Control of refractory cardiac arrhythmias with amiodarone.

Amiodarone hydrochloride was used to treat 19 patients with symptomatic arrhythmias refractory to quinidine sulfate, procainamide hydrochloride, disopyramide phosphate, antazoline hydrochloride, lidocaine hydrochloride, bretylium tosylate, propranolol hydrochloride, phenytoin sodium, and practotol acetanilide given to the limit of tolerance. In 17 patients, attacks were completely controlled. Arrhythmias treated successfully included recurrent supraventricular tachycardias, recurrent supraventricular tachycardias with Wolff-Parkinson-White syndrome, and refractory ventricular arrhythmias including recurrent ventricular tachycardia and ventricular fibrillation complicating acute coronary heart disease. Control was confirmed by continuous ECG monitoring both in the hospital and when ambulatory and was maintained for up to four years. Attacks of supraventricular tachycardia were reduced from 7.9/mo to one attack every 53.5 months on amiodarone. Hospital admissions for arrhythmias were reduced from 34 the year before treatment to none the year after. Therefore, amiodarone is an excellent drug for control of many refractory arrhythmias, but two patients with recurrent atrial fibrillation were refractory to this treatment.     

Patients with supraventricular tachycardia presenting with aborted sudden death: incidence, mechanism and long-term follow-up

A total of 13 (4.5%) of 290 patients with aborted sudden death had either documented (7; 54%) or strong presumptive evidence of supraventricular tachycardia that deteriorated into ventricular fibrillation. Six (46%) of the 13 had an accessory conduction pathway and either atrial fibrillation (5 patients) or paroxysmal atrioventricular (AV) reentrant tachycardia (1 patient) that deteriorated into ventricular fibrillation. Three patients with AV node reentrant tachycardia and four with atrial fibrillation and enhanced AV node conduction presented with supraventricular arrhythmias that deteriorated into ventricular fibrillation. Patients were treated with medical, surgical or catheter ablative procedures designed to prevent recurrences of supraventricular arrhythmias. Four patients received an implanted automatic defibrillator, but none had an appropriate device discharge. Over a follow-up period of 41.6 +/- 33.6 months, 12 patients are alive without symptomatic arrhythmias. One patient died because of severe chronic lung disease and heart failure. Supraventricular tachycardia was the cause of aborted sudden death in approximately 5% of patients referred for evaluation of sudden cardiac death. Treatment directed at prevention of supraventricular tachycardia was associated with an excellent prognosis. Current treatment techniques appear to obviate the need for automatic defibrillator therapy in these patients.     

Continuous rapid atrial pacing to control recurrent or sustained supraventricular tachycardias following open heart surgery.

A technique is described to control recurrent or sustained supraventricular tachycardia associated with rapid ventricular rates following open heart surgery. The technique utilizes a pair of temporarily implanted atrial epicardial wire electrodes to pace the heart. In one group of patients with recurrent atrial flutter and 2:1 A-V conduction, continuous rapid atrial pacing at 450 beats/min produced and sustained atrial fibrillation. The ventricular response rate immediately slowed when compared to that during atrial flutter, and if further slowing was required, it was easily accomplished by the administration of digitalis. Another group of patients with different arrhythmias (recurrent paroxysmal atrial tachycardia, sustained ectopic atrial tachycardia, or sinus rhythm with premature atrial beats which precipitated runs of atrial fibrillation) was treated with continuous rapid atrial pacing to produce 2:1 A-V block. In all instances, the continuous rapid atrial pacing suppressed the supraventricular tachycardia and maintained the ventricular response rate in a therapeutically desirable range. It was demonstrated that the technique is safe, effective, and reliable.     

