When I was first in the practice of cardiology, a heart attack was a fearsome problem. Our tools for handling it were primitive especially in light of what we know about the process and its management with today’s technology. Over the years, the understanding of coronary artery disease, coronary thrombosis, lipids, etc. have blossomed along with a greater and greater sophistication in dealing with a heart attack. In addition, with time, research, and the burgeoning of our tools, the understanding of the variability in the presentation of heart attacks have led to an increased capability in handling such cases.
Despite our new technology, a major element in cardiac diagnosis for over a century has been, and still is, the electrocardiogram invented in 1903 by Willem Einthoven, a Dutch physiologist. It remains today a critical tool in much of cardiology, including in the diagnosis and management of heart attacks. The alterations in the EKG during a heart attack can help assess the possible severity of the attack and possibly the prognosis.
What exactly is a STEMI Heart Attack?
A STEMI is a full-blown heart attack caused by the complete blockage of a heart artery. A STEMI heart attack is taken very seriously and is a medical emergency that needs immediate attention. STEMI stands for ST elevation myocardial infarction. “ST elevation” refers to a particular pattern on an EKG heart tracing and “myocardial infarction” is the medical term for a heart attack. So STEMI is basically a heart attack with a particular EKG heart-tracing pattern.
When someone is being evaluated for chest pain the EKG tracing is done as soon as possible to help see if it’s the heart. An ST-elevation myocardial infarction (STEMI) is a combination of symptoms of chest pain and a specific STEMI EKG heart tracing. The EKG has to meet what is called STEMI criteria to make a correct diagnosis, just like an NSTEMI will provide another set of specific diagnostic criteria. The EKG also provides information as to which part of the heart the blocked artery is supplying, for example an anterior vs. a posterior STEMI vs. an inferior STEMI. An anterior STEMI is the front wall of the heart, and the most serious. A posterior STEMI is the back wall of the heart. An inferior STEMI is the bottom wall of the heart.
What Happens to the Heart?
In a heart attack there is sudden rupture of an unstable part of the wall in a heart artery (coronary artery). This leads to a build up of clot in an attempt to heal it. However this clot formation results in total blockage of the artery. Unfortunately, this total blockage leads to loss of blood supply to the heart beyond that point. The heart muscle stops working within minutes of this and dies within minutes to hours unless the artery can be opened up and illustrates what is the primary goal in tratment –––– to rescue as much heart muscle as possible. For this reason every minute from the onset of a heart attack is absolutely critical. Often the patient doesn’t make it to the hospital due to sudden death due to a malignant heart rhythm. For those that leave it too long to get help or for those in whom the heart attack isn’t treated, the heart muscle dies and is replaced by a non beating scar.
The most important part of any STEMI treatment protocol is to get to the hospital as quickly as possible, so basically to call 911 immediately!!! In a STEMI, an artery is blocked and treatment centers on opening this up as quickly as possible. The preferred way to do this is by performing something known as an angioplasty and stent placement. In this procedure the artery is opened up working through a small tube passed into the heart either from the wrist or the groin. In some cases this cannot be performed quickly enough (less than 90-120 minutes) because of being too far away from a hospital equipped to do these things, and in order to avoid a significant delay in any treatment, clot busting drugs are used. Unfortunately these clot busters are not as good since they are less likely to open the artery and are also associated with bleeding complications. However, they are better than no treatment at all. So sometimes we have to use them.
In addition to this, a number of other treatments are used. Painkillers such as morphine are required to settle down pain and reduce anxiety. Oxygen is administered to those who are breathless or have heart failure. EKG monitors are attached so that potentially lethal arrhythmias such as ventricular fibrillation or even less dangerous but still significant arrhythmias such as inappropriate sinus tachycardia or atrial fibrillation with a rapid heart rate can be identified and treated. Blood thinners such as heparin, aspirin and other platelet inhibitors (clopidogrel/ticagrelor) are used to improve outcomes and prevent more heart attacks.
Educating patients and their families is one of the most critical aspects of care after a STEMI. Several new medicines are started after a heart attack, several of which may be needed lifelong. Patients need to be sure they take the medications prescribed to have a benefit. I’ll address these briefly later. Stopping smoking is essential. It’s important patients follow up with their doctors. Drugs should be used to control blood pressure. After a STEMI patients will be enrolled in cardiac rehabilitation that is a program they should attend on a regular basis. This involves exercise, addressing questions such as time of return to physical activities and dietary concerns. Following these things after the STEMI is arguably as important as treating the STEMI itself.
What exactly is a Non-STEMI Heart Attack
As previosly indicated, ST refers to the ST segment, which is part of the EKG heart tracing used to diagnose a heart attack. NSTEMI stands for Non-ST segment-elevation myocardial infarction. Nevertheless, a NSTEMI is still a type of heart attack, although presenting in a somewhat less acute manner than a STEMI. A myocardial infarction is, of course, the medical term for a heart attack.
How is a NSTEMI diagnosed?
In addition to signs such as chest pain, a heart attack is diagnosed mainly two ways. First is a blood test that shows elevated levels of certain markers of heart damage such as cardiac troponin. Secondly is by looking at the EKG heart tracing. As we have already shown, if there is a pattern known as STsegment-elevation on the EKG, this is called a STEMI, short for ST elevation myocardial infarction. If there is elevation of the blood markers suggesting heart damage, but no ST elevation seen on the EKG tracing, this is known as a NSTEMI, a non ST segment elevation myocardial infarction. A NSTEMI may be associated with other EKG changes such as ST segment depression. Often looking at the EKG helps us to locate the area of the heart that is affected.
Treatment of Non STEMI Myocardial Infarction
In addion to the EKG, part of the way of diagnosing a NSTEMI is by a blood test called troponin that is indicative of heart damage. Although the troponin test is great in that it does not miss heart attacks, it is not specific for heart attacks alone. Once the patient’s problem is diagnosed as a NSTEMI, the treatment strategy will typically include an echocardiogram to look at heart muscle functioning. Initially, blood-thinning agents will be given such as aspirin and the blood thinner heparin. These medicines have been proven to improve outcomes in patients with NSTEMI. There may be other medicines given such as a beta-blocker or nitrates. Many patients will then go for a heart catheterization. This test involves injecting dye into the heart arteries to look for blockages. In the case of severe blockages, treatment in the form of a stent or multiple stents may be required. Sometimes there are so many blockages that bypass surgery is advised.
Prognosis after a NSTEMI
A NSTEMI IS a heart attack, so the treatment of that applies here as well. Medicines are prescribed that have been proven to save lives in the long term for heart attack sufferers. Depending on factors such as symptoms and heart function, a number of medicines may be prescribed. Lifestyle changes and modification of risk factors are key in preventing recurrence. It is important for smokers to stop smoking. Blood pressure control and control of diabetes are key. A post-heart attack exercise plan should be incorporated into a daily lifestyle if possible. Often NSTEMI patients will be sent to cardiac rehab to receive education on the important of exercise and begin a program in a supervised environment.
Common Medicines Prescribed After a Non STEMI or STEMI Myocardial Infarction
Aspirin, antiplatelet agents, Beta-Blockers, ACE-Inhibitors and Statins are often prescribed.
STEMI vs NSTEMI – Which is Worse?
The bottom line is that both are bad. STEMI is seen as more of an immediate emergency because there is a known total occlusion of a heart vessel that needs opening urgently. In terms of long-term outcomes, they have equal health implications. Patients with NSTEMI often have other illnesses such as ongoing critical illness, diabetes, kidney disease, and other that means they have a generally high risk over the long term. Both STEMI and NSTEMI need aggressive treatment over the short and long term.