VT / SVT quiz

Fascicular tachycardia usually responds to calcium channel antagonists. (link)

The most specific clinical feature of ventricular tachycardia is canon a waves in the JVP as it implies A-V dissociation. (link)

The most specific ECG feature of ventricular tachycardia is absent RS complexes in any precordial lead. (link)

The mean energy required to electrically cardiovert ventricular tachycardia in an adult using a biphasic defibrillator is 50J. (link)

The percentage of ventricular tachycardia expected to be reverted to sinus rhythm in an adult by a single bolus dose of 100mg of lignocaine is only 20%. (link)

The most effective medication to terminate ventricular tachycardia in an adult is probably procainamide, with a reversion rate of about 75%. (link)

The average age of Brugada syndrome at presentation is 30 years of age. (link)

The estimated correct dose of adenosine for a 2 year old boy with SVT is 1.2mg (0.1mg/kg). (link)

The correct defibrillation emergency setting for synchronised cardioversion of SVT in a 2 year old boy is 12J (1J/kg). Previously the recommended energy setting was 0.5 J/kg). (link)

Electrical alternans occurs in approximately 10-20% of cases of SVT and is not associated with either an accessory pathway or cardiac tamponade. (link)

Lange Jervil Nielsen syndrome is associated with prolonged QTc, not with an accessory pathway. Accessory pathways are associated with; Ebstein’s anomaly 10%, HOCM, Tuberous sclerosis, Pompe disease and Leber’s hereditary optic neuropathy (LHON). (link)

Verapamil is the most likely to revert the patient in this situation. Adenosine is relatively contraindicated in stimulant ingestion (especially caffeine) and is less effective than verapamil at rates, 175/min., recurrence is also more likely due to its short duration of action. Valsalva is unlikely to revert (30%), especially with sympathetic stimulation. Cardioversion may be effective, but recurrence is likely in this situation. (link)

Both adenosine and verapamil are considered safe in pregnancy. There is no evidence that Valsalva is less effective in pregnancy and electrical cardioversion is not the treatment of choice for haemodynamically stable patients. (link)

ST depression during SVT is common and poorly predictive of IHD – further investigation with an ESST is usually recommended. Chest pain preceding or following an episode of SVT should be treated on its merits. ST – T wave changes may persist for days after reversion. ST elevation is present in 70% of SVT in patients with accessory pathways and does not usually indicate a proximal left main occlusion. (link)

The ventricular rate in VT is usually > 150/min but may be < 150/min in patients taking anti-arrhythmics, but nearly always > 120/min. A rate of < 100 is called AIVR. Ventricular rate alone cannot be used to differentiate SVT from VT. (link)