Crochetage in Two or More Inferior Leads Is Associated With Stroke-Associated Patent Foramen Ovale
This retrospective multicenter study found that while single-lead crochetage is not associated with stroke, the presence of crochetage in two or more inferior leads is an independent predictor of stroke-associated patent foramen ovale, even after adjusting for high-risk anatomical features.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
For millions of adults, a small, harmless flap of tissue remains inside the heart, a leftover from before birth that never fully sealed shut. This opening, known as a patent foramen ovale, is a common feature of human anatomy, present in roughly one out of every four people. In most cases, it causes no trouble and is discovered only by chance. However, for a smaller group of people who suffer from sudden strokes or transient ischemic attacks with no clear cause, this same opening becomes a suspect. The concern is that a blood clot could form in the legs or veins, slip through this tiny door, travel directly to the brain, and cause a blockage. The great challenge for doctors is distinguishing between the millions of people who have this opening but will never have a stroke, and the few who carry a dangerous version of it. While advanced heart imaging can spot risky features like a floppy wall or a large opening, researchers have long searched for a simpler, non-invasive clue hidden in the heart's electrical signals.
A team of researchers from Turkey set out to investigate a specific electrical pattern called the crochetage sign. This pattern appears on a standard electrocardiogram, the test that records the heart's electrical rhythm, as a small notch or split in the upward spike of the heartbeat wave, specifically in the leads that look at the bottom of the heart. While this sign has been seen in people with heart defects, its connection to stroke risk in patients with a patent foramen ovale has been unclear. The researchers wanted to know if this electrical notch was a reliable marker for a dangerous heart opening, and whether the number of places where the notch appeared mattered. To find out, they gathered data from nearly one thousand patients across four major hospitals. They divided these patients into two groups: those who had suffered a stroke or a temporary stroke-like event and were found to have the heart opening, and those who had the same heart opening but had never had any cerebrovascular problems.
The study involved a careful, blind review of the heart recordings. Two experts, who did not know the medical history of the patients, examined the electrocardiograms to see if the notch was present. They categorized the findings based on how many of the three lower leads showed the sign. Some patients had the notch in just one lead, while others had it in two or three. When the researchers compared the two groups, a clear pattern emerged. The presence of the notch in a single lead did not help distinguish between the stroke patients and the healthy controls; it appeared just as often in both groups. However, the story changed completely when the notch appeared in two or more leads. This multi-lead pattern was significantly more common in the patients who had suffered a stroke.
After adjusting for other known risk factors like age, high blood pressure, and diabetes, the researchers found that having the notch in two or more leads was an independent predictor of stroke-associated heart openings. In fact, patients with this multi-lead pattern were about twice as likely to have a stroke-associated opening compared to those without it. The study also revealed that this specific electrical pattern was strongly linked to the physical structure of the heart's dividing wall. Patients with the multi-lead notch were much more likely to have an aneurysm of the septum, a condition where the wall between the heart's upper chambers is unusually large and floppy, or to have a wall that moves excessively. This suggests that the electrical signal is reacting to the physical instability of the heart wall rather than just the size of the opening or the amount of blood flowing through it.
The findings offer a new way to look at a common heart condition. While the most powerful predictor of stroke risk remained the physical characteristics of the heart opening itself, such as a large gap or a floppy wall, the multi-lead electrical notch provided additional, independent information. The researchers concluded that the mere presence of the notch is not enough to signal danger; it is the extent of the pattern, appearing in multiple leads, that matters. This distinction helps explain why previous studies on the topic have produced conflicting results, as some may have counted any presence of the sign as significant. By focusing on the number of leads involved, this study suggests that a simple, widely available test could help doctors identify which patients with a heart opening are truly at risk, potentially guiding decisions on whether to close the opening to prevent future strokes.
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