Search

Objective: To assess the role of myocardial contrast echocardiography (MCE) in early identification of myocardial viability in patients with residual segmental dysfunction after myocardial infarction and primary angioplasty (PA), in comparison with dobutamine stress echocardiography (DSE), using late functional recovery as gold standard., Design: Prospective study for comparison of the two methods., Setting: Hospital., Patients: 17 patients (11 male, 53 +/- 11 years old) were consecutively included, with a first myocardial infarction and PA, with residual segmental akinesis or dyskinesis and good echocardiographic window., Methods: All patients underwent: a) baseline echocardiographic study, MCE, and DSE obtained at 4.0 +/- 1.2 days after PA; b) late echocardiographic study performed at 4.4 +/- 0.8 months after PA. MCE was performed with Optison, administered as a slow infusion via a peripheral vein and a modality of real-time perfusion imaging with power pulse inversion and flash and subsequent data acquisition of triggered end-systolic images. Segmental contractility and perfusion were assessed using a 16-segment model. Perfusion assessment was qualitative (three perfusion patterns) and quantitative (ratio of maximal intensity between dysfunctional segments and contralateral normal segments). The viability criterion for MCE was defined as homogenous enhancement in 50% of wall thickness in each segment. The standard criterion for myocardial viability was defined as late functional recovery. 6., Results: Viability was present in 56 (63.6%, Group 1) of dysfunctional segments and was absent in the remaining 32 (36.4%, Group 2). The sensitivity of DSE for viability was 80.0%, while specificity was 86.5%. The positive and negative predictive values were, respectively, 91.8% and 69.6%. MCE yielded a sensitivity of 96.5% and specificity of 78.1%, while positive and negative predictive values were respectively 86.2% and 94.1%. With the two methods together, the positive predictive value was 90.3% and negative was 80.0%. The intensity ratio was higher for viable segments (Group 1) in comparison with non-viable ones (Group 2; p<0.005). 7., Conclusions: This study showed a potentially valuable role for MCE in assessing viability in patients with myocardial infarction and PA. In comparison with DSE, MCE yielded a higher negative predictive value as well as a high positive predictive value. The use of both methods together is promising as a useful tool for early assessment of viability after primary angioplasty.

Introduction: Type I familial amyloid polyneuropathy (FAP I) is an autosomal dominant inherited disorder due to a genetic defect in transthyretin and is characterized by deposition of amyloid in various organs and tissues. The principal manifestations are related to polyneuropathy and dysautonomia. The aim of this study was to assess cardiac involvement and to correlate the findings with neurological status., Methods: 34 patients with FAP (15 male and 19 female; mean age 43 +/- 15 years) underwent I123-labeled metaiodobenzylguanidine (MIBG) myocardial scintigraphy in order to evaluate cardiac sympathetic innervation. In addition they underwent ambulatory blood pressure monitoring (ABPM) and two-dimensional and Doppler echocardiography. Neurological involvement was quantified according to a neurophysiologic score (EMG; 0 = no abnormality and 100% = maximal disability)., Results: The mean value of cardiac MIBG uptake was 1.75 +/- 0.5 (normal = 2.6 +/- 0.3) and correlated inversely with the EMG score (r = -0.67; p = 0.001). In 27 (79%) of the 34 patients there was a decrease in MIBG accumulation, in 18 (53%) an alteration in the circadian BP pattern and/or an increase in systolic and/or diastolic BP loads at night, and in 17 (50%) left ventricular hypertrophy and/or diastolic dysfunction. Twenty-two patients were symptomatic and had a mean EMG score of 37.7 +/- 25% (group I). The remaining 12 were asymptomatic and without neurological involvement (group II). Group I was characterized by older age (48 +/- 15 vs. 33 +/- 10.2 years, p = 0.01), lower MIBG uptake (1.5 +/- 0.4 vs. 2.2 +/- 0.5, p = 0.001), higher systolic (129 +/- 16 vs. 119 +/- 6 mmHg, p = 0.01) and diastolic daytime BP (82 +/- 10 vs. 76 +/- 6 mmHg, p = 0.05), and higher systolic (119 +/- 17 vs. 105 +/- 7 mmHg, p = 0.01) and diastolic nocturnal BP (71 +/- 11 vs. 62 +/- 9 mmHg, p = 0.01) than patients in group II. In 21/22 patients in group I and in 6/12 in group II there was a decrease in cardiac MIBG activity. Sixteen patients in group I and 2 in group II had abnormal circadian BP pattern. Left ventricular hypertrophy was only seen in group I., Conclusions: Patients with FAP have a high incidence of cardiac denervation and an abnormal circadian BP pattern. These alterations in cardiac autonomic function precede the development of clinical manifestations and may be an important factor in determining the optimal timing for liver transplantation, which is currently the only way to control the progression of the disease.

