What is a subxiphoid cardiac impulse?

Subxiphoid Cardiac Impulse: Definition and Clinical Context

The subxiphoid cardiac impulse refers to cardiac pulsations that can be visualized or palpated in the subxiphoid (below the xiphoid process) region, typically assessed during physical examination or as an anatomical landmark for cardiac imaging and procedures. 1

Anatomical Location and Clinical Significance

• The subxiphoid region is located just below the xiphoid process in the epigastric area, where the liver provides a sonographic window to the heart 1
• In this location, the heart lies immediately behind the sternum, requiring the examiner to direct attention toward the patient's left shoulder at an angle almost parallel with the horizontal plane in a supine patient 1
• The xiphoid process serves as a critical anatomical landmark positioned between the sternal body and umbilicus, with the subxiphoid area providing direct access to cardiac structures 2

Physical Examination Findings

• In patients with hypertrophic cardiomyopathy, a prominent point of maximal impulse may be present, which can be shifted laterally and either bifid or trifid in character 1
• The subxiphoid area allows palpation of cardiac impulses, particularly useful when standard precordial examination is limited by body habitus or clinical circumstances 1
• Firm downward pressure is required in the subxiphoid region, especially in patients with protuberant abdomens, to adequately assess cardiac pulsations 1

Clinical Applications

Ultrasound Imaging

• The subcostal four-chamber view (also called subxiphoid view) is obtained by placing the ultrasound probe just under the rib cage or xiphoid process, directed toward the patient's left shoulder with the probe marker at 9 o'clock 1
• This view demonstrates the right atrium, tricuspid valve, right ventricle, left atrium, left ventricle, and pericardial spaces both anterior and posterior to the heart 1
• The subxiphoid approach is particularly valuable when standard parasternal or apical windows are inadequate due to anterior abdominal trauma or body habitus 1

Diagnostic Procedures

• The subxiphoid approach provides access for pericardiocentesis in cardiac tamponade, using the liver as a sonographic window while avoiding coronary, pericardial, and internal mammary arteries 1
• Subxiphoid pericardial window is the standard diagnostic approach for suspected cardiac injuries in hemodynamically stable patients with penetrating trauma near the heart 3, 4
• This approach has demonstrated 100% accuracy with no false-positive or false-negative results in diagnosing cardiac injuries, with minimal morbidity (1.3%) 4

Common Pitfalls and Caveats

• Adequate visualization requires firm downward pressure and proper angulation toward the left shoulder; insufficient pressure will fail to obtain views posterior to the sternum 1
• The subxiphoid window may be impossible in patients with anterior abdominal trauma, requiring alternative cardiac windows such as parasternal or apical four-chamber views 1
• When performing subxiphoid procedures, aortic dissection is a major contraindication to pericardiocentesis 1
• The subxiphoid approach is superior to chest wall-based imaging for demonstrating obstructive lesions in the proximal right ventricular outflow tract and provides better visualization of interatrial and interventricular septae with less false dropout 5