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Biomedical subjects

A S Manolis

Publications and source records attributed to A S Manolis.

At least 55 records · Page 3Linked to original sources
PubMed1996

Perioperative and long-term results with mapping-guided subendocardial resection and left ventricular endoaneurysmorrhaphy.

BACKGROUND: Surgical ablation of the arrhythmogenic focus in patients with life-threatening ventricular tachyarrhythmias can be curative. However, the surgical techniques have been plagued by a high perioperative mortality rate (averaging approximately 12%). Reconstruction of the left ventricle may reduce mortality. METHODS AND RESULTS: Reconstruction of the left ventricle with a pericardial patch, or endoaneurysmorrhaphy, was performed with mapping-guided subendocardial resection for recurrent ventricular tachycardia in 25 patients over a 5-year period. Postoperatively, electrophysiological studies were conducted to assess the results of surgery, which were further evaluated during long-term follow-up with survival analyses. The study included 25 patients, 60 +/- 9 years of age, with coronary artery disease, discrete left ventricle aneurysms, and malignant ventricular tacharrhythmias. Left ventricular ejection fraction was 24 +/- 6% preoperatively. Left ventricular endocardial mapping, endocardial resection, and endoaneurysmorrhaphy were performed in all patients. There was no operative or postoperative (30-day) mortality. Postoperative ventricular tachycardia was induced in 2 of the 25 patients (8%); left ventricular function increased to 32 +/- 9% (range, 19% to 52%). At a mean follow-up of 37 +/- 16 months (range, 6 to 65 months), there had been 6 deaths, including 1 sudden cardiac death, 2 congestive heart failure deaths, and 3 noncardiac deaths. Analysis of multiple variables failed to identify predictors of postoperative inducibility, sudden cardiac death, cardiac death, or total mortality. CONCLUSIONS: Endoaneurysmorrhaphy with a pericardial patch combined with mapping-guided subendocardial resection frequently cures recurrent ventricular tachycardia with low operative mortality and improvement of ventricular function. Long-term follow-up demonstrates low sudden cardiac death rates.

Aged↗
PubMed1995

Radiofrequency ablation of atrial insertion of left-sided accessory pathways guided by the "W Sign".

INTRODUCTION: The aim of this study was to evaluate the efficacy of radiofrequency (RF) ablation of the atrial insertion of left-sided accessory pathways with guidance by a specific morphologic characteristic of the local electrogram, which we call the "W sign." This represents the shortest local atrioventricular (AV) interval during sinus rhythm in patients with manifest preexcitation or the shortest local VA interval during AV reciprocating tachycardia and/or ventricular pacing in patients with concealed accessory pathways. METHODS AND RESULTS: The transseptal technique was used in 31 patients (18 men, 13 women; aged 32 +/- 13 years), and RF ablation of 33 accessory pathways (26 manifest and 7 concealed) was attempted. Patients presented with palpitations (n = 16), presyncope (n = 10), or syncope (n = 5). The clinical arrhythmia was AV reciprocating tachycardia (n = 24) or atrial fibrillation (n = 7). In 21 patients (68%) electrophysiologic study and RF ablation were performed at a single session. Accessory pathways were left posteroseptal (n = 5) or left free wall (n = 28). The "W sign," formed from merging of the local atrial and ventricular electrograms, was identified at all successful sites prior to ablation. Ablation was successful in all patients. A median of 7 RF lesions were delivered per patient. The fluoroscopy time was 76 +/- 48 minutes; total procedure time was 5.4 +/- 1.9 hours. No significant complications occurred. Early recurrence (< or = 24 hours) occurred in 1 patient; during 6 +/- 4 months, accessory pathway conduction recurred in another patient. CONCLUSION: We conclude that RF ablation of the atrial insertion of left accessory pathways can be very successful when guided by the "W sign."

Adolescent↗
PubMed1994

Radiofrequency catheter ablation for cardiac tachyarrhythmias.

