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Torsade de pointes. Mechanisms and management
C Napolitano1, S G Priori, P J Schwartz
1Istituto di Clinica Medica Generale e Terapia Medica, Università degli Studi di Milano, Italy.
Drugs
|January 1, 1994
Summary
Torsade de pointes, a type of ventricular tachycardia, is linked to a prolonged QT interval. Its exact electrophysiological cause remains unclear, with theories including re-entry or triggered activity.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Torsade de pointes (TdP) is a polymorphic ventricular tachycardia with a distinct ECG pattern.
- It is associated with a prolonged QT interval, observed before the arrhythmic event.
- Prolonged QT syndromes, causing TdP, are categorized as idiopathic (LQTS) or acquired (iatrogenic, metabolic).
Purpose of the Study:
- To review the definition, management, and underlying mechanisms of Torsade de pointes.
- To discuss the clinical conditions associated with prolonged QT intervals and TdP.
- To explore the proposed pathogenetic hypotheses for TdP onset.
Main Methods:
- Literature review of clinical studies and experimental observations.
- Analysis of electrocardiographic characteristics of TdP.
- Discussion of proposed electrophysiological mechanisms.
Main Results:
- Torsade de pointes is characterized by a twisting QRS axis and a preceding prolonged QT interval.
- Both idiopathic and acquired prolonged QT syndromes can lead to TdP.
- Clinical guidelines exist for TdP management, but mechanisms are debated.
Conclusions:
- The precise electrophysiological mechanisms of Torsade de pointes are not fully understood.
- Current hypotheses include re-entry due to refractory period dispersion or triggered activity from after-depolarizations.
- Further research is needed to elucidate the definitive cause of TdP.