Ventricular arrhythmias, mainly ventricular tachycardia and ventricular fibrillation, are the most common cause of sudden cardiac death. As a doctor, you can help improve your cardiac patients' overall health. You can help them decrease their chance of death with a proper diagnosis. A proper diagnosis leads to the right treatment and gives patients the tools needed to make healthy lifestyle changes.
Continue reading to learn more about diagnosing ventricular arrhythmias in the cardiology community. We also recommend checking out our EKG/ECG Interpretation book and our best-selling EKG/ECG Interpretation Workbook on Amazon if you want to learn more.
1. Understanding Ventricular Arrhythmias
There are two main types of life-threatening ventricular arrhythmias that your patients might be suffering from. They are ventricular tachycardia (VT) and ventricular fibrillation (VF). Both of these disorders of the heart can be dangerous and ultimately life-threatening when they go untreated. (Premature ventricular contractions, or PVCs, are also common, but in a structurally normal heart they are usually benign.)
VT occurs when electrical signals are sent from the heart's lower chambers (ventricles) at a more rapid pace than normal, producing three or more consecutive ventricular beats. Increased periods of tachycardia mean that cardiac patients might experience symptoms including:
- Weakness
- Dizziness
- Fatigue
- Palpitations
The sudden drops in blood pressure and the lack of oxygen to the brain can result in fainting and loss of consciousness during a VT episode. VT can also deteriorate into VF and cardiac arrest.
In ventricular fibrillation, the electrical activity of the ventricles is rapid and completely disorganized, so the ventricles quiver instead of contracting. As a result, the heart can't pump blood to the rest of the body (including the brain). This causes immediate loss of consciousness and loss of pulse (cardiac arrest), and death within minutes unless CPR and defibrillation are started right away.
2. Knowing the Possible Causes of Arrhythmia
There are several factors (both internal and external) that may cause arrhythmias. Your patients might have underlying heart problems like coronary artery disease (especially a previous heart attack) and cardiomyopathy. They might have heart inflammation or infections that can affect their heart rhythms.
The use of toxins and stimulants can also cause you to develop an issue with the heart. Things like alcohol, cocaine, and even some prescription and OTC drugs can cause a reaction in the body.
Genetics can also cause ventricular arrhythmias and other heart problems to develop in seemingly healthy individuals. Certain health conditions (e.g., electrolyte abnormalities such as abnormal potassium levels, or hyperthyroidism) can increase your risk of developing an arrhythmia. The patients' lifestyle can also impact their risk of cardiac events occurring.
3. Testing and Monitoring Heart Rhythms
When diagnosing a possible arrhythmia, a cardiologist will perform a physical evaluation. They will look for physical signs that a heart problem exists. A cardiologist will check the patient's blood pressure and listen for heart murmurs.
A cardiologist will also review the patient's medical history. They will inquire about their family history. If it's a genetic disorder, a cardiologist may recommend testing for the patient's family members.
Ideally, an electrocardiogram (ECG) is recorded while the abnormal heart rhythm is happening. This is to get an accurate reading of the arrhythmia. A cardiologist will read the ECG to determine what type of arrhythmia their patients might have.
You can learn more about ECG interpretation in our EKG/ECG Interpretation book.
Cardiac imaging, such as ultrasound (echocardiography) and cardiac MRI, can give the cardiologist a clearer view of the condition of the patient's heart.
When further testing is required, a cardiologist may suggest that their patients wear a Holter monitor. These are heart monitors that record heart activity continuously, usually for 24 to 48 hours. This data is then sent to the cardiologist who can examine the sample for irregularities.
Physical activity may cause heart patients to experience the symptoms of their heart condition. This is where the exercise stress test comes into play. A tilt table test is used when a patient has unexplained fainting.
An exercise stress test monitors heart activity while the patient walks on a treadmill or rides a stationary bike. The tilt table test monitors heart rate, heart rhythm, and blood pressure as the patient is moved from lying flat to an upright position.
An EP study is an invasive procedure that involves the placement of pacing wires into the heart. The wires enter the heart through blood vessels. This test allows a heart doctor to evaluate the electrical system within the heart.
Echocardiograms (also known as echo) use sound waves to evaluate the structure and function of heart muscles and valves.
All of these things work together to give a cardiologist the proper diagnosis for their patients.
4. Treating Heart Arrhythmia
Some of your patients may not require a heart arrhythmia treatment. For example, occasional PVCs in a structurally normal heart usually need no treatment beyond reassurance. As a doctor, you may find that the best thing for these patients is having them attend regular arrhythmia checkups. This can help to ensure the condition is not getting worse over time. Sustained VT and VF, however, always need prompt treatment.
Other patients may need to take medication, such as beta-blockers or antiarrhythmic drugs. VT that makes a patient unstable needs an immediate shock (synchronized cardioversion, or defibrillation for polymorphic VT), and VF or pulseless VT needs immediate CPR and defibrillation. Note that vagal maneuvers are a treatment for supraventricular tachycardia (SVT), not for ventricular arrhythmias. Catheter procedures may also be necessary.
Some patients may need a procedure or surgery to prevent further cardiac events from occurring. You might recommend:
- Implantable cardioverter-defibrillator (ICD) insertion
- Catheter ablation
- Coronary bypass surgery (when coronary artery disease and ischemia contribute to the arrhythmia)
It is your responsibility to weigh the risks and benefits of major surgery to treat arrhythmia. You need to do your research before presenting these options to your patients.
Lifestyle changes can support, but not replace, medical treatment of a heart condition. A healthy diet and regular exercise can reduce the chance of cardiac arrest. Yoga and meditation can help alleviate the stress of everyday life as well as the strain that stress places on the heart.
Diagnosing Ventricular Arrhythmias
The process that goes into diagnosing ventricular arrhythmias helps cardiologists help their patients. You should consider reading Medical Creations' EKG/ECG Interpretation book. It can help you understand how to read ECGs to determine and diagnose arrhythmias.
For more information on ECG interpretations and how they are used in the diagnostic process surrounding heart arrhythmias, check out our EKG/ECG Interpretation book on Amazon.