Related Experiment Videos
Quinidine syncope in children
Insights
Children with heart disease taking quinidine are at higher risk for syncope. This cardiac arrhythmia drug can cause dangerous side effects, including fatal arrhythmias, in pediatric patients.
Area of Science:
- Pediatric Cardiology
- Clinical Pharmacology
- Cardiac Electrophysiology
Background:
- Quinidine syncope is a known complication in adult patients with cardiac arrhythmias.
- Factors influencing quinidine syncope in pediatric populations are not well-defined.
- Understanding these factors is crucial for safe and effective pediatric arrhythmia management.
Purpose of the Study:
- To identify clinical, electrocardiographic, and pharmacologic factors associated with quinidine syncope in children.
- To compare characteristics of pediatric patients who experienced syncope versus those who did not while on quinidine therapy.
Main Methods:
- Retrospective comparison of clinical, anatomic, electrocardiographic, roentgenographic, and pharmacologic data.
- Two groups were analyzed: six pediatric patients with syncope (Group A) and 22 without syncope (Group B).
- Statistical analysis included chi-square test for significant associations.
Main Results:
- A significant association was found between heart disease and quinidine syncope in children (chi-square = 10.2, p = 0.001).
- All syncopal patients (Group A) had heart disease, compared to 15/22 non-syncopal patients (Group B).
- No significant differences were observed in age, quinidine serum concentration, or corrected QT interval between groups.
- Two syncopal patients died, and two experienced hypokalemia; syncope occurred within 8 days of therapy initiation in three patients.
- Ventricular arrhythmias, including sustained ventricular tachycardia, were observed in all syncopal patients.
Conclusions:
- Children with underlying heart disease are at a significantly higher risk for developing quinidine syncope.
- Quinidine therapy in pediatric patients, especially those with structural heart disease, requires careful monitoring for syncope and arrhythmias.
- Early recognition of syncope and associated arrhythmias is critical due to potential fatal outcomes.
Abstract:
Quinidine syncope and factors associated with it are well known among adult patients treated for cardiac arrhythmias. To define factors that may influence the occurrence of syncope in children taking quinidine, the clinical, anatomic, electrocardiographic, roentgenographic and pharmacologic data were compared in six patients with syncope (Group A) and 22 patients without syncope (Group B). There was a significant (chi-square = 10.2, p = 0.001) relation between heart disease and quinidine syncope: all six Group A (syncopal) patients had heart disease whereas 15 of the 22 Group B (non-syncopal) patients had no structural heart disease. In contrast, no significant difference was noted between Group A and Group B patients in mean age (11.4 versus 11.4 years), mean quinidine serum concentration (2.9 versus 2.3 micrograms/ml), mean corrected QT interval before quinidine (0.43 versus 0.40 second) or mean corrected QT interval during quinidine therapy (0.46 versus 0.46 second) or between those taking digitalis and those not. Two of the six Group A (syncopal) patients died during therapy, one 6 days after initiating therapy and one suddenly at home 6 months after beginning quinidine. Another two of the six Group A patients exhibited hypokalemia (both 2.9 mEq/liter) at the time of syncope, 2 weeks and 6 months, respectively, after initiation of quinidine therapy; both survived. Syncope occurred within 8 days of initiation of quinidine therapy in three of the six patients. Sustained ventricular tachycardia was observed during quinidine associated arrhythmia in three of six patients with syncope; nonsustained ventricular tachycardia or complex ventricular ectopic activity while on this therapy was observed before syncope in the other three patients in Group A.(ABSTRACT TRUNCATED AT 250 WORDS)