Dilated cardiomyopathy can be idiopathic or be caused by many potentially treatable conditions. We report a complex case of peripartum heart failure associated with hypothyroidism and hypoparathyroidism. Myocardial biopsy suggested that hypothyroidism was the main cause for the dilated pattern, but hypocalcemia played a critical role in acute decompensation of heart failure during hospitalization. After a long and clinically complicated hospital stay, correction of hypothyroidism and hypocalcemia resulted in near-normal cardiac function.

Objectives: To estimate the efficacy of myocardial contrast echocardiography (MCE) by harmonic power imaging (HPI), in evaluation of perfusion in one-vessel coronary disease treated by angioplasty, using myocardial scintigraphy as gold standard., Study Design: Prospective comparative study., Setting: Ambulatory., Population: We included 33 patients (pts), aged 53.5 +/- 9 years, 27 male., Inclusion Criteria: pts with one-vessel coronary disease (> or = 70% stenosis), with indication for angioplasty; sinus rhythm; good echocardiographic window with harmonic imaging. Exclusion criterion: previous myocardial infarction., Methods: All patients underwent myocardial scintigraphy and HPI together with stress echocardiography, both followed by angioplasty (stenting in ten). HPI and myocardial scintigraphy were repeated, in all patients, at three months after intervention. Ten patients were re-assessed by coronary angiography for ischemia on the scintigraphic study. For the HPI exam, Levovist was selected as contrast and dipyridamole as stress agent (0.56 mg/kg). Perfusion was assessed visually and classified by HPI and scintigraphy studies as: 1 (normal), 2 (reduced), or 3 (absent). For analysis, the left ventricle was divided into 16 segments., Results: Of the 43 coronary angiograms performed (ten at three months after angioplasty), 38 showed 70% stenosis, none occlusive or subocclusive. We analyzed 1056 left ventricle segments, from 66 HPI and myocardial scintigraphy studies (before and after angioplasty). Analysis was impossible or doubtful in 4.9%. Baseline and stress HPI detected 216 perfusion abnormalities. Global concordance between the segmental perfusion score obtained by HPI and scintigraphy was 66.2%, which became 76.3% when two groups were considered: a) score 1 b) score 2 and 3 together. In comparison with scintigraphy, HPI sensitivity for detection of perfusion abnormalities was 79.3% (higher for anterior septum, anterior and lateral wall) and specificity was 91.4% (higher for septum, inferior wall and apical segments). HPI correctly identified the location of coronary stenosis in 73.5% of patients., Conclusions: In our study, HPI was a feasible and promising method for assessment of perfusion in one-vessel coronary disease and chronic ischemia. In comparison with myocardial scintigraphy, a high concordance for perfusion score was found, as well as high sensitivity and specificity for detection of perfusion abnormalities.

Objectives: To evaluate the role of contrast Doppler echocardiography in the assessment of aortic stenosis severity, in comparison with the conventional method and using the catheterization study as the gold standard., Study Design: Prospective comparative study., Setting: Echocardiography Laboratory of Cardiology Department., Population: We included 36 consecutive patients, 20 male, aged 67 +/- 11 years, referred for catheterization study to evaluate aortic stenosis severity., Methods: All patients underwent conventional and contrast Doppler echocardiography and catheterization study. For contrast Doppler, we used Levovist (300 mg/ml infusion). We analyzed the following echocardiographic parameters: a) left ventricle dimensions, wall thickness and function; b) aortic valve morphology; c) post-stenotic aortic valve flow--peak velocity, velocity-time integral, peak gradient, mean gradient; d) left ventricle outflow tract flow--peak velocity, velocity-time integral; e) aortic valve functional area; f) acquisition time and Doppler signal intensity for post-stenotic aortic valve flow. Catheterization parameters analyzed: a) peak aortic valve gradient; b) mean aortic valve gradient., Results: Contrast Doppler yielded higher peak gradients than conventional Doppler (85.6 +/- 30.2 vs 72.6 +/- 26.1 mmHg, p < 0.001), as well as higher mean gradients (51.4 +/- 19.0 vs 44.2 +/- 15.9 mmHg, p < 0.001). Peak gradients obtained with contrast Doppler correlated with those obtained invasively (r = 0.88, p < 0.001), although the values were higher (85.6 +/- 30.2 vs 73.6 +/- 32.0 mmHg, p < 0.001). There was no difference between mean contrast Doppler gradients and mean catheterization gradients, which showed a high correlation (r = 0.89, p < 0.001). There was no difference between peak and mean gradients obtained by conventional Doppler and invasively, which yielded correlations of 0.73 and 0.75, respectively (p < 0.001). The sensitivity of contrast Doppler for detection of severe aortic stenosis was 100% for peak gradient and 84% for mean gradient, while for conventional Doppler it was 68% and 58%. The specificity of contrast Doppler was 65% for peak gradient and 88% for mean gradient, while for conventional Doppler it was, respectively, 58% and 88%. Acquisition time for aortic flow visualization was lower (p < 0.001) and flow intensity higher for contrast Doppler, in comparison with conventional Doppler., Conclusions: In this study, contrast Doppler yielded high correlations with invasive data and higher sensitivity and specificity for detection of severe aortic stenosis than conventional Doppler. It is a useful method for evaluation of aortic stenosis severity.

