Cardiac arrhythmia is defined by an abnormal beating of the heart that can be irregular, too slow, too fast, or a combination of any of these features. Tachycardias are a form of cardiac arrhythmias that produce a regular rhythm but are too fast which exceed the normal of 100 bpm. The normal heart rate is around 60 to 100 bpm.
Tachycardia can be classified according to the location where the abnormal heartbeat occurs. Supraventricular tachycardia starts in the atria, the upper portion of the heart. Ventricular tachycardia starts in the ventricles, the lower chambers of the heart.
The abnormal pulses in the ventricles or atria interrupt the normal firing of the sinoatrial node which is the heart’s natural pacemaker. This causes the heart to beat swiftly.
The rapid heart rate doesn’t give the heart enough time to fill before it contracts which limits the flow of blood to the rest of the body.
Ventricular tachycardia makes the heart extremely inefficient because it occurs in the large pumping chambers of the heart which makes it more serious than supraventricular tachycardia. The symptoms of ventricular tachycardia are normally more severe and tend to be fatal compared to that of supraventricular tachycardia. Supraventricular tachycardia is not life-threatening but it can cause inconvenience such as physical and emotional problems. Supraventricular tachycardia becomes a major concern if the individual experiences frequent episodes of it or if the episodes are longer than the usual.
Supraventricular tachycardia or SVT is an abnormally rapid heart rhythm emerging from improper electrical activity in the atria or upper portion of the heart. They start from the atria or the atrioventricular node.
Ventricular tachycardia or VT is a heart rhythm that comes from the ventricles or the lower chambers of the heart and it produces a heart rate of 120 bpm or greater.
Symptoms of SVT
- Chest pain
- Feeling faint
- Shortness of breath
Symptoms of VT
- Chest discomfort
Causes of SVT
SVT is often linked with fatigue and anxiety, and excessive use or intake of alcohol, nicotine, and caffeine. It is occasionally linked with diseases such as mitral valve disease and heart attack.
Causes of VT
VT can be linked with different types of heart conditions like prior heart attack, cardiomyopathy, coronary artery disease, myocarditis, or valvular heart disease. Other types of VT may be due to genetic abnormalities, certain medications, or abnormal blood chemistry.
Differences between SVT and VT
These are the factors used to evaluate and differentiate VT and SVT:
Age: SVT normally affects individuals who are less than 35 years of age. VT usually affects individuals who are more than 50 years of age.
History: SVT is usually caused by heart conditions such as mitral valve replacement (MVR), and Wolff-Parkinson syndrome (WPW). VT is caused by heart conditions such as myocardial infarction (MI), congestive heart failure (CHF), coronary artery bypass graft (CABG), and mitral valve replacement (MVR).
Cannon A Waves: Cannon A Waves are not present in SVT but they are present in VT.
Arterial Pulse: There is no variation in the arterial pulse of SVT while there is a variation in the arterial pulse in VT.
First Heart Sound: The first heart sound for SVT is not variable while it is variable for VT.
Fusion Beats: Fusion beats are not present in SVT but they are present in VT.
AV Dissociation: AV dissociation is not present in SVT but it is present in VT. P Waves can be spotted at a different rate to the QRS complexes for VT.
Quanton Resonance Systems: The QRS rate for SVT is less than 0.14 seconds while the QRS rate for VT is more than 0.14 seconds.
Axis: The axis is normal or slightly normal for SVT. In VT, the results for the Leukocyte Antibody Detection or LAD test shows an axis below -30.
Vagal Maneuvers: The vagal maneuvers slows or terminates with SVT while there is no response when it comes to VT.
The presence of a delta wave, broad QRS complexes, and short PR intervals of less than 120 milliseconds are signs of SVT.
The presence of Northwest axis, P Waves, QRS complexes with different rates, and complexes that are extremely broad in deviation are signs of VT.
SVT and VT can both be diagnosed or assessed using an echocardiography or ECG. SVT and VT can be differentiated by checking the ECG features. In ECG, the medical person who administers it attaches nodes to different parts of the chest while a graph is being emitted. Cardiac monitors can also be used to monitor the heart patterns continuously.
SVT is usually treated by using AV-node drugs. It works by normalizing dysrhythmias. AV-node drugs do not work for VT because they only make the condition of the patient worse.
VT can be treated with intravenous drugs or cardioversion especially for individuals who don’t have symptoms but have had episodes of VT lasting for more than 30 seconds. Drugs that can be used to treat VT are amiodarone, procainamide, and lidocaine. Catheter ablation or the insertion of a catheter in the heart to deliver the energy of a specific cold or frequency.