Arrhythmias In Adults Research Articles

377 Electrophysiological properties and radiofrequency catheter ablation for arrhythmias in adults associated with congenital heart disease

377 Electrophysiological properties and radiofrequency catheter ablation for arrhythmias in adults associated with congenital heart disease

958 Investigation of undocumented arrhythmias in adults late after repair of tetralogy of Fallot: a risk stratification study

958 Investigation of undocumented arrhythmias in adults late after repair of tetralogy of Fallot: a risk stratification study

958 Investigation of undocumented arrhythmias in adults late after repair of tetralogy of Fallot: a risk stratification study

958 Investigation of undocumented arrhythmias in adults late after repair of tetralogy of Fallot: a risk stratification study

377 Electrophysiological properties and radiofrequency catheter ablation for arrhythmias in adults associated with congenital heart disease

377 Electrophysiological properties and radiofrequency catheter ablation for arrhythmias in adults associated with congenital heart disease

Introduction of nurse led DC cardioversion service in day surgery unit: prospective audit

Problem Atrial fibrillation is the most common persistent arrhythmia in adults and carries an increased risk of thromboembolism and stroke. Electrical (DC) cardioversion is an effective treatment, but logistical difficulties...

Perioperative cardiac arrhythmias

Cardiac arrhythmias are a significant cause of morbidity and mortality in the perioperative period. While literature on antiarrhythmic agent use in postoperative and non-surgical intensive care settings is expanding, randomized clinical trials examining the use of these agents in the perioperative period are scarce. Nonetheless, as our understanding of the relevant molecular targets for manipulating cardiac excitability grows, the range of options for treating arrhythmias during surgery expands. In the sections that follow, these molecular targets are used as a basis for clinical management strategies for arrhythmias in adults during surgery and anaesthesia. In addition, the controversy surrounding droperidol and its reported proarrhythmic effects will be addressed. Finally, since pacemakers and implantable cardioverter-defibrillators (ICD) have gained widespread use in the treatment of tachyarrhythmias and bradyarrhythmias, a basic understanding of their perioperative function and management is discussed.

Predicting late sudden death from ventricular arrhythmia in adults following surgical repair of tetralogy of Fallot.

Tetralogy of Fallot was the first complex congenital cardiac defect to undergo open repair. The life expectancy and quality of life of those surviving surgery is now good, although late survival is compromised by the occurrence of sudden death. The emergence of successful methods for both the prevention of arrhythmias (including valve replacements and electrophysiological ablation) and the treatment of arrhythmias when they occur (including implantable defibrillators), has meant the identification of those at risk is of even greater importance. This paper reviews the predictive methods currently available to the practising physician caring for these increasingly common patients.

Atrial Fibrillation in the Elderly.

Atrial fibrillation (AF) is the most common sustained arrhythmia in adults, and its incidence and prevalence increase progressively with age. As a result, AF-associated morbidity and mortality increase with age. Therefore, because even asymptomatic AF markedly increases the risk of stroke and other embolic events, aggressive treatment is warranted in order to avoid the potentially devastating sequelae of this condition. Goals for the treatment of AF in the elderly population should primarily focus on alleviation of symptoms and prevention of strokes, while minimizing potential toxic effects of polypharmacy. Rate control should be optimized with atrioventricular (AV) nodal- blocking agents. The decision of anticoagulation should be individualized for each patient, balancing the risk of stroke against the risk for major bleeding complications. In elderly patients without symptoms, rate control and anticoagulation is the preferred method of treatment. Antiarrhythmic therapy to maintain sinus rhythm is generally reserved for patients with significant symptoms attributable to AF. However, simply maintaining sinus rhythm has not been proven to decrease stroke risk; therefore, long-term anticoagulation is recommended even in patients who are in sinus rhythm on antiarrhythmic drugs. AV nodal ablation with implantation of a pacemaker is a safe and excellent method of rate control for elderly patients who do not respond adequately to pharmacotherapy. Other invasive procedures, such as pulmonary vein isolation and Cox-Maze operations, are associated with high risks of complications in the elderly and are generally not recommended. Postoperative AF is common in the elderly population, and its development in high-risk patients should be anticipated and promptly treated to avoid potential hemodynamic compromise and prolonged hospitalization.

