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Programmed ventricular stimulation with up to 3 extrastimuli at the right ventricular apex was performed in 52 patients with spontaneous nonsustained ventricular tachycardia (VT) associated with coronary artery disease. There were 44 men and 8 women, aged 66 ± 9 years (range 45 to 86). The mean left ventricular ejection fraction was 41 ± 14%. Nonsustained VT was asymptomatic in 10 patients (19%), while the arrhythmia was detected during evaluation of palpitations in 5 patients (10%), presyncope in 11 (21%) and syncope in 26 patients (50%). All patients were tested in the drug-free state and were classified as having no inducible arrhythmia (31 patients, group I), or an inducible arrhythmia (21 patients, group II). The age, gender, type of heart disease, symptoms and left ventricular ejection fraction were similar in both groups. Group I patients had a higher overall incidence of syncope. Group I patients received no therapy, while group II patients received antiarrhythmic therapy guided by electropharmacologic testing. At 21 ± 17 months there was no sustained VT in either group. There were 3 deaths in group I patients, including 1 sudden, 1 nonsudden cardiac and 1 noncardiac death. In group II patients 6 deaths occurred including 4 nonsudden cardiac and 2 noncardiac deaths. In patients with nonsustained VT and coronary artery disease undergoing programmed ventricular stimulation, the incidence of significant arrhythmic events is low in those without therapy with no inducible arrhythmia, and in those with an inducible arrhythmia with therapy guided by electrophysiologic testing.

A 52 year old man was investigated for fever of unknown origin and a grade II/IV systolic murmur. The ECG and chest radiograph were normal. The patient had normocytic anaemia, moderate thrombocytosis, and elevated C reactive protein (CRP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Investigations for collagen vascular disease were …

To review the radiofrequency ablation method, describe the technique, and discuss the indications, results, and limitations of its use in patients with cardiac tachyarrhythmias.Peer-reviewed reports in the literature by clinical investigators who use radiofrequency catheter ablation as identified by a MEDLINE search and our own experience with this intervention in 214 patients with cardiac tachyarrhythmias.All articles reporting results of radiofrequency ablation for cardiac tachyarrhythmias and articles describing the ablation technique or comparing it with direct-current or surgical methods.Percutaneous catheter ablation of cardiac arrhythmias using high-voltage, direct current was limited by a high complication rate and a need for general anesthesia. This method was recently replaced by a new safe and efficacious technique using low-voltage, high-frequency (radiofrequency) alternating current. Nonsurgical cure of many supraventricular arrhythmias is now feasible with radio-frequency ablation, especially in patients with accessory pathways or atrioventricular nodal reentrant tachycardia. For these arrhythmias, success rates are greater than 90%. The indications for ablation include preexcitation syndromes, atrioventricular nodal reentrant tachycardia, and other selected atrial and ventricular tachyarrhythmias refractory to antiarrhythmic drug therapy. The efficacy and safety profile of this technique has made it feasible for children as well as adults.Percutaneous radiofrequency catheter ablation has evolved as a safe and effective method for managing and curing the two most common forms of supraventricular tachycardia: those associated with preexcitation syndromes and atrioventricular nodal reentrant tachycardia. Further studies are needed to determine the efficacy of this method or to evaluate alternative transcatheter techniques in patients with atrial tachycardias and, more importantly, in the large population of patients with ischemic ventricular tachycardia.

The development of nonthoracotomy lead systems for the implantable cardioverter defibrillator has ushered in a new era in the field of device therapy for malignant ventricular tachyarrhythmias. Surgical mortality and morbidity are thus significantly reduced, the hospital stay is shortened, and the cost of such therapy is lowered. Although several problems (mainly lead related) were initially encountered with earlier-generation systems, improvements have made this less invasive method of defibrillator therapy an attractive alternative to conventional epicardial implants. It is rapidly becoming a first-choice approach in the treatment of malignant ventricular tachyarrhythmias. Transvenous leads were used in combination with a subcutaneous patch for effective defibrillation in the majority of patients, according to most published reports, while the number of "transvenous only" systems being implanted has been steadily increasing. A description of currently available nonthoracotomy lead defibrillator systems and a discussion of the clinical results, advantages, and limitations of their use are presented herein. (Arch Intern Med. 1994;154;617-622)

To provide a comprehensive review of the causes, current diagnostic evaluation, and treatment of syncope.New data and knowledge in this evolving field were critically analyzed by doing a MEDLINE search on syncope supplemented by selective review of English language literature citations in the Index Medicus before 1980.We reviewed approximately 200 published articles on syncope and closely related topics as well as using our own clinical experience. We selected articles if they addressed the pathophysiology of syncope, classification and causes, differential diagnosis, noninvasive and invasive evaluation, and current therapy.Syncope is a common clinical problem, occurring in 30% to 50% of the adult population. The prognosis for syncope depends on its cause. Cardiac syncope has the worst prognosis and therefore mandates thorough evaluation and prompt treatment. Diagnostic evaluation is made difficult by the transient nature of the episodes and the many causes. Noninvasive testing reveals the cause of syncope in approximately 50% of cases. More extensive evaluation, including invasive electrophysiologic studies, has assumed a larger role in defining the cause of syncope in selected patients with structural heart disease in whom a noninvasive evaluation has been nondiagnostic. Recently tilt-table studies have been proposed as a clinically useful noninvasive test for vagally mediated syncope.A rational stepwise diagnostic and therapeutic approach to patients with syncope can be developed by initially doing a careful history and physical examination followed by a noninvasive evaluation and selective use of additional, more specialized or invasive tests. Future research should focus on defining the validity and utility of current diagnostic testing in syncope and on exploring further the pathophysiology of patients with recurrent, unexplained syncope.