Spectrum of regular tachycardias with wide QRS complexes in patients with accessory atrioventricular pathways

Reciprocating tachycardia and atrial flutter or fibrillation are the rhythm disorders most frequently documented in patients with accessory atrioventricular (A-V) pathways. Reciprocating tachycardia typically results in a regular tachycardia (140 to 250/min) with a normal QRS pattern, although on occasion bundle branch block aberration occurs. Atrial flutter or fibrillation may result in an irregular ventricular response, with the QRS configuration being normal or exhibiting bundle branch block or various degrees of ventricular preexcitation, or both. Although much less common than either reciprocating tachycardia or atrial flutter/fibrillation, regular tachycardias with a wide QRS complex suggestive of ventricular preexcitation are observed in patients with accessory pathways. Excluding functional or preexisting bundle branch block, several arrhythmias may cause these electrocardiographic findings which may mimic those of ventricular tachycardia.In the present study a variety of arrhythmias that resulted in tachycardias with a wide QRS complex were examined in 163 patients with accessory pathways who underwent clinical electrophysiologic study for evaluation of recurrent tachyarrhythmias. Twenty-six patients (15 percent) manifested a regular tachycardia with a wide QRS complex suggesting ventricular preexcitation. Atrial flutter with 1:1 anterograde conduction over an accessory pathway (15 of 26 patients, 58 percent) was the most frequent arrhythmia and was usually associated with a heart rate of 240/min or greater (12 of 15 patients). Reciprocating tachycardia with conduction in the anterograde direction over an accessory pathway (antidromic reciprocating tachycardia) occurred in 7 of 26 patients (27 percent), and resulted in a slower ventricular rate than atrial flutter (217 ± 22 versus 262 ± 42, P < 0.01). Other arrhythmias included reciprocating tachycardia with reentry utilizing a fasciculoventricular or nodoventricular connection (two patients, 8 percent), reciprocating tachycardia with reentry in the atrium or A-V node and anterograde accessory pathway conduction (one patient, 4 percent) and ventricular tachycardia (one patient, 4 percent).In this study the clinical electrophysiologic diagnostic features of several arrhythmias which cause tachycardias with a wide QRS compex suggesting ventricular preexcitation are outlined. It is apparent that definitive arrhythmia diagnosis during these tachycardias is often complex and usually requires careful study using intracardiac electrode catheter techniques.     

Arrhythmogenic implications of non-iatrogenic thyroid dysfunction

We studied all patients with hyperkinetic and hypokinetic arrhythmias, who were recovered in the Cardiology Department and Arrhythmologic Centre of S. Chiara Hospital in Trento between 1983 and 1987. From these we selected all the patients who, on admission, had clinical and biochemical symptoms of dysthyroidism. Of the 2465 patients with cardiac arrhythmias, 93 (3.8%) had an evident thyroid pathology which was due to chronic amiodarone treatment in 42 (44.6%) and was primary and non-iatrogenic in 51 (55.4%). In the latter the thyroid pathology consisted of hyperthyroidism in 43 cases (toxic nodular goitre or Graves' disease), and of hypothyroidism in 8. As regard the types of arrhythmias, hyperthyroidism is predominant in patients with atrial fibrillation (70%) and in those with paroxysmal supra-ventricular reciprocating tachycardia (11.5%), but it is also present in patients with hyperkinetic ventricular arrhythmias (14%). Hypothyroidism is found in patients with hyperkinetic ventricular arrhythmias (25%), atrial fibrillation (37.5%) and atrio-ventricular block (37.5%). The average age of the hyperthyroid population with atrial fibrillation is higher than that of patients with paroxysmal supraventricular reciprocating tachycardia. The control of the thyroid pattern, especially as regards atrial fibrillation and paroxysmal supraventricular reciprocating tachycardia results in absence of arrhythmic episodes even without treatment in 40% of cases, and in an easier drug control in the other cases. Our study indicates that it is necessary to carry out systematic research of a thyroid dysfunction in all patients with cardiac arrhythmias, especially as regards women, atrial fibrillation and paroxysmal supraventricular reciprocating tachycardia. It is also evident that in order to achieve long-term control over hyperkinetic arrhythmia it is very important to overcome hyperthyroidism.     

