Supraventricular Tachycardia - Dubai Cardiology Clinic
- Supraventricular Tachycardia, SVT’s are rapid rhythm originated from the atrium or atrioventricular node in the absence of bundle branch of block. It gives normal QRS conduction and this kind of arrhythmia is also called narrow complex tachycardia’s. There is multi-mechanism to this kind of arrhythmia as what we called the reentrant arrhythmia or automaticity, this is what we called spontaneous repetitive firing from a single focus and the third mechanism is what we called the triggered arrhythmia, which is dependent with membrane potential that follows the action potential or we can call that, after-depolarization can cause this kind of SVTs.
- A step in diagnosing this kind of disease first is to do Electrocardiogram or ECG. This procedure allows us to determine which kind of supraventricular tachycardia or SVT’s is present. This procedure can determine if the rhythm is Regular, where most likely an atrial fibrillation or atrial flutter with variable conduction or multifocal atrial tachycardia; or Irregular Atrial flutter where the T waves are seen in a rate of 240 – 320 bpm and the presence of P waves that preside the QRS complexes with conduction of 2-1 : 3-1.
- Moreover, there are also several kinds of Regular-type SVT’s. These include sinus tachycardia, sinus node reentry, atrial flutter, atrial tachycardia also called as “AV nodal reentry tachycardia” or “junction tachycardia”. Sinus Tachycardia and Junction Tachycardia usually have very gradual onset, whereas the other type of SVTs, their onsets are more suddenly.
- In SVTs, the rate can also be helpful in differentiating the types since Sinus Tachycardia cannot typically go over 240 bpm. With morphology, it can help determine the kind of Arrhythmias. Also, if retrograde P waves are negative in the inferior leads, it is in favor for AVNRT or Junctional Tachycardia. Sinus Tachycardia has an onset and termination that were gradual, and the heart rate is between 100-200 bpm, the P waves are identical to Normal Sinus Rhythm but are relationship block.
- One non-invasive treatment we can give to the patient with sinus tachycardia, is to have him do a vagal maneuver to slow down the heart rate gradually. We can attempt to slow the heart rate through pharmaceutical way with the use of beta blockers. For the sinus node reentry, the onset and termination is sudden the heart rate is between 100 – 160 bpm, P wave was identical to Normal Sinus Rhythm, R to P relationship is long and in this type of Arrhythmias in Supraventricular Tachycardia can be treated quickly by the Intravenous Therapy using Adenosine, Verapamil and diltiazem.
- Carotid massage will also be helpful and Beta Blockers and calcium channel blockers can be prescribed. For atrial flatter the onset and termination usually sudden with heart rate usually more than 300 bpm, P waves flutters with heart rate between 250 – 340 bpm, R – P relationship are defined due to flutter waves and prominent neck veins palpation of about 300 per minute.
- Clinical findings for atrial flutter secondary to ventricular response in addition to any underlying cardiac disease include dizziness, palpitation, angina, tight chest pain, dyspnea, fatigue, weakness and occasional syncope. Once the diagnosis of atrial flutter is made, patient’s status will be monitored, and cardioversion will be performed immediately.
- Cardioversion can be accomplished by synchronized direct current DC Cardio Version. In addition, rapid atrial placing is another method of treatment for this kind of Arrhythmias and finally, Rapid pharmacological cardio version could be considered with intravenous agent such as Abutilide, which is a class 3 Anti-arrhythmic drugs. Catheter Ablation for reentrance Sequent can be done as a last resort.
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