Ultrasound: Cardiac Exam
Purpose: identify possible causes of hemodynamic instability, respiratory distress, assessment of volume status.
Probe
The phased array can be used for the entire exam. The curvilinear can also be used for the subxiphoid and IVC views.
Views
There are 4 basic views, including the parasternal long axis, parasternal short axis, the apical four chamber and the subcostal view. Additionally, the inferior vena cava can be visualized.
Cardiac ultrasound is more challenging to learn than most other ultrasound studies, because probe usage (position, angle, rotation, translation, etc) have drastic impact on visualization. It’s necessary to understand what is shown in each view, so take time reviewing these so you can have a better appreciation for what you are seeing when you perform a study on a real patient. One recommendation, if it is difficult to visualize the heart, moving the patient into the lateral decubitus with their left side down can significantly improve visualization as the heart is closer to the chest wall in this position.
For video and pictorial explanations of the views, please refer to these sites.
Findings
Gross abnormalities- decreased ventricular function, arrhythmias
Profound hypovolemia
Small hyperdynamic left ventricle with end-systolic collapse
Inferior vena cava- assess volume status, either static measurement of diameter or calculation of collapsibility (>50% correlates with volume responsiveness). Respiratory variation (collapsibility/distensibility index).
Takotsubo cardiomyopathy
Akinesia of the apical and mid-ventricular segment, hypercontractile basal segments.Â
Apical sparing (dilated).
Acute cor pulmonale
Respiratory disorder→ pulmonary hypertension→ right heart failure. Dilated right heart.
Cardiac tamponade
Effusion with end-diastolic collapse of the right atrium, effusion in front of the aorta
Pulmonary embolism
Free-floating thrombus in the right ventricle or pulmonary artery; right ventricular dilation/ systolic dysfunction; septal bowing into the left ventricle; dilated IVC without inspiratory collapse. Most sensitive/ specific indirect sign- right ventricular apical sparing (McConnell's sign).
References