Arrhythmia in hypertrophic cardiomyopathy: exercise and 48 hour ambulatory electrocardiographic assessment with and without beta adrenergic blocking therapy

Submaximal treadmill exercise electrocardiography and 48 hour ambulatory electrocardiographic monitoring were performed in 30 patients with hypertrophic cardiomyopathy both with and without beta adrenergic blocking therapy. During ambulatory electrocardiographic monitoring 1 patient (3 percent) had no arrhythmia, 14 patients (46 percent) had supraventricular tachycardia or paroxysmal atrial fibrillation, 13 (43 percent) had multiform or paired ventricular extrasystoles and 8 (26 percent) had ventricular tachycardia. The frequency of these ventricular arrhythmias was almost identical with and without beta adrenergic blocking drugs (mean dose in "propranolol equivalents" 280 mg daily). With beta blocking therapy fewer patients had supraventricular tachycardia; however, the difference was not significant. During exercise testing 18 patients (60 percent) had ventricular extrasystoles and 3 patients (10 percent) had paired ventricular extrasystoles and the frequency was almost identical with and without beta adrenergic blocking therapy. No routine echocardiographic or hemodynamic measurement predicted the serious ventricular arrhythmias. It is concluded that asymptomatic ventricular arrhythmia is a common occurrence in patients with hypertrophic cardiomyopathy and its frequency is not reduced with beta adrenergic blocking therapy. Because occult arrhythmia may be the cause of sudden death it is important to detect it in these patients so that an effort can be made to improve prognosis with specific antiarrhythmic treatment.     

Arrhythmias and their treatment in patients with heart failure

Heart failure is almost without exception associated with arrhythmias, which may be either supraventricular or ventricular. Supraventricular arrhythmias include frequent supraventricular extrasystoles, and episodic or chronic atrial fibrillation. The absence of atrial contraction may further reduce cardiac output, as may impaired control of QRS frequency. Therefore, supraventricular arrhythmias may be markers of the degree of heart failure and these arrhythmias will respond to heart failure therapy including diuretics, nitrates and, possibly, angiotensin-converting enzyme (ACE) Inhibitors. Ventricular rate will be controlled by cardiac glycosides and further rate reduction obtained by verapamil or diltiazem. The rationale for this therapy is to optimize heart rate without compromising contractility. Severe heart failure is generally accompanied by severe ventricular arrhythmias including repetitive forms.

Improving left ventricular function by ACE inhibition is accompanied by a reduction in the number of ventricular premature complexes and also a reduction in the rate of ventricular tachycardia. ACE inhibition reduces mortality but does not seem to influence sudden death rate, and sudden death patients may have different neurohormonal responses compared with patients destined to die of progressive heart failure. Uncontrolled trials with class IA or class III antiarrhythmic drugs have suggested that prognosis may be improved, but other studies have pointed out the increased risk of proarrhythmic responses in patients with low ejection fraction.     

Repetitive responses to ventricular extrastimuli: incidence and significance in patients without organic heart disease

Of 110 patients without organic heart disease undergoing electrophysiologicalevaluation, 72 patients (65%) manifested some form of repetitiveventricular response to ventricular stimulation. In 58 (53%)bundle branch re-entry was induced and in 19 patients (17%)intraventricular re-entry. In five patients (4%) both typesof repetitive responses were initiated. The indication for studywas documented as ventricular tachycardia or fibrillation in13% of the patients, supraventricular tachycardia in 51% andWolff-Parkinson-White syndrome, syncope or conduction disturbancesin the remaining patients. The incidence of clinical and inducibleventricular tachycardia or fibrillation was 8 and 2% respectively,in the group of patients manifesting only bundle branch re-entry,37 and 32% in patients with intraventricular re-entry and 8and 11% in patients without repetitive ventricular responsesduring ventricular stimulation. The predictive value of intraventricularre-entry as an indicator of severe ventricular arrhythmias was36%. We conclude that in our population of patients without organicheart disease, bundle branch re-entry is a frequent findingand is not related to ventricular arrhythmias, that intraventricularre-entry is less frequent and although it is associated witha higher incidence of ventricular tachycardia or fibrillation,it is a poor predictor of these arrhythmias in this study population.     

