Third-Degree Heart Block: Dispelling Misconceptions and Appropriate Treatment Approach

QUESTION

ou are treating a patient complaining of chest pain. Upon placing a 4 lead EKG you identify the patient to be profoundly bradycardic with a narrow QRS, and complete dissociation between the QRS and P waves. You inform your partner this patient is in a third-degree heart block, but your partner disagrees and states that third-degree heart blocks must have a wide QRS. Your partner proceeds to call a STEMI alert and asks you to start loading the patient. The QA process later investigated this call and discovered that your partner was incorrect about pretty much everything.

• Explain how a third-degree heart block can have a narrow QRS.
• Why do you think it’s such a common misconception that third-degree heart blocks can only be wide?
• Why is it inappropriate to call a STEMI alert on this patient?
• What should have been the appropriate treatment plan?
• Should this patient have been a “load and go?”

ANSWER

Third-Degree Heart Block: Dispelling Misconceptions and Appropriate Treatment Approach

Introduction

This essay discusses a scenario involving a patient presenting with chest pain, wherein a healthcare provider identifies the patient to be in a third-degree heart block with a narrow QRS complex. However, the provider’s partner disagrees, asserting that third-degree heart blocks must have a wide QRS complex. As a result, the partner initiates a STEMI (ST-elevation myocardial infarction) alert and suggests loading the patient. The Quality Assurance (QA) process later reveals the partner’s misconception. This essay aims to address the misconceptions surrounding third-degree heart blocks, the reason behind the common misconception, the inappropriateness of calling a STEMI alert in this case, the appropriate treatment plan, and whether the patient should have been a “load and go” case.

Third-Degree Heart Block with a Narrow QRS

Contrary to common belief, third-degree heart block can present with a narrow QRS complex. In third-degree heart block, also known as complete heart block, there is complete dissociation between the atria and ventricles. This means that the atria and ventricles beat independently, resulting in no coordination between P waves and QRS complexes on the electrocardiogram (EKG). In some cases, the escape rhythm originating from the ventricles may have a narrow QRS complex, resembling a normal rhythm.

Misconception Regarding Third-Degree Heart Blocks

The misconception that third-degree heart blocks can only be wide QRS complexes likely stems from the association between wide QRS complexes and bundle branch blocks. Bundle branch blocks often accompany advanced heart blocks, including third-degree heart block. As a result, the assumption is made that third-degree heart blocks always present with a wide QRS. However, it is important to recognize that the presence of a narrow QRS complex does not exclude the possibility of a complete heart block.

Inappropriateness of Calling a STEMI Alert

Calling a STEMI alert in this patient with a third-degree heart block and a narrow QRS complex is inappropriate. STEMI alerts are typically reserved for cases of ST-elevation myocardial infarction, which is indicative of acute coronary artery occlusion and requires urgent intervention, such as percutaneous coronary intervention (PCI) or thrombolytic therapy. In the scenario described, the patient’s symptoms and EKG findings are more consistent with a conduction abnormality (third-degree heart block) rather than an acute myocardial infarction.

Appropriate Treatment Plan

The appropriate treatment plan for a patient with a third-degree heart block involves addressing the bradycardia and providing support for cardiac output. This may include:

Assessing the patient’s hemodynamic stability: If the patient is unstable or experiencing hemodynamic compromise, immediate intervention may be required, such as transcutaneous pacing or pharmacological therapy.
Establishing intravenous access: Intravenous access should be established to administer medications or fluids if necessary.
Consulting a cardiologist or electrophysiologist: A specialist should be consulted to evaluate the need for temporary or permanent pacemaker placement.
Continuous cardiac monitoring: Close monitoring of the patient’s cardiac rhythm and vital signs is crucial to detect any deterioration or changes in condition.

Suitability for “Load and Go”

The patient in this scenario is not suitable for a “load and go” approach. “Load and go” refers to rapidly transporting a patient to a specialized cardiac center for immediate intervention, typically in cases of suspected ST-elevation myocardial infarction. However, since the patient’s presentation is more indicative of a conduction abnormality (third-degree heart block) rather than an acute myocardial infarction, the appropriate course of action would be to stabilize the patient’s condition before considering transfer to a cardiac center or facility equipped for cardiac interventions.

Conclusion

It is crucial to address misconceptions surrounding third-degree heart blocks to ensure accurate clinical decision-making. In the scenario presented, the patient’s narrow QRS complex in the presence of a third-degree heart block challenged the commonly held belief that third-degree heart blocks must always have a wide QRS complex. Calling a STEMI alert was inappropriate as the patient did not exhibit signs of an acute myocardial infarction. Instead, the focus should have been on managing the bradycardia and addressing the underlying conduction abnormality. By recognizing and appropriately responding to the patient’s condition, healthcare providers can ensure optimal care and prevent unnecessary interventions.