Welcome to another ultrasound-based case, part of the “Ultrasound For The Win!” (#US4TW) Case Series. In this peer-reviewed case series, we focus on real clinical cases where bedside ultrasound changed management or aided in diagnoses. In this case, a 43-year-old man presents to the Emergency Department after a syncopal episode.
A 43-year-old man presents to the Emergency Department with a complaint of a syncopal episode. He is a landscaper and reports that on his lunch break he experienced a brief ‘head rush’ while seated and subsequently ‘passed out’ for approximately 20 seconds. He denies any associated chest pain, dyspnea or palpitations. There were no witnessed tonic-clonic movements, no tongue biting, no loss of bowel or bladder control, and no post-ictal state. He had been feeling well recently with no previous episodes of pre-syncope or syncope. He currently feels well and has no complaints. Review of symptoms was otherwise negative. His past medical history includes a thirty pack-year smoking history. He does not take any medications and denies illicit drug use.
On physical examination, you observe a man of normal body habitus who is in no distress. His heart sounds are regular without murmurs, and his lungs are clear to auscultation bilaterally. Extremities are warm with no edema.
BP 138/93 mm Hg
P 74 bpm
RR 18 respirations/min
O2 99% saturation on room air
T 35.3 C
- Cardiogenic syncope (arrhythmia, ischemia, conduction block)
- Intracranial event (subarachnoid hemorrhage, vertebrobasilar migraine, brain stem TIA)
- Orthostatic hypotension
- Pulmonary embolism
- Vasovagal syncope
Given the patient’s abnormal ECG, the emergency physician performed a focused bedside echocardiogram.
Ultrasound Image Quality Assurance (QA)
Immediately evident on the bedside echo is a severely depressed ejection fraction (EF), and the likely cause of his syncopal event. In comparison to a previous #US4TW case discussing regional wall motion abnormalities, this cardiac echo appears to be globally hypokinetic with a severely depressed ejection fraction. Although this “eyeball method” is effective for seasoned echocardiographers1, it is helpful for the emergency physician to have fast and easily applicable bedside measures to aid in qualitatively assessing ejection fraction. One of the available tools is the E-point septal separation (EPSS). This measurement can be visually estimated, or measured directly using M-mode (M for motion), instead of standard B-mode imaging.
EPSS correlates well with ejection fraction2 and in the hands of an emergency physician can rule out severe left ventricular dysfunction (EF < 30%) with a high sensitivity.3 During early diastole, the anterior mitral valve leaflet normally “slaps” or closely approximates the ventricular septum. On M-mode, this correlates to the E-wave (Figure 4). The A-wave is formed by the atrial contraction at end diastole. The smallest distance between the E-wave and the interventricular septum is the EPSS. An EPSS greater than 0.7 cm correlates with a reduced EF.2,3 A caveat to this is in patients with dilated cardiomyopathy, in which case the EPSS may not be indicative of EF. In patients with a normal EF, the anterior leaflet should touch or very closely approach the septum, or result in “septal slap”.
In a focused emergency-physician performed echo, EF can be placed into 1 of 3 different categories:
|Ejection Fraction Categories|
|Normal/Hyperdynamic||EF > 50%|
|Moderately Depressed||EF 30-50%|
|Severely Depressed||EF < 30%|
With minimal focused echo training, it has been shown that emergency sonographers can estimate EFwith good correlation to a complete echocardiogram and also to a cardiologist’s interpretation.4–6 However, as an echocardiogram uses two-dimensional images to represent a complex three-dimensional structure, multiple views must be used to confirm your findings.
In our case, EPSS is grossly abnormal and well beyond 0.7 cm. With this measure and evidence of global hypokinesis in multiple views, a cardiogenic cause for the patient’s syncope is much higher on the differential.
Disposition and Case Conclusion
Cardiology was consulted in the ED for suspected cardiogenic syncope. While awaiting the consultant to arrive, the patient had another syncopal event in the ED and ventricular fibrillation was evident on the cardiac monitor. He spontaneously converted after approximately 10 seconds.
On admission to hospital the patient’s complete echocardiogram demonstrated global hypokinesis with an ejection fraction of 26%. Cardiac catheterization demonstrated no significant coronary artery disease. On further history, the patient admitted to drinking approximately 6 pints of beer daily for over 2 years. He was seen by electrophysiology and received an implantable cardioverter defibrillator for alcohol-related cardiomyopathy. He was discharged home in stable condition with no further events.
Take Home Points
- Bedside echocardiography can be a useful supplemental diagnostic tool to risk-stratify patients who present to the Emergency Department with possible cardiogenic syncope.
- E-point septal separation (EPSS) is a valuable quantitative bedside measure that can be used to aid in the assessment of left ventricular ejection fraction.
- Caveats to the bedside echo for assessment of ejection fraction include using at least 2 views to reduce probability of falsely normal readings, patients with dilated cardiomyopathy, and obtaining adequate cardiac windows.