Chapter 15: Echocardiography
High-quality echocardiographic images require optimal resolution, that is, the ability to distinguish two individual objects separated in space. Which of the following will not yield high-resolution images?
The answer is C. (Hurst’s The Heart, 14th Edition, Chap. 15). Short wavelengths yield excellent resolution in echo imaging (option A) because the shorter the cycle length, the smaller the object that will reflect the signal and be detected by the echo scanner. Because wavelength is inversely related to frequency, transducers that emit a high-frequency signal (≥ 3.5–7.0 MHz) yield high-resolution images (option B). Because ultrasonic beams diverge as they propagate away from the transducer, the width of the beam can become sufficiently great to encompass multiple targets and decrease resolution (option D). The degree of beam divergence is also less with high-frequency sonic energy than with low-frequency signals.
There has been a great deal of interest in using mitral inflow velocity patterns to evaluate left ventricular diastolic properties. Which of the following variables is not capable of influencing transmitral filling velocities?
D. Position of the Doppler sample volume
The answer is E. (Hurst’s The Heart, 14th Edition, Chap. 15). The abnormal mitral inflow patterns are often useful in suggesting the presence and severity of diastolic dysfunction. Several variables other than diastolic function, however, are capable of influencing transmitral filling velocities. Transmitral Doppler filling dynamics are affected by the age of the patient (option A), concomitant mitral regurgitation, high-flow states, changes in heart rate (option B),1 respiration (option C), and the position of the Doppler sample volume within the mitral valve orifice (option D).2
A 55-year-old woman with no prior cardiac history was admitted to the emergency department complaining of a 6-month history of dyspnea. On physical examination, she had jugular venous distension, distended abdomen secondary to hepatomegaly and tense ascites, severe bilateral lower limbs pitting edema, and an S3 gallop. After an initial management she was referred to the cardiologist, who performed an echocardiography, and some of the images are illustrated in Figure 15-1. Based on the echo’s findings, which of the following is the most likely diagnosis?