Objectives: To evaluate the association between patterns of pulmonary transvalvular and venous flows in patients with ischemic heart disease, assessed by Doppler echocardiography, and invasive measurements of left ventricular (LV) diastolic pressures., Population: Thirty-seven patients with clinical diagnosis or suspicion of coronary heart disease and referred for coronary angiography; all were in sinus rhythm, and had no known valvular heart or chronic pulmonary disease., Methods: The following were recorded during transthoracic Doppler echocardiography: acceleration time (AT) and total ejection time (ET) of right ventricular outflow; duration of the flow at atrial contraction (a duration) and duration of the "A" wave of mitral inflow (A duration). These data were correlated with the values of LV filling pressures previously obtained by cardiac catheterization., Results: We found a significant correlation of LV end-diastolic pressures with the difference a-A duration (r = 0.75; p < 0.001) and also with the ratio AT/ET (r = -0.73;.

In this work particular emphasis is paid to the contribution of His bundle recordings associated with atrial pacing to the understanding of the Wolff-Parkinson-White syndrome. The methodology used for the electrophysiological studies is described in detail. The value of this particular type of recordings in WPW is demonstrated by the analysis of some illustrative cases which led us to a better knowledge of the electrocardiographic changes, and to the separation of several patterns of ventricular preexcitation and their relationship to the different anatomical pathways postulated for this syndrome. In some instances it was possible to caractherize the reentry circuit of reciprocating paroxysmal tachycardias and to estimate the refractory periods of the normal and the accessory pathways. These later data may be of value for a more rational therapeutic approach of the paroxysmal arrhythmias in the WPW syndrome.

The use of primary angioplasty in the treatment of acute myocardial infarction (AMI), as opposed to fibrinolysis, is well established, as long as performed by an experienced team. The benefits are "time-dependent", hense the rational for the sentence "Time is Muscle". It is very important to assess the time factor, mainly if the therapeutic option is primary angioplasty, since it is necessary to set up a full range of conditions related to this type of specific treatment (human, material and logistical). In the current study was analysed the in and out of hospital time sequence of 99 patients with AMI that underwent primary PTCA during the year of 1999. The main goal was to assess if the performance of this procedure outside regular working hours could have any significant impact on the "time of in-hospital ischemia". The different time durations were prospectively recorded according to a protocol that was previously established and filled for each patient by the lab team. The authors conclude that: a) the average in-hospital time delay in the treatment of AMI by PTCA was not significantly influenced by the fact that the procedure was performed outside the regular working hours of the lab; b) the main component of the "ischemic in hospital time" corresponds to the time between the patient's admission and the decision making time for PTCA. Although the average decision making time for PTCA is too long and must be optimized, the average total in hospital ischemic time (99-105 minutes) compares favorably with other previous reports in the literature.

Objective: To evaluate operated type A aortic dissection by Magnetic Resonance Imaging (MRI), in order to detect long-term complications and identify prognostic indexes of evolution., Design: Prospective study with a three-year period of follow-up. Prognosis evaluation., Settings: Outpatient Clinic at Hospital de Santa Maria and Magnetic Resonance Imaging Center at Hospital da Cruz Vermelha., Patients: A sample of 37 patients submitted to type A aortic dissection surgery, included sequentially, after exclusion of those with contraindication to MRI., Methods: Initial evaluation (clinical and MRI study) at 3 to 4 months and at 1, 2 and 3 years after surgery. The mean follow-up time was 39.3 +/- 2.9 months. We evaluated the following complications over the aorta (aortic graft and five segments of residual aorta) and the aortic valve: aneurysm, pseudoaneurysm, rupture, re-dissection, progressive aortic valve regurgitation, reoperation and death. The prognostic indexes analysed were: presence of residual flap; false lumen patency; presence of re-entry points; false lumen to aorta dimension ratio; initial aortic dimension; increase of aortic dimension., Results: All patients, with the exception of three that died, remained asymptomatic., Complications: Aneurysm was detected in 45.9% of patients, located in one or more segments; rupture occurred in three patients, preceded by aneurysm and pseudoaneurysm development; moderate or severe aortic regurgitation was detected in 47.8% of patients. Prognostic indexes: 1. Aneurysm development in each segment yeilded a significant association with: presence of residual flap in the same and other segments; higher initial dimension of the same and other segments, with the exception of the abdominal segment; higher increase in dimension of the same and other segments, with the exception of the abdominal segment; 2. Moderate or severe aortic regurgitation development showed a tendency to association with higher increase in dimension of proximal ascending aorta. 3. No association was found between aneurysm and aortic regurgitation development., Conclusions: Patients operated for type A aortic dissection had a high incidence of late complications which lead to reoperation and in some cases death. The presence of a residual flap, increased aortic dimensions and higher increase rate of aortic dimensions were associated with a complicated evolution. MRI was a very useful technique for long-term monitoring and to identify prognostic indexes of evolution.

