From the Research
Introduction to Cardiac Bigeminy
Cardiac bigeminy is a type of arrhythmia characterized by the alternation of normal and premature heartbeats. The evaluation of cardiac bigeminy is crucial for determining the underlying mechanism and guiding treatment.
Mechanisms of Cardiac Bigeminy
The mechanisms of cardiac bigeminy can be divided into several categories, including:
- Ectopic firing, which can arise from the atria or ventricles 1
- Failure of impulse generation or conduction, which can result in bradycardia or other arrhythmias 1
- Re-entrant mechanisms, which can be triggered by premature ventricular complexes (PVCs) or other factors 2
Evaluation of Cardiac Bigeminy
The evaluation of cardiac bigeminy involves analyzing the electrocardiogram (ECG) to determine the underlying mechanism. This can include:
- Identifying the type of bigeminy, such as atrial, junctional, or ventricular bigeminy 1
- Analyzing the coupling interval and the relationship between the premature beats and the underlying cardiac rhythm 2
- Looking for signs of prolonged ventricular repolarization, such as a long corrected QT interval 2
Treatment of Cardiac Bigeminy
The treatment of cardiac bigeminy depends on the underlying mechanism and the presence of symptoms. This can include:
- Symptomatic treatment with digitalis or quinidine for atrial bigeminy 1
- Suppressive drugs for ventricular bigeminy 1
- Implantation of an artificial pacemaker for certain types of bigeminy 1
Differential Diagnosis
The differential diagnosis of cardiac bigeminy includes other types of arrhythmias, such as:
- Torsade de pointes (TdP) 2
- Polymorphic ventricular tachycardia (VT) 2
- Monomorphic VT 2
- Alternating bundle branch block aberration 3
Caveats
It is essential to note that the evaluation and treatment of cardiac bigeminy can be complex and require a thorough understanding of the underlying mechanisms. Additionally, the presence of bigeminy can be a sign of underlying cardiac disease, and further evaluation may be necessary to determine the cause of the arrhythmia 4, 5