The author used several plays on word that succintly imply the matters at hand.
The first thing we see is her description of the main character's condition as "heart trouble"- what sort of trouble exactly is her heart going through? We later realize it was more than just a muscle not working optimally.
There is also a detachment from points of views in the story. What the reader understands about the main character may not be exactly what is meant to be understood. Only the main character knows, we only get wisps of it through irony such as the release she felt when she heard about the death, when she died of "the joy that kills", and when she allowed us for once to look into her character's inner qualities to realize that she is actually a woman in a personal prison, who feels about to be set free.
There is also symbolism: Nature in the story changes with her emotions: It rains when she is said, it clears up when she is internally rejoicing: Could she also have caused her "heart troubles" herself by staying with a loveless man?
Chopin's maneuver in her narrative is for the main character to tease the reader into wondering what could possibly be happening inside her mind and soul. It is interesting that this story is so short and powerful, and yet still leaves the reader with so many questions on details. That is a way to separate the narrative from the emotional catharsis of the reader, and that shows tremendous skill and talent on Chopin's part.
One of Kate Chopin's skills is her use of figurative language. In "The Story of an Hour" she successfully employs the use of extended metaphor. The story begins with a reference to Mrs. Mallard's "heart" condition:
"Knowing that Mrs. Mallard was afflicted with a heart trouble, great care was taken to break to her as gently as possible the news of her husband's death."
And the final line again refers to her "cause of death:"
"When the doctors came they said she had died of heart disease--of the joy that kills."
Chopin uses the ailments of the physical heart as a metaphor for the protagonist's conflict with her self as well as the external conflict with her oppressive husband. She successfully extends this metaphor to engage the reader in the plot driven by these conflicts.
Reading this story in the context of Kate Chopin's other works can help your understanding even though the story certainly stands on its own as well. Like many of Chopin's other stories and her novel The Awakening, "The Story of an Hour" closely examines the emotions of a woman who has been trapped in a marriage. Note that we are first only introduced to her as "Mrs. Mallard"--we don't know that she is "Louise" until about 2/3 of the way through the story: it is her identity as the wife of Brently Mallory that matters in her world. Among the most significant elements Chopin uses to convey her theme are irony and foreshadowing. It is ironic, first, that Mrs. Mallard experiences joy, not sorrow, at the news of her husband's death. But this irony is compounded when Brently Mallard appears, unharmed, having been far from the scene of the accident, and Mrs. Mallard dies "of heart disease" (a double meaning and a further instance of irony). Even more irony is heaped upon this moment when the doctors determine that she died of "the joy that kills" though we know that she had actually embraced the freedom from her stifling marriage that she thought had come to her.
All of these instances of irony are supported through tone and diction; you might also note the oxymoron "monstrous joy." Characterization, omniscient narration, and setting provide the foreshadowing (clues) through which the ironic outcome of the story develops. To note how carefully crafted this story is, you might take a look at the hypertext of the story developed by Professor Ann Woodlief (see link below). If you click on the hyperlinks, you will read probing questions that assist you in understanding Chopin's revealing and tightly controlled diction.