PURPOSE: To review the radiofrequency ablation method, describe the technique, and discuss the indications, results, and limitations of its use in patients with cardiac tachyarrhythmias. DATA SOURCES: 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. STUDY SELECTION: 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. RESULTS OF DATA SYNTHESIS: 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. CONCLUSIONS: 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.

Atrioventricular Node↗
PubMed1994

Transvenous endocardial cardioverter defibrillator systems. Is the future here?

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.

Defibrillators, Implantable↗
PubMed1994

Antitachycardia pacing and low-energy cardioversion for ventricular tachycardia termination: a clinical perspective.

When incorporated into tiered therapy implantable cardioverter defibrillators (ICDs), antitachycardia pacing (ATP) techniques have proved useful for termination of sustained monomorphic ventricular tachycardias (VT) and have the advantages of rapid delivery, absence of patient discomfort, and minimal battery drain. The efficacy of low-energy cardioversion (LEC) is similar to that of pacing techniques for VT termination, but LEC has the disadvantages of patient discomfort, atrial proarrhythmia, and greater battery drain compared with ATP. Acceleration of VT occurs with similar frequency with each technique. Neither technique should be used without back-up defibrillation capability in an ICD. VT termination algorithms are currently empiric and require repetitive arrhythmia induction and trials of ATP or LEC. Future studies of the risk and benefits of each technique are likely to define optimal programming strategies in tiered therapy ICDs.

Algorithms↗
PubMed1994

Fully transvenous cardioverter defibrillators: rare need for subcutaneous patch with two newer-generation systems.

In published series of nonthoractomy ICDs, there has invariably been a need for combining transvenous lead(s) with a subcutaneous patch to obtain adequate DFTs. Since the newer generation transvenous lead ICD systems became available for clinical investigation, we have tested and implanted 38 such systems in patients with drug-refractory malignant ventricular arrhythmias who were first seen with aborted sudden death (n = 10), syncope (n = 3), or sustained ventricular tachycardia (n = 25). These patients (mean age 60 +/- 15 years) had coronary artery disease (n = 25), congenital heart disease (n = 1), or cardiomyopathy (n = 12) as the underlying heart disease and a mean left ventricular ejection fraction of 34% +/- 16%. Seventeen (45%) patients had previous cardiac surgery (coronary bypass and/or valve replacement). The transvenous lead system included the Endotak C (single) lead of CPI (n = 27) or the EnGuard double-lead system of Telectronics (n = 11). The integrated pace/sense/defibrillation lead(s) were usually introduced via the left cephalic vein; after endocardiac positioning and testing, the leads were tunneled to the abdominal pocket in which the ICD device was implanted. DFTs were adequate for all patients (100%) and averaged 13.5 +/- 5.4 J (range 2.4 to 25 J). A subcutaneous patch or array was needed in only three patients. Because of protocol requirements, a subcutaneous patch or electrode array was intraoperatively tested in another three patients but was finally not implanted because better DFTs were achieved with the transvenous lead-alone configuration. The leads were combined with second-generation devices in 12 patients and third-generation ICDs in 26 (68%) patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Radiofrequency ablation of left-sided accessory pathways: transaortic versus transseptal approach.

