Emergency Medical Services (EMS) Agency


Paramedics respond to a 60 year-old male with history of lung cancer in moderate respiratory distress.  He reports one month of increasing dyspnea on exertion and one week of shortness of breath at rest.  Since last night, he has not been unable to lay down due to trouble breathing.  He denies any fever, chest pain, or gastrointestinal symptoms.

Vital signs are blood pressure 90/70, HR 140, RR 22, O2 saturation 100% on 2L of home oxygen via nasal cannula.  His lungs are clear to auscultation.  Neck veins are prominent.  He has no peripheral edema.


ECG from WikEM1



Rate:                                                 140 bpm
Rhythm:                                            Sinus Rhythm – there are p waves before each QRS
ST Segment Elevation >1mm
In 2 or more contiguous Leads?:
Reciprocal Changes:                        N/A
Other Abnormalities:                       The QRS complexes alternate in morphology

This ECG pattern is called electrical alternans and is seen in some cases of cardiac tamponade.  Beat-to-beat, the normally-conducted QRS complexes alternate in height.  This pattern results from the heart swinging backwards and forwards in a large pericardial effusion.   Electrical alternans is a relatively rare finding, but if present in a patient with a clinically consistent presentation, one should suspect cardiac tamponade.  More common ECG findings in patients with cardiac tamponade are sinus tachycardia and low QRS voltage.

As is true in this case, patients will typically be hypotensive and have narrow pulse pressure.   Pulse pressure is the difference between systolic and diastolic blood pressure; values lower than 25% of the systolic blood pressure are narrow.  In general, this is an early sign of shock.  Additional supportive findings for cardiac tamponade in this patient include elevated JVP with clear lungs.  Malignancy is the most common cause of non-traumatic cardiac tamponade.  The patient’s lung cancer has caused the pericardial effusion leading to tamponade.

As fluid accumulates in the pericardial space, the pressure increases which reduces ventricular filling and cardiac output.  Therefore, there is reduced preload to the ventricles.  Therefore, IV fluids would be the first most important intervention in this hypotensive patient with suspected cardiac tamponade.

Cardiac tamponade does not have a specific Provider Impression.  Since this patient’s primary presentation of the tamponade is respiratory distress, it is reasonable to choose Respiratory Distress/Other in this patient (RDOT), which includes non-pulmonary and unknown causes of respiratory distress, and to manage the patient per TP 1237, Respiratory Distress.  The patient should receive Normal Saline 1L rapid infusion for his hypotension and should be continued on his home oxygen at 2L/min.  If his condition worsens, high-flow oxygen is appropriate, with continued fluids unless he develops evidence of pulmonary edema.  CPAP and nitrates are contraindicated in this preload-dependent condition.

The patient requires ALS transport to the MAR for rapid evaluation of cardiac tamponade via cardiac ultrasound.  Definitive treatment is a pericardiocentesis, where fluid is aspirated out of the pericardial sac.


  1. https://wikem.org/wiki/Pericardial_effusion_and_tamponade. Accessed July 18, 2019.

Author: Dr. Nichole Bosson, MD, MPH