The acute hemodynamic effects of intravenous methyldopa were studied in six patients with chronic congestive heart failure (New York Heart Association class IV) at 4-6 hours after a 750-mg bolus (period A) and 6-12 hours after a maintenance infusion of 1-2 mg/minute (period B). For period A, the most consistent and striking finding was a significant (48%) fall in pulmonary wedge pressure (33 +/- 6 to 17 +/- 2 mm Hg; p less than 0.05). Stroke volume increased 39% (23 +/- 3 to 32 +/- 4 ml/m2; p less than 0.05), while peripheral vascular resistance decreased 15% (3331 +/- 363 to 2841 +/- 241 dynes.s.cm-5; p less than 0.05). Heart rate fell from 97 +/- 7 to 76 +/- 3 beats/minute (p less than 0.05) with a nonsignificant decline in mean right atrial pressure (18 +/- 4 to 9 +/- 1 mm Hg). These hemodynamic changes were either sustained or enhanced during period B. Concomitant clinical improvement was also noted. As an agent with potent vasodilatory and antiadrenergic properties, methyldopa permitted a rise in stroke volume by virtue of unloading and possible inhibition of sympathetic activity that led to increased density of beta-adrenergic receptors of the heart (up-regulation). Significant reduction of ventricular filling pressure was attributed to venodilation and probable improved diastolic function. In selected patients with severe congestive heart failure, particularly underscored by excessive sympathetic tone, methyldopa may be considered as an alternative agent to improve cardiac performance and clinical symptomatology.

The strategy of placing prophylactic patches for the automatic implantable cardioverter-defibrillator (AICD) without the AICD was employed in 34 patients with coronary artery disease at risk for postoperative ventricular tachycardia undergoing coronary bypass graft surgery (12 patients) or subendocardial resection (22 patients). Patients were selected on the basis of the presence of preoperative sustained ventricular tachycardia (25 patients) or ventricular fibrillation (9 patients) and absence of control of the arrhythmia with 3.6 ± 1.3 antiarrhythmic drugs by programmed stimulation. Patients having subendocardial resection were also selected on the basis of multiple configurations of ventricular tachycardia, inability to map the tachycardia or posterior wall aneurysm.The surgical mortality rate was 12%, with two deaths after coronary bypass graft surgery and two deaths after subendocardial resection. The AICD patches were removed in 1 of the 34 patients a few hours after surgery because of left atrial laceration and bleeding. Among 10 patients surviving coronary bypass surgery alone, ventricular arrhythmia was not inducible in 6 and in 4 it remained inducible postoperatively. One of the four patients with inducible arrhythmia had the AICD implanted with use of local anesthesia; the other three were treated with drugs. Among 20 patients surviving subendocardial resection, ventricular arrhythmia was noninducible in 15 and remained inducible in 5. Three of these five patients had an AICD implanted; the other two were treated with drugs.At 12 ± 7 month follow-up, there were no late deaths. One patient with an inducible arrhythmia after coronary bypass surgery who was treated with drugs had a recurrence 4 months after discharge and received the AICD. One patient without an inducible arrhythmia after subendocardial resection had an AICD implanted for arrhythmia recurrence 1 year later. Thus, 6 (20%) of the 30 patients surviving surgery required an implanted AICD postoperatively. No late complications from the patches have occurred.In conclusion, selective placement of prophylactic AICD patches in patients at risk for postoperative ventricular tachycardia is safe and obviates the need for subsequent thoracotomy in the 20% of patients who eventually need the AICD.

