If the QT Is prolonged wouldn't the QRS Always be widened?

[BSN_Studnt]

So, I was thinking (random thought) if the QT interval is prolonged wouldn't that always mean there has to be some widening of the QRS ?

[offlabel]

It measures the time interval of 2 events, ventricular depolarization and repolarization. So, depending on which one (or both) of those events are prolonged, that corresponding element of the ekg will be prolonged as well.

So the answer is "sometimes".

[/username, BSN, RN]

Not always. You can have normal depolarization (QRS), which will be narrow, and delayed repolarization (QT).

[Pheebz777, BSN, RN]

The QRS complex will always be narrow in a heart with a normal functioning conduction system and a supraventricular pacemaker. The QRS will be prolonged in a BBB or from a ventricular source (PVC) since both signals will be conducted from muscle to muscle tissue in the myocardium outside of the normal conduction system pathways.

So to answer your question, a prolonged QT interval does not necessarily prolong the QRS. A prolonged QRS is always originating from a conduction issue. (BBB, Ventricular pacemaker, elevated K+)

[murseman24, MSN, CRNA]

no

[ambersky004, BSN, RN]

The QT interval is the time from the start of the Q wave to the end of the T wave. From the time taken for ventricular contraction and relaxation. How fast the ventricles recharged for the next cycle.

While the QRS duration is how fast the ventricles contracts.

It's not always that way. But both prolongation of these two will cause a lethal arrhythmias.

[GSDlvrRN, MSN]

Yass. Nerds ? #telenerds

[Nursing Au]

On 3/2/2019 at 1:12 PM, Pheebz777 said:

The QRS complex will always be narrow in a heart with a normal functioning conduction system and a supraventricular pacemaker. The QRS will be prolonged in a BBB or from a ventricular source (PVC) since both signals will be conducted from muscle to muscle tissue in the myocardium outside of the normal conduction system pathways.

So to answer your question, a prolonged QT interval does not necessarily prolong the QRS. A prolonged QRS is always originating from a conduction issue. (BBB, Ventricular pacemaker, elevated K+)

Your reply "A prolonged QRS is always originating from a conduction issue. (BBB, Ventricular pacemaker, elevated K+)" is not complete.

Type 1C antiarrhythmic drugs can potentially cause prolonged QRS and QT.

Some patients at a cardiac ward are likely to have antiarrhythmic medications.

[Pheebz777, BSN, RN]

On ‎4‎/‎19‎/‎2019 at 1:20 AM, Nursing Au said:

Your reply "A prolonged QRS is always originating from a conduction issue. (BBB, Ventricular pacemaker, elevated K+)" is not complete.

Type 1C antiarrhythmic drugs can potentially cause prolonged QRS and QT.

Some patients at a cardiac ward are likely to have antiarrhythmic medications.

Yes, they alter the action potential thus delaying conduction.