The normal heart rate for an adult falls between sixty and one hundred heartbeats per minute when the adult is at rest. A heart rate above one hundred beats per minute is considered too fast and is classified as tachycardia. This can be both caused by or the result of several dangerous conditions. Symptoms ranging from dizziness to cardiac arrest can be attributed to tachycardia.
Types of tachycardia
Atrial or supraventricular tachycardia refers to a fast heart rate that is triggered in the heart’s upper chambers, the right and left atria. A normal increase in heart rate in response to stress, illness or trauma is referred to as sinus tachycardia. The sinoatrial node sends out normal electrical signals and has been called the heart’s natural pacemaker. When the signals go out faster than usual, tachycardia is present. Sinus tachycardia can be triggered by anxiety, fever, emotional distress or strenuous exercise. It usually subsides after the stress or event causing the rapid heartbeat goes away.
When the high heart rate originates in the heart’s lower chambers, the ventricles, ventricular tachycardia occurs. Also called V-tach or VT, the condition takes place when an abnormal amount of electrical signals from the ventricles conflicts with the natural, or sinoatrial, signals. This results in a faster heart rate that compromises proper blood flow. Heartbeats as high as 170 per minute have been recorded with ventricular tachycardia.
Causes of ventricular tachycardia
According to the National Institutes of Health, ventricular tachycardia occurs most often in individuals with structural heart disease. Myocarditis, or inflammation, a heart attack, cardiomyopathy resulting in an enlarged or rigid heart muscle and a lack of coronary artery blood flow can all cause the heart to beat faster than it should. Heart valve disease may also increase the possibility of ventricular tachycardia.
An imbalance of electrolytes, the minerals in the body with an electrical charge, may also lead to V-tach. A disease called sarcoidosis that causes inflammation of tissues has also been linked to ventricular tachycardia. Changes in the blood’s potassium levels and a lack of proper oxygen have also been observed in cases of VT.
Other factors beyond structural damage and existing medical conditions that contribute include side effects from medication, the influence of illicit drugs such as cocaine and excessive use of caffeine or alcoholic beverages.
Extreme cases of ventricular tachycardia may result in cardiac arrest. However, other symptoms that may be less obvious include dizziness or lightheadedness, heart palpitations and shortness of breath. Additionally, nausea and losing consciousness could be symptoms.
Diagnosis and treatment
If someone is in distress from VT and experiencing cardiac arrest, chest pain, rapid pulse or fainting, immediate action is required. A 911 emergency call should be made and CPR or electric shock may be necessary.
After an episode signaling the possibility of VT takes place, a cardiologist will take the cause into consideration when evaluating the best treatment. VT can be diagnosed through the use of a Holter monitor, a device worn for up to 48 hours to record the rhythms of the heart. An electrocardiogram (ECG) test that determines the heart’s electrical activity may also be used.
To correct the damage created by VT, ablation procedures may be performed. Radiofrequency ablation uses heat to eradicate the damage while cryoablation employs cold temperatures. Additionally, a cardio inverter defibrillator (ICD) could be implanted. This monitors the heart’s rhythms and sends electrical signals to correct any abnormal heartbeats.
Medications that helps prevent and manage VT are available, too. The cardiologist will consult with the patient regarding the proper procedure or medicine that is best for each case.
To learn more about the impact and treatment of ventricular tachycardia, log on to vascularhealthclinics.org.