Cardiac Arrhythmia: Premature Ventricular Contractions (PVC) - When The Heart Skips a Beat
What is PVC?
Premature ventricular contractions (PVC) are one of the most common, and relatively less dangerous type of heart rhythm disorders.
Almost every person has experienced the phenomenon of "skipped beat". A PVC occurs when the heartbeat is initated rather by the ventricles than the sinoatrial or sinus node.
This review is an attempt to give a relatively parallel focus to both digest-like language and a deeper understanding of this rhythm disorder. As PVCs are relatively common, people still tend to over-dramatize it's - nowadays considered normal - presence over a course of a normal day.
ECG characteristics of PVCs
- Bizarrely shaped QRS complexes,
- QRS wider than 120 ms,
- They are not preceeded by P wave,
- The T wave is usually large and its direction is the opposite of the QRS complex.
ECG finding of PVCs
People may report the presence of PVC with a feeling of a "skipped beat", often followed by a strong beat, and generally a feeling of suction in the chest, a feeling of flopping of the heart followed by a strong pound . There are other symptoms like:
- feeling of fainting
- chest pain
When do these symptoms occur?
Premature ventricular contracions are usually asymptomatic, although symptoms may occur in stressful situations, often during prolonged stress periods, cardiac stress resulting from physical exercise. An adrenaline rush resulting from a scary situation or unexpected stressful environment can also cause trouble to normal heart rhythm thus causing ectopic beat.
Causes of Cardiac origin:
- Mitral valve prolapse
- Myocardial contusion
- Acute myocardial infarction (MI)
- Tachycardia (Heart rate greater than 100/min)
Causes of Non-Cardiac origin:
- Electrolyte disorders (hypokalemia, hypomagnesemia, or hypercalcemia)
- Medications (eg, digoxin, tricyclic antidepressants, aminophylline, amitriptyline, pseudoephedrine, fluoxetine)
- Other drugs (eg, cocaine, amphetamines, caffeine, alcohol)
- Hormone imbalances (eg, menopause in women)
Since PVCs are most of the time of benign nature, usually there's no abnormal cause behind a PVC. Since PVCs are frequent among healthy individuals too, the main cause can be:
- Stimulating agents (caffeine, nicotine, amphetamines, cocaine)
- Hyperventilation from exercise (higher oxygen levels in the blood due to increased breathing rate)
Are there other causes that may refer to an underlying abnormality?
Yes, there exist a huge amount of underlying conditions that may provoke PVCs whether it is mediated directly or not, cardiac or non-cardiac, the causes are as follows:
- Bradycardia (Heart rate greater than 60/min)
- Cardiomyopathy (Ischemic, Dilated, Hypertrophic, Infiltrative)
Dr. Stephen Sinatra on PVC
When to seek medical care
If the feeling of skipped heartbeats is causing troubles in the normal course of the day, and a stressful mental state is developing (eg, fear of aggravation of the current symptom, fear of death) or simply PVC is continuously generating symptoms thus generating malaise, medical advice should be sought.
Is the consultation with a family doctor the best choice?
In case PVC is experienced rarely, consultation with personal family doctor is absolutely enough. However if PVC is causing troubles both physically and mentally, emergency medical care is the most effective option to choose from.
In case I visit the ER, what should I expect from the physician?
Usually an emergency physician performs several procedures:
- ECG in order to exclude other heart conditions, structural abnormalities causing similar symptoms
- Laboratory tests also are common since electrolyte disturbances can cause abnormal heart rhythm
- 24-hour Holter monitor in order to determine if a cardiac electrical instability is present
- Electrophysiologic exam is recommended for patients requiring pharmacological treatment with symptomatic PVC and a normal heart structure, and patients with PVC and structural heart disease too, for whom risk of sudden cardiac death is considerable
- Exercise stress test in order to exclude conditions like coronary ischemia, exercise-induced arrhythmias
Other Types of Arrhythmia
- Cardiac Arrhythmia: Premature Atrial Contractions (PACs)
Premature atrial contractions (PACs) are one of the most common heartbeat disorders (arrhythmia) without serious consequences, in some cases it may precipitate into atrial fibrillation or atrial flutter.
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