárdica en el bloqueo de rama derecha y en el hemibloqueo anterior.

The aim of this study was to determine the diagnostic accuracy of myocardial perfusion SPECT (single photon emission computed tomography) with technetium labeling in patients with right bundle branch block (RBBB) and with left anterior hemiblock (LAH). One hundred seven patients (53 RBBB, 54 LAH) for whom coronary angiography results were available were selected. The gold standard for diagnosis was based on two coronary angiography criteria: a) stenosis equal to or greater than 50% in at least one coronary artery, and b) completely normal coronary angiography. The sensitivity of SPECT was approximately 90% in both RBBB and LAH. Specificity was 58% and 50%, respectively, for the first criterion, but was 85.7% and 87.5%, respectively, for the second criterion.

[Localization and quantification of myocardium at risk by myocardial perfusion SPECT during coronary artery occlusion]. / Localización y cuantificación del área en riesgo mediante tomografía computarizada por emisión de fotones simples de perfusión miocárdica durante la oclusión arterial coronaria.

INTRODUCTION AND OBJECTIVES: The aim of this study was to analyze the distribution and extent of the myocardium at risk using polar maps obtained with myocardial perfusion SPECT. Myocardial perfusion of territories irrigated by the left anterior descending (LAD), right coronary (RCA) and left circumflex artery (CX) was studied with the help of a technetium-radiolabeled tracer during occlusion of the vessels in the course of percutaneous coronary angioplasty. PATIENTS AND METHOD: We studied 50 patients (24 LAD, 15 RCA and 11 CX). The 99mTc compound was injected immediately after inflation of the balloon, and the artery was occluded for approximately 90 seconds. Tomographic images were acquired, and polar maps showing the extent of the ischemic region (uptake < 50% of maximum) were generated. RESULTS: Mean percentage extent of the ischemic territory was 49.8 +/- 10.3% (minimum 35%, maximum 67%), for the proximal LAD, 39.8 (8.3%) (minimum 20%, maximum 51%) for the mid LAD, 20.3 (7.6%) (minimum 8.3%, maximum 35%) for the RCA, and 21.3 (10.8%) (minimum 10.2%, maximum 30%) for the CX. CONCLUSIONS: The contours and extent of the jeopardized myocardial territory found during coronary occlusion allowed us to generate polar maps that illustrated actual coronary risk. The distribution and extent of the areas at risk differed from those in polar maps generated by most current applications used with myocardial perfusion SPECT.

[Early myocardial perfusion gated-SPECT in patients with chest pain and non-diagnostic ECG in the emergency department]. / Gated-SPECT precoz de perfusión miocárdica en los pacientes con dolor torácico y electrocardiograma no diagnóstico en urgencias.

OBJECTIVE: To analyze the value of early resting myocardial perfusion gated-SPECT in patients with chest pain and non-diagnostic ECG in the emergency department. PATIENTS AND METHOD: 222 patients (49% women, mean age 61 [13] years) with atypical chest pain and with non-diagnostic ECG were randomized into two groups. Group A comprised 111 patients in whom early resting myocardial perfusion gated-SPECT (<6 hours since the end of chest pain) was performed and CK-MB mass and troponin I were determined at 0, 4 and 8 hours. Group B comprised 111 patients with conventional management in the emergency department without gated-SPECT. RESULTS: Myocardial perfusion gated-SPECT was positive in all 8 patients with increased levels of CK-MB mass and troponin I. This corresponded to a sensitivity and a negative predictive value of 100% for the diagnosis of AMI. Specificity was 84% and positive predictive value was 33% when doubtful results were considered as negative. The number of patients admitted (18.4% vs 32.7%, P<.027) and length of stay (13 [6] hours vs 15.9 [8.6] hours, P<.009) in the emergency department were lower in group A. CONCLUSIONS: In patients with atypical chest pain and non-diagnostic ECG in the emergency department, early resting gated-SPECT was highly sensitive and showed good negative predictive value for the diagnosis of AMI, but positive predictive value was low. This technique may reduce the number of hospitalized patients and length of stay in the emergency department.