Cardiac arrhythmias in patients with surgical repair of Ebstein's anomaly

Preoperative, perioperative and postoperative arrhythmias in 52 consecutive patients who underwent operation for Ebstein's anomaly were reviewed. There were 25 male and 27 female patients (mean age 18 years, range 11 months to 64 years). Thirty-four patients had one or more documented arrhythmias preoperatively (18 had paroxysmal supraventricular tachycardia, 10 had paroxysmal atrial fibrillation or flutter, 13 had ventricular arrhythmia and 3 had high grade atrioventricular block). Seven patients without documented arrhythmias had a history typical of tachyarrhythmias. During the perioperative and early postoperative periods, 14 patients had atrial tachyarrhythmias and 8 had ventricular tachycardia or ventricular fibrillation. There were seven deaths between day 1 and 27 months after operation. Five of these deaths were sudden (all in male patients, aged 12 to 34 years), and four of the patients had had perioperative ventricular tachycardia or ventricular fibrillation. One patient was taking one antiarrhythmic agent and another patient was taking two at the time of sudden death. Of the 18 patients with paroxysmal supraventricular tachycardia and 9 patients with paroxysmal atrial fibrillation or flutter preoperatively who were followed up for a mean of 40 and 36 months, respectively, 22 and 33% continued to have symptomatic tachycardia. Of the 11 patients (mean age 9 years) without preoperative documentation or symptoms of arrhythmia, follow-up data were obtained (range 1 to 144 months, mean 31) in 9 patients. None died suddenly or developed symptomatic arrhythmia.     

Akuttherapie lebensbedrohlicher tachykarder Rhythmusstörungen

Life-threatening supraventricular tachyarrhythmias include atrial fibrillation, atrial flutter, AV-nodal reentrant tachycardia with rapid ventricular response and preexcitation syndromes combined with atrial fibrillation. Ventricular tachyarrhythmias still remain one of the leading causes of death; these arrhythmias include monomorphic and polymorphic ventricular tachycardia, torsade de pointes tachycardia, ventricular fibrillation and ventricular flutter. In all patients with tachycardias, an attempt should be made to differentiate between narrow (QRS duration < 0.12 s) or wide QRS complex (QRS duration ≥ 0.12 s) tachycardias. In the assessment of patients (pts) with supraventricular/ventricular tachyarrhythmias, attention should be given to identify whether the tachycardia is associated with worsening angina or low cardiac output. In pts with narrow QRS complex tachycardias or pts with atrial fibrillation and preexcitation syndromes immediate synchronized cardioversion should be performed if signs or symptoms of instability (hypotension, evidence of end-organ dysfunction, worsening angina) exist. In pts with a stable hemodynamic situation, vagal maneuvers, adenosine or calcium channel blockers can be used. Management of atrial flutter usually centers on cardioversion or rapid atrial pacing to normal sinus rhythm. In the treatment of patients with deemed unstable ventricular tachycardia (VT), electrical cardioversion is the treatment of choice. In more stable patients, ajmaline is the preferred agent after myocardial infarction and lidocaine if myocardial ischemia is present. In pts with torsade de pointes tachycardias aggressive steps must be taken to prevent degeneration of this rhythm to ventricular fibrillation (VF). Magnesium sulfate has recently been demonstrated efficacious and is currently considered first-line drug therapy. Transcutaneous overdrive pacing should be attempted if magnesium is unsuccessful. The pt with pulseless VT or VF demands early electrical countershock.     

Clinical pharmacology of the new beta-adrenergic blocking drugs. Part 5. Pindolol (LB-46) therapy for supraventricular arrhythmia: a viable alternative to propranolol in patients with bronchospasm.

