From the Guidelines
Bigeminy is primarily caused by premature ventricular complexes (PVCs), which are common and increase in frequency with age, and can be triggered by various factors including electrolyte imbalances, caffeine, alcohol, nicotine, and stress, as well as underlying heart conditions and certain medications. According to the 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death 1, PVCs are found in about 50% of all people with or without heart disease on longer term monitoring. The presence of PVCs on 2 minutes of monitoring of middle-aged patients was associated with increased risk of both ischemic heart disease events and mortality, with or without prevalent ischemic heart disease 1. Some key factors that contribute to bigeminy include:
- Electrolyte imbalances, particularly low potassium, magnesium, or calcium
- Caffeine consumption, alcohol use, and nicotine
- Stress and certain medications, such as digoxin, sympathomimetics, and some antiarrhythmics
- Underlying heart conditions, including coronary artery disease, heart failure, cardiomyopathy, and valvular heart disease
- Other contributing factors, such as hyperthyroidism, sleep apnea, and certain lung diseases It is essential to evaluate bigeminy to rule out serious underlying conditions, particularly if accompanied by symptoms like dizziness, chest pain, or shortness of breath, as the detection of PVCs, particularly if multifocal and frequent, is generally considered a risk factor for adverse cardiovascular outcomes 1.
From the Research
Causes of Bigeminy
- Bigeminy is a cardiac arrhythmia characterized by the alternation of normal and premature heartbeats, which can be ventricular or atrial in origin 2, 3.
- Premature ventricular complexes (PVCs) are a common cause of bigeminy, and they can lead to degraded cine cardiac MRI (CMR) images 2.
- Atrial bigeminy, on the other hand, can result in decreased left ventricular function, as shown in a study where coupled pacing simulating atrial bigeminy significantly reduced LV function in dogs 3.
- The exact mechanisms of bigeminy are not fully understood, but it is thought that premature complexes can disrupt normal heart function and lead to changes in cardiac structure and function 3.
- Imaging techniques such as cardiac MRI (CMR) can be used to visualize the contraction pattern of PVCs in bigeminy, which may be helpful in planning ablations and localizing the site of origin of the ectopic beats 2.
Potential Consequences of Bigeminy
- Bigeminy can lead to decreased left ventricular function, as shown in the study on atrial bigeminy 3.
- Premature ventricular complexes (PVCs) can also lead to the development of cardiomyopathy, as suggested by the study on PVC-induced cardiomyopathy 3.
- The correlation between the visually assessed site of the initial contraction of the ectopic beats and the site of origin found by electroanatomic mapping can be used to localize the site of origin of PVCs 2.