Article updated July 24, 2017
EMS providers may encounter cardiac issues even in the fit and healthy population. Tachycardia is defined by any heart rate over 100 beats per minute. While this may be considered a normal physiological response to stress or exercise, a narrow complex tachycardia can be extremely harmful and can lead to death if not recognized and treated efficiently and effectively.
The EKG Club experts created this case for these learning objectives:
- Basic: Recognition of narrow complex tachycardia.
- Intermediate: Identifying the range of therapies available to treat this rhythm (e.g. valsalva, drugs).
- Advanced: Awareness of possible contraindications to adenosine and the co-administration of adenosine. Being prepared for that period of “asystole” that often occurs during treatment.
Patient Presentation: Fit-looking male with palpitations
One day, while enjoying the morning sun, you are dispatched to the workplace of a 36-year-old male with palpitations at 0935 hours. The location is not far from where you are sitting, so it takes only about five minutes with lights and sirens to reach the scene. You arrive at the two-story office building of a local financial services office. The receptionist leads you through the building, where you find a man seated at his desk with several of his workmates nearby looking concerned. The patient is a fit-looking male who appears to be in minimal distress.
Patient Assessment Findings:
Beginning the assessment, your general impression of the patient is that he is a seemingly-healthy young man in minimal distress. He tells you that he has noticed his heart racing for the last 30 minutes and denies experiencing any other symptoms. You escort him to the ambulance because he insists on walking himself and he denies experiencing dizziness upon standing.
You find the following during the secondary assessment:
Patient’s vital signs:
Heart Rate: 146 bpm
Respirations: 20 rpm
Blood Pressure: 106/65 mm Hg
SpO2: 97 percent room air
Pain: 0/10
Patient past medical history:
None
Allergies:
No known drug allergies
Meds:
None
Initial 12-lead EKG:
You perform a quick head-to-toe assessment and find nothing abnormal to report. Your partner sets up the cardiac monitor, attaches the electrodes, and acquires a 12-lead EKG.
Initial EKG (click for larger image)
The computed interpretation is:
HR 143 bpm
PRI N/A
QRSd 84 ms
QT/QTc 274ms/423ms
Paxis N/A
QRSaxis 67
Taxis 53
The machine intepretation is:
***Age and Gender Specific Analysis***
Supraventricular Tachycardia
Nonspecific ST abnormality
Abnormal EKG
Remember to follow a standardized process for EKG interpretation.
- Rate & Rhythm: Regular, rapid at 143 bpm
- P-wave: Present after QRS - short RP interval
- PR interval: None
- QRS interval: 84ms
- QRS complex & mean axis: Normal
- ST segment: Unremarkable
- T wave: Unremarkable
- U wave: Unremarkable
- QT interval: Unremarkable
Answer these questions about the 12-lead EKG and the patient.
- What is the rhythm?
- What treatments are appropriate?
- What are the contraindications to drug therapy?
Patient Response to Treatment for tachycardia:
You have a transport time of 20 minutes. You take a look at your partner who, without further discussion, moves into setting up two large-bore IV accesses and O2, initially via nasal cannula at 4 lpm. You ask your patient to forcefully cough and to strain. However, the rhythm remains unchanged. After not hearing any bruits over the carotids, you apply a 10-second massage to the left carotid and then to the right, but without any change. Your partner suggests contacting medical command for pharmacological intervention.
Upon speaking with medical command, your partner describes a stable, narrow-complex tachycardia that is unresponsive to valsalva maneuvers and vagus nerve stimulation. The physician on duty asks the ETA to the closest facility, which you reply to be 20 minutes. The physician then proceeds to order the administration of a fast IVP of 6 mg of adenosine.
You inform your patient that you will administer a drug that will help him restore a normal rhythm. While still monitoring the cardiac rhythm, you administer 6 mg IVP of adenosine via the right antecubital fossa, followed by a 20 mL bolus of saline and elevation of the extremity to further speed the transport of the medication. Shortly after, the heart monitor shows asystole. However, your patient does not lose consciousness and after 10 seconds, a slower sinus rhythm is restored. You obtain a second EKG for comparison.
Second 12-lead EKG (click for larger image):
The computed interpretation is:
HR 102 bpm
PRI 208ms
QRSd 84 ms
QT/QTc 310ms/404ms
Paxis 76
QRSaxis 66
Taxis 59
The machine intepretation is:
***Age and Gender Specific Analysis***
Sinus Tachycardia
Otherwise normal EKG
Routine EKG Interpretation
This is additional interpretation based on following a checklist for 12-lead EKG interpretation.
- Rate & Rhythm: Regular, slightly rapid sinus tachycardia
- P-wave: Present, a bit wide
- PR interval: First degree AV block
- QRS interval: 84ms (unremarkable)
- QRS complex & mean axis: Normal
- ST segment: Slightly elevated in II, aVF, and V3 but not significant
- T wave: Unremarkable
- U wave: Unremarkable
- QT interval: Unremarkable
Pleased with the results, you now proceed to transport the patient to the hospital.
Patient follow-up: Narrow complex tachycardia prehospital assessment and treatment
