Heart Rhythm Conditions – Welcome to the group

SVT, which involves the upper chambers, over time can lead to heart failure but not likely "sudden death." That would be ventricular tachycardia. You may have misunderstood something the doctor said about your condition, may want to confirm with him or her, as thinking about "sudden death" would certainly be distressing.

There are two types of medicines, one for rate control when in tachycardia and one for rhythm regulation. Whichever of those two you need your cardiologist and/or EP will tell you.

Metoprolol interferes with adrenergic receptors in the heart. It prevents reactivity in the myocytes which makes them ramp up more easily and speed up their output.
https://cvpharmacology.com/cardioinhibitory/beta-blockers
The many anti-arrhythmics do the same thing, but with calcium, sodium, and potassium.
https://my.clevelandclinic.org/health/drugs/22867-what-are-antiarrhythmics
I'm not aware of a medicine that treats ventricular tachycardia per se, but there may be one. Either that or a pacemaker.

Edit (added after looking): https://www.drugs.com/condition/ventricular-tachycardia.html

So how does medication correct Tqachycardia?

Ventricular tachycardia is indeed potentially lethal, and in just a few minutes. Depends on the heart's overall condition and history. SVT is not lethal, and many live with it largely untreated for years. It's the symptoms that make the difference. Some patients don't know they're fibrillating or in flutter, but the ECG will show it clearly. Others know because they feel faint, breathless, or they feel the thumping of the irregularly irregular beats of the chaotic atrium beating out of step with the ventricles below it.

https://www.uptodate.com/contents/nonsustained-ventricular-tachycardia-clinical-manifestations-evaluation-and-management
Risk of NSVT for cardiac arrest apparently is when it is accompanied by structural heart issues like valve problems.

@gift440 I have afib with rapid ventricular response with heart rate up to 200. That is why I asked you for more info.

I am 72 years old and developed a heart rhythm problem after having Covid in 2022. I was told it was not AFib, but have been on a low dose of Metoprolol for over a year. I had a hysterectomy/prolapse surgery this past June and was told that my O2 level went down off and on while sleeping, so this past week did a sleep study and they said I had AFib during the study. I want to learn more so I can manage this.

See reply under my login name.
It’s in literature.
Talk to cardiologist about. Expiation should come from heart dr not patient.
Not taking meds yet so no opinion.

It’s in the literature. Google it. Explanation is there. Or ask your cardiologist. I read it.

Really don’t want to discuss as no meds have been RX for me as yet .

I read my type is rare and not much is known about it so it’s not a layman’s place to pass on info.

I’ve had the near faint symptoms for over 25 years. Thought bp drop. Yes but had to do with heart condition, I recently learned.

My cardiologist said so. Lower chamber of heart is where mine is. Says can have cardiac arrest or heart failure in literature. It’s called NSVT.

I don’t want to discuss it.