Dual chamber pacemaker implantation has been investigated as a possible treatment modality for patients with advanced congestive heart failure (CHF) who do not respond to current pharmacologic approaches. By optimizing atrioventricular contraction with pacing, hemodynamics have been shown to improve in short-term studies. The long-term benefits of therapy have not been demonstrated conclusively, and clinical trials are now in progress to study pacemaker implantation with and without implantable cardioverter defibrillators as a possible therapeutic option.

The incidence of heart failure (HF) is increasing while numerous pharmacological breakthroughs have been accomplished in the last two decades. Mortality remains high and is comparable to mortality due to oncologic disease. Coronary artery disease and hypertension are the primary causes of heart failure in Western societies while valvular heart disease is a significant cause in economically underdeveloped societies. While there are many pharmacological therapies for systolic disfunction, little is known about the optimal way to treat diastolic dysfunction. Although William Withering described the properties of digitalis in 1785, two hundred years passed before a scientific trial documented its benefit in HF. Skilled dissection and probing of the molecular basis of cardiac muscle contraction led to the development of numerous compounds postulated to be more effective than digitalis, only to disappoint repeatedly in numerous trials. In contrast, ACE inhibitors (ACEI) revolutionized the management of HF and it is unlikely that another class of agents will show dramatic improvements like the ACEI. Therefore, the pharmacological therapy of HF is proving to be more an art than a science, as numerous agents have to be tuned against each other to produce an overall effect that is beneficial.

Objective: To compare the epidemiological characteristics and immediate results of all first single lead VDD pacemaker (PM) implantations with those of an equal number of dual chamber DDD PM, implanted during a 5-year period in a tertiary-care hospital., Population and Methods: A total of 41 patients (pts) (25 males, mean age of 69.0 +/- 11.8 years) underwent a VDD PM implantation, from 30-11-92 to 15-9-97. This group was compared with an equal number of patients (28 males, mean age of 69.9 +/- 7.31 years) with a DDD PM implanted in the same period, selected by a criterion of immediate temporal proximity of procedure. For each patient we collected the clinical and electrocardiographic (ECG) indications for PM implantation, parameters of atrial (AS) and ventricular (VS) sensing and ventricular pacing (VP), X-ray exposure time (XRT) and complications., Results: In the VDD group, 46.3% of the patients had syncope, 51.2% had complete AV block on the ECG, and 14.6% were PM-dependent. Analyzed procedure-related parameters were as follows: P-wave amplitude: 2.1 +/- 0.6 V; AS threshold: 1.2 +/- 0.7 V; R-wave amplitude: 9.1 +/- 3.3 V; VS threshold: 7.0 +/- 2.0 V; VP thresholds: 0.68 +/- 0.24 mA, 0.43 +/- 0.12 V (for a spike duration of 0.5 ms); ventricular impedance: 644.9 +/- 132.0 ohm; XRT; 7' 43" +/- 8' 23". There were two minor complications, for an incidence of 4.9% (one local hematoma and a vagal reaction). In the DDD group the clinical and ECG characteristics were similar, but there was a 22.0% prevalence of sinus-node dysfunction, VS 0% in the VDD group). The P-wave amplitude and AS threshold were significantly (p < 0.005) better (2.8 +/- 0.9 V and 2.8 +/- 0.9 V respectively). The other parameters were similar to those of the VDD group., Conclusions: The immediate results of VDD PM implantation are good and comparable with those of DDD PM, although with worse acute AS parameters.

Magnetic resonance imaging (MRI) is a diagnostic technique used clinically in cardiology over the last ten years. It offers great advantages over other methods as it is noninvasive, does not use radiation, is tomographic and multiplanar. MRI is a very flexible technique based on the interaction between atomic nuclei, usually hydrogen, and external magnetic fields. This leads to image formation and to other important functional diagnostic information. MRI has undergone great technical developments and has proven to be most useful in several areas: cardiovascular structure; global and regional cardiac function; cardiovascular flow; coronary anatomy; myocardial perfusion and metabolism. The initial clinical diagnostic goals of MRI were mainly the anatomic characterization of aortic pathology, congenital heart disease, pericardium diseases and cardiac masses. With the development of cine MRI and, more recently, with rapid imaging and flow evaluation techniques, it has been increasingly used in the functional assessment of cardiovascular diseases. The functional study of the above mentioned clinical pathologies is now possible and information can also be obtained in other important areas; cardiac volumes and function; cardiovascular shunts, valvular heart disease; ischemic heart disease (ischemia detection, infarction quantification, coronary anatomy and flow). It also has an important role in myocardial characterization and is promising for myocardial metabolism, evaluated by spectroscopy. The goal of this review is the presentation of the main MRI techniques and the present clinical applications of this imaging method in cardiovascular diagnosis.