Detecting and diagnosing arrhythmias in adults with congenital heart disease.

Arrhythmias are a major cause of morbidity and mortality in adults with congenital heart disease; they can range from occult asymptomatic sinus node disease to sudden death. Detecting and diagnosing these arrhythmias presents a challenge when caring for these patients. A high index of suspicion is necessary, as well as a thorough understanding of the underlying heart defect and subsequent surgical interventions. A careful history, noninvasive evaluation, and in some cases invasive testing are all necessary to determine arrhythmias in this population.

Therapy of atrial fibrillation

Atrial fibrillation is the most common cardiac arrhythmia in adults. Paroxysmal atrial fibrillation terminates spontaneously, whereas the persistent form terminates only after medical or electrical cardioversion. Permanent atrial fibrillation cannot be cardioverted. Restoration of sinus rhythm can be achieved by antiarrhythmic drugs or electrical cardioversion, both performed under continuous electrocardiographic monitoring. If atrial fibrillation has lasted longer than 48 hours or the precise time of onset cannot be determined, there are two alternative approaches: systemic anticoagulation to achieve an international normalised ratio (INR) of 2.0 to 3.0 for at least three weeks, followed by cardioversion; or cardioversion guided by transesophageal echocadiography indicating the absence of thrombus. Several drugs have been shown to be effective for the maintenance of sinus rhythm. Anticoagulant therapy is mandatory for a minimum of three weeks after cardioversion. In case of drug refractory, highly symptomatic atrial fibrillation the indication for radiofrequency catheter ablation should be discussed, although the value of this new method is still under evaluation.

Anticoagulation in management of atrial fibrillation

Atrial fibrillation is the most common cardiac arrhythmia in adults. The prevalence of atrial fibrillation rises with age, reaching as high as 9% in those 70 years and older. Currently there are 2.2 million affected people in the United States, with twice the mortality rate of age-matched controls in sinus rhythm. Epidemiologic studies show atrial fibrillation to be responsible for as many as 15% of the total number of strokes, a higher incidence of dementia, cardiac function compromise, and decreased quality of life. Recent studies indicate that rate control and rhythm restoration are equally effective strategies in the treatment of atrial fibrillation, with a trend toward better survival in patients treated for rate control and anticoagulation. Data from several randomized controlled studies on stroke prophylaxis provided consistent evidence of the superiority of adjusted-dose warfarin over aspirin. Guidelines developed by the American College of Cardiology, the American Heart Association, the European Society of Cardiology, and ACCP provide a convenient decision-making framework for the practicing physician. The safety and effectiveness of anticoagulation in clinical practice were found to be equal to those in major trials with rigorous controls. Despite the proven effectiveness and safety of oral anticoagulation for thromboembolism prophylaxis in atrial fibrillation, warfarin remains underused, especially among the elderly (75 years and older), who are at the greatest risk of stroke and would likely benefit the most from prophylactic anticoagulation.

Anticoagulation in management of atrial fibrillation.

Atrial fibrillation is the most common cardiac arrhythmia in adults. The prevalence of atrial fibrillation rises with age, reaching as high as 9% in those 70 years and older. Currently there are 2.2 million affected people in the United States, with twice the mortality rate of age-matched controls in sinus rhythm. Epidemiologic studies show atrial fibrillation to be responsible for as many as 15% of the total number of strokes, a higher incidence of dementia, cardiac function compromise, and decreased quality of life. Recent studies indicate that rate control and rhythm restoration are equally effective strategies in the treatment of atrial fibrillation, with a trend toward better survival in patients treated for rate control and anticoagulation. Data from several randomized controlled studies on stroke prophylaxis provided consistent evidence of the superiority of adjusted-dose warfarin over aspirin. Guidelines developed by the American College of Cardiology, the American Heart Association, the European Society of Cardiology, and ACCP provide a convenient decision-making framework for the practicing physician. The safety and effectiveness of anticoagulation in clinical practice were found to be equal to those in major trials with rigorous controls. Despite the proven effectiveness and safety of oral anticoagulation for thromboembolism prophylaxis in atrial fibrillation, warfarin remains underused, especially among the elderly (75 years and older), who are at the greatest risk of stroke and would likely benefit the most from prophylactic anticoagulation.

