Electrophysiologic effects and clinical efficacy of flecainide in children with recurrent paroxysmal supraventricular tachycardia.

The electrophysiologic effects of intravenous flecainide were evaluated in 16 patients aged 9 +/- 4 years: 15 with recurrent paroxysmal supraventricular tachycardia (SVT) and 1 with overt accessory pathway and history of syncope. Eleven patients had an accessory pathway; it was concealed in 2, overt in 9 and in 10 of these patients an orthodromic atrioventricular reentrant tachycardia was induced. Five patients without accessory pathway had an atrioventricular nodal reentrant tachycardia. After intravenous flecainide (1.5 mg/kg) the effective refractory period of the atrium and ventricle increased significantly; the anterograde and retrograde effective refractory periods of the atrioventricular node did not. Flecainide blocked retrograde conduction in the accessory pathway in 4 patients (effective refractory period 245 +/- 41 ms) and anterograde conduction in 8 of 9 patients (effective refractory period 284 +/- 57 ms). The mean cycle length of orthodromic reciprocating tachycardia and atrioventricular nodal reentrant tachycardia increased significantly. After flecainide tachycardia was noninducible in 6 patients with orthodromic reciprocating tachycardia and in 1 with atrioventricular nodal reentrant tachycardia. It was inducible but nonsustained (less than or equal to 30 seconds) in 1 patient with orthodromic reciprocating tachycardia and in 3 with atrioventricular nodal reentrant tachycardia. Fifteen patients continued oral flecainide treatment for 19 +/- 11 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Right bundle branch block, persistent ST-segment elevation in V1-V3 and sudden cardiac death: always a distinct syndrome?

Right bundle branch block, persistent ST segment elevation in right precordial leads and sudden cardiac death, unexplainable by currently known disease, define a new distinct clinical and electrocardiographic syndrome. This report describe a patient with these features, whose physical examination, echocardiography, chest computed tomography and right ventricular angiography were normal. However, despite the negativity of these examinations, cardiac nuclear magnetic resonance allowed the identification of right ventricular dysplasia. Thus, right ventricular dysplasia should be considered in the differential diagnosis of the syndrome characterized by right bundle branch block, persistent ST segment elevation and sudden cardiac death.

[Acute treatment with verapamil of paroxysmal supraventricular tachycardia and atrial flutter in paediatric age (author's transl)]. / Trattamento acuto della tachicardia parossistica sopraventricolare e del flutter con verapamil, nell'etá pediatrica.

43 patients, 3 days to 12 years old, presented 68 paroxysms of supraventricular tachycardia and 2 crises of atrial flutter. 6 patients had a WPW syndrome and only 7 had an associated cardiac disease; the remaining had no other complaint but the arrhythmia. Verapamil, administered in the dose of 0.125-0.25 mg/Kg intravenously, interrupted critically the tachycardia in virtually all cases. The flutter was converted to atrial fibrillation with a slower ventricular rate. No adverse effects were observed but in two cases: one had a cardiac arrest promptly relieved and another a ventricular bradycardia corrected by atropine. Both cases had received an overdose of the drugs.

[Isolated enlargement of the right atrium. Description of a successfully operated case]. / Ingrandimento isolato dell'atrio destro. Descrizione di un caso operato con successo.

We report a case of isolated right atrial enlargement. The patient was an 11 year old boy who had life-threatening supraventricular arrhythmias. Diagnosis was basically performed by Echo-2D Doppler. The surgical treatment performed on cardiopulmonary by-pass, was followed by immediate conversion to sinus rhythm. Histological examination showed chronic inflammatory aspects. Postoperative Echo-2D (2 years later) showed a moderate right atrial enlargement.

Electrophysiological effects and clinical efficacy of propafenone in children with recurrent paroxysmal supraventricular tachycardia.