The right atrial appendage (RAA) of 23 randomly selected autopsied patients was examined at necropsy, and data related to orifice size and appendicular depth measurements and features of the endocardial surface were recorded. The study included 21 men and 2 women aged 71 +/- 15 years (range, 32-91); underlying coronary artery disease was present in 16 patients. The orifice size of the RAA measured 2.0 +/- 1.0 cm (range, 0-5 cm). The orifice size was slightly, but not significantly, smaller in patients over age 70 years compared with those younger than 70. In hearts weighing more than 450 g, the orifice was significantly larger (2.6 cm) than in hearts weighing less (1.4 cm). The appendicular depth averaged 1.2 +/- 0.7 cm (range, 0-2.5 cm), and a significant difference was noted in patients older and younger than 70 years (depth of 0.9 cm vs. 1.5 cm; p less than 0.05). The RAA depth was 0.5 cm or less in 8 patients (35%), 6 of whom represented patients older than 70 years. Antemortem mural thrombi within the RAA were found in three hearts and completely filled the lumen in one. The suitability of the RAA as a site for atrial pacing and secure electrode implantation, particularly when anatomical deficiencies are identified, was also considered. Atrial lead displacement, a relatively common postoperative complication, may be related more to implantation within a shallow appendicular fossa and/or one with larger orifice than to faulty technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Our present study indicates that sinus or paranodal and not ventricular tachycardia was inducible, presumably facilitated by intrinsic cellular derangements, which in this child were most expressed in the sinus region. The fact that ventricular tachycardia was not inducible at EP study suggests that the mechanism is an automatic focus (or foci) in the ventricle(s). Sinus entrance block as well as the inconsistent rate response to decremental atria1 pacing make a definite distinction between triggered and reentrant sinus tachycardia difficult. Although seemingly paradoxical, stabilization of the bidirectional tachycardia to a bigeminal rhythm following metaproterenol administration indicates a potential treatment regimen that incorporates improvement both of the muscle paralysis and ventricular dysrhythmias associated with this disorder.

Surgical therapy with mapping-guided subendocardial resection was used in 30 patients with drug-refractory ventricular tachycardia. Results of preoperative, intraoperative and postoperative electrophysiologic evaluation and long-term clinical follow-up are reported. Left ventricular aneurysm was located in the inferior wall in 8 patients and in the anterior wall in 22. Left ventricular mapping was performed in 15 patients preoperatively and in all 30 patients intraoperatively. Subendocardial resection was supplemented with cryoablation in 26 patients and with laser photocoagulation in 4. Coronary bypass surgery was performed in 27 patients. The surgical mortality rate was 10%; the three deaths were due to cardiogenic shock, pneumonia and sepsis, respectively.At postoperative electrophysiologic study, ventricular tachycardia was inducible in 8 (30%) of 27 patients. previously ineffective antiarrhythmic drugs were effective in preventing the induction of ventricular tachycardia in four of these eight patients. Two of the remaining four patients received an automatic implantable cardioverterdefibrillator; the other two were treated with amiodarone. At a mean follow-up period of 18 ± 17 months (range 1 to 52), there has been one sudden death and one nonfatal recurrence of ventricular tachycardia in the 18 patients without inducible arrhythmias postoperatively. Among the eight patients with inducible ventricular tachycardia after subendocardial resection, there has been one nonfatal ventricular tachycardia recurrence.Thus, among the 27 patients surviving surgery, 17 (63%) were cured with surgery alone, and another 7 (26%) had their ventricular tachycardia controlled with drugs (n = 5) or the defibrillator (n = 2). Inability to completely map the tachycardia, a clinical history of cardiac arrest requiring resuscitation and the presence of myocardial infarction within 2 months predicted postoperative arrhythmia inducibility and recurrence.

By measuring plasma levels of D-dimer, a product of fibrin degradation, we sought to investigate whether the application of radiofrequency (RF) energy might activate endogenous thrombotic mechanisms.Quantitative determination of D-dimer, a bio-chemical marker of thrombus formation and reactive fibrinolysis, helps to diagnose activation of the coagulation system. It remains controversial whether endocardial lesions produced during RF catheter ablation of arrhythmogenic foci have a thrombogenic effect, and the issue of the need for antithrombotic therapy after RF ablation is still unresolved.We made serial determinations of plasma D-dimer levels by enzyme immunoassay before insertion of catheters, after completion of electrophysiologic study (EPS) but before RF ablation, immediately after RF ablation and before discharge (at 48 h) from the hospital in 37 patients undergoing RF ablation (22 men, 15 women; mean [+/-SD] age 37 +/- 18 years, range 12 to 74; 16 +/- 16 lesions produced) of accessory (n = 17) or slow (n = 12) pathways, atrial (n = 4) or ventricular foci (n = 3) or the atrioventricular node (n = 1). D-dimer levels were also measured in 26 age-matched control subjects undergoing EPS only.In the RF ablation group, the mean D-dimer levels increased from a baseline value of 29 +/- 28 to 62 +/- 56 micrograms/liter after EPS (p0.0001). However, after RF ablation, D-dimer levels increased to much higher levels (188 +/- 138 micrograms/liter, p0.0001). There was no correlation of D-dimer levels with the number of RF lesions produced or the duration of the procedure. At 48 h after the procedure, D-dimer levels decreased (75 +/- 67 micrograms/liter) but still remained significantly elevated compared with baseline values (p = 0.0001). Three were no significant differences in baseline (25 +/- 21 micrograms/liter) and post-EPS (51 +/- 50 micrograms/liter) measurements between control subjects and patients. During RF ablation, intravenous heparin was given to nine patients who still demonstrated high plasma D-dimer levels after RF ablation.As reflected by elevated plasma D-dimer levels, RF ablation has a thrombogenic effect that persists through 48 h after the procedure. This effect needs to be taken into account when considering antithrombotic therapy in patients undergoing RF ablation.

