1/6. The clinical course of multifocal atrial tachycardia in infants and children.OBJECTIVES: This study outlines the clinical course, treatment and the late outcome of infants and children with multifocal atrial tachycardia (MAT). BACKGROUND: Multifocal atrial tachycardia is defined by three distinct P-waveforms, irregular P-P intervals, isoelectric baseline between P-waves and rapid rate on an electrocardiogram. Several smaller prior reports have described pediatric patients with MAT, but their long-term outcome has not been fully assessed. methods: The clinical records, echocardiograms and long-term follow-up of patients with MAT were reviewed and compared to previous reports of MAT. RESULTS: Fourteen boys and seven girls (median age 1.8 months) presented with MAT. At diagnosis, six patients had respiratory illness, of whom two were critical. Ten were asymptomatic. Seven patients had structural heart disease (SHD), one of whom died. Four of 15 patients (27%) with echocardiograms had diminished ventricular function. Ventricular rates were 111 to 253 beats/min (mean 181 beats/min). Median duration of the arrhythmia was 4.9 months (mean 6.7 months). Electrical cardioversion was attempted in 4 patients without success and 15 patients received antiarrhythmic medication. Seventeen patients were followed for a mean of 60 months. Four patients were lost to follow-up. There were no late arrhythmias. CONCLUSIONS: The majority of children with MAT are healthy infants under one year of age; a few may exhibit mild to life-threatening cardiorespiratory disease. Less often, MAT accompanies SHD. Mild ventricular dysfunction may be observed in the presence of MAT, but symptoms are few and resolution is generally complete. Response to antiarrhythmic agents is mixed, and cardioversion is of no avail. Finally, long-term cardiovascular and developmental outcome depends principally on underlying condition; for otherwise healthy children, it is excellent.- - - - - - - - - - ranking = 1keywords = ventricular dysfunction, dysfunction (Clic here for more details about this article) |
2/6. Tachycardiomyopathy: a diagnosis not to be missed.The prognosis of dilated cardiomyopathy is generally poor. In the vast majority of cases the cause of the ventricular dysfunction is irreversible but occasionally potentially curable causes are identified. Tachycardiomyopathy is a rare and potentially treatable cause of heart failure. A patient with a particularly severe case who had an excellent outcome is presented.- - - - - - - - - - ranking = 1keywords = ventricular dysfunction, dysfunction (Clic here for more details about this article) |
3/6. Successful catheter fulguration of the His bundle in a postoperative Mustard patient after unsuccessful fulguration of ectopic atrial foci.Incessant supraventricular tachycardia (SVT) resistant to pharmacological agents may cause cardiac dysfunction requiring more aggressive therapy. We present the case of a 12-year-old postoperative Mustard patient who developed biventricular heart failure due to an atrial ectopic tachycardia resistant to amiodarone. Using endocavitary direct current fulguration techniques, catheter ablation of the His bundle was successfully performed after unsuccessful attempts at ablation of the ectopic atrial foci. After placement of a permanent transvenous rate responsive ventricular pacemaker, the patient's clinical status and cardiac function improved. Endocavitary fulguration of the His bundle is technically feasible after the Mustard procedure and should be considered for treatment of selective cases of pharmacologically resistant SVT.- - - - - - - - - - ranking = 0.00083383787520929keywords = dysfunction (Clic here for more details about this article) |
4/6. Proarrhythmic effects of class Ic drugs.Three cases managed with class Ic antiarrhythmic drugs but with subsequent aggravation of arrhythmias are reported herein. A 58-year-old man given 300 mg of flecainide for atrial flutter developed sinus arrest and transient ventricular fibrillation. A 42-year-old man with a postoperative condition of tetralogy of fallot who received 300-mg doses of flecainide for sustained ventricular tachycardia had spontaneous sustained ventricular tachycardia. A 74-year-old man given 150 mg of propafenone for atrial tachycardia developed sustained ventricular tachycardia. The present cases illustrate that class Ic drugs may exacerbate ventricular arrhythmias, and their use may reveal concealed sinus node dysfunction. This may be due to marked slowing of conduction and prolonged ventricular refractoriness, which are characteristic of the class Ic drugs; also, it is probable that the patients' underlying cardiac conditions served as contributing factors.- - - - - - - - - - ranking = 0.00083383787520929keywords = dysfunction (Clic here for more details about this article) |
5/6. Cardiovascular collapse due to intravenous verapamil in two patients with persistent atrial tachycardia.Intravenous verapamil was given to two haemodynamically stable patients with persistent atrial tachycardia, resulting in circulatory arrest requiring CPR in one and collapse with unrecordable blood pressure in the other. Both responded to resuscitation and tachycardia was subsequently controlled with propranolol in one and sotalol in the other. Factors contributing to the cardiovascular collapse included: (i) left ventricular dysfunction; and (ii) failure to convert the tachycardia to sinus rhythm. It was concluded that verapamil may be dangerous in supraventricular tachycardia not due to atrioventricular (AV) junctional re-entry, despite normal blood pressure and perfusion, particularly if left ventricular dysfunction were present. If the diagnosis of AV junctional re-entry is in doubt, adenosine is preferable as it is less likely to cause haemodynamic collapse and will assist in making the diagnosis.- - - - - - - - - - ranking = 2keywords = ventricular dysfunction, dysfunction (Clic here for more details about this article) |
6/6. Radiofrequency catheter ablation of ectopic atrial tachycardia.Ectopic atrial tachycardia (EAT) is an uncommon type of supraventricular tachycardia. It is usually chronic, incessant and resistant to pharmacologic therapy. Radiofrequency catheter ablation, which has become one of the treatments of choice for the more common types of supraventricular tachycardia, has recently also been shown to be effective in EAT. Radiofrequency catheter ablation was attempted in three patients with incessant EAT. Two of the patients, aged 7 and 13 years, had signs of left ventricular dysfunction, and the EAT originated in the left atrium. The remaining patient, aged 72 years, had a right EAT with normal left ventricular function. Radiofrequency ablation was guided by endocardial atrial mapping to locate the site of earliest atrial activation. Ablation was successful in all three patients, with complete cure of the tachycardia for a follow-up period of 12 to 19 months. Radiofrequency catheter ablation of EAT is highly successful and should be considered as one of the treatments of choice for this arrhythmia.- - - - - - - - - - ranking = 1keywords = ventricular dysfunction, dysfunction (Clic here for more details about this article) |