Pindolol (LB-46) is a new beta-adrenoceptor blocking agent with intrinsic sympathomimetic activity. In order to evaluate the efficacy of pindolol in the treatment of patients with supraventricular arrhythmias and propranolol-induced bronchospasm, 18 patients with paroxysmal supraventricular tachycardia, atrial fibrillation, atrial flutter, multifocal atrial tachycardia or junctional tachycardia, were treated with placebo followed by pindolol in intravenous and then oral form. Following a no-response placebo period (in all patients), intravenous pindolol converted six out of seven patients with paroxysmal supraventricular tachycardia to normal sinus rhythm. In six patients with atrial fibrillation, three reverted to normal sinus rhythm, and three remained in atrial fibrillation but with a slower ventricular response (less than 100 beats/minute). Of two patients with atrial flutter, one converted to normal sinus rhythm, while the other patient failed to respond. Both patients with junctional tachycardia and one with multifocal atrial tachycardia converted to normal sinus rhythm. Long-term oral pindolol therapy sustained these responses in most patients, as documented by serial Holter ECG studies. There was no deterioration in indices of airway resistance ($\text{FEV}{}_{\mathrm{1·0}}\text{VC}$) in patients treated with pindolol (both intravenously and orally), in contrast to a marked deterioration in $\text{FEV}{}_{\mathrm{1·0}}\text{VC}$ in the same patients treated with propranolol. Pindolol appears to be a reasonable substitute for propranolol in patients with bronchospastic illness who require beta-blockade for control of supraventricular arrhythmias.     

AMIODARONE THERAPY FOR LIFE THREATENING OR REFRACTORY CARDIAC ARRHYTHMIAS

Amiodarone was used in 40 patients with life-threatening or refractory tachyarrhythmias. Eighteen patients had recurrent ventricular tachycardia of whom 13 had suffered a cardiac arrest. Control has been excellent or good in 17 of these 18 patients during an average follow-up period of 10 months. A further 22 patients had supraventricular arrhythmias, including three with Wolff-Parkinson-White syndrome and paroxysmal atrial fibrillation. In 20 of these control has been excellent or good. The mean daily maintenance dose of amiodarone was 300 mg for patients with ventricular tachyarrhythmias and 200 mg for those with supraventricular tachyarrhythmias. Side-effects were common and included corneal microdeposits, skin rash and discolouration, alteration in thyroid function, and symptomatic bradycardia. Serious adverse effects were uncommon however and necessitated discontinuation of the drug in only two patients. Amiodarone did not appear to precipitate or exacerbate cardiac failure in any patient although many had severe left ventricular dysfunction. We conclude that amiodarone is effective in the therapy of life-threatening or refractory cardiac arrhythmias.     

Efficacy of Atrial Antitachycardia Functions for Treating Atrial Fibrillation: Observations in Patients with a Dual-Chamber Defibrillator

In patients with conventional indication for ICD implantation, atrial fibrillation may occur in more than 50% during the life-span of the device and may lead to severe adverse events. Dual chamber defibrillators with atrial antitachycardia functions, including prevention algorithms, arrhythmia detection capability and atrial therapy options (antitachy pacing and cardioversion) have been recently introduced. The aim of this review is to examine the effectiveness of these new devices and to identify patients who may benefit. We recently studied 112 patients who received the device because of life-threatening ventricular arrhythmias. Fifty-five percent of them had atrial fibrillation prior to implantation. During the follow-up (one year on average), 27% had at least one episode of sustained atrial tachyarrhythmia. Effectiveness of atrial antitachy pacing was 71% on regular atrial tachycardia and 36% on irregular atrial tachyarrhythmias. Atrial shock efficacy was over 90% when adequately programmed. Interestingly, near half of the episodes started as regular atrial tachycardia and accelerated and became less organized in few minutes. Early delivery of antitachy pacing may increase success rate and decrease the need for atrial shock. Furthermore, it may prevent atrial remodeling and reduce atrial fibrillation burden.Based on our experience, we recommend that all patients with a class I indication for defibrillator implantation (related to risk of ventricular arrhythmias) who have a history of or are at risk of developing atrial tachyarrhythmias should receive a dual chamber defibrillator equipped with atrial antitachycardia functions. Furthermore, patients either with a history of heart failure, with poor functional capacity (functional class III or IV), depressed left ventricular ejection fraction, a need for monitoring of atrial rhythm, or in whom there is some concern about appropriate detection of ventricular arrhythmias, may benefit from a single device capable of managing ventricular and supraventricular arrhythmias.     