Prevalence of and risk factors for atrial fibrillation and intra-atrial reentrant tachycardia among patients with congenital heart disease

Atrial arrhythmias are common late sequelae of congenital heart disease (CHD), and several reports have documented their high prevalence in the late postoperative period. 1 Bink-Boelkens M.T. Meuzelaar K.J. Eygelaar A. Arrhythmias after repair of secundum atrial septal defect the influence of surgical modification. Am Heart J. 1988; 115: 629-633 Crossref PubMed Scopus (43) Google Scholar , 2 Roos-Hesselink J. Perlroth M.G. McGhie J. Spitaels S. Atrial arrhythmias in adults after repair of tetralogy of Fallot Correlations with clinical, exercise, and echocardiographic findings. Circulation. 1995; 91: 2214-2219 Crossref PubMed Scopus (225) Google Scholar , 3 Gelatt M. Hamilton R.M. McCrindle B.W. Connelly M. Davis A. Harris L. Gow R.M. Williams W.G. Trusler G.A. Freedom R.M. Arrhythmia and mortality after the Mustard procedure a 30-year single-center experience. J Am Coll Cardiol. 1997; 29: 194-201 Crossref PubMed Scopus (393) Google Scholar , 4 Gelatt M. Hamilton R.M. McCrindle B.W. Gow R.M. Williams W.G. Trusler G.A. Freedom R.M. Risk factors for atrial tachyarrhythmias after the Fontan operation. J Am Coll Cardiol. 1994; 24: 1735-1741 Crossref PubMed Scopus (231) Google Scholar These arrhythmias are associated with impaired quality of life, increased risk of thromboembolism, and death. They are difficult to control, with variable response to antiarrhythmic drug therapy, repeated cardioversion, and ablative and surgical intervention. The etiology, mechanism, and clinical significance of intra-atrial reentry tachycardia (IART) have been characterized in patients with CHD by epidemiologic study, 4 Gelatt M. Hamilton R.M. McCrindle B.W. Gow R.M. Williams W.G. Trusler G.A. Freedom R.M. Risk factors for atrial tachyarrhythmias after the Fontan operation. J Am Coll Cardiol. 1994; 24: 1735-1741 Crossref PubMed Scopus (231) Google Scholar in animal models, 5 Rodefeld M.D. Bromberg B.I. Schuessler R.B. Boineau J.P. Cox J.L. Huddleston C.B. Atrial flutter after lateral tunnel construction in the modified Fontan operation a canine model. J Thorac Cardiovasc Surg. 1996; 111: 514-526 Abstract Full Text Full Text PDF PubMed Scopus (82) Google Scholar and by electroanatomic mapping and ablation. 6 Love B.A. Collins K.K. Walsh E.P. Triedman J.K. Electroanatomic characterization of conduction barriers in sinus/atrially paced rhythm and association with intra-atrial reentrant tachycardia circuits following congenital heart disease surgery. J Cardiovasc Electrophysiol. 2001; 12: 17-25 Crossref PubMed Scopus (95) Google Scholar In contrast, atrial fibrillation (AF) is less well understood in these patients. This study describes a large cohort of patients with CHD with late atrial arrhythmias. We sought to identify the clinical and temporal characteristics that distinguish patients with AF and with IART, and to ascertain whether there was any temporal evolution between the 2 arrhythmias.

Management of ventricular arrhythmias in adults with congenital heart disease.

The management of ventricular arrhythmias in adults with congenital heart disease is becoming increasingly more important. Ventricular arrhythmias are associated with a number of congenital heart defects (particularly tetralogy of Fallot), and sudden death. A number of invasive and noninvasive methods have been applied to identify those patients at risk, although indications and the prognostic value of these tests are unclear. Treatment of ventricular arrhythmias in this population include antiarrhythmic medications, catheter ablation, surgery, and implantable cardiac defibrillators.

Geophysical variables and behavior: CIII. Days with sudden infant deaths and cardiac arrhythmias in adults share a factor with PC1 geomagnetic pulsations: implications for pursuing mechanism.