Primary coronary angioplasty is a reperfusion method increasingly used for the treatment of acute myocardial infarction. Several studies are reviewed, demonstrating a reduction in mortality and morbidity, namely due to recurrent ischaemia and haemorrhagic stroke, in comparison to thrombolysis. This benefit seems larger in high risk patients, such as those with cardiogenic shock, anterior wall infarction, elderly patients and those with contraindications thrombolysis or with a non diagnostic electrocardiogram.

The purpose of this study was to assess the results of the treatment of malignant ventricular tachyarrhythmias guided by electrophysiologic studies. Thirty patients with ventricular arrhythmias, aged 56.6 +/- 14.1 years, were submitted to EP testing. The clinical presentation of arrhythmia was sustained monomorphic ventricular tachycardia in 24 (80%), non-sustained ventricular tachycardia in three and another three were survivors of sudden cardiac death. Twenty five patients (83%) had evidence of structural heart disease and left ventricular ejection fraction was less than 40% in 16 (53%). Antiarrhythmic drugs were considered effective when sustained monomorphic ventricular tachycardia was noninducible or significantly slowed in serial EP testing. Sustained monomorphic VT was induced in 19 patients (63%) and an effective drug therapy was found in 13 (68%). In the other 11 patients sustained arrhythmias were not induced, although in six of them the study was done already under antiarrhythmic drugs, that were continued in the follow-up. In the six patients in which an effective drug regimen could not be found and in two sudden death survivors with primary ventricular fibrillation and negative EP testing, an Implantable Cardioverter-Defibrillator was implanted. After 17.8 +/- 10.5 months, there was recurrence of the arrhythmia in 4 (18%) of the 22 patients on antiarrhythmic drugs and half of the patients with ICDs received appropriate therapy from the device. Three patients (10%) died in the follow-up, of which only one due to sudden death. We conclude that selection of optimal antiarrhythmic treatment based on the results of EP testing, is associated with decreased episode recurrence and sudden death.

Purpose: To compare the utility of unipolar versus bipolar mapping to guide radiofrequency catheter ablation of manifest left-sided accessory pathways., Setting: University Hospital, Patients and Interventions: We studied twelve patients with a mean age of 42 +/- 13 years, submitted to a successful left-sided accessory pathway ablation. Detailed mapping was performed with the ablation catheter, recording simultaneous unipolar (distal electrode) and bipolar electrograms, in sinus rhythm. Twenty-three recordings were analyzed, including twelve successful, and eleven unsuccessful sites. The following measurements were analyzed: atrial and ventricular amplitude; interval between atrial and ventricular electrogram onset; interval between onset of ventricular electrogram and delta wave; interval between ventricular electrogram activation and delta wave and; unipolar morphology, classified as P-rS, P-QS or PQS., Main Results: Accessory pathway ablation required a mean of 6.3 +/- 7.9 (median of 2) energy applications. Analysis of the electrogram revealed that ventricular activation was significantly earlier in successful versus unsuccessful sites. Unipolar morphology was also different according to the ablation result: among unsuccessful applications the P-rS configuration occurred in one, and the P-QS in ten cases, while in successful sites, seven had P-QS, and five had PQS morphology., Conclusions: Unipolar recordings are useful to guide radiofrequency catheter ablation of manifest left-sided accessory pathways and should be used in association with bipolar electrograms.

Objective: To describe the results of radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT) by using a mixed electrophysiologic/anatomic mapping technique., Design: Consecutive patients with AVNRT, submitted to AV node modification between November 1992 and March 1995., Setting: Cardiology Department at an University Hospital., Interventions: Twenty consecutive patients with AVNRT were submitted to AV node modification. The ablation technique included two sequential steps. Initially, a detailed electrophysiologic mapping was performed with the ablation catheter, positioned near the coronary sinus ostium, looking for a specific recording: fractionated atrial electrogram, suggestive "slow pathway" potential and a ratio of atrial: ventricular electrogram amplitude > 1. In case of failure, after 5 applications of radiofrequency energy, an anatomic technique was used. The fluoroscopic image, in left anterior oblique projection, was used to guide catheter progression, and the radiofrequency energy applied sequentially in the posterior (P), followed by medium (M) and anterior (A) septal areas if needed. Radiofrequency energy was applied a power of 16-36 watts for 30-60 sec. If a His bundle deflection > 0.0025 mV was recorded, energy was not applied., Measurements and Results: Suppression of a AVNRT was initially obtained in 19 patients (95%). A mean of 8.3 +/- 6.1 energy application were required. Mean during of the entire procedure was 142 +/- 45 min and the fluoroscopy duration was 22 +/- 12 min. There were no complications. The location of successful ablation areas was: P in 15 patients, M in three and A in one. After a mean follow up of 10 +/- 6 months, two patients had recurrence of AVNRT. A second procedure was successful in the initially failed patient and in these two recurrences., Conclusions: A mixed electrophysiologic/anatomic mapping technique to perform radiofrequency catheter ablation of AVNRT was associated with high efficacy and no complications.

