Bystander coronary sinus diverticulum and left anterolateral accessory pathway.

Left posteroseptal accessory pathways have been described inside coronary sinus diverticula. We here describe the case of a patient who was suffering from recurrent episodes of paroxysmal supraventricular tachycardia and had a concealed accessory pathway located in the left anterolateral margin of the mitral annulus and a left posterior coronary sinus diverticulum associated with an aneurysmal coronary sinus vein. In the electrophysiological study, an orthodromic supraventricular tachycardia was induced and reproduced. We performed a successful radiofrequency ablation of the pathway. Our case provides evidence of the coexistence of concealed accessory pathways capable of sustaining orthodromic tachycardia coexisting with a bystander posterior coronary sinus diverticulum and aneurysmal coronary sinus vein.

Left ventricular function and autonomic nervous system balance during two different stages of the menstrual cycle.

We studied the left ventricular function and cardiac autonomic nervous system balance variations during two different stages of the menstrual cycle. These two variables, as well as plasmatic estradiol and progesterone concentrations, were measured in a drug-free state in 20 women (29+/-6 year-old) with regular menstrual periods. A clinical evaluation, an echo-Doppler and a Valsalva manoeuvre were performed in all the patients on the third day of their menstrual cycle (follicular phase) and three days prior to their next menstrual cycle (luteinizing phase). When comparing the results obtained in these two phases, a statistically significant increase was put forward in plasmatic estradiol (50.6+/-24 vs. 127.3+/-52.8 pg/ml) and progesterone (0.37+/-0.42 vs. 11.92+/-10.8 ng/ml) concentrations, Valsalva index (1.55+/-0.22 vs. 1.67+/-0.33; P=0.044) and E/A mitral wave ratio (1.63+/-0.36 vs. 1.75+/-0.35, P=0.02). The right and left atrial volumes, left ventricular volumes and ejection fraction were similar in the two menstrual phases studied. We conclude that the autonomic nervous system balance and the left ventricular diastolic function suffer significant changes during the luteinizing phase of the menstrual cycle in normal women.

Cardiac arrhythmias during two different stages of the menstrual cycle.

We have frequently observed that female patients report an association between their arrhythmias and their menstrual period but little is known about such an association. We studied 25 female patients 25.9+/-7.3 year-old with regular menstrual periods. Thirteen patients were evaluated because they suffered from cardiac symptoms and complained of arrhythmia aggravation during their menstrual period. Twelve normal female patients formed the control group. The evaluation was performed in a drug-free state. All the patients had a 24-h Holter study performed during the 7th day of their menstrual cycle and 3 days before the following menstrual period. No patient had sustained arrhythmia during the monitoring periods. When comparing the two Holter recordings we did not find statistically significant differences with respect to either the total count of supraventricular and ventricular premature beats or the heart rate.

QT-interval dispersion in malnourished children.

BACKGROUND: Little is known about the electrocardiographic (ECG) QT interval and its variability in malnourished children. HYPOTHESIS: The study of the QT interval and its dispersion in malnourished children was undertaken to determine whether the QT interval and its variability are increased in these children. METHODS: In 40 children (20 malnourished and 20 controls) aged 12.2 +/- 14.4 months (23 male) a conventional ECG was performed for computing heart rate, heart rate variability, corrected QT interval, and QT-interval dispersion. A blood sample was obtained for measuring hemoglobin, hematocrit, plasma protein, and plasma electrolytic concentrations. RESULTS: Corrected heart rate, heart rate variability, and QT Interval were similar in both groups. When compared with the control group, the malnourished children had greater corrected QT-interval dispersion, and that dispersion was more accentuated in the precordial leads. They also had repolarization abnormalities (flattened or inverted T waves and U waves). Hemoglobin, hematocrit, plasma protein, and plasma electrolytic concentrations were lower in the malnourished children. However, the ECG findings showed no statistically significant relationship with either the blood parameters, the severity or type of malnutrition, and the size or the weight of the children. CONCLUSIONS: QT-interval dispersion is increased in malnourished children and the dispersion is more accentuated in the precordial leads.