Objective: Vascular closure devices (VCDs), such as the Angio-Seal, a three-component hemostatic plug, have greatly facilitated the routine clinical practice in the catheterization laboratory. The manufacturer recommends a local angiogram before Angio-Seal deployment. However, from the outset, we employed a simplified routine of deploying this VCD, i.e. without use of local angiography. Methods: The Angio-Seal was employed without a preceding femoral arteriogram over 8 years in 2074 consecutive patients, 72% presenting with acute coronary syndromes and subjected to coronary angiography (n = 1032) or PCI n = 1042) via a transfemoral approach with use of heparin and dual antiplatelet therapy. Results: Deployment of the VCD was successful in 99.4%. Complete hemostasis was obtained in 98% of cases. In 14 patients, Angio-Seal deployment failed. Mean time for placement of Angio-Seal was

Summary Purpose : The purpose of this study was to examine exercise tolerance in patients with COPD from measurements of resting pulmonary function parameters. Methods : A total of 57 COPD patients were administered the pulmonary function test (PFT) and cardiopulmonary exercise test. The results were analyzed and essentially linear relationships emerged when each subject's V O 2 peak was plotted against his individual PFT parameters. Those significant contributors were then introduced in a stepwise multiple regression analysis to determine the best predictor of the V O 2 peak. Results : Stepwise multiple regressions in variables revealed that peak oxygen consumption ( V O 2 peak) was predicted best by the following equation: V O 2 peak=(maximum voluntary ventilation×0.024)+(forced mid-expiratory flow×0.47)+(body surface area×0.988)−0.913 ( r = 0.90 ; r 2 = 0.81 SE=0.29L/min). Conclusion : We conclude that exercise capacity was predicted from measurements of resting pulmonary function parameters with excellent accuracy in the COPD patient.

After extensive evaluation in clinical investigation, the class Ic antiarrhythmic agents flecainide and encainide have recently been approved for the treatment of ventricular arrhythmias. Preliminary reports indicate that these drugs may be useful in the treatment of a variety of supraventricular tachycardias, including atrioventricular reciprocating tachycardia and atrial fibrillation in the setting of Wolff-Parkinson-White (WPW) syndrome. 1–5 This prospective study was undertaken to evaluate systematically the electrophysiologic effects, clinical efficacy and tolerance of flecainide and encainide in patients with the WPW syndrome.

To examine the feasibility of using a noninvasive temporary pacemaker for termination of well-tolerated supraventricular (SVT) and ventricular tachycardia (VT), a standard external demand pacemaker was modified to allow stimulation with single or multiple extrastimuli and overdrive pacing. To evaluate the efficacy, safety and tolerance of external cardiac programmed stimulation, a standard arrhythmia termination protocol was used in 223 tachycardias in 22 patients. The technique of external cardiac programmed stimulation was used in 209 episodes of SVT in 13 patients. It terminated 95% of the episodes with success in 19 of 20 episodes of atrioventricular nodal reentrant tachycardia and 179 of 189 episodes of atrioventricular reciprocating tachycardia. Of 198 episodes of SVT terminated by the technique 168 (85%) were terminated by a single extrastimulus and 28 (14%) by double extrastimuli. Only 2 episodes of SVT required overdrive pacing for termination. External cardiac programmed stimulation did not result in atrial fibrillation or arrhythmia acceleration. Of 14 episodes of sustained monomorphic VT 5 were terminated by external cardiac programmed stimulation. One tachycardia was terminated by a single extrastimulus, 1 by double extrastimuli and 3 by overdrive pacing. Arrhythmia acceleration occurred once and was terminated by endocardial pacing. On 27 separate occasions patient evaluation of maximal discomfort included 4 ratings of mild, 10 of moderate, 11 of severe and 2 of intolerable discomfort. External cardiac programmed stimulation is effective and safe in patients with well-tolerated sustained supraventricular or ventricular arrhythmias.

Serum concentrations of lidocaine and its metabolites monoethylglycinexylidide (MEGX) and glycinexylidide (GX) were measured in seven patients after discontinuation of intravenous lidocaine necessary for control of spontaneous arrhythmias prior to electrophysiologic study. Standard loading doses of lidocaine were given intravenously followed by 2 mg/min infusions for 79.5 ± 6.5 hours. Electrophysiologic studies all started more than 5 half-lives or 7.5 hours after discontinuation of intravenous lidocaine. Local anesthesia with subcutaneous lidocaine (mean 162 ± 96 mg) was administered in six patients. Plasma concentrations of lidocaine and its metabolites were determined at the termination of the infusion, 2 and 4 hours afterwards, at the start of the electrophysiologic study prior to local anesthesia, and at the end of the study. Levels were also determined at 12 and 24 hours after discontinuation of the infusion. Mean plasma concentrations of lidocaine, MEGX, and GX at the start of the study were 1.02, 0.86, and 0.62 μg/ml, respectively. These had increased to 2.78, 0.92, and 0.68 by the end of the electrophysiologic study. One patient with coronary artery disease and prior out-of-hospital ventricular fibrillation had a therapeutic lidocaine level and no inducible arrhythmia at the time of the initial study. At a subsequent electrophysiologic study, no lidocaine or metabolites were detected in the serum and ventricular fibrillation was induced. Thus using the reported half-life of 90 minutes and discontinuing lidocaine 5 half-lives prior to electrophysiologic evaluation does not ensure lack of electrophysiologic effects of the parent compound or its metabolites. Lidocaine given for local anesthesia further increases lidocaine and metabolite levels. To avoid significant electrophysiologic sequelae, intravenous lidocaine should be discontinued for as long as possible prior to programmed stimulation. Local anesthesia with lidocaine should also be minimized or an alternate anesthetic agent should be used. Serum levels of lidocaine and its metabolites should be determined if electrophysiologic effects are suspected at the time of the study.