Coronary artery disease is one of the leading causes of death in developed countries and one of the factors contributing to high mortality associated with noncardiac surgical procedures. This is the reason why is so important to correctly assess surgical risk in patients with ischemic heart disease. These patients can be evaluated by a simple clinic examination, electrocardiogram and chest X-ray. In asymptomatic patients or in patients with angina (Class I-II), normal electrocardiogram and chest X-ray, the operative risk is low. On the other hand, patients with severe heart failure (Class IV NYHA), unstable angina or acute myocardial infarction have a high surgical risk. The exercise stress testing must be performed in some cases in order to identify preoperative factors (electrocardiographic ischemic changes, low functional capacity) that might affect the development of cardiac events after noncardiac surgery. When not possible a thallium-dipyridamole scintigraphy should be considered. We discuss preoperative indications for coronary angiography and coronary revascularization. Coronary artery bypass surgery must be thought based on clinic severity, therapeutic results, left ventricular function and patient age, among other factors.

Objectives: To assess the safety and efficacy of radiofrequency atrio-ventricular junctional ablation., Design: Consecutive group of patients with refractory atrial tachyarrhythmias in whom catheter ablation of the atrio-ventricular junction was performed., Setting: Cardiology Department at University Hospital., Interventions: Atrio-ventricular junctional ablation was performed in 13 patients with a mean age of 53 +/- 13 years. Among six patients there was no evidence of organic heart disease, two had operated congenital heart disease, two had hypertensive heart disease, one had rheumatic heart disease with a prosthetic valve and the other had ischemic heart disease. The indication for ablation was drug-refractory atrial tachyarrhythmia in all patients: atrial fibrillation with uncontrolled rate in eight patients, atrial flutter in three, atrial tachycardia in one and inappropriate sinus tachycardia in one. An average of 3.7 +/- 0.9 anti-arrhythmia drugs was previously ineffective or associated with significant side-effects. Radiofrequency energy was applied between the distal pole of the ablation catheter and an indifferent cutaneous electrode with intensity of 40-65 volts for 30-60 secs. The ablation was initially performed utilizing the classical technique with the ablation catheter across the tricuspid valve. In the case of failure, an alternative method was used, with the ablation catheter positioned in the left ventricular septum. After the procedure a VVI-R permanent pacemaker was inserted in all patients., Measurements and Results: Atrio-ventricular junctional ablation was successful in all patients after an average of 4.4 +/- 3.7 radiofrequency applications. The classical technique was successful in 11 patients (85%). The average amplitude of the His bundle electrogram recorded in the successful sites was not significantly different from the average maximum amplitude at unsuccessful sites (0.1 +/- 0.05 mV vs. 0.17 +/- 0.12 mV). There were no complications related to the procedures. During a mean follow-up of 7 +/- 4 months there was functional and symptomatic improvement in all patients. The only significant complication was an episode of sustained ventricular tachycardia that occurred three months after the ablation in a patient with Tetralogy of Fallot., Conclusions: In patients with refractory atrial tachyarrhythmias, atrio-ventricular junctional ablation is a safe and effective therapeutic option. The alternative technique should be reserved for cases of unsuccessful ablation with the classic method. Due to its potential significant side-effects, this therapy should be a last alternative option.

Our purpose was to assess the efficacy and safety of intravenous ATP for the acute termination of paroxysmal supraventricular tachycardia. There were 14 women and 10 men, aged 38 +/- 15 years. Three patients had evidence of structural heart disease (Ebstein's anomaly associated to atrial septal defect, operated mitral stenosis with insertion of a mechanical heart valve and CAD respectively). Twelve patients had Wolff-Parkinson-White syndrome and another had undergone surgical ablation of an accessory pathway. At the time of electrophysiologic testing, ATP was administered during episodes of paroxysmal supraventricular tachycardia, via a central vein, in incremental doses of 5, 10 and 20 mg followed by a flush of 10 c.c. of isotonic saline. The mechanism of the arrhythmia was orthodromic AV reentrant tachycardia in 19 (79%), AV nodal reentrant tachycardia in 4 (16.6%) and atrial tachycardia in one patient. The mean frequency of the tachycardia was 174 +/- 33 b.p.m. A dose of 5 mg was effective in 16 patients (66%), 5 required 10 mg and two required 20 mg for termination of the tachycardia. In the patient with atrial tachycardia ATP was not effective. The average time after injection to termination of the arrhythmia was 16 +/- 8 seconds. Orthodromic AV reentrant tachycardia was interrupted in the AV node limb in all but one patient and AV nodal reentry was terminated in the "slow-pathway" in three of the four patients. Nine patients had premature ventricular complexes, isolated or in couplets, after the termination of the SVT. Three patients had immediate recurrence of the SVT.(ABSTRACT TRUNCATED AT 250 WORDS)