[Evolution of systolic function and myocardial perfusion, evaluated by gated-SPECT, in the first year after acute myocardial infarction]. / Evolución de la función sistólica y de la perfusión micárdica valorada mediante gated-SPECT durante el primer año despuésde un infarto agudo de miocardio.

INTRODUCTION AND OBJECTIVES: Systolic function and myocardial perfusion are evaluated before hospital discharge and can change during follow-up. The purpose of this study was to evaluate these parameters by gated-SPECT in the first year after acute myocardial infarction. PATIENTS AND METHOD: We studied 74 consecutive patients with a first uncomplicated acute myocardial infarction (49 infero-lateral and 25 anterior) by stress-rest 99mTc-tetrofosmin and rest-gated-SPECT before hospital discharge (6-8 days after admission) and one year after myocardial infarction. RESULTS: The ejection fraction (EF) increased > 5% in 51% of infero-lateral infarcts and 28% of non-revascularized anterior infarcts. EF increased significantly (48.4 8% to 54.6 8.7%; p < 0.0001, mean difference: 6.2; 95% IC, 2.8-9.5) and systolic volume decreased (51.3 19.2 ml to 44.3 19.4 ml; p = 0.001; mean diff.: 7.67; 95% IC, 1.5-13.8) in infero-lateral infarctions. The rest perfusion index in the necrotic region improved (2.3 0.57 to 2.17 0.58; p = 0.004; mean diff.: 0.18; 95% IC, 0.003-0.36) in infero-lateral infarcts and the ischemia index remained unchanged between the first and second studies. CONCLUSIONS: Left ventricular systolic function can change during the first year of evolution, a significant improvement being seen in infero-lateral infarctions. The ejection fraction increased > 5% in half of these patients, as opposed to only a quarter of anterior infarctions. This improvement was associated to increased myocardial perfusion at rest.

Evolución de la función sistólica y de la perfusión miocárdica valoradas mediante gated-SPECT durante el primer año después de un infarto agudo de miocardio / Evolution of systolic function and myocardial perfusion, evaluated by Gated-SPECT, in the first year after acute myocardial infarction

Introducción y objetivos. La función sistólica ventricular izquierda y la perfusión miocárdica pueden experimentar cambios durante el seguimiento y la evolución de un infarto agudo de miocardio. El objetivo de este estudio es su valoración mediante gated-SPECT. Pacientes y método. Se ha estudiado a 74 pacientes consecutivos con un primer infarto agudo de miocardio no complicado (49 inferolaterales y 25 anteriores) mediante 99m Tc-tetrofosmina de esfuerzo-reposo y gatedSPECT de reposo antes del alta hospitalaria y al año de evolución. Resultados. Entre el primer y el segundo estudios, la fracción de eyección aumentó > 5 por ciento en un 51 por ciento de los infartos inferolaterales y en un 28 por ciento de los infartos anteriores no revascularizados. El aumento de la FE (de 48,4 ñ 8 por ciento a 54,6 ñ 8,7 por ciento; p < 0,0001; diferencia media, 6,2; IC del 95 por ciento, 2,8-9,5) y el descenso del volumen sistólico (de 51,3 ñ 19,2 ml a 44,3 ñ 19,4 ml; p = 0,001; diferencia media, 7,67; IC del 95 por ciento, 1,5-13,8) alcanzaron valores estadísticamente significativos en los infartos inferolaterales. Los índices de perfusión en reposo en la región del infarto mejoraron entre los dos estudios en los infartos inferiores (de 2,3 ñ 0,57 a 2,17 ñ 0,58; p = 0,004; diferencia media, 0,18; IC del 95 por ciento, 0,003-0,36), sin cambios en los índices de isquemia. Conclusiones. La función sistólica ventricular izquierda puede cambiar durante el primer año de evolución, mejorando especialmente en los infartos inferolaterales. En la mitad de éstos, pero sólo en una cuarta parte de los anteriores, la fracción de eyección aumentó más de un 5 por ciento entre el primer y el segundo estudios. Esta mejoría se asoció a un incremento de la perfusión miocárdica en reposo (AU)

[Exercise-induced left bundle-branch block in patients with coronary artery disease versus patients with normal coronary arteries]. / El bloqueo de rama izquierda inducido por el ejercicio en pacientes con y sin enfermedad coronaria.