We describe three patients, each with a cardiovascular presentation of Munchausen's syndrome. Two patients' symptoms masqueraded as unstable angina (cardiopathia fantastica); one required intra-aortic balloon counterpulsation, while repeated cardiac catheterizations revealed normal coronary arteries. The third patient, with at least 27 documented hospital admissions, first presented as the cardiopathia fantastica variety and progressed to recurrent thromboembolism and limb amputations as a result of iatrogenic complications induced by angiographic and surgical procedures (arteritis factitia).

This report summarises the limitations of current pacemakers during exercise, and the status and potential clinical applications of rate-responsive pacemakers. The truly physiological pacemaker, which by definition maintains both atrioventricular (AV) synchrony and rate control for maximum haemodynamic benefit, remains the objective of current research efforts

Amiodarone was used in 86 patients with ventricular tachycardia (VT) (67 patients) or ventricular fibrillation (19 patients) secondary to coronary artery disease. The mean ± standard deviation left ventricular ejection fraction was 30 ± 12% (range 8 to 65%). Prior trials with 4 ± 1.2 alternate anti-arrhythmic agents had been unsuccessful. Amiodarone was loaded at dosages of 1,200 to 1,800 mg/ day, with maintenance dosages of 400 to 600 mg/ day. Drug efficacy was evaluated by programmed stimulation at 10 to 14 days in 68 patients. In 38 patients sustained VT or ventricular fibrillation was inducible (group I), whereas 30 patients (group II) had either no inducible VT (8) or had nonsustained VT induced (22). Holter monitoring was used to assess drug efficacy in 18 patients (group III). All patients were evaluated at 3- to 6-month intervals with Holter monitors for efficacy and a standard protocol for toxicity. During a long-term follow-up of 18 ± 16 months, sudden death occurred in 5 patients and nonfatal arrhythmia recurrences were detected in 16. The actuarial probability of freedom from fatal and nonfatal arrhythmia recurrences at 24 months was 0.52 for group I, 0.97 for group II and 0.68 for group III. The mode of induction, rate change or hemodynamic tolerance of the induced ventricular tachycardia did not predict arrhythmia recurrence. Among the clinical variables analyzed, only an ejection fraction of ≤30% was identified as a significant predictor of arrhythmia recurrence. Nonsudden cardiac death occurred in 21 patients, including 19 from heart failure and 2 from myocardial infarction. Noncardiac death occurred in 7 patients. The overall incidence of side effects was 65% (severe toxicity requiring drug discontinuation occurred in 10% and moderate toxicity requiring drug suspension or dosage reduction in 38%). Thus, in patients receiving amiodarone for drug-refractory ventricular tachyarrhythmias, early electrophysiologic studies have prognostic value. Fewer arrhythmia recurrences were observed in patients who had no inducible VT or had nonsustained VT induced, as compared with those with inducible sustained VT. Total mortality in patients administered amiodarone was high. Most deaths were from heart failure. Toxicity from amiodarone requiring drug discontinuation, suspension or dosage reduction was common.

Seventy-seven patients with drug-refractory sustained ventricular tachycardia (VT) (28 patients) or ventricular fibrillation (VF) (49 patients) underwent implantation of an automatic cardioverter defibrillator (AICD). The 67 men and 10 women, with a mean age of 60 ± 12 years (range 18 to 79), had coronary artery disease (60 patients), idiopathic cardiomyopathy (eight patients), mitral valve prolapse (four patients), hypertensive heart disease (one patient), Ebstein's anomaly (one patient), long QT syndrome (one patient), and primary electrical disease (two patients). The mean left ventricular ejection fraction was 35 ± 16% (range 10% to 75%). Sustained VTVF was induced in 64 patients (83%) at baseline electrophysiologic testing. A mean of 4.1 ± 1.3 antiarrhythmic drugs failed to control the arrhythmia. Associated surgery at AICD implantation included coronary artery bypass in 19 patients, coronary bypass with aneurysmectomy in six patients, and aneurysmectomy alone in one patient. Five patients had only prophylactic patches implanted during aneurysmectomy or coronary bypass and the AICD device was subsequently implanted under local anesthesia to prevent arrhythmia recurrence or to control persistently inducible VT. Operative mortality was 2.6% with two deaths from intractable VF. Fifty-two patients (69%) continued receiving antiarrhythmic drugs to suppress spontaneous VT. During a mean follow-up of 15 ± 13 months (range 1 to 63), six patients died: two suddenly due to probable pulse generator failure (> 2 years old), one of acute myocardial infarction, two of heart failure, and one of respiratory failure. By life table analysis, the 1-, 2- and 3-year overall cardiac survival was 95%, 95%, and 87%, respectively, and the fatal arrhythmia survival was 100%, 100%, and 92%, respectively. Late complications occurred in 10 patients and included two pocket infections, two postpericardiotomy syndromes, five premature battery depletions, and one accidental device deactivation. Twenty-six patients (35%) have received a total of 253 appropriate shocks for VTVF recurrences. Another 15 patients (20%) have had a total of 282 shocks deemed inappropriate. Thus the AICD is effective in the prevention of sudden death in patients in whom antiarrhythmic drugs or surgery have failed, with an acceptable operative risk and long-term complication rate.