Study Objective: To review our eleven year experience in the implantation and follow-up of permanent Pacemakers in the paediatric age group., Design: Retrospective study., Setting: Children submitted to permanent cardiac Pacing implantation and accompanied in the Pacing Center of the Hospital de Santa Maria., Patients: Children from both sexes, aged from neonate to 14 years old, with brady-dysrhythmia and indication for permanent cardiac Pacing implantation., Material and Methods: From November 1980 to September 1991, 16 children had permanent Pacemaker implantation. We describe the clinical and electrocardiographic characteristics of the population, mode of Pacing used, technical data from the implantation and evolution., Results: One children died due to associated cardiac defect not related to the Pacemaker. The other 15 children remain in follow-up with normofunctioning Pacemakers and free of symptoms. We had to perform 11 reinterventions in 8 children due to generator or electrode problems (28,2 months reintervention interval)., Conclusions: Improvements in Pacemaker technology and a careful technique of implantation can significantly reduce the morbidity associated to permanent pacemaker implantation in this age group.

Objective: To describe the experience and results in the diagnosis and catheter ablation of atrioventricular accessory (AP) pathways during the initial electrophysiologic study., Design: We performed catheter ablation at the time of an initial electrophysiologic study in 22 consecutive patients (12 W and 10 M, mean age 42 +/- 15) with Wolff-Parkinson-White syndrome or supraventricular tachycardia., Setting: Cardiology Department at University Hospital., Interventions: The precise AP mapping was performed with the ablation catheter (4 mm distal electrode and deflectable tip) according to the earlier ventricular activation during sinus rhythm or the earlier atrial activation during ventricular pacing or orthodromic reentrant tachycardia. For left-sided pathways the ablation catheter was positioned on the mitral annulus retrogradely across the aortic valve, while for right-sided pathways it was positioned on the tricuspid annulus or near the coronary sinus os. Radiofrequency energy was applied for 20-60 segs with 55-65 Volts., Measurements and Results: Seventeen AP were manifest and five were concealed. AP were left lateral in 11 patients (50%), left posterior in 5, and right postero-septal, right posterior or antero-septal in 2 patients each. The ablation was initially successful in 18/22 (82%), with 9 +/- 8 radiofrequency applications. Mean duration of the entire procedure was 145 +/- 59 min and the fluoroscopy duration was 39 +/- min. There were no major complications. During 2-9 months of follow-up AP conduction returned in two patients., Conclusions: Radiofrequency catheter ablation of AP is effective and safe and can be performed at the time of an initial electrophysiologic test, avoiding the need for long-term antiarrhythmic drug therapy or surgical ablation.

The authors selected 37 permanent pacemaker patients followed for eleven successive months, with symptomatology eventually related to the pacing system. An Holter ambulatory monitorization was performed to all of them during 24 hours. Twenty one had single chamber systems and the others double chamber. Twelve malfunctions were found in ten patients. Six due to "undersensing", 4 related to "oversensing", and 2 from loss of capture. Two patients had tachycardia pacemaker mediated. An inadequate mode of pacing was found in other two cases. Fifteen rhythm disturbances not related to the pacemaker systems were registered in thirteen patients: supra-ventricular in 9; ventricular greater than or equal to 3 degree of lown in 5; and 2nd degree A.V.B. Mobitz type I in one case. Four patients were submitted to surgical intervention in order to modify the mode of pacing. It was also necessary to reprogram ten patients. The Holter Ambulatory Electrocardiography revealed to be an important diagnostic method for the detection of intermittent malfunction of pacing systems. The occasional changes of cardiac rhythm not linked with pacing were also revealed.

The R-on-T phenomenon was observed in two patients with narrow QRS complexes and repetitive supraventricular tachyarrhythmias. Case 1 had a typical Lown-Ganong-Levine syndrome in which the shortening of the P-R interval was due to a reduction of the A-H interval. In Case 2 the P-R interval (140 msec) was not short but the A-H interval was at the lower limits of normal (50 msec) and the P-A interval at the upper limits of normal (40 msec). Both patients showed the R-on-T phenomenon during periods of 1:1 A-V conduction occurring during atrial stimulation at a rate of 200/min (Case 1) and atrial flutter with a rate of 300/min (Case 2). Although total A-V conduction time was prolonged, the magnitude of this prolongation appeared to have been less than that occurring in normal subjects. This was attributed to the presence of an accessory pathway bypassing the area where the most significant delay occurred at the A-V node. The findings in Case 2 suggest, but do not prove, that a similar bypass might be operative in patients with atrial flutter with periods of 1:1 conduction, regardless as to whether the R-on-T phenomenon is, or is not, present.