PIP: This study aims to determine electrocardiogram (ECG) QT-interval dispersion and its variability in malnourished children of Venezuela. The sample population consisted of 40 children (20 malnourished and 20 well nourished). A conventional ECG was performed for computing the heart rate, heart rate variability, corrected QT-interval, and QT-interval dispersion. In addition, blood samples were obtained to measure hemoglobin, hematocrit, plasma protein, and plasma electrolyte concentrations. Findings showed that the corrected heart rate, heart rate variability, and QT-interval were similar in malnourished and well-nourished children. Moreover, malnourished children demonstrated a greater corrected QT-interval dispersion and that dispersion was more accentuated in the precordial leads. They also had repolarization abnormalities (flattened or inverted T waves and U waves). Hemoglobin, hematocrit, plasma protein, and plasma electrolyte concentrations were lower in malnourished children. However, the ECG findings showed no statistical significant relationship with either blood parameters, the severity or type of malnutrition, and the size or the weight of the children.

[Tachycardiomyopathy in patients with and without subacute cardiac pathology. Experiences at the Cardiovascular Center of Merida, Venezuela]. / Taquicardiomiopatía en pacientes con y sin patología cardiaca subyacente. Experiencia en el Centro Cardiovascular de Mérida-Venezuela.

We report our experiences with tachycardia-induced cardiomyopathy. Nine patients (3-56 years old) had incessant supraventricular tachycardia and congestive heart failure. The cardiac eco-Doppler evidenced a significant increase of cardiac volumes and mild tricuspid and mitral regurgitation. The ejection fraction (EF) was 0.31 +/- 0.12, the end diastolic volume was 162 +/- 48 cc and the end systolic volume, 116 +/- 54 cc. Four patients had accessory pathways, 3 atrial flutter, 1 A-V nodal reentrant tachycardia, and 1 ectopic atrial tachycardia. Two patients had Chagasic myocarditis. Only in one chagasic patient a decreased number of tachycardia episodes was achieved, this patient died. The autopsy revealed cerebellar and pulmonary emboli. In the other 8 patients the arrhythmia was well controlled. In these, the ventricular volumes decreased, the EF increased to 0.51 +/- 0.14 (p = 0.00006), and the congestive heart failure remitted. We conclude that incessant tachycardia produces a symptomatic dilated cardiomyopathy in patients with and without structural heart disease. The arrhythmia control is followed by an increase in cardiac function and a remission of heart failure symptoms.

Effects of electroconvulsive therapy on cardiac function in patients without heart disease.

In order to determine whether electroconvulsive therapy (ECT) alters left-ventricular function in patients without heart disease, we studied 11 patients who had a normal cardiovascular system and were submitted to ECT. Left-ventricular function was assessed by means of a clinical examination and an echocardiographic evaluation performed before the ECT and 20 min and 6 h after ECT. Twenty minutes after ECT, the patients' end-systolic volume was increased (p = 0.003), whereas the ejection fraction (p = 0.004) and E to A ratio were decreased (p = 0.004 and 0.028, respectively). These indexes returned to the normal control value 6 h later. None of our patients presented any clinical signs of heart failure. We conclude that in some patients, ECT produces a significant and transient decrease in left-ventricular systolic and diastolic function.

Cardiac arrest following holiday heart syndrome.

We describe the case of a patient who, after a binge, had an episode of ventricular fibrillation (holiday heart syndrome) and was successfully resuscitated. In the electrophysiological study, we found dual atrioventricular nodal pathways, an atrioventricular effective refractory period of 210 ms, and an inducible atrial fibrillation with a ventricular response of 210 bpm that produced hemodynamic collapse. Atrioventricular nodal modification by radiofrequency ablation was successfully performed. The patient stopped drinking alcohol and has remained completely asymptomatic. In this case, ventricular fibrillation was probably caused by the fibrillating atria combined with a fast AV node.

Results of electrophysiologic studies in patients with acute Chagasic myocarditis.

BACKGROUND: As the acute stage of Chagas' myocarditis is rarely detected, little is known about the electrophysiologic characteristics of that stage. HYPOTHESIS: This investigation was undertaken to conduct an electrophysiologic study of the properties of the heart during the acute phase of Chagasic myocarditis. METHODS: We studied eight patients who had positive xenodiagnosis, positive mice culture, and positive complement fixation test for Chagas' disease. RESULTS: Trypanosoma cruzi were identified in all of the patients' stained blood samples. Right ventricular endomyocardial biopsies were obtained, evidencing a distinct infiltrate of lymphocytes that confirmed the diagnosis of acute myocarditis. The cardiac dimensions and the ventricular systolic and diastolic function were preserved in all patients. The electrocardiogram evidenced conduction defects in two patients. The signal-averaged electrocardiogram displayed late potentials in three patients. In the electrophysiologic study, atrial fibrillation or flutter was induced in four patients. When compared with control patients, Chagasic patients were found to have greater values of atrial threshold, A-H interval, and atrioventricular (AV) nodal effective refractory period. The H-V interval was mildly prolonged in two patients, but the dynamic AV nodal conduction was preserved (1:1 conduction during right atrial stimulation at a cycle length of 400 ms) in all the Chagasic patients. The ventricular parameters were within normal limits, and no sustained ventricular arrhythmia could be induced. CONCLUSIONS: Patients with mild acute Chagasic myocarditis may suffer from electrical abnormalities and arrhythmias that are more evident at the supraventricular level and the AV junction.