If geomagnetic-mediated stimuli trigger many sudden infant deaths, then the days in which they and hospital admissions for cardiac arrhythmias for adults occur should share a similar source of variance. Factor analyses of the days in which a sudden infant death occurred in Ontario or adults were admitted for one of eight categories of cardiac crisis in the Sudbury (Ontario) Region for the year 1984 supported the hypothesis. This factor, with which infant deaths and adult cardiac arrhythmias each shared about 40% of their variance, also shared about 40% of the variance with a factor with which about 35% of the variance in daily occurrence of geomagnetic pulsations (0.2 Hz to 5 Hz) was associated. These results are consistent with the important role of geomagnetic variables in the occurrence of transient electrical anomalies in brain function rather than cardiac blood flow.

Atrial Arrhythmias in Adults After Repair of Tetralogy of Fallot

The long-term success of intracardiac repair of tetralogy of Fallot is hampered by the occurrence of arrhythmias. Numerous studies have stressed the potential role of ventricular arrhythmias. However, the importance of other arrhythmias in the morbidity of these patients appears to be underestimated. Furthermore, most follow-up studies have been limited to children or adolescents, whereas many patients have reached adulthood after earlier repair of tetralogy of Fallot. The aim of the present study was to determine the incidence of atrial fibrillation, atrial flutter, and other supraventricular arrhythmias in adult patients after intracardiac repair for tetralogy of Fallot and their correlation with surgical and clinical findings. The study group consisted of 53 consecutive patients referred to the Thoraxcenter adult congenital heart disease clinic. They underwent repair at a mean age of 9.1 years (range, 0.7 to 55 years). The median age at the time of study was 23.2 years (range, 15 to 57 years; mean age, 26.6 years), and the mean duration of follow-up of 17.5 years (range, 1.4 to 32 years) after surgery. Records were reviewed extensively for evidence of arrhythmias. The follow-up study included routine 12-lead ECG, 24-hour continuous ambulatory monitoring, and echocardiography, and 46 patients underwent exercise testing. Sinus node dysfunction was recorded in 19 patients (36%), of whom 4 required a permanent pacemaker. Atrial fibrillation or flutter was found in 12 patients, and other supraventricular tachycardias were found in 6. The former were more frequently of older age at follow-up. Antiarrhythmic therapy and cardioversion were typically directed at control of atrial (and not ventricular) tachyarrhythmias. Ten patients (19%) showed nonsustained ventricular tachycardia; they were older at initial surgery and older at follow-up and had more intracardiac repairs and longer cardiopulmonary bypass times. Despite an emphasis on ventricular ectopy in past series, the main sources of morbidity in adult patients after surgical correction of tetralogy of Fallot emanated from atrial arrhythmias, which were present in one third of the patients.

Treatment of ventricular arrhythmias in children without structural heart disease with class IC agents as guided by invasive electrophysiology

Although the efficacy of class IC antiarrhythmic agents in the treatment of supraventricular and ventricular arrhythmias in adults has been clearly demonstrated, serious proarrhythmic effects have been reported. 1 These agents have also proven useful in the pediatric population, but there is growing concern that similar proarrhythmic potential exists. 2,3 Recognizing that these drugs, although very useful, may also be deadly, we have adopted a protocol at the Medical University of South Carolina that uses invasive ventricular stimulation after drug administration to help assess the risk/benefit ratio of these agents in the treatment of ventricular arrhythmias. Since mid-1987, all 23 children with ventricular arrhythmias treated with IC agents have had invasive stimulation performed after drug administration to evaluate efficacy or proarrhythmia, or both. Ten of these children with structurally normal hearts, treated solely with IC agents, were tested in the electrophysiology laboratory both before and after drug administration; data from these 10 patients were used in this investigation (Table I). I Class IC Therapy for Pediatric Ventricular Arrhythmias as Evaluated by Electrophysiologic Studies Pt. Age(yr) &Sex Clinical Arrhythmia VT Induced Before IC Therapy IC Therapy VT Induced After IC Therapy EPS 1 2F VT + Encainide 0 2 2F VT + Flecainide 0 3 5F VT + Flecainide 0 4 5M VT + Flecainide 0 5 8F VT + Flecainide 0 6 8F VT + Flecainide + 7 13M VT(NS) +(NS) Flecainide 0 8 15M VT(NS) +(NS) Flecainide 0 9 16M AF(NS) VT(NS) +(NS) Flecainide 0 10 18M VT(NS) +(NS) Encainide 0 AF = atrial flutter; EPS = electrophysiologic study; IC = class IC agent; NS = nonsustained; VT = ventricular tachycardia; + = present; 0 = absent.