The aim of this study was to compare the efficacy of transaortic (n = 54) and transseptal (n = 28) techniques during radiofrequency (RF) ablation of left accessory pathways (n = 75) in both left posteroseptal and free-wall locations in 73 consecutive patients (mean age 32 +/- 15 years). The transseptal approach included transseptal puncture and use of a retained long sheath in the left atrium (n = 24) or direct insertion of the mapping/ablation catheter via a patent foramen ovale (n = 4). Transseptal RF ablation was used as the primary method in 23 patients or at a separate session after the transaortic RF ablation failed in 5 patients. Transaortic RF ablation was used as primary method in 50 patients and after failed transseptal ablation in 4 patients. Transaortic ablation was successful in 47 (87%) of 54 procedures, transseptal ablation in 24 (86%) of 28 procedures, with total RF ablation success in 70 (96%) of 73 patients. The transseptal puncture/long sheath method was successful in 23 (96%) of 24 patients. This latter technique resulted in more stable positioning and easier manipulation of the ablation catheter. Switching from transseptal puncture/long sheath to transaortic technique was needed in 1 of 24 patients, from transseptal/patent foramen ovale approach to the transaortic route in 3 of 4 patients, and from the transaortic to the transseptal approach at a separate session in 5 patients. The age of patients and number of RF lesions were similar in the two groups. Fluoroscopy time was lower for the transseptal group (81 +/- 57 vs 121 +/- 81 min; p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Radiofrequency ablation of slow pathway in patients with atrioventricular nodal reentrant tachycardia. Do arrhythmia recurrences correlate with persistent slow pathway conduction or site of successful ablation?

BACKGROUND: Residual slow pathway conduction in the form of persistent jump in the atrioventricular (AV) conduction time or atrial echo beats is a common finding after successful radiofrequency (RF) ablation of the slow pathway in patients with AV nodal reentrant tachycardia (AVNRT). Sites of successful RF ablation of the slow pathway may be located anteriorly in the tricuspid annulus (cephalad to the coronary sinus os) or posteriorly (at, within, or caudal to the coronary sinus os). The aim of this study was to investigate whether arrhythmia recurrences correlate with persistent slow pathway conduction or site of successful ablation. METHODS AND RESULTS: Among 55 patients with symptomatic AVNRT having RF ablation, 23 patients (42%) (group 1) had evidence of persistent dual AV nodal pathway physiology and/or echo beats, whereas in 32 patients (group 2), slow pathway conduction had been completely eliminated. With regard to ablation sites, 14 patients (25%) (group A) had their slow pathway successfully ablated at an inferoposterior site, whereas in 41 patients (group B), the ablation site was located anteriorly to the coronary sinus os. The study patients included 17 men and 38 women, aged 37 +/- 18 years. The electrophysiological study and RF ablation were performed in a single session in 50 patients (91%). After the first session, the technique was successful in all patients (100%), with elimination of AVNRT and without affecting AV conduction. A mean of 9 +/- 6 lesions were applied. The total procedure time averaged 4 +/- 1 hours. Fluoroscopy time was 41 +/- 25 minutes. Except for transient AV block in 1 patient, no other complications occurred. Over 12 +/- 8 months, a total of 7 patients (13%) had recurrence of AVNRT, and 6 of them underwent successful repeat slow pathway RF ablation. Recurrence rate was 9% (2 patients) for group 1, with persistent jump or echo beats, and 16% (5 patients) for group 2, without residual slow pathway conduction (P = NS). Five of the recurrences (71%) were noted in group A and 2 in group B. Thus, the recurrence rate was 36% for group A (5 of 14 patients), with posterior ablations, and 5% for group B (2 of 41 patients), with anterior sites of successful RF ablation (P < .05). CONCLUSIONS: After successful RF ablation of the slow pathway in patients with AVNRT, residual slow pathway conduction does not correlate with clinical tachycardia recurrences. However, the site of successful RF ablation of the slow pathway does correlate with arrhythmia recurrences. More recurrences are observed when the site is located inferoposteriorly, at or below the os of the coronary sinus, as compared with medial and anterior locations of the ablation site.

Adolescent↗
PubMed1993

Plasma level changes of fibrinopeptide A after uncomplicated coronary angioplasty.