INTRODUCTION AND OBJECTIVES: Exercise-induced left bundle-branch block does not always denote the presence of underlying coronary artery disease. The aim of this study was to analyze the clinical characteristics and evolution of patients with rate-dependent left bundle-branch block. PATIENTS AND METHOD: 9,318 consecutive exercise stress studies were reviewed. The clinical characteristics and evolution (mean follow-up: 6.9 years) of 20 patients with exercise-induced left bundle-branch block in which coronary angiography had been performed were analyzed. RESULTS: Eight out of 20 patients had normal coronary arteries (group A) and 12 had coronary artery disease (group B). Peak O2 consumption, peak myocardial O2 consumption, and heart rate when block appeared (132 20 vs. 95.4 23 beats/min; p = 0.002) were significantly higher in group A. Seven of the 8 patients with normal coronary arteries had chest pain coinciding with the first beat of left bundle-branch block. There were no deaths during follow-up in group A, but permanent left bundle-branch block appeared in 5 patients of this group who experienced disappearance of exercise-related pain. There were 3 deaths in group B and 2 patients had acute myocardial infarction during follow-up. One patient in each group developed atrioventricular block and required pacemaker implantation. CONCLUSIONS: In contrast with patients with left bundle-branch block and coronary artery disease, the prognosis of patients with painful left bundle-branch block and normal coronary arteries is good. However, the development of permanent left bundle-branch block is frequent. Atrioventricular block, although rare, may occur.

El bloqueo de rama izquierda inducido por el ejercicio en pacientes con y sin enfermedad coronaria / Exercise-induced left bundle-branch block in patients with coronary artery disease versus patients with normal coronary arteries

Introducción y objetivos. La aparición de un bloqueo de rama izquierda inducido por el ejercicio no siempre significa presencia de enfermedad coronaria subyacente. El motivo de este estudio fue analizar las características clínicas y evolutivas de los pacientes con bloqueo de rama izquierda dependiente de la frecuencia. Pacientes y método. Se revisaron 9.318 estudios ergométricos de esfuerzo practicados de forma consecutiva y se estudiaron las características clínicas y evolutivas (seguimiento medio: 6,9 años) de los 20 pacientes que presentaron bloqueo de rama izquierda dependiente de frecuencia y en los que se disponía de coronariografía. Resultados. Un total de ocho de los 20 pacientes tenían coronarias normales (grupo A) y 12 tenían enfermedad coronaria (grupo B). El consumo máximo de O2, el consumo miocárdico de O2 y la frecuencia cardíaca en el momento de aparición del bloqueo (132 ñ 20 frente a 95,4 ñ 23 lat/min; p = 0,002) fueron significativamente superiores en el grupo A. Siete de los 8 pacientes del grupo A presentaron dolor precordial coincidiendo con el primer latido en que apareció el bloqueo. No hubo ningún caso de fallecimiento en el grupo A, y en cinco de los 8 pacientes de este grupo se observó evolución a bloqueo de rama izquierda permanente con desaparición del dolor inducido por el esfuerzo. En el grupo B, 3 pacientes fallecieron y dos presentaron un infarto durante el seguimiento. Un paciente de cada grupo evolucionó a bloqueo auriculoventricular completo. Conclusiones. A diferencia de los pacientes con bloqueo de rama izquierda dependiente de frecuencia y enfermedad coronaria, el pronóstico de los pacientes con bloqueo de rama izquierda doloroso y coronarias normales es muy bueno en cuanto a mortalidad, aunque pueden evolucionar a bloqueo de rama izquierda permanente y, excepcionalmente, a bloqueo auriculoventricular (AU)