Comparison of lidoflazine and quindine in prophylactic treatment of arrhythmias.

The efficacy of quinidine versus lidoflazine therapy was compared in the maintenance of sinus rhythm after electrical cardioversion for atrial flutter or fibrillation in a group of 35 patients. Both quinidine and lidoflazine were relatively ineffective in maintaining sinus rhythm after cardioversion. Lidoflazine was also used to prevent supraventricular and ventricular tachycardias in a miscellaneous group of patients; one of these with paroxysmal supraventricular tachycardia developed runs of venttricular tachycardia soon after starting lidoflazine. The trial was stopped after 4 patients died while receiving lidoflazine, on the suspicion that their deaths may have been related to drug-induced arrhythmias. The arrhythmogenic potential of lidoflazine when used in patients with supraventricular arrhythmias constrasts with reports of its apparent safety in large numbers of patients with angina pectoris.     

Comparison of lidoflazine and quindine in prophylactic treatment of arrhythmias.

The efficacy of quinidine versus lidoflazine therapy was compared in the maintenance of sinus rhythm after electrical cardioversion for atrial flutter or fibrillation in a group of 35 patients. Both quinidine and lidoflazine were relatively ineffective in maintaining sinus rhythm after cardioversion. Lidoflazine was also used to prevent supraventricular and ventricular tachycardias in a miscellaneous group of patients; one of these with paroxysmal supraventricular tachycardia developed runs of venttricular tachycardia soon after starting lidoflazine. The trial was stopped after 4 patients died while receiving lidoflazine, on the suspicion that their deaths may have been related to drug-induced arrhythmias. The arrhythmogenic potential of lidoflazine when used in patients with supraventricular arrhythmias constrasts with reports of its apparent safety in large numbers of patients with angina pectoris.     

Inappropriate Single Chamber ICD Discharges due to Supraventricular Tachycardia with High Degree Atrioventricular Block

Supraventricular tachycardia with rapid ventricular response is well recognized as the more frequent cause of single chamber ICD inappropriate therapies.We report here a 18-year-old-woman with surgically corrected transposition of the great arteries who received repetitive inappropriate discharges from an ICD implanted for ventricular tachycardia. Rapid atrial activity during episodes of supraventricular tachycardia with high degree atrioventricular block was oversensed as ventricular fibrillation by a single chamber ICD causing repetitive painful discharges. Pharmacological treatment of the supraventricular tachycardia solved the problem.     

Is There Space for Surgery in the Treatment of Tachyarrhythmias?

Curative treatment of both supraventricular and ventricular tachyarrhythmias started with the introduction of surgical therapy. Surgical treatment modalities were often very successful and associated with low mortality and morbidity, especially in patients with various supraventricular tachyarrhythmias. However, results were acceptable in patients with ventricular tachyarrhythmias, with often a very complex and extended arrhythmogenic area associated with structural heart disease. Because of the development and proven effectiveness of catheter ablation and defibrillator implantation, the role of surgical therapy became limited. In the treatment of supraventricular arrhythmias, surgical therapy is an option after failure of catheter ablation. Since His-bundle catheter ablation is only a palliative treatment for atrial fibrillation, the potentially curative Maze operation may be an acceptable alternative. However, its potential against formation of intracavitary thrombi has not yet been proven. In the treatment of ventricular tachyarrhythmias, ischemia related polymorphic ventricular tachycardia and ventricular fibrillation can be treated very effectively by revascularization. Map-guided surgery is an appropriate treatment modality for patients with monomorphic ventricular tachycardia and an extended arrhythmogenic area. However, patients with very poor left ventricular function may have an unacceptable perioperative risk. In patients with congenital long QT syndrome who are refractory to beta blocking agents, left-sided sympathectomy is the most appropriate choice.     