Fibrinopeptide A (FPA) is a small polypeptide cleaved from fibrinogen by thrombin, has a short half-life, and is considered a sensitive biochemical marker of thrombin activity, fibrin generation, and ongoing thrombosis. Increased plasma levels of FPA have been reported in various procoagulable and thrombotic medical and cardiovascular disorders, including acute myocardial infarction, unstable angina, and sudden cardiac death. However, activation of thrombosis by the arterial injury incurred during coronary angioplasty has not been systematically examined with use of plasma FPA measurements. To detect and monitor activation of thrombosis by coronary angioplasty, plasma levels of FPA were obtained by venipuncture and measured by radioimmunoassay before, immediately after, 24 to 48 h later, and 1 and 3 months after uncomplicated coronary angioplasty. From December 1990 through June 1991, FPA was measured in 30 patients (28 men and 2 women, aged 54 +/- 9 years) with coronary artery disease who were undergoing coronary angioplasty. The mean left ventricular ejection fraction was 55 +/- 7%. The dilated vessel was the left anterior descending coronary artery in 20 patients (together with a second vessel in 2), the right coronary artery in 9, and the left circumflex in 1. The procedure was successful and free of major complications in all patients. Before angioplasty the FPA levels averaged 6.50 +/- 1.18 ng/ml. Shortly after angioplasty they rose to 20.20 +/- 7.91 ng/ml (p = 0.08) despite intravenous heparin. At 24 to 48 h and after heparin had been discontinued for at least 4 h, the mean FPA levels were significantly higher (32.33 +/- 10.86 ng/ml) compared with baseline values (p = 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1993

Effects of coronary artery bypass grafting on ventricular arrhythmias: results with electrophysiological testing and long-term follow-up.

Myocardial revascularization was performed in 56 patients with coronary artery disease who presented with ventricular tachycardia (VT) (n = 39) or ventricular fibrillation (n = 17). There were 46 men and 10 women, aged 65 +/- 10 years. Three vessel (n = 42) or left main disease (n = 4) was present in 82%. Left ventricular ejection fraction averaged 36% +/- 11%. Electrophysiological studies were performed preoperatively in all patients; 50 (89%) had inducible ventricular arrhythmias. Sustained monomorphic VT was induced in 40 patients (cycle length 284 +/- 61 msec). Reproducible symptomatic nonsustained VT was induced in four patients and ventricular fibrillation in six patients, while six patients had no inducible arrhythmia. Preoperatively the patients with inducible VT failed 3.3 +/- 1.2 drug trials during electrophysiological studies. In addition to coronary bypass, 22 patients also received an automatic implantable cardioverter defibrillator (ICD), 26 patients received prophylactic ICD patches, and 1 patient had resection of a false aneurysm. There were no perioperative deaths. Postoperative electrophysiological studies were performed in all 56 surgical survivors. Ventricular tachyarrhythmia could not be induced in the six patients who had no inducible VT preoperatively and in 13 of 40 (33%) with preoperatively inducible sustained VT or in 19 of 50 (38%) patients with any previously inducible ventricular arrhythmia, thus a total of 25 patients (45%) had no inducible VT postoperatively. Of the remaining, 11 patients were treated with antiarrhythmic drugs alone, 11 had already received an ICD (combined with drugs in 7), and another 9 received the ICD postoperatively (combined with drugs in 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Cost-effectiveness of radiofrequency ablation compared with other strategies in Wolff-Parkinson-White syndrome.