Among the most important coronary risk factors are a diet rich in saturated fatty acids, cholesterol and calories, hypercholesterolemia, high blood pressure and excessive smoking. The typical pain can be elicited by putting a strain on the patient, e.g. climbing stairs. The disappearance of the pain after treatment with nitroglycerine is one of the most important pointers. Treatment is with nitroglycerine which, moreover, remains the drug of choice, also with nitrates such as pentaerythritol tetranitrate and with betablockers like propranolol. Favorable results have also been reported with a combination of isosorbide dinitrate and propranolol.

The electrophysiologic effects of the antiarrhythmic agent disopyramide phosphate given intravenously were studied in 10 patients with cardiac disease. Studies included determinations of sinus recovery time and refractoriness of the atria, the atrioventricular (A-V) node and the His-Purkinje system. Measurements were performed at rest and 15 and 30 minutes after administration of disopyramide. Serum drug levels were measured at these times. Sinus recovery time was shortened at both 15 and 30 minutes, with an average decrease of 39.5 and 146.2 msec, respectively (P less than 0.01). Atrial refractoriness was not altered significantly, but tended to be reduced; the mean effective refractory period was 289.5 msec before administration of disopyramide and 259 and 270 msec 15 and 30 minutes, respectively, after administration. The functional refractory period of the atrioventricular (A-V) node was definitely prolonged in seven patients 15 minutes after administration of disopyramide. The relative refractory period of the His-Purkinje System was not altered. Although this study does not elucidate the mechanism by which disopyramide acheives its antiarrhythmic effects, animal work has shown that it is similar to that of quinidine. In the doses used the drug does not seem to cause first, second or third degree A-V block or fascicular or bundle branch block; it did not increase the severity of first degree A-V block in the three patients with this disturbance. The drug may be particularly useful when arrhythmias are associated with slow sinus rates.

Electrograms were recorded from the His bundle area, right ventricular apex, right ventricular inflow tract, and left ventricular apical endocardium in four patients (aged, 1, 1, 1.5, and 16 years) with Wolff-Parkinson-White syndrome type B. In beats without preexcitation: (a) delayed activation of the right ventricular inflow tract reflected the occurrence of a conduction disturbance through the "distal" or "peripheral" ramifications of the right bundle branch; and (b) the slightly earlier activation of the left ventricular apical endocardium (in reference to the right ventricular apex) may have been due to an earlier emergence from the divisions of the left bundle branch, presumably due to the greater length of the right bundle branch. In beats with preexcitation: (a) the "incomplete" right bundle branch block pattern was concealed because the right ventricular inflow tract was activated before the right ventricular apex; (b) the delta-right ventricular apical intervals were shorter than those of adults with Wolff-Parkinson-White type B; and (c) arrival of excitation at the left ventricular endocardium was a function, either of the impulse emerging from the left bundle branch, or of that propagating from the preexcited site. Therefore, the delta-left ventricular apical endocardial intervals were considered to have represented conduction time from preexcited region to endocardium of left ventricle only when it could be proven that the conduction time (from atrial site of origin to left ventricular apical endocardium) was shorter through the right sided accessory pathway than through the normal pathway. This study suggests that some beats, which may be interpreted as representing "pure" Wolff-Parkinson-White type B complexes from epicardial maps, may in reality be "fusion" complexes.

The present treatment of angina pectoris is briefly examined. It would appear from the literature published over the last three years that no cure has yet been found. Improvement in prognosis may be expected, particularly in stable forms. Existing clinical, ECG and angiocardiographic methods of diagnosis are described. Better awareness of the factors responsible for angina, coupled with more accurate diagnosis, enable clinical improvement to be achieved in a large number of cases by means of rationally planned medical or surgical management.

Electrophysiologic studies including His bundle recording, atrial, and ventricular stimulation, were performed in three symptomatic patients with persistent atrial standstill of unknown etiology. The rhythm was junctional in two cases and ventricular in one. In two cases, evidence suggestive of associated impairment of the His bundle conduction system was found. The atria were inexcitable at multiple sites and no retrograde conduction to the right atrium could be elicited by ventricular pacing. Follow-up in the three cases, respectively for 48, 42 and 12 months after pacemaker implantation, revealed no return of spontaneous atrial electrical activity.

Proper placement of pacemaker catheters can be facilitated by recording endocardial electrograms from the catheters. These electrograms are also helpful in the investigation of pacemaker failure. Endocardial contact is indicated by S-T segment elevation. When bipolar catheters are used, these "contact currents" may be visible in electrograms from the tip or ring electrodes, or both. Right ventricular cavity electrograms are characterized by their high voltage and are influenced by intraventricular conduction defects and acute myocardial infarction. Serial changes have been described indicating myocardial injury, infarction, and healing in the area underlying the catheter tip.