To determine the reversibility of the effects of flecainide on accessory pathways, electrophysiologic studies were performed in the drug-free control state, after flecainide loading and with isoproterenol infusion during flecainide treatment in 12 patients with symptomatic preexcitation syndrome. After the baseline drug-free evaluation, oral flecainide was given in dosages of 50 to 200 mg twice daily (mean daily dose 282 +/- 75) for at least 4 days before the repeat electrophysiologic study. Isoproterenol infusion was given in dosages of 1 to 4 micrograms/min to increase the heart rate at rest by 50%. Anterograde block in the accessory pathway was observed in 3 patients with flecainide therapy, whereas in the other patients the anterograde refractory period increased from 243 +/- 20 to 315 +/- 23 ms (p less than 0.05). The shortest preexcited RR interval during atrial fibrillation lengthened from 234 +/- 27 ms before flecainide to 313 +/- 38 ms (p less than 0.05). Retrograde block occurred in 2 patients after flecainide, whereas the retrograde refractory period of the accessory pathway increased from 247 +/- 26 to 337 +/- 45 ms in the other patients. Orthodromic atrioventricular reciprocating tachycardia, inducible in 10 patients before therapy, became noninducible in 3 patients. Its rate was significantly slowed in the other 7 patients (from 346 +/- 50 to 471 +/- 81 ms). In 2 patients the tachycardia was nonsustained during flecainide treatment. Atrial fibrillation, inducible in all patients at baseline, was rendered nonsustained and more difficult to induce in 7 patients with flecainide. When isoproterenol was infused during flecainide treatment, complete anterograde (3 patients) or retrograde block (2 patients) persisted in the accessory pathway.(ABSTRACT TRUNCATED AT 250 WORDS)

A case is presented of a defibrillator patch erosion, inappropriate shocks, and high defibrillation thresholds in a 59-year-old man requiring thoracotomy for proper diagnosis and management.

A wavelet transform (WT) based filtering of the high resolution electrocardiogram is proposed in this study. The overcomplete time-scale decomposition of the row signal is achieved in the first step by convolution with the quadratic spline wavelet. The small scale data are passed by the filtering algorithm at locations where the wavelet coefficients correlation at adjacent scales is high and suppressed if the correlation is small. The filtered signal is reconstructed from the set of filtered scales through the inverse WT. A comparison with the Wiener filter proved that the wavelet filtering performed better in passing the useful high-frequency data from the QRS terminal part. The denoising results obtained on real signals were similar with 0.6 /spl mu/V root-mean-square noise endpoint signal averaged ECG.

Two types of new-generation transvenous implantable cardioverter defibrillator (ICD) systems, incorporating a two-coil (62 patients, group 1) versus single-coil (32 patients, group 2) lead system were compared among 94 consecutive patients. The two groups were comparable in age (58 +/- 13 vs 59 +/- 14 years), presenting arrhythmia (ventricular tachycardia versus ventricular fibrillation 77%/21% vs 84%/13%), cycle length of induced VT (294 +/- 4 vs 289 +/- 44 ms), number of unsuccessful antiarrhythmic drugs (1.7 +/- 0.8 vs 1.7 +/- 0.7), and left ventricular ejection fraction (35 +/- 12% vs 34 +/- 9%). Both systems were successfully implanted strictly transvenously in all patients. Biphasic shocks were used in all patients. Active shell devices were used in 79% and 84% patients of groups I and II, respectively (P = NS). Intraoperative testing revealed comparable defibrillation threshold (DFT) values (10.2 +/- 3.7 J in group 1 versus 9.3 +/- 3.6 J in group 2 system), and pacing threshold (0.7 +/- 0.3 vs 0.7 +/- 0.3 V), but R wave amplitude and lead impedance were lower in group 1 (13 +/- 5 vs 16 +/- 5 mV, P = 0.003; and 579 +/- 115 vs 657 +/- 111 ohms, P = 0.002, respectively). Lead insulation break requiring reoperation occurred in one patient with an Endotak lead, and two patients with Transvene leads had initially high DFT with a single one-lead/active can system, which was converted to a two- or three-endocardial-lead/inactive can configuration. We conclude that both single-coil and two-coil transvenous ICD systems were associated with high rates of successful strictly transvenous ICD implantation and a low incidence of lead-related complications. Significant differences were noted in the sensed R wave and lead impedance, probably reflecting the active fixation characteristics of the Transvene lead. However, in order to obviate the sporadic need for implantation of additional endocardial leads, as was the case in two patients in this series, a double-coil lead may be preferable.