BACKGROUND: Patients with Wolff-Parkinson-White syndrome fall into four risk groups: those with (1) prior cardiac arrest, (2) paroxysmal supraventricular tachycardia or atrial fibrillation (PSVT/AF) with hemodynamic compromise, (3) PSVT/AF without hemodynamic compromise, and (4) no symptoms. METHODS AND RESULTS: For each group, we developed a cost-effectiveness analysis examining five clinical management strategies: (1) observation, (2) observation until a cardiac arrest dictates the need for therapy, (3) initial drug therapy guided by noninvasive monitoring, (4) initial radiofrequency ablation (RFA), and (5) initial surgical ablation. We used a Markov simulation model to estimate life expectancy and costs for patients whose ages are between 20 and 60 years. The model includes the risks of cardiac arrest, PSVT/AF, drug side effects, procedure-related complications and mortality, the efficacy of drugs and RFA, and costs. Based on literature and expert opinion, we assumed that the annual risks of cardiac arrest are 0.01%, 0.05%, and 0.5%, respectively, in patients who are asymptomatic, who had PSVT/AF without hemodynamic compromise, or who had PSVT/AF with hemodynamic compromise. We also assumed that RFA has an overall efficacy of 92% in preventing cardiac arrest and arrhythmias. Our model predicts that RFA should yield a life expectancy greater than or equal to other strategies. In cardiac arrest survivors and patients who have had PSVT/AF with hemodynamic compromise, our model suggests that RFA should both prolong survival and save resources. For patients with PSVT/AF without hemodynamic compromise, the marginal cost-effectiveness of attempted RFA (followed by conservative treatment if the RFA fails) ranges from $6600 per quality-adjusted life year (QALY) gained for 20-year-old patients to $19,000 per QALY gained for 60-year-old patients. For asymptomatic patients, RFA costs from $174,000 per QALY gained for 20-year-old patients to $540,000 per QALY gained for 60-year-old patients. CONCLUSIONS: Our analysis supports the emerging practice of performing RFA in patients with Wolff-Parkinson-White syndrome who survive cardiac arrest or who experience PSVT/AF but also supports the current practice of observing asymptomatic patients.

Adult↗
PubMed1993

The clinical spectrum and diagnosis of syncope.

Syncope is a symptom of a wide variety of underlying disorders. As such, it is a common and challenging clinical problem with different pathophysiologic mechanisms and prognostic implications. The clinical spectrum of etiologies of syncope includes disorders classified as cardiovascular, noncardiovascular and unexplained. Generally, in patients in whom an initial diagnosis can be made, in the majority this is usually accomplished by a detailed history and thorough physical examination, that includes orthostatic vital signs and carotid sinus pressure. In the remaining cases, that can be as many as 50% of patients, the objective of subsequent noninvasive evaluation is to diagnose the cause of syncope, but also to stratify the patients in those with and those without underlying structural heart disease, and selectively apply additional more specialized or invasive tests. Cardiac syncope, and particularly when ventricular tachycardia is the cause, has the worst prognosis with 20 to 30% one-year mortality. This realization prompts rigorous effort in diagnosing or excluding an arrhythmic cause and applying aggressive therapy in such high risk patients. Thus, if after conventional noninvasive testing the etiology of syncope remains elusive in patients with underlying structural heart disease, electrophysiologic studies should be performed. Electrophysiologic studies identify a potential cause in up to two thirds of these patients. Treatment based on electrophysiologic diagnoses is effective in preventing syncope recurrences but may also reduce cardiac mortality. In patients without structural heart disease, head-up tilt testing has been very useful in diagnosing neurally mediated syncope and guiding its therapy. Finally in patients with recurrent syncope which remains unexplained despite extensive testing, a loop monitor may record the rhythm during an episode and provide or exclude a diagnosis. The discussion in this article serves as a brief overview of the clinical spectrum of syncope and describes a stepwise and systematic approach to diagnosis of this common, albeit challenging, medical problem, with emphasis on recent developments in the syncope work-up.

Arrhythmias, Cardiac↗
PubMed1992

Limited clinical utility of endomyocardial biopsy in patients presenting with ventricular tachycardia without apparent structural heart disease.

