Exam 9 Flashcards
POCUS: uses
*may identify presence of disease
*screening populations at risk of heart disease
*useful tool in medical education
*useful for periodic checks to known abnormality and how it responds to treatment
POCUS is helpful in Rapid Diagnosis of:
- pleural/pericardial effusion/tamponade
-ventricular size, wall thickness, global function
-segmental wall motion abnormalities
-LA and IVC size
-signs of pulmonary embolus
-heart failure symptoms with or without preserved EF
-intravascular volume assessment
-guidance of pericardiocentesis and transverse pacing wire placement
POCUS: highest diagnostic accuracy
-presence or absence of a pericardial effusion
-presence or absence of LV systolic dysfunction
POCUS: Limitations
-lower accuracy for regional wall motion and vascular heart disease
-missed diagnosis due to an inexperienced operator or suboptimal image quality
-limited recording capacity so accurate reporting is essential
3D Acquisition Modalities
3D usefulness
-Quantification of LV volume and EF
-Evaluation of MV pathology
-Guidance of transcatheter procedures
-Promising in RV volumes/EF
3D display/graphs
Measures of Myocardial Mechanics
-Displacement: the distance a cardiac structure or myocardial element moves between 2 consecutive image frames (distance cm)
-Velocity: the speed of movement of a cardiac structure or myocardial element (velocity cm/s)
-Strain: the fractional change in length of a myocardial segment; a unitless measure of myocardial deformation (positive/negative percentage %)
-Strain Rate: the rate of change in strain with units of 1 per second
-Rotation: the circular motion of the LV myocardium around its long axis (degrees)
-Twist: the absolute difference in rotation between the LV base and apex (degrees)
-Torsion: the gradient in rotation angle from base to apex (degrees per cm)
Advantages of STE over Advanced TDI
-measures all mechanics (limited rotation, twist, torsion)
-simpler data acquisition with multiple simultaneous measurements presented
-lack of angle dependence
-direct measurement of strain
-circumferential and radial in addition to longitudinal strain
-ability to do analysis after image acquisition
Interpreting STE display
tracking the motion of small bright spots on the gray scale image as they move during the cardiac cycle
Function of Agitated Saline
allows for the detection of shunts by the appearance of contrast in the left heart within one to two beats of contrast appearance in the right heart
Advantages of ICE
-primarily for monitoring invasive procedures
-allows physician to evaluate pre-procedure, position during procedure, check effectiveness after procedure
-well tolerated, accurate, provides continuous monitoring
ICE probe positions and uses
- positioned in IVE, RA, and RV
IVUS modality (Intravascular Ultrasound)
-uses 30-50 MHz transducer element on a steerable catheter that is positioned in the coronary arteries during interventional coronary procedures
-assess effectiveness of PCI
-used when standard angiographic data are inadequate to evaluate the length and severity of narrowing and the composition of plaque which guides the therapeutic approach
How pharmacological agents simulate stress
-increases the strength of contraction and HR
-ischemia is induced by increasing the myocardial oxygen demand by exercise or pharmacologic interventions
Stress Echo Acquisition
-use Plax or A3, PSAX PM, A4, or A2: all myocardial segments visualized in at least one but preferably two views
-compare rest with exercise images
-record images in digital cine loop format
Dobutamine Protocol
-administered via IV in increments to increase HR and contractility
-administered at low dose (5ug/kg/min) and increase quantity every 3 mins until target HR is achieved or 40 ug/kg/min
-have emergency meds/equipment in case of adverse effects
-monitor 12 lead EKG, symptoms, BP, wall motion views at each stage
-quad display: rest, low dose, high dose, and recovery
-helpful in identifying shunned or hibernating myocardium
Shunned Myocardium
patient received thrombolytic in the field
Hibernating Myocardium
patient discovered to have undiagnosed resting wall motion abnormality
Viable myocardium
benefits from revascularization
-increased contractility with low dose but loses contractility with higher dose (biphasic response)
Alternate approaches to Stress Echo
-Stress Test
-Nuclear Test
-Coronary Angiography
-PET: Pharmacologic Position Emission Tomography
-Computed Tomography Coronary Angiography
-Cardiac Magnetic Resonance Imaging
Diastolic Dysfunction Benchmark
HCM Indication
LV function and Lung Images
MR parameters
MS benchmark
Assessing LF-LG AS
Flow Reserve:
Without Flow Reserve:
Classical LF-LG AS
PW doppler LVOT, CW doppler AV, LV views
EF < 50%, MPG < 40mmHg, AVA < 1cm2
Paradoxical LF-LG AS
EF ≥ 50%, SVI < 35 ml/m2 , AVA < 1 cm2, AVAI < .6 cm2/m2, MPG < 40mmHg at rest