Relationship between autonomic nervous system test results, ejection fraction and inducibility of sustained ventricular arrhythmias by means of electrophysiological studies.

Autonomic nervous system dysfunction and low left ventricular ejection fraction have been associated with an increased incidence of cardiac arrhythmias and sudden death. This research was conducted to determine whether Valsalva ratio (longest to shortest R-R interval during Valsalva manoeuvre), R-R variability (standard deviation of R-R intervals in a 60-second electrocardiographic recording strip), and corrected QT interval permit the identification of those patients with an inducible sustained ventricular arrhythmia when submitted to electrophysiological studies. We also evaluated the ejection fraction as a predictive index of inducibility. We studied 42 patients (21 males), 38 +/- 19 years old, who were submitted to an electrophysiological study in order to evaluate supraventricular (control group: n = 16) or ventricular arrhythmias (n = 26). The patients studied for the evaluation of ventricular arrhythmias presented structural and functional cardiac damage. Their ejection fraction (0.41 +/- 0.17) was significantly reduced (p = 0.01) when compared to that of the control group (0.61 +/- 0.08). The patients with cardiac damage had abnormal autonomic nervous system test results. None of the measurements was significantly related to the inducibility of sustained ventricular tachyarrhythmias in the group of patients who had structural and functional involvement. The finding of abnormal cardiac autonomic nervous system indices and low ejection fraction can be related to structural heart disease, but neither the abnormal cardiac autonomic nervous system indices nor the low ejection fraction allows us to identify the patients who will develop inducible sustained ventricular tachyarrhythmias when submitted to electrophysiological study.

Heart rate and heart rate variability changes induced by right atrial pacing.

This research was conducted to determine (1) whether heart rate and R-R interval variability are modified by atrial pacing, and (2) whether these changes (if they do occur) are related to the inducibility of tachyarrhythmias during electrophysiological studies. We studied 42 patients who were referred for electrophysiological evaluation of supraventricular (n = 16) or ventricular arrhythmias (n = 26). The patients studied for the evaluation of ventricular arrhythmias had structural and functional cardiac damage. The patients evaluated because of supraventricular arrhythmias had normal ejection fraction and on structural cardiac damage. In these patients a significant decrease in R-R interval (P = 0.0002) and in its standard deviation (P < 0.005) was observed following atrial pacing. No significant heart rate or R-R interval standard deviation change was observed after pacing in the patients with structural heart disease. The heart rate or R-R interval variability changes did not allow us to discriminate the patients with inducible ventricular arrhythmias from those without such arrhythmias. We conclude that right atrial pacing induces a heart rate increase and R-R variability decrease in patients without heart disease. In patients with cardiac damage the responses are blunted, and do not permit the identification of patients who have ventricular arrhythmias inducible by means of electrophysiological studies.

[Sudden death in patients with chagasic myocarditis]. / Muerte súbita en pacientes con miocarditis chagásica.

We review the literature on sudden cardiac death in patients with chagasic myocarditis. Taking into account the published data, we discuss the differences between sudden cardiac death that occur in chagasic patients and that of patients with other cardiac diseases in particular with ischemic heart disease. On the basis of these differences, alternative physiopathological mechanisms are proposed: in chagasic patients, tachyarrhythmias are more frequently mediated by post-potential activity, and thus a larger proportion of brady-asystolic sudden death occurs.

[Relationship between HLA antigens and the HIV infection in patients from the state of Zulia]. / Estudio de la relación entre antígenos HLA y la infección por VIH en pacientes del estado de Zulia.