The reproducibility of heart rate variability (HRV) from 24 hour recordings has been established. But it has not been evaluated in the time and frequency domain whether short electrocardiographic segments show reproducible measurements. The authors analyzed Holter recordings of 28 patients and HRV was estimated in two sequential 10 min segments. The analysis was performed with the Oxford Excell II ver. 7.1 system. Both time and frequency domain parameters were found to be highly reproducible in the two successive segments. Consequently, comparison of short electrocardiographic segments is valid and they can be used in order to assess the effect of various interventions on the HRV.

Background: Late potentials (LP) on signal‐averaged electrocardiography (SAECG), recorded 6 to 30 days after an acute myocardial infarction (AMI), identify patients at risk for late arrhythmic events. Angiotensin‐converting enzyme (ACE) inhibitors have been shown to reduce ventricular remodeling and cardiovascular mortality after AMI. Hypothesis: The aim of this study was to investigate the effect of early (< 24 h) administration of captopril on the presence of LP on Days 6–30 after AMI. Methods: The study included 117 patients with a first AMI; 63 patients (53 men and 10 women, aged 59±12 years), 35 with an anterior and 28 with an inferior AMI (44 thrombolyzed), received early captopril therapy. The control group consisted of 54 age‐matched patients (39 men and 15 women, aged 60 ± 12 years), 19 with an anterior and 35 with an inferior AMI (31 thrombolyzed, p = NS), who did not receive early therapy with an ACE inhibitor. The mean left ventricular ejection fraction was similar in both groups (48 vs. 46%). Time domain analysis of SAECG was performed using a band‐pass filter of 40–250 Hz. Late potentials were considered present if any two of three criteria were met: (1) Filtered QRS duration (QRSD) > 114 ms, (2) root‐mean‐square voltage of the last 40 ms of the QRS complex (RMS) > 20 m̈V, and (3) duration of low amplitude (< 40 m̈V) signal of the terminal portion of the QRS (LAS) > 38 ms. Results: In the two groups of patients there were no differences in mean values of SAECG parameters. No patient was receiving any antiarrhythmic drugs. In the captopril group LPs were present in 9 of 63 patients (14%) and in the control group in 17 of 54 patients (31 %) (p =0.046). There was no difference in the number of patients with a patent infarct‐related artery in the two groups (76 vs. 59%). Conclusion: Captopril treatment early after an AMI reduces the incidence of LPs recorded on Days 6–30 and may thus favorably affect the arrhythmogenic substrate.

A previous report described our preliminary experience with a highly successful pacing lead removal system (VasoExtor). Extending this experience, we found it necessary to use additional tools to enhance the success of percutaneous lead extraction with this system. In the present series, we used the standard locking stylets (S and K), and recently, one newer type of stylet (Magic) over the last 3 years in 34 patients to extract 48 pacemaker leads in 31 patients and 3 defibrillator (ICD) leads in 3 patients. Lead extraction was carried out in 23 men and 11 women (aged 64 +/- 17 years) because of pacemaker infection (n = 21), pacemaker (n = 8) or ICD (n = 3) lead malfunction, or prior to ICD implant (n = 2). Leads were in place for 3.5 +/- 3.7 years. Infections, involving pocket and lead(s), were due to S. epidermidis (n = 13), S. aureus (n = 6), S. aureus plus E. coli (n = 1), for fungi (n = 1). Of the 48 pacing leads, 31 were ventricular, 15 atrial, and 2 were VDD leads. The ICD leads were two double-coil leads (CPI) and one single-coil lead (Telectronics). Using the S (n = 12), K (n = 8), or Magic (n = 3) stylets, all pacing leads in 23 patients and the ICD leads in 2 patients were successfully removed from a subclavian approach using the locking stylets. However, in nine (26.5%) patients ancillary tools were required. In four patients, lead fragments were captured with use of a noose catheter, a pigtail catheter, and a bioptome from a right femoral approach. In two patients, locking could not be effected and a noose catheter from the right femoral vein was used, aided by a pigtail and an Amplatz catheter and a bioptome to remove three leads. In a patient with an ICD lead, a combined subclavian (stylet S) and right femoral approach (noose catheter) was required. In a patient with a dysfunctional ventricular lead 12 years old, a motor drive unit was used to facilitate the exchange of locking stylets, but extraction failed. In another patient, a fragment of a dysfunctional ventricular lead remained intravascularly despite resorting to a femoral approach. Finally, lead removal was completely (32/34, 94%) or partially (1/34, 3%) successful in 33 (97%) of 34 patients for 50 (98%) of 51 leads without complications. In conclusion, to enhance the success of pacing or ICD lead extraction with use of the VascoExtor locking stylets, an array of ancillary tools were required in more than one fourth of patients.