Surgical treatment of right atrial focal tachycardia in adults

Although successful operative treatment of atrial focal tachycardia has been reported in children, there are only isolated reports of surgical treatment of this arrhythmia in adults. In this case series of eight patients (aged 10 to 53 years) with drug-resistant right atrial focal tachycardia, results of electrophysiologic studies, surgical techniques and long-term follow-up are described. Atrial focai tachycardia was reproduced during etectrophysiologic study, and endocardial mapping localized the earliest onset of atrial activation in the right atrium in all patients.Epicardial mapping confirmed the location of atrial tachycardia foci in seven of eight patients whose tachycardia was inducible intraoperatively. Of four patients treated with epicardial cryoablation alone, two had recurrent tachycardia and required a second procedure. None have had arrhythmia recurrence, in all four patients aftar right atrial excision (two of whom had intraoperative recurrence of atrial focal tachycardia alter epicardial cryoablation alone), there has been no recurrence during a clinical follow-up period of 11 to 67 mouths (mean 30).It is concluded that in adult patients 1) electrophysiologic study with endocardial and epicardial mapping permits successful surgical treatment of atrial focal tachycardia; 2) epicardial cryoablation alone may be associated with recurrence of atrial focal tachycardia either intraoperatively or postoperatively; and 3) subtotal right atrial resection appears to be a well tolerated procedure with no long-term recurrence of atrial focal tachycardia.

Acute termination of supraventricular tachyarrhythmias in children by transesophageal atrial pacing

S upraventricular tachyarrhythmia, in contrast to arrhythmias in adults, is the most common abnormal tachycardia in infants and chi1dren.l When the tachyarrhythmia is reentrant, conversion by physiologic, pharmacologic or electrical interruption of conduction within a limb of the circuit is highly probable. Manipulation of physiologic vagal tone, the obviously preferred mode, is not successful or feasible in a number of patients. Pharmacologic manipulation has been the most commonly used; however, digoxin and propranolol may require several hours for conversion. Intravenous administration of verapamil offers prompt termination2v3; however, in newborns it may be unsuccessful and carries the risk of hypotension, bradycardia, apnea and negative inotropy, especially in patients with coexisting congestive heart failure.4 Electrical conversion by transvenous atria1 pacing or by direct current cardioversion requires invasive entry for 1 technique and frequently general anesthesia for the other. Recent reports from our institution5-7 as well as from otherssvg have demonstrated the usefulness, simplicity and safety of transesophageal atria1 burst pacing for conversion of reentrant tachyarrhythmias in infants and children. The technique, however, has not been included among the recent recommendations of several authorities.10-12 Our purpose, therefore, is to report our experience with transesophageal pacing in infants and children so that the technique may be more widely known. 43 14f4 8-20 43 5f2 3-10

The Relationship Between Sinoatrial Conduction Time and Sinus Cycle Length During Spontaneous Sinus Arrhythmia in Adults

It is well known that atrioventricular conduction varies as a function of atrial rate. However, rate related changes in sinoatrial conduction time (SACT) have not been examined. To determine the relationship between SACT and sinoatrial cycle length (SCL) in man, atrial and His bundle electrograms were recorded during atrial premature stimulation in each of nineteen patients with sinus arrhythmia. Ten of nineteen had asymptomatic, intermittent sinus bradycardia; 3/19 had persistent sinus bradycardia with nonspecific symptoms; 6/19 were felt to represent the sick sinus syndrome. In 18/19 individuals, there was a clearcut, inverse, linear relationship between SACT and SCL, i.e., as SCL increased, SACT decreased. Although this resembles the increase in PR interval that occurs with a decrease in atrial cycle length during atrial pacing, it contrasts sharply with the unchanged or increased PR interval that accompanies spontaneous increases in SCL. Although the range of patients' SACTs at any given SCL was large, the slope of ΔSACT/ΔSCL was remarkably similar in most patients and was quite steep. One patient had episodes of 2:1 S-A block. As predicted, these occurred only at her shortest SCLs. Possible explanations for this behavior are considered and the clinical relevance of these observations is discussed.