A cardiac ultrasound, also known as an echocardiogram, is a medical imaging procedure that uses high-frequency sound waves to generate detailed images of the heart. These sound waves bounce off heart tissues, creating “echoes” that a computer then translates into moving pictures of the heart’s internal structures. This non-invasive test allows healthcare providers to visualize the heart’s four chambers, its four valves, and the major blood vessels nearby. The purpose of a cardiac ultrasound is to assess the heart’s structure and how well it is functioning.
Reasons for a Cardiac Ultrasound
Doctors often order a cardiac ultrasound to investigate various heart-related symptoms or to monitor known heart conditions. It helps diagnose issues such as chest pain, shortness of breath, or the presence of a heart murmur. The test can also identify changes in electrocardiogram (ECG) results, which are electrical recordings of heart activity.
These conditions include heart valve disease, where valves may be narrowed or leaking, and heart failure, which affects the heart’s pumping strength. It can also help detect congenital heart conditions, blood clots, or even tumors within the heart.
Common Cardiac Ultrasound Views
Cardiac ultrasound “views” refer to the different angles or perspectives from which the heart is imaged, allowing for a comprehensive assessment of its structures. These views are obtained by positioning the ultrasound transducer on specific areas of the chest. Since bone reflects ultrasound waves, the heart must be viewed between the ribs to ensure clear images. The most common views are obtained from parasternal, apical, subcostal, and suprasternal “windows”.
The parasternal long-axis (PLAX) view is frequently the initial image obtained during a comprehensive examination. This view visualizes the left atrium, left ventricle, the left ventricular outflow tract, and the aortic root. It also allows for imaging of the aortic and mitral valves, as well as the ascending aorta. This view is useful for assessing the contractility and chamber size of the left ventricle and the function of the aortic and mitral valves.
From the parasternal long-axis view, the transducer can be rotated to obtain the parasternal short-axis (PSAX) view. This view provides cross-sectional images of the heart at various levels, resembling slices of the heart. It helps in evaluating the left ventricular walls and assessing all major coronary distributions around the left ventricle. The PSAX view is useful for assessing the function and size of the ventricles and the shape of the valves.
The apical four-chamber (A4C) view is obtained by placing the transducer near the point of maximal impulse. This view allows for visualization of all four heart chambers: the left and right atria, and the left and right ventricles. It is valuable for assessing the size and function of all four chambers and for measuring blood flow across the mitral and tricuspid valves.
The apical two-chamber (A2C) view is generated by rotating the transducer from the apical four-chamber view. This view directly visualizes the left atrium, mitral valve, and left ventricle. It shows the true anterior and inferior walls of the left ventricle, which helps in assessing regional heart muscle function.
The subcostal view is obtained by placing the transducer just below the rib cage. It is useful for assessing for fluid around the heart (pericardial effusions), atrial or ventricular septal defects, and overall chamber size and function. The suprasternal view is obtained by placing the transducer above the sternum at the base of the neck. This view is used to visualize the aorta and its major branches, providing information on conditions like aortic dissection or aneurysm.
What Happens During the Procedure
Undergoing a cardiac ultrasound is a straightforward and painless process that requires minimal preparation. Patients can eat, drink, and take their regular medications before the test. There is no need for fasting or special dietary restrictions.
During the procedure, the patient lies on an examination table. A sonographer, a technician trained in ultrasound technology, will apply a special gel to the chest. This gel helps the ultrasound transducer, a small handheld device, glide smoothly over the skin and ensures the sound waves travel effectively to and from the heart. The sonographer then moves the transducer across different areas of the chest to capture the various views of the heart. The entire test takes between 30 to 60 minutes.
What Doctors Learn from the Views
By analyzing the different cardiac ultrasound views, doctors gather a wealth of information about the heart’s structure and function. They can assess the size and shape of the heart’s chambers, identifying any enlargement or abnormal thickness. The images also allow for evaluation of the heart valves, determining if they are opening and closing properly or if there is narrowing (stenosis) or leaking (regurgitation).
The pumping strength of the heart muscle, often referred to as ejection fraction, is also determined through these views. Doctors can observe how well the heart’s walls contract and relax, which is important for diagnosing conditions like heart failure. Additionally, the presence of any fluid accumulation around the heart, known as pericardial effusion, can be identified. This comprehensive information aids in accurate diagnosis, helps in monitoring the progression of known heart conditions, and guides treatment planning to improve patient outcomes.