Search

Atrial flutter is a rare but potentially lethal arrhythmia, characterized by a rapid regular atrial rate, accompanied by variable degrees of atrioventricular block. Two cases of neonatal atrial flutter are described. The first case was diagnosed in utero at 38 weeks of gestation and converted to sinus rhythm by electric shock on the eighth day of life. Case two, diagnosed at 11 days old, with a background of acute bronchiolitis and tachycardia associated with a cardiac tumor, was refractory to electrical cardioversion. Both cases proved difficult to convert to sinus rhythm, but there was clinical improvement and no recurrence. These two cases exemplify the variability of outcomes achieved with anti-arrhythmic agents and direct current cardioversion.

Objective: Evaluate, based on the evolution of new biochemical markers of cardiac damage, if electrical cardioversion (ECV) causes myocardial injury., Methods: Seventy-six patients (P) submitted to elective ECV for atrial fibrillation or atrial flutter were evaluated. Creatine phosphokinase (CPK), CK-MB activity, CK-MB mass, myoglobin and cardiac troponin I (cTnI) were measured before, and 6 and 24 hours after ECV., Results: ECV was successful in 58 P (76.3%). Cumulative energy (CE) was up to 350 joules (J) in 36 P, from 500 to 650 J in 20 P and from 900 to 960 J in 20 P; the mean energy delivered being 493 J (+/- 309). The levels of cTnI remained within normal limits in all 76 P. The increase of cumulative energy led to an elevation of CPK levels (> p value = 0.007), CK-MB activity (> p value = 0.002), CK-MB mass (> p value = 0.03), and myoglobin (> p value = 0.015). A positive correlation between the cumulative energy and CPK peaks was observed (r = 0.660; p < 0.001), CK-MB activity (r = 0.429; p < 0.0001), CK-MB mass (r = 0.265; p = 0.02), and myoglobin (r = 0.684; p < 0.0001), as well as between the number of shocks and the CPK peaks (r = 0.770; p < 0.001), CK-MB activity (r = 0.642; p < 0.0001), CK-MB mass (r = 0.430; p < 0.0001), and myoglobin (r = 0.745; p < 0.0001)., Conclusion: ECV does not cause myocardial injury detectable by cTnI measurement. Elevations of CPK, CK-MB activity, CK-MB mass and myoglobin result from skeletal muscle injury and are positively correlated with the CE delivered or with the number of shocks.

In recent years, considerable progress has been achieved on the understanding of the mechanisms of the different supraventricular tachyarrhythmias. These advances have led to the development of rational procedures that can effectively cure most of the patients. Radiofrequency catheter ablation is highly effective in supraventricular tachycardia, with favorable cost-benefit analysis compared to lifelong antiarrhythmic drug therapy and should be considered as an initial option. In atrial fibrillation, only few patients are currently considered for non-pharmacologic therapeutic modalities, but this number should grow as this is the area of most promising research and the one expected to make more progress in the years to come.

Purpose: To describe the presentation, diagnosis and treatment of fetal supraventricular tachyarrhythmias in a series of fetuses followed in a tertiary Fetal Cardiology Center., Methods: Twenty-five fetuses with diagnosis of supraventricular tachyarrhytmia were reported from January 1989 to October 1997, among 3117 pregnant women referred for fetal cardiac evaluation., Results: There were 17 fetuses with the diagnosis of supraventricular tachycardia (SVT) and 8 patients with atrial flutter (AF). Gestational age ranged from 26 to 40 weeks. Twelve patients were hydropic at presentation (6 with SVT and 6AF). Four fetuses with SVT showed structural abnormalities (two with Ebsten's anomaly and two with VSD). All patients were admitted to the Fetal Cardiology Unit for monitoring and treatment. Among 17 fetuses with SVT, twelve showed good response to digoxin administration, but this drug was not useful in any of the patients with flutter. In two patients with SVT and in six with AF, the pregnancy was interrupted to perform post-natal cardioversion. The mortality rate was 3/17 in the SVT group (including 2 patients with ebstein's anomaly and 0/8 in the flutter group), Conclusion: Fetal supraventricular tachyarrithmias are rare in the general population. Nevertheless, the fetus may present with severe heart failure and death. Considering the satisfactory therapeutic response, accurate diagnosis and early treatment of these conditions are extremely important.