A middle-aged man lies bare-chested for a heart scan, and what should be a clinical moment turns into a quiet daydream. The speaker notices the young woman's perfume, the warmth of her arm, and the pressure he imagines against his back. He laughs at himself, but gently, happy that his body can still be stirred by the idea of a young person's touch.
Meanwhile she talks about blood pressure, cholesterol and medicines, and the contrast is part of the poem's charm. Beneath the daydream sits a sober awareness of time: the heart is in its "fifty fifth year," its walls thickening, its muscles weakening. The word "echo" works twice, as the sound of the scan and as memories of youth, love and heartbreak.
The mood is tender, wry and a little wistful. The speaker is self-mocking but not ashamed, and the closing line, about falling in love with all the women in the world, feels both comic and quietly aching.