Twenty-four patients aged 10.1 +/- 4.5 (mean +/- SD) years with recurrent paroxysmal supraventricular tachycardia underwent an electrophysiological study. Eleven patients had an overt and seven had a concealed accessory connection; six patients had no accessory connection. An orthodromic reciprocating tachycardia was inducible in 17 of 18 patients with an accessory connection, and an atrioventricular nodal reentrant tachycardia was inducible in four of six patients without accessory connection. After administration of propafenone, the sinus cycle length decreased. Intra-arterial, intranodal, and His-ventricle intervals and QRS duration increased. The atrial and ventricular effective refractory periods and anterograde and retrograde effective refractory periods of the atrioventricular node increased. The cycle length at which nodal second-degree block occurred increased. Of 18 patients with accessory connection, propafenone prolonged retrograde conduction in all, blocked anterograde conduction in five, and prolonged it in six. The drug terminated the orthodromic reciprocating tachycardia in all 17 patients and the atrioventricular nodal reentrant tachycardia in three of four patients. In three of four patients with atrioventricular nodal reentrant tachycardia and in 15 of 17 patients with orthodromic reciprocating tachycardia, the tachycardia was no longer inducible or nonsustained after propafenone. A follow-up of 26 +/- 10 months revealed that the drug when orally administered to all patients prevented recurrences of tachycardia in 15 of 18 patients with and in four of six patients without accessory connection. The results of short-term drug testing with propafenone predict the response to long-term oral therapy with this drug.

[Clinical aspects of dilated cardiomyopathy in pediatric age]. / Aspetti clinici della cardiomiopatia dilatativa in età pediatrica.

Natural history and prognostic factors of dilated cardiomyopathy in pediatric age are not well identified so far. The course of the disease, often, presents "odd" characteristics: some of the patients show clinical improvement, someone remains unchanged and some of them have a negative evolution in a very short time. It is necessary to identify the group of patients having a poor outcome in order to define prognostic factors of impending death so that a cardiac transplant could be offered to them as a reasonable therapeutic choice. Twenty-two children, 9 males and 13 females (median age 5 +/- 5 years) with dilated cardiomyopathy were studied. Their natural history was followed for a period of 40 +/- 30 months. Clinical data, laboratory studies (electrocardiogram, Holter monitoring, echocardiogram M-mode, 2-D, Doppler and chest X-ray) were taken into consideration. At the end of follow-up period 7 patients showed improvement in cardiac status (31.8%), 7 remained unchanged (31.8%) and 8 (36%) got worse; 9 died. The survival curve showed a rate of 72% at 12 months and of 59.3% at 60 months. Of 9 died patients, 2 died suddenly and seven for congestive heart failure. Clinical findings and laboratory investigations of 13 survived patients (Group I) and 9 died patients (Group II) were compared to establish the risk factors of poor outcome. The fractional shortening is the only significant factor of poor outcome (p less than 0.025). Other negative factors were identified more in Group II than in Group I.(ABSTRACT TRUNCATED AT 250 WORDS)

Flecainide single oral dose for management of paroxysmal supraventricular tachycardia in children and young adults.

The efficacy of a single oral dose of flecainide to terminate paroxysmal supraventricular tachycardia (PSVT) was evaluated in 25 children and young adults. The subjects were selected from a group of 35 patients with recurrent attacks of PSVT evaluated by means of electrophysiologic study and intravenous electropharmacologic testing with flecainide. In all 25 patients the induced PSVT was stopped by intravenous flecainide and was then no longer inducible or nonsustained. All patients had normal hearts. At least 48 hours after acute intravenous testing, 25 patients underwent electrophysiologic study with a transesophageal catheter and PSVT was induced in all of them: atrioventricular reentrant tachycardia in 16 and atrioventricular nodal reentrant tachycardia in nine. During stable tachycardia, a single oral dose of flecainide (2.9 +/- 0.3 mg/kg; 2.5 to 3.3 mg/kg) was administered. This approach was effective for termination of PSVT in 22 patients. The mean plasma level of flecainide at cessation of tachycardia was 277 +/- 92 ng/ml (150 to 500 mg/ml). All 22 patients who responded were given a single oral dose of flecainide for recurrences of PSVT during follow-up. During a period of 12 +/- 7 months (2 to 27 months) a total of 134 spontaneous episodes of PSVT were reported, and 127 of these episodes were terminated with periodic management. Thus oral periodic flecainide seems useful for management of PSVT in selected patients.

