Sending to the Cath Lab? Ensure an Accurate ECG First

GE Healthcare

As healthcare centers bolster their efforts to reduce door-to-balloon times among STEMI patients, many facilities are now reckoning with the flip side of that coin: that is, the more providers send cases to the cath lab, the higher the risk of false activations: patients getting sent to catheterization who don't really have STEMI.

One study in JRSM Cardiovascular Disease puts that risk into a before/after context, noting that inappropriate activations of the cath lab occurred in less than 10% of cath lab cases before 2013, the year when the American Heart Association and American College of Cardiology issued guidelines that recommended activating the cath lab within 10 minutes of the first ECG. In the years since those recommendations, the false activation rate has jumped up to 15 to 40%.

Many of these false activations—some as high as 72%—are linked to clinicians misreading ECGs and interpreting waveforms as indicating STEMI when they actually do not. Often, the initial ECGs are performed by EMTs or ED physicians, and it's only after the cath lab activation that a cardiologist reviews the ECG to determine whether to call off reperfusion.

These risks notwithstanding, ECG is still critical to diagnostic decision-making, particularly within the "golden hour" of STEMI interventions. However, the impact of false activation on financial costs and quality of care emphasizes the importance of ensuring that initial ECG is interpreted accurately.

Implications of Inappropriate Cardiac Catheterization Activation

When a false activation occurs, the cancellation most often takes place before patients have a chance to undergo catheterization. Still, patients may experience a range of lasting repercussions from that initial wrong diagnosis.

Importantly, every minute spent pursuing a STEMI misdiagnosis is a minute lost from treating the underlying concern correctly. As the authors in JRSM Cardiovascular Disease emphasize, sometimes those underlying concerns may be quite serious, even if they are not myocardial infarction. For example, many critical conditions can cause ST elevations, including intracerebral hemorrhage, aortic dissection, and pulmonary thromboembolism. If interventions such as administration of anticoagulants are made based on a false STEMI assumption, it could deteriorate care even further.

Though obviously not as dire as the risk of delayed interventions for life-threatening conditions, there are also cost considerations tied to false cath lab activation. In one estimate from a study in Cardiovascular Diagnosis & Therapy examining the financial burden of after-hours cancellations, authors quantified a $350 cost for activations that were canceled before catheterization took place. If catheterization was done, that burden more than doubled to $865—and would no doubt come with greater risks to patients undergoing a major procedure that wasn't needed.

To learn more about the power of the ECG in today's clinical landscape, browse our Diagnostic ECG Clinical Insights Center.

Ensuring an Accurate Diagnosis

As guidelines suggest, every patient should still be referred to the catheterization lab within 10 minutes of an initial abnormal ECG that indicates STEMI, but given the risks of false activations, providers should be cautiously aware of the variants that can conflate diagnoses.

Aside from more critical conditions, such as a pulmonary embolism, the JRSM Cardiovascular Disease paper lists many others that can contribute to ST elevations and increase the likelihood of STEMI misdiagnoses. These include electrolyte abnormalities, acute pericarditis, and even natural manifestations in some patient populations. As the Cardiovascular Diagnosis & Therapy paper adds, left ventricular hypertrophy is another contributor to ST elevation that can be misdiagnosed as STEMI, particularly in African Americans.

Clinicians must understand which ECG patterns do and do not indicate STEMI, and they should also factor in medical history, symptoms like angina, and other chart details in their diagnoses, even if they must make those determinations quickly. Fortunately, emergent technology such as artificial intelligence for ECG interpretation could help physicians connect multiple data points to accelerate diagnostic decisions.

ECG remains a vital tool for making immediate point-of-care decisions regarding suspected STEMI patients, but as with any tool, users must operate from the correct manual for the best outcomes. Everyone who will interpret ECGs (even ED physicians and EMTs) should understand the nuances of sending patients to the cath lab, including what signs warrant activation. STEMI or not, every minute matters, so make the most of each one.