PURPOSE: Some genetic factors associated to the HLA system phenotypes may allegedly predispose to the development of infection in patients exposed to the human immunodeficiency virus (HIV). So the aim of this study was to assess if certain HLA antigens are positive or negative risk factors in the development of AIDS in Zulia State. PATIENTS AND METHODS: A total of 62 samples were studied, 31 from HIV seropositive subjects and 31 form healthy individuals. The patients were subclassified into four groups in accordance with Atlanta's CDC guidelines. Tests for histocompatibility including HLA-A-B-C, DR and DQ typing were performed with Terasaki's technique. VIH positivity was determined by ELISA and confirmed by Western Blot. The statistical evalub1p4n was performed with the chi 2 test for antigen frequency comparison, the relative risk (RR) was estimated with the Ryder and Svelgaard test, and the inferential analysis was made by means of non-parametric statistics. RESULTS: Most patients were included in CDC's groups II and IV, 48.4% and 29.0%, respectively. Increased B35 and DQw2 and decreased B39 and DR2 antigens were found when comparing the HLA distribution in the sample and the antigenic frequency of the population. RR > 1 was observed in the infected patients A for A1, A3, A10, A11, B5, B7, B12, B14, B35, B61, CW4, DR4, DRW52 and DQW2 HLA antigens. A positive association between symptomatic infected patients and antigen B35 was present (X = 7.045). CONCLUSION: The findings reported here suggest that antigen B35 is a major risk factor for the development of AIDS.

Use of electrophysiological studies in the diagnosis and treatment of cardiac patients with left ventricular dysfunction and high grade ventricular ectopy.

We studied the sudden death occurrence in 28 patients (23 males, age 59.2 +/- 15.6 years) who had a documented cardiac disease with left ventricular dysfunction (ejection fraction < or = 0.4) and high grade ventricular ectopy. None had suffered from spontaneous sustained ventricular arrhythmia and/or syncope. Their diagnosis and treatment were guided by electrophysiological studies. Electrophysiological studies were performed in the antiarrhythmic drug-free state. In cases when sustained ventricular arrhythmias could be induced, antiarrhythmic treatment was prescribed according to the results of the electrophysiological studies. In cases of non-inducibility, no antiarrhythmic treatment was prescribed. The patients were followed up for a period of 20.6 +/- 11.2 months. The end points were occurrence of documented spontaneous sustained ventricular arrhythmia and sudden death. None of the 19 non-inducible patients experienced sudden death or spontaneous sustained ventricular arrhythmia. Two of the nine inducible patients died suddenly (P = 0.1). The 3-year sudden death mortality rate of the whole group was 7.5%. We conclude that when cardiac patients with high grade ventricular ectopy and left ventricular systolic dysfunction are treated according to the results of electrophysiological studies, it can be expected that their 3-year mortality rate will be low and significantly inferior to that reported for conventionally treated patients.

Hemodialysis changes the QRS amplitude in the electrocardiogram.

We studied eight patients to determine whether changes occur in the QRS amplitude when these patients are submitted to hemodialysis. The following variables were assessed before and after each (N = 28) hemodialysis session: (1) plasma sodium and potassium concentrations, (2) QRS amplitude, (3) the heart rate and its variability, (4) ventricular volumes, ventricular mass, ejection fraction and circumferential fiber shortening, (5) arterial pressure and end systolic stress, and (6) body weight. QRS amplitude was computed as the algebraic sum of the positive and negative waves of each QRS complex of the electrocardiogram. QRS amplitude changes were compared to body weight, ventricular volumes, ventricular mass, ejection fraction, circumferential fiber shortening, plasma potassium and sodium concentrations, arterial pressure, end systolic stress, heart rate, and R-R variability. After the hemodialysis sessions we found a significant increase (P = 0.0006) in QRS amplitude and a significant decrease in body weight (P = 0.0001), end diastolic volume (P = 0.043), plasma potassium concentration (P = 0.000001), end systolic stress (P = 0.025) and systolic arterial pressure (P = 0.023). Hemodialysis did not produce significant changes in the other variables. The statistical analyses performed did not show any significant influence of any of the measured variables on the QRS amplitude change. The QRS amplitude increases after hemodialysis but the cause of this increase is still unclear.

Cardiovascular responses to Valsalva maneuver in physically trained and untrained normal subjects.