A 43-year-old woman was undergoing radiofrequency catheter ablation of a symptomatic supraventricular tachycardia when a patent foramen ovale (PFO) was detected with passage of the diagnostic electrocatheter into the left atrium. Prior echocardiographic studies had been unrevealing. Upon questioning during the procedure, the patient now admitted to frequent and disabling daily migraine attacks, while her family described two recent brief episodes of disorientation and dysarthria, consistent with transient ischemic attacks. The patient was informed of the option of future closure of the PFO, but she insisted on having this done concurrently with her ablation procedure. After successful ablation of the slow pathway considered responsible for the supraventricular tachycardia, an Amplatzer closure device was utilized and the PFO was successfully closed during the same procedure. A postprocedural transesophageal echocardiogram showed complete sealing of the PFO, while over the ensuing 10 months the patient reported virtual elimination of her daily attacks of migrainous headaches, limited to a single episode the day after the procedure and none thereafter.

• Atypical manifestations of pulmonary toxicity and previously unreported autonomic nervous system dysfunction complicating amiodarone therapy were observed in a patient being treated for sustained ventricular tachycardia. Pulmonary and hepatic nodules on computed tomographic scan masquerading as metastatic carcinoma were initially noted. Focal infiltrates and a large left pleural effusion mimicking infection, malignant neoplasm, or collagen vascular disease became manifest at a later stage. Autonomic dysfunction presented as incapacitating orthostatic hypotension and persisted for six weeks after amiodarone withdrawal. The pleuropulmonary toxic effects were reversible on discontinuation of amiodarone therapy, and resolution was hastened by short-course steroid treatment. ( Arch Intern Med 1987;147:1805-1809)

The automatic implantable cardioverter defibrillator was conceived by Mirowski as an implantable device for detection and termination of ventricular fibrillation. Since the initial human implant of the defibrillator in 1980, there has been a dramatic expansion of the clinical experience with more than 5000 implants. The technology of the device, which is now capable of sensing and terminating both ventricular tachycardia and fibrillation, has evolved rapidly. Although still not an ideal antiarrhythmic device, it has already had a major impact on arrhythmic mortality with a marked reduction in the sudden death rates in a high-risk patient population. (JAMA. 1989;262:1362-1368)

• The insights into the mechanisms of supraventricular tachycardias provided by the techniques of intracardiac recording and programmed cardiac stimulation have had a major impact on our therapeutic approach to this common problem. These techniques have led to a more systematic analysis and precise interpretation of the standard surface electrocardiogram. An accurate diagnosis of the mechanism of supraventricular tachycardia can be made in the majority of patients using the electrocardiogram aided by special leads (eg, Lewis leads) and bedside maneuvers. Identification of the likely electrophysiologic mechanism allows for a more rational and effective approach to both acute and chronic therapy. ( Arch Intern Med 1987;147:1706-1716)

Pericardial effusion, a common cardiac manifestation of myxedema,1,2is rarely associated with cardiac tamponade; to our knowledge, only 19 reports of this phenomenon appear in the English literature.3-7In all reported cases, identification of tamponade was largely derived from clinical and echocardiographic examination, and available hemodynamic data were described in only one report. In this presentation, the hemodynamic measurements relevant to the diagnosis of cardiac tamponade and the dynamic physiologic alterations subsequent to pericardiocentesis are more fully elucidated by reference to the recently described hemodynamic concept of pericardial constraint.8,9 REPORT OF A CASE A 63-year-old obese man was admitted to the coronary care unit because of increasing dyspnea and swollen legs over the preceding several weeks. Digitalis and furosemide had been prescribed for presumed heart failure. At the time of hospital admission, the patient had overt tachypnea, respiratory distress, and cyanosis. Blood pressure was 100/60 mm Hg

• Thirty-four drug addicts with endocarditis were studied to evaluate the prognostic significance of vegetation size and its short-term changes, as determined by two-dimensional echocardiography. Among 43 episodes of endocarditis, vegetations were detected in 27 (63%), confined to the tricuspid valve in 20 patients, mitral valve in one, aortic valve in two, and both tricuspid and mitral valves in four. All vegetations were large (≥1 cm) (mean maximal dimension, 1.7±0.5 cm). Medical cure was achieved in all 16 patients without vegetations and in 18 (90%) of 20 patients with tricuspid valve vegetations. One patient with tricuspid vegetation and polymicrobial infection died of respiratory failure. Surgery was required for one patient with tricuspid vegetation, all three patients with isolated left-sided endocarditis, and two of four patients with multivalve involvement. Short-term changes of tricuspid valve vegetations during therapy (one to eight weeks) did not correlate with clinical outcome. Although large tricuspid vegetations may occasionally identify a subset at risk for complications, most patients with isolated tricuspid valve endocarditis have a benign prognosis. ( Arch Intern Med 1988;148:2461-2465)