These past three months I've had five ekgs, a stress test, an echocardiogram, an MRI, worn a holter monitor, had electrical currents run through my heart, and been injected with adrenaline in an attempt to figure out how and why my heart beats irregularly. Today I know about as much about my heart as I did in December. But I do know that I feel just about every contraction in my chest because my heart pounds hard against my breast and rattles my rib cage. And I do know that sometimes my heart beats too fast—sometimes 233 beats per minute—and still it keeps going and that means it is strong. And, for now, maybe that’s enough to know to know this: I am grateful my heart beats at all, because—for all of us, always—that is a courtesy and not an obligation, and my body's generosity humbles me.