To determine the cardiac pathology underlying ventricular tachyarrhythmias, endomyocardial biopsy was performed in 14 patients, 10 men and 4 women, with a mean age of 40 years (range 17-63) and no apparent structural heart disease, presenting with high-density symptomatic nonsustained ventricular tachycardia (VT) (n = 4), sustained VT (n = 6), and ventricular fibrillation (n = 4). The absence of coronary or valvular heart disease was documented by cardiac catheterization. The mean left ventricular ejection fraction was 56 +/- 10%. Noninvasive assessment of the ventricular arrhythmia was made in all patients with Holter monitoring and/or exercise testing, while invasive evaluation with programmed electrical stimulation was performed in 13 patients. Biopsy findings included subendocardial and interstitial fibrosis in 7 patients, and monocytes containing periodic acid Schiff (PAS) positive vacuoles in 1 patient; biopsy was normal in 6 patients. There was no relationship between the presence or absence of pathologic abnormalities on biopsy and left ventricular ejection fraction, presenting or induced arrhythmias, or prognosis. Pathologic evidence supporting a specific treatable diagnosis was not present in any biopsy. Drugs to suppress spontaneous (3 patients) or induced (8 patients) VT were instituted, while 2 patients were not treated. In 1 patient who was resuscitated from out-of-hospital cardiac arrest an automatic defibrillator was implanted. In 24.6 months of mean follow-up there was 1 nonfatal arrhythmia recurrence, 1 noncardiac death, and 1 sudden death in a patient with fibrosis on biopsy, an ejection fraction of 45%, and both inducible and spontaneous sustained VT suppressed with an antiarrhythmic agent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Cost-effectiveness of the implantable cardioverter-defibrillator: effect of improved battery life and comparison with amiodarone therapy.

The implantable cardioverter-defibrillator (ICD) greatly reduces the incidence of sudden cardiac death among patients with recurrent sustained ventricular tachycardia and fibrillation who do not respond to conventional antiarrhythmic therapy. A cost-effectiveness analysis was performed, comparing the ICD, amiodarone and conventional agents. Actual variable costs of hospitalization and follow-up care were used for 21 ICD- and 43 amiodarone-treated patients. Life expectancy and total variable costs were predicted with use of a Markov decision analytic model. Clinical event rates and probabilities were based on published reports or expert opinion. Life expectancy with an ICD (6.1 years) was 50% greater than that associated with treatment with amiodarone (3.9 years) and 2.5 times that associated with conventional treatment (2.5 years). Assuming replacement every 24 months, ICD lifetime treatment costs (in 1989 dollars) for a 55-year old patient are expected to be $89,600 compared with $24,800 for amiodarone and $16,100 for conventional therapy, yielding a marginal cost/effectiveness ratio for ICD versus amiodarone therapy of 1f429,200/year of life saved, which is comparable to that of other accepted medical treatments. If technologic improvements extend average battery life to 36 months, the marginal cost/effectiveness ratio would be $21,800/year of life saved, and at 96 months it would be $13,800/year of life saved. Patient age at implantation did not significantly affect these results. If quality of life on amiodarone therapy is 30% lower than that with the ICD, the marginal cost/effectiveness ratio decreases by 35%. If the quality of life for patients receiving drugs is 40% lower than that of patients treated with an ICD, use of the defibrillator becomes the dominant strategy.

Amiodarone↗
PubMed1992

Electrophysiological and electropharmacological studies in pre-excitation syndromes: results with propafenone therapy and isoproterenol infusion testing.

To study the electrophysiological effects of oral propafenone on accessory pathways and determine the potential for catecholamine-mediated reversal of these effects, comprehensive electrophysiology studies (EPS) were conducted in 11 patients with manifest (n = 9) or concealed (n = 2) pre-excitation syndrome. EPS were performed at baseline (in the drug-free state), after oral propafenone loading, and with isoproterenol infusion during propafenone therapy. The study group included 10 men and 1 woman with a mean age of 39 +/- 13 years, who presented with symptoms of palpitations (n = 6), presyncope (n = 3) and syncope (n = 2). The clinical arrhythmia was atrioventricular reciprocating tachycardia (n = 6), atrial flutter/fibrillation (n = 3), or both (n = 2). During the baseline EPS the accessory pathway location was identified as left (n = 6) or septal (n = 5). The mean anterograde effective refractory period was 265 +/- 42 ms, the shortest pre-excited RR interval 259 +/- 20 ms and the retrograde refractory period 258 +/- 39 ms. Orthodromic atrioventricular reciprocating tachycardia was induced in 10 patients (mean cycle length = 324 +/- 31 ms). Antidromic reciprocating tachycardia was induced in one patient (cycle length = 340 ms). In all the 11 patients EPS were repeated after 4 days of oral propafenone loading (668 +/- 226 mg daily) when drug steady state was expected to have been achieved. One additional patient had baseline EPS but developed clinical arrhythmia recurrences after propafenone loading and thus he was excluded from the study; follow-up EPS were conducted on procainamide.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1992