Treatment of paroxysmal supraventricular tachycardia in infancy with digitalis, adenosine-5'-triphosphate, and verapamil: a comparative study.

The treatment of paroxysmal supraventricular tachycardia (PSVT) in infancy with digitalis, adenosine triphosphate (ATP) and verapamil is reported. Treatment was successful in about 90% of the patients treated with ATP and verapamil and in 61--71% of the patients treated with digitalis (Lanatoside C). Verapamil terminated the tachycardia within 2 minutes of administration in most instances and ATP in less than 1 minute. Digitalis, however, took as long as 2 hours; it was therefore excluded as the drug of first choice in emergencies, and is better suited for treating patients with poor hemodynamics. Side effects with ATP are common but short-lived. With verapamil, side effects are rare, but may be serious if certain contraindications are not taken into account. Digitalis in the dose used in this trial rarely produced side effects. We conclude that ATP or verapamil is the drug of first choice for quick termination of PSVT in infancy.

[Electrophysiologic effects and clinical efficacy of propafenone in pediatric patients with paroxysmal supraventricular reentrant tachycardia]. / Effetti elettrofisiologici ed efficacia clinica del propafenone in pazienti di età pediatrica con tachicardia parossistica reciprocante sopraventricolare.

Twenty patients (pts) with recurrent paroxysmal supraventricular tachycardia (PSVT), 12 female and 8 male, aged 9.8 +/- 4.7 years, underwent an electrophysiologic study (EPS) in order to assess the effects of propafenone (Pf) administered intravenously (1.5 mg/Kg in 3'). Thirteen pts (Group I) had an accessory pathway (AP) which was concealed in 5 and overt in 8 and in 12 of them an orthodromic atrioventricular reentrant tachycardia (ORT) was induced. In 5 of 7 pts (Group II) without AP an idio-nodal reentrant tachycardia (AVNRT) was induced. After Pf the sinus cycle length decreased significantly from 668 +/- 165 to 612 +/- 109 msec and PA, AH, HV intervals and QRS duration increased significantly from 35 +/- 11, 71 +/- 18, 34 +/- 6 and 73 +/- 12 to 43 +/- 11, 87 +/- 15, 39 +/- 9 and 85 +/- 10 msec respectively. The atrial and ventricular effective refractory period (ERP) increased from 216 +/- 18 and 211 +/- 19 to 227 +/- 21 and 217 +/- 21 msec respectively. The anterograde and retrograde nodal ERP and anterograde and retrograde Wenckebach point increased from 240 +/- 48, 227 +/- 28, 278 +/- 37 and 287 +/- 38 to 270 +/- 58, 330 +/- 32, 340 +/- 59 and 408 +/- 37 msec respectively. Pf terminated the tachycardia (T) in all 12 pts of Group I after prolongation of the cycle length which increased from 299 +/- 46 to 383 +/- 69 msec.(ABSTRACT TRUNCATED AT 250 WORDS)

[Electrophysiological effects and clinical efficacy of flecainide in childhood patients with supraventricular reciprocating paroxysmal tachycardia]. / Effetti elettrofisiologici ed efficacia clinica della flecainide in pazienti di età pediatrica con tachicardia parossistica reciprocante sopraventricolare.

