Lecture 7 8/27/24 Flashcards
What are the characteristics of M-mode echocardiography?
-“time-motion” echo
-single line of ultrasound
-provides unidimensional view of the heart
What are the characteristics of 2D echocardiography?
-lines of ultrasound are transmitted in an arc
-image has a triangular shape
-tomographic image is rapidly updating resulting in illusion of “real time”
-discrete frame rate
What is the depth on an echo?
the distance from the transducer
What are the characteristics of doppler echo?
-frequency shift results when sound waves are reflected from moving objects
-magnitude of the frequency shift is mathematically related to the velocity of the moving object
What is a spectral doppler?
-graph of velocity vs time
-flow toward the transducer is shown above the baseline, while flow away is below the baseline
What is doppler color flow?
-color pixels are superimposed on echo image
-blue color is flow away, red color is flow towards
-high velocities cannot be displayed
How can mitral valve regurgitation be identified using doppler color flow?
by identifying color originating from the mitral valve when the valve appears closed
What are the benefits of using M or 2D echocardiography?
-provides delineation of specific cardiac structures
-allows for quantitative assessment of cardiac structure and evaluation of function
What are the benefits of using doppler echocardiography?
-localization of murmur origins
-ability to quantify pressure differences across narrowings in circulation
What are the limitations of echocardiography?
-provides relatively little information regarding the consequences of cardiac dysfunction
-chest films are still gold standard for diagnosing left-sided CHF
What is TFAST?
thoracic focused assessment with sonography for triage
What is blood pressure?
force/area, usually measured in mmHg
What are the methods for measuring blood pressure?
direct:
-arterial catheter
indirect:
-doppler-cuff method
-oscillometric method
-photoplethysmography
How does systemic hypertension relate to heart disease?
systemic hypertension can cause heart disease, but heart disease can NOT cause systemic hypertension
What are the systolic BP values of importance when evaluating for systemic hypertension?
- < 160 mmHg: normal
- > 160 mmHg with target organ damage: indicates presence of hypertension
- between 160 and 180 with no target organ damage: recheck; repeated credible high values may indicate hypertension
Which organs are the target of damage with systemic hypertension?
-retinas
-kidneys
-heart
What are biomarkers?
objectively determined characteristics that may play a role in diagnosis, risk stratification, and evaluation of disease progression/response to therapy
What are the functional roles of natriuretic peptides?
-fluid homeostasis/sodium diuresis
-blood pressure regulation/vasodilation
What is the stimulus for natriuretic peptide release?
increases in cardiac stretch
What is the diagnostic utility of BNP?
-BNP is released by atrial and ventricular cardiomyocytes in response to increases in ventricular filling pressures
-indicates heart failure state
What is the physiology of troponin?
complex of sarcomeric regulator proteins consisting of Tn-I, Tn-C, and Tn-T components
What are the diagnostic characteristics of troponin?
-cardiac isoform of Tn-I only occurs in cardiac myocytes
-rises in blood troponin reflect cardiac necrosis or myocardial damage
-Tn-I concentration is used in the diagnosis of acute myocardial infarction (humans)
