You Tied a Love Knot in My Heart is from the Carters final session in 1941. The only related lyrics seem to be a song recorded in the 1930s:

THERE'S A LOVE KNOT IN MY LARIAT
written and recorded by Wilf Carter aka Montana Slim

I'll be thinking of you pal at sunset time
Thinking of the happy days gone by
There beneath the dear old western sky
And I'll tell you just the reason why,

There's a love knot in my lariat,
And it's waiting for a blue eyed gal you bet,
While I'm riding the range all day
My old lasso seems to say, it twines around an ornery stray,
There's a love knot in my lariat
And it's waiting for my little prairie pet
When I swing my old lasso you'll hear my yodel ay ee hoo
There's a love knot in my lariat.

Probably the only related lyrics would the title. Perhaps that was enough to get Maybelle started.

YOU TIED A LOVE KNOT IN MY HEART- Maybelle Carter 1941

You tied a love knot in my heart, dear
When you said you'd be my bride
Oh, how well I remember
As we strolled side by side

Leaves were falling all around us
Roses withered on the ground
You tied a love knot in my heart, dear
That can never be unwound
    [INSTRUMENTAL BREAK]

The only thing that I have left now
Is this little string of down
With a little love knot in it
That she held tight in her hand

As I stood there by her bedside
As I look into your eyes
You tied a love knot in my heart, dear
That can never be untied
    [INSTRUMENTAL BREAK]

There's a heart tonight that's lonely
There's a heart tonight that's sad
For God has took you from me
Dearest pal I ever had

She's gone to sing up in heaven
God needed her there by his side
You tied a love knot in my heart, dear
That can never be untied