Amiodarone therapy in symptomatic,sustained refractory atrial and ventricular tachyarrhythmias

Amiodarone was utilized in 70 patients with symptomatic, sustained refractory tachyarrhythmias. Of these, 29 had atrial arrhythmia (20 recurrent atrial fibrillation and nine sustained supraventricular tachycardia). Control was achieved in eight with supraventricular tachycardia and in 16 with atrial fibrillation. Recurrence has been prevented in these 24 patients (83%) during an average follow-up of 13.4 months. An additional 41 patients had recurrent ventricular tachycardia. In 19 with symptoms consisting of dizziness or lightheadedness without syncope or clinically apparent hemodynamic compromise, treatment was limited to amiodarone. Of these, 14 responded (74%) and have been free of arrhythmia during an average follow-up of 13 months. In 22 who experienced either syncope or life-threatening hemodynamic impairment, amiodarone was added to those agents which had only partially suppressed advanced grades of ventricular premature beats. Fourteen of these patients (64%) have remained free of recurrent ventricular arrhythmia during an average follow-up of 12 months. After drug loading, maintenance therapy consisted of a daily dose ranging from 200 to 600 mg. Only mild side effects have been encountered in the 17 patients (23%) with any untoward responses. This experience confirms that oral amiodarone is an effective and safely applied agent against recurrent refractory atrial tachyarrhythmia and sustained intractable ventricular tachycardia with moderate symptoms. While also efficacious in refractory sustained life-threatening ventricular tachyarrhythmia, usage of the agent is often difficult in this condition owing in part to insufficient information concerning amiodarone pharmacokinetics.     

Hypertrophic myocardiopathy (II). 24-hour electrocardiographic monitoring and its relation to the echocardiographic characteristics

Seventy-two patients with hypertrophic cardiomyopathy were evaluated by 24 hours of electrocardiographic ambulatory monitoring. The results were related to echocardiographic extent of hypertrophy, left ventricular outflow obstruction at rest, and transmitral flow parameters. Also, the symptoms and functional classification of NYHA were related to ventricular arrhythmias. Ventricular arrhythmias were detected in 68% of our patients: high degree of ventricular ectopia in 26 (36.1%), and ventricular tachycardia in 14 (19.4%). Most important supraventricular arrhythmias were: atrial fibrillation in 7 patients, atrial flutter in one, and supraventricular tachycardia in five. Asymmetric hypertrophy type I of Maron classification showed the lower number of ventricular arrhythmias. High degree of ventricular arrhythmias were more frequent in patients with: apical hypertrophy, worse functional classification of NYHA (I: 20%; II: 50%; III: 80%), and in patients with impaired distensibility detected by Doppler (80.7% vs 56.7%; p less than 0.05). There was no relationship between left ventricular outflow obstruction at rest and ventricular arrhythmias.     

Clinical Results with Catheter Ablation: AV Junction, Atrial Fibrillation and Ventricular Tachycardia

With the limitations of pharmacologic and device therapies for atrial fibrillation and ventricular tachycardia, catheter ablation is assuming a larger role in the management of patients with these common arrhythmias. Multiple case series and clinical trials have helped to define the evolving role of these techniques for ablation of the atrioventricular node, atrial fibrillation, and ischemic ventricular tachycardia. Based on very low complication rates, excellent efficacy and proven outcomes with radiofrequency ablation of the atrioventricular node, this approach with permanent pacing should play a larger role in the treatment of symptomatic patients with permanent atrial fibrillation. While linear ablation of atrial fibrillation has limited clinical utility for the treatment of this common arrhythmia, the results of multiple case series of focal atrial fibrillation ablation indicate the potential for an expanding role of this curative technique. Catheter ablation techniques for ventricular tachycardia in the setting of coronary artery disease have a role as supplemental therapy to the implantable cardioverter defibrillator in patients with recurrent pharmacologically refractory ventricular arrhythmias requiring frequent device interventions.