I’m lying on my left side while the technician moves the transducer over my bare chest. Nine months after my stroke, and six months after my PFO closure, I’ve come to see whether the occluder that my cardiologist implanted over the hole in the septum between my atria is doing what it’s supposed to do, which is to keep my blood from shunting from my right atrium to my left. That’s how a clot traveled to my brain in September. That’s what we’re trying to keep from happening again. I was lucky the first time; I left the hospital after two days with no impairments. A second time, though? I might not be so lucky.

It’s chilly in the exam room, and I’m trying my best not to think about the ultrasound waves bouncing off the structures of my heart and what they might show. Soon, the nurse will inject a saline solution that contains bubbles into my IV, and the ultrasound will determine whether any of those bubbles are able to pass through the occluder, which is two titanium rings filled with mesh, one ring on either side of the PFO. We want those bubbles to stay out of my left atrium.

I’m thinking about baseball, specifically the arc of a fly ball rising, rising, rising and then the descent into the webbing of a mitt. I used to stand in the front yard of our farmhouse and throw a baseball into the air and then position myself under it with my glove. I’d throw the ball on the roof and let it roll down the slope so I could dash toward it, diving, trying to make a shoe-string catch. I’d throw the ball into the air near the wire fence around the yard, so I’d have to jump, extend my arm behind the fence and snag a ball that looked like it might be uncatchable. My favorite team was the Yankees, and I particularly enjoyed the slick-fielding third baseman, Clete Boyer. When my cousin visited, I’d ask him to hit sharp ground balls to my right and left so I’d have to dive to stab them and keep them from getting through my imagined infield. When I played Pony League ball, I was a late-inning defensive replacement. I prided myself on my glove work, able to dig low throws out of the dirt, able to leap and snare high tosses. I specialized in the spectacular save, in rescuing what seemed to be lost.

I’m thinking about all this as the bubbles enter my bloodstream and make their way to my heart. I think of Holden Caulfield and his fantasy of catching kids running through a field of rye before they go over the cliff. “That’s all I’d do all day,” he tells his sister, Phoebe. “I’d just be the catcher in the rye and all. I know it’s crazy, but that’s the only thing I’d really like to be. I know it’s crazy.”

It’s all crazy, this life. I’ve come to think that we’re all afloat, drifting here and there. I’ve come to believe that this is what living is, this random sequence of circumstances. We can convince ourselves we have all our ducks in a row, our lives mapped out just the way we want them, and then in an instant everything can change. My father knew this. In November, 1956, the shucking box on his corn picker clogged and he reached in without shutting down the power-take-off that turned the snapping rollers. The rollers took in his hands, and there he was at that point where his life divided into before and after.

Now mine does, too: the years before my stroke, and now whatever years are to follow it. But I’m trying not to think of that as the technician maps the bubbles’ journey to and from my heart. I’m thinking of soap bubbles, the kind kids blow from a wand, and dandelion fuzz, and the whirly-gig maple seeds twirling down from trees, and paper boats drifting along a stream, and those parachute men I used to toss up into the air and then watch float to the ground. I’m thinking of a baseball rising in the air and coming to settle in the mitt of a little boy, a boy with a hole in his heart, a hole no one will know about for a long, long time, a boy who years later as a man will feel a childlike glee when his doctor calls to tell him the results of the bubble test. Perfect. It was perfect. Nothing got through.