What would best explain a point of maximal impulse (PMI) located above and to the left of the normal location in a young patient?

From the Guidelines

The most likely explanation for a point of maximal impulse (PMI) located above and to the left of the normal location in a young patient is a condition that causes elevation of the diaphragm, such as pregnancy or other space-occupying lesions in the chest cavity, which can shift the heart's position. When considering the potential causes of an elevated PMI, it's essential to think about conditions that can displace the heart within the thoracic cavity. According to the emergency ultrasound imaging criteria compendium by the American College of Emergency Physicians 1, the normal location of the PMI is in the fifth intercostal space and inferior to the nipple, but this can vary greatly among individuals. Some key points to consider when evaluating an elevated PMI include:

• The patient's medical history and current symptoms
• The presence of any conditions that could cause diaphragmatic elevation, such as pregnancy or space-occupying lesions
• The results of a thorough cardiac examination, including auscultation and echocardiography Given the information provided, it's crucial to prioritize a thorough evaluation to determine the underlying cause of the elevated PMI, as this finding can have significant implications for the patient's morbidity, mortality, and quality of life. In clinical practice, it's vital to rely on the most recent and highest-quality evidence, such as the study by the American College of Emergency Physicians 1, to guide decision-making and ensure optimal patient outcomes.

From the Research

Point of Maximal Impulse (PMI) Location

The location of the point of maximal impulse (PMI) can be indicative of various cardiac conditions. A PMI located above and to the left of the normal location in a young patient may be due to several factors, including:

• Right ventricular enlargement or hypertrophy, which can cause the PMI to shift upwards and to the left 2, 3
• Congenital heart diseases, such as those that affect the right ventricle, which can also lead to an abnormal PMI location 2
• Pulmonary hypertension, which can cause right ventricular dilation and subsequent shift of the PMI 4, 3

Right Ventricular Enlargement

Right ventricular enlargement can be assessed using various imaging modalities, including echocardiography and computed tomography (CT) scans. Studies have shown that:

• Echocardiography can be used to measure right ventricular dimensions and function, including the assessment of tricuspid regurgitation severity and right ventricular systolic pressure 3, 5
• CT scans can be used to subjectively assess right ventricular enlargement, with a high degree of agreement between readers 6

Clinical Implications

The clinical implications of a PMI located above and to the left of the normal location in a young patient depend on the underlying cause. However, it is essential to note that:

• Right ventricular dysfunction is a common finding in patients with chronic heart failure, and its assessment is crucial for determining prognosis and guiding treatment 3
• Accurate and quantitative imaging of the right ventricle is necessary to evaluate its size and function, and to guide clinical decision-making 5