Effect of successful coronary angioplasty on the signal-averaged electrocardiogram.

The effect of successful coronary artery angioplasty on the signal-averaged electrocardiogram (SAECG) was examined in 50 patients (41 men, 9 women, aged 55 +/- 8 years) with stable (26 patients) or unstable angina (24 patients) and good overall left ventricular function (ejection fraction = 55% +/- 8%). The SAECG was recorded before and within 24-48 hours after the angioplasty and was filtered at 40-250 Hz, with 250 beats averaged. The noise level averaged 0.57 +/- 0.15 microV before and 0.56 +/- 0.17 microV after the procedure. There was no overall significant difference between pre- and postangioplasty SAECGs. Subgroup analysis showed that 14 patients had a significant increase of the root mean square voltage of the last 40 msec of the filtered QRS that was independent of noise level changes, previous myocardial infarction, stable or unstable angina status, positive or negative baseline SAECG, or vessel being dilated. Eleven patients (22%) had late potentials at baseline, of whom four (36%) lost them after angioplasty, while one patient developed them after the procedure, all due to root mean square voltage changes. Thus, successful angioplasty exerted no significant overall effect on the SAECG, suggesting that the substrate of late potentials was not grossly altered by the procedure in our patients. However, there appear to be some patients, constituting approximately one third of this study population, who derive a favorable influence on the SAECG from angioplasty, a subgroup that needs to be further defined in future studies.

Angina Pectoris↗
PubMed1990

Electrophysiologic and electrocardiographic effects, efficacy and safety of encainide in malignant ventricular arrhythmias associated with coronary artery disease.

The electrophysiologic and electrocardiographic effects, efficacy and safety of encainide were evaluated in 48 patients with coronary artery disease undergoing programmed stimulation for ventricular tachyarrhythmias. The study group included 41 men and 7 women, aged 64 +/- 8 years (mean +/- standard deviation), who had presented with nonsustained ventricular tachycardia (VT) (4 patients), sustained VT (32), ventricular fibrillation (8) or unexplained syncope (4). The left ventricular ejection fraction averaged 34 +/- 13%. The arrhythmias induced at the baseline, drug-free electrophysiologic study included nonsustained VT in 8 patients, sustained VT in 35 and ventricular fibrillation in 5. All patients had failed greater than or equal to 1 class IA and a combination of class IA and IB agents (mean 2.2 +/- 1.1 drugs) before encainide. Oral encainide was given in a mean daily dose of 80 +/- 11 mg for greater than or equal to 3 days before repeat programmed stimulation. Encainide was discontinued before follow-up electrophysiologic testing in 5 patients due to spontaneous development of new sustained VT. Of the 43 patients undergoing electropharmacologic testing with encainide, 5 had no inducible arrhythmia. In 9 patients VT was inducible by fewer extrastimuli, in 2 patients a previously stable VT required cardioversion, whereas in 28 patients VT remained inducible by the same number of or more extrastimuli. Thus, encainide prevented the induction of VT or ventricular fibrillation in 5 of 48 patients (10%), while it had a possible proarrhythmic effect in 15 patients (31%). Of the 5 patients without inducible VT administered long-term encainide therapy, 1 returned within 4 weeks of hospital discharge with VT recurrence.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