The electrophysiologic effects of intravenous (i.v.) flecainide were evaluated in 13 patients (pts) with recurrent paroxysmal supraventricular tachycardia (PSVT): 6 pts had an overt accessory pathway, 2 a concealed anomalous pathway and 5 had an idionodal reentrant tachycardia (AVNRT). Another patients with overt preexcitation underwent electrophysiologic testing as part of a diagnostic investigation for syncope. After flecainide the effective refractory period of the right atrium and retrograde AV node, and anterograde and retrograde Wenckebach point significantly increased. The drug blocked retrograde conduction on the accessory pathway in 3 pts whereas anterograde conduction was blocked in all 7 pts with overt anomalous pathway. The mean cycle length of the atrioventricular reentrant tachycardia (AVRT) and of the AVNRT increased respectively from 269 +/- 34 msec to 332 +/- 25 msec (P less than .005) and from 286 +/- 9 msec to 380 +/- 64 msec (P less than .05). After i.v. flecainide, reentrant supraventricular tachycardia was no longer inducible in pts with AVRT and 1 with AVNRT, inducible but non sustained (less than or equal to 30 seconds in duration) in 1 pt with AVRT and in 3 with AVNRT. Thirteen pts continued oral flecainide treatment for a mean of 7.2 +/- 3.6 months (range 3 to 12 months). Tachycardia recurred in all 3 pts whose arrhythmia remained inducible and sustained after i.v. flecainide, and in 1 of 10 pts whose re-entrant supraventricular tachycardia was suppressed (6 pts) or inducible but non sustained (4 pts). Thus flecainide is an highly effective and well tolerated drug for the control of PSVT in infancy. The electrophysiologic drug testing with flecainide predicts its efficacy during chronic therapy in most patients.

[Prevalence of hyperkinetic arrhythmias in a healthy infantile and adolescent population: correlations between standard ECG, stress test and dynamic ECG]. / Prevalenza di aritmie ipercinetiche in una popolazione infantile e adolescente sana: correlazioni fra ECG standard, prova da sforzo ed ECG dinamico.

We evaluated 250 males and 250 females 4 to 17.99 years old, randomly recruited among school-children. Cardiac and other diseases were excluded. All the subjects were studied with a standard ECG iun the standing and supine position for a minute. Three hundred children underwent a treadmill exercise test according to Bruce's protocol and 50 of them had a 24-hour ambulatory ECG monitoring. Sinus arrhythmia was present in 94% of the children in supine position and in 87% of them while they were standing. Only one child had atrial and ventricular premature beats. In a boy a slow ventricular tachycardia was recorded. One child had a WPW and a girl a short PR interval; both were asymptomatic. The exercise test did not induce any arrhythmias and the slow ventricular tachycardia, in the previously mentioned boy was suppressed during exercise and reappeared during the recovery period. The premature beats were greatly reduced in the child who had them during the standard ECG recording. The 24-hour ambulatory ECG monitoring showed only minor degrees of premature atrial and ventricular beats in 24% of the children studied by this method. The maximum number of premature beats was 39 in 24 hours and never exceeded the first grade of Lown's classification. We conclude that a good correlation exists among the three employed techniques in the study of the prevalence of tachyarrhythmias in healthy children. This is the first study that compares these three techniques in a pediatric population.

Intravenous amiodarone in acute anterior myocardial infarction: a controlled study.

A randomized, single-blind controlled study intended to assess the potential benefits of intravenous amiodarone in anterior myocardial infarction is presented. Three hundred nineteen patients entered the study, 159 received amiodarone infusion, and 160 received glucose-insulin-potassium (GIK) infusion. Basal characteristics were similar in the two experimental groups, who were randomized on a consecutive basis. Exclusion criteria were shock or pulmonary edema, hypotension, inferoposterior infarction, bradycardia, antrioventricular block, severe diabetes, and other major diseases. Patients aged 27 to 70 years, with a Q-wave anterior infarction, initiated 12-40 hours earlier at the time of admission, entered the trial. Other entry criteria were heart rate higher than 80 beats/min and systolic blood pressure higher than 100 mmHg. Amiodarone was administered in saline infusion 10-20 mg/kg, within 4 to 10 hours, through a central vein. GIK infusion consisted of 150-300 g of glucose, 25-50 IU of insulin, and 80-120 mEq of KCl in 1000 cc of water at a rate of 1.5-2.0 ml/g/hour. Both groups received digitalis, nitrates, sedatives, and diuretics as needed. Although individually the major endpoints of death, reinfarction, and sustained supraventricular and ventricular arrhythmias did not differ significantly, each was less in the amiodarone group than in the control, and the sum of all adverse events was significantly lower for the amiodarone patients (p less than 001). Heart failure and conduction disturbances were not different in the two groups. This study shows that amiodarone, with its vasodilating and antiarrhythmic properties, may be beneficial in acute anterior infarction, but further studies on larger populations will be necessary in order to show a reduction of mortality rate.