To elucidate whether the Valsalva maneuver (VM) can distinguish different degrees of normal ventricular function and parasympathetic tone, we studied 10 physically untrained and 18 trained normal individuals who regularly performed isotonic exercises. Both groups were submitted to an exercise stress test. An electrocardiogram and an M-mode echocardiogram were recorded before and during VM. The arterial pressure, heart rate and ventricular function responses to the maneuver were evaluated. The end diastolic volume, ejection fraction, circumferential fiber shortening and left ventricular posterior wall thickness were greater at rest in the trained group than in the untrained one. In both groups, during the straining phase of the VM the volumes and end systolic stress decreased and the systolic function indexes increased, but the changes were more pronounced in the trained subjects. In spite of these differences, the arterial pressure and heart rate responses were similar in both groups. It can thus be concluded that only changes in ventricular function distinguish physically trained vs untrained subjects during VM.

The effects of cardioversion and defibrillation on left ventricular systolic function.

The purpose of this research was to evaluate the left ventricular systolic function behavior after cardioversion and defibrillation. The study included 18 adult patients who had direct current cardioversion or defibrillation performed for conversion of spontaneous or induced arrhythmias. All patients were submitted to a careful medical evaluation and an M-mode echocardiogram before cardioversion or defibrillation. The clinical and echocardiographic evaluations were repeated immediately after, and 6 and 12 h following the countershock. Six hours after cardioversion or defibrillation a statistically significant (p = .04) decrease in contractility (circumferential fiber shortening and ejection fraction) was observed without significant changes in preload (end diastolic volume), heart rate or afterload (end systolic stress and diastolic arterial pressure). Within 12 h, the left ventricular systolic dysfunction disappeared. The impairment of systolic function was independent of the amount of energy used, the type of arrhythmia, the rhythm after cardioversion or defibrillation and the etiologic cardiac diagnoses. There was a significant (p = .03) direct, negative and linear correlation between left ventricular systolic indices (ejection fraction and circumferential fiber shortening) before the countershock and the amount of decrease in systolic function after the countershock. In spite of the fact that most patients had a low ejection fraction, none of them presented clinical signs of heart failure. Defibrillation and cardioversion produce a transient decrease in cardiac contractility which is independent of the amount of energy used and does not produce clinical signs of heart failure.

Vitamin E and ventricular fibrillation threshold in myocardial ischemia.

The effect of vitamin E on the ventricular fibrillation threshold was studied in an experimental model of acute myocardial ischemia. An anterior thoracotomy was performed on 23 anesthetized Wistar rats. The ventricular fibrillation threshold was measured. Vitamin E was then administered intravenously to an experimental group (n = 11) and a placebo to a control group (n = 12). The ventricular fibrillation threshold was measured again. Finally, the left anterior descending coronary artery was occluded, producing anteroapical myocardial ischemia. The ventricular fibrillation threshold was measured again. This threshold did not vary significantly when vitamin E or the placebo was administered before occluding the coronary artery but after the occlusion a threshold decrease in the placebo group was observed, whereas no such decrease was manifested in the vitamin E-treated group. The results suggest that vitamin E prevents ventricular fibrillation in acute myocardial ischemia in rats.

Valsalva maneuver: a test of the functional state of cardiac innervation in Chagasic myocarditis.

The ratio between maximal and minimal R-R intervals measured during the Valsalva maneuver is an adequate means of studying the functional state of the cardiac parasympathetic nervous system. We studied the changes in heart rate evoked during the Valsalva maneuver in 49 asymptomatic Chagasic patients with different degrees of myocardial involvement. The Chagasic patients were divided in three groups. Twelve patients had no evidence of heart disease except for an abnormal myocardial biopsy. Sixteen patients had a normal electrocardiogram but revealed evidence of localized myocardial damage as shown by left ventricular cineangiography. Twenty-one patients had abnormal electrocardiograms and revealed multiple areas of abnormal left ventricular wall motion. The Valsalva ratio (mean +/- standard error) was 1.62 +/- 0.12 for controls, 1.52 +/- 0.10 for those with an abnormal biopsy, 1.48 +/- 0.06 for those with localized myocardial damage, and 1.31 +/- 0.04 for those with an abnormal electrocardiogram. There were no statistically significant differences between the control group (normal sero-negative subjects) and those patients with normal electrocardiograms. Results in those with an abnormal electrocardiogram, however, were statistically different (P less than 0.05) from the other groups. These results are in discordance with the commonly accepted hypothesis that cardiac parasympathetic denervation causes a dilated myocardiopathy in patients with chronic Chagasic myocarditis.