Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
Well, after checking the files, I’ve discovered the one that’s overflowing this week. It’s the one about the ills that plague us all. So off we go to the medicine file for a story about what will get most of us in the end.
MORE COMMON THAN WE BELIEVE
So-called “silent” heart attacks may be much more common than previously believed, according to researchers at Duke University Medical Center. Studies show that each year, nearly 200,000 people in the U.S suffer a heart attack but may not realize it. These “silent” heart attacks aren’t reported because they don’t cause any pain – or at least any pain that patients believe is related to their heart – and they don’t leave behind any telltale irregularities on electrocardiograms (ECGs also called EKGs).
This new research suggests that these heart attacks (now called unrecognized myocardial infarctions, or UMIs) may be happening much more frequently than physicians had suspected. Duke investigators also found that these attacks were associated with a surprisingly high risk of untimely death.
Physicians can usually tell when a heart attack has recently occurred by signature changes on ECGs and in certain blood enzyme levels. But if a heart attack happened in the distant past, physicians rely on the appearance of a specific alteration on an ECG called a Q-wave, which signals the presence of damaged tissue.
This research shows that not all silent heart attacks produce Q-waves on an electrocardiogram. They used something called delayed enhancement cardiovascular magnetic resonance, or DE-CMR, and discovered that this new technique was particularly good at telling damaged tissue from healthy tissue.
Researchers used DE-CMR to examine185 patients suspected of having coronary artery disease but who had no record of any heart attacks. All of them were scheduled to undergo angiography to find out if excess plaque had narrowed or blocked any of their arteries. Investigators followed the patients for two years to see if the presence of any unrecognized non-Q-wave heart attacks were associated with a higher risk of death.
They found that 35 percent of the patients had evidence of a heart attack and that non-Q-wave attacks were three times more common than heart attacks that produced the traditional symptoms. Non-Q-wave attacks were also more common among those with more severe coronary artery disease. In addition, researchers discovered that those who suffered silent heart attacks had an 11-fold higher risk of death from any cause and a 17-fold higher risk of death due to heart problems, when compared to patients who did not have any heart damage.
Right now, there are no specific guidelines about how patients with silent heart attacks should be treated. If they happen to be identified, they’re usually treated similarly to those patients where heart disease has already been documented. Future studies will likely examine how common unrecognized heart attacks are in other patient groups and how they should be treated.
So we still don’t know how to identify these silent heart attacks, but that’s not the case with detecting the effects of stroke.
THE EYES HAVE IT
Researchers at Johns Hopkins and the University of Illinois have found that a simple, one-minute eye movement exam performed at the bedside worked better than an MRI to distinguish new strokes from other less serious disorders in patients complaining of dizziness, nausea and spinning sensations.
The study was of 101 patients, who were already at higher than normal risk of stroke because of factors including high blood pressure or high cholesterol, and were all seen at OSF St. Francis Medical Center in Peoria, Ill.
The project, spearheaded by a Johns Hopkins neurologist in collaboration with colleagues at the University of Illinois in Peoria, found that the quick, extremely low-cost exam caught more strokes than the current gold standard of MRI, suggesting that if further research on broader populations confirms these results, physicians may have a way to improve care and avoid the high costs of MRI in some cases.
Dizziness is a common medical problem, responsible for 2.6 million emergency room visits annually in the United States. While the vast majority of dizziness complaints are caused by benign inner-ear balance problems, about 4 percent are signals of stroke or transient ischemic attack (TIA, a condition that often warns of impending stroke in the coming days or weeks). Because more than half of patients with dizziness who are experiencing strokes show none of the classic stroke symptoms — one-sided weakness, numbness, or speech problems — emergency room physicians are estimated to misdiagnose at least a third of them, losing the chance for quick and effective treatment.
The study of eye movement tests was suggested by previous research showing that people experiencing a stroke have eye-movement alterations that correlate with stroke-damage to various brain areas and that these are distinct from eye-movement alterations seen with benign ear diseases. Some patients, for example, can’t immediately adjust their eye position if their heads are quickly turned to the side, or they experience jerky eye movements as they try to focus on a doctor’s finger when looking to either side.
All of the patients in the current study were seen after complaining of severe dizziness that had lasted for several hours continuously, and all had at least one risk factor for stroke. The researchers selected them to increase the chance that they would find strokes in this population. None of the patients had a history of previous dizzy spells and more than half sought care at the Peoria medical center’s ER, though some were inpatients at the hospital or were transferred from other area hospitals.
The researchers gave each patient an exam comprised of three eye-movement tests. They looked for inability to keep the eyes stable as patients heads were rotated rapidly to either side;, they looked for jerkiness as patients tracked a doctor’s finger to the right and left, and they checked eye position to see if one eye was higher than the other. Each patient then received an early MRI, the highest-quality neuroimaging test available to confirm stroke in dizzy patients. Patients with eye tests suggesting stroke but without stroke on the first MRI scan underwent a repeat scan.
In the end, 69 patients were diagnosed with stroke and 25 with inner-ear conditions. The remainder had other neurological problems. Using only the three eye-movement tests, the researchers had correctly diagnosed all of the strokes and 24 of 25 with inner-ear conditions. By contrast, initial MRI scans were falsely negative in 8 of the 69 stroke patients, who were later correctly diagnosed with follow-up MRIs.
Though the researchers emphasize the need to verify their results in a larger and more general population of patients with dizziness, they think the initial findings are “incredibly promising.” If they hold true, testing eye movements could have several advantages over MRI. For example, while the wait time for an MRI can be several hours or more, physicians can perform all three eye-movement tests in a minute or less. Also, the eye-movement tests are “basically free,” compared to $1000 or more for an MRI.
Free sounds good to me. And along with the simple tests that you can perform, we can save the lives of stroke victims. You do know what those tests are, don’t you? If you suspect someone is having a stroke, ask them to do three things. First have them SMILE! If the smile is noticeably crooked, it’s a warning sign. Then have them TALK. Ask them to repeat a simple sentence like “It’s sunny out today” or “I live on the beautiful island of Guam.” Then have them RAISE both arms and keep them in the air for five seconds. You can also grasp both their hands and tell them to squeeze with both of them.
If the person fails more than one of these simple tests, dial 911 immediately. With stroke, time=brain. The more time you wait, the more brain you lose. And if you’re anything like me, you don’t have a lot of brain to lose!
And now a lovely little positive tale for all us fish lovers!
KEEPING IT FRESH
An edible coating that extends the freshness of fish may also increase health benefits according to a new study done at Oregon State University.
The study, published in Food Chemistry, found fish oil added to an invisible “food wrap” made from citosan — a substance found in crustacean shells that keeps out bacteria and fungi — not only kept lingcod fillets fresh in the refrigerator for three weeks and in the freezer three months but also tripled the amount the omega-3 fatty acids normally found in lingcod.
The coating, which does not affect the color of the fish, also reduced rancidity both refrigerated and frozen samples when compared with the uncoated fillets and also kept the frozen fish moister. It delayed the growth of microorganisms in the fresh fillets, and it prevented their growth in the frozen ones.
The research indicates many health benefits including lowered heart disease risk linked to increased omega-3 fatty acids in the diet. While oily fish like salmon, mackerel and sardines are rich in omega-3 fatty acids, leaner fish such as cod, grouper and swordfish contain much less.
So, when are we going to see this fancy new coating at our local fish market? Not any time soon, I fear, but then fish never lasts very long around my house anyway because someone always eats it!