CCVTC cheat sheet

The heart has four chambers: right atrium, right ventricle, left atrium, left ventricle; the left ventricular wall is thickest (normally 6–10 mm) to generate systemic pressures.

The cardiac cycle: diastole (ventricular filling) comprises isovolumetric relaxation, rapid filling, diastasis, and atrial systole; systole comprises isovolumetric contraction, rapid ejection, and reduced ejection.

Normal left ventricular ejection fraction (LVEF) is 55–70%; stroke volume (SV) = end-diastolic volume (EDV) − end-systolic volume (ESV); cardiac output (CO) = SV × heart rate.

The Frank-Starling law: increased preload (ventricular stretch) increases stroke volume up to an optimal point; excessive preload leads to reduced efficiency.

Coronary arteries: left main divides into left anterior descending (LAD) and circumflex (LCx); right coronary artery (RCA) supplies the right ventricle and inferior wall; LAD supplies anterior wall and anterior two-thirds of the septum.

The cardiac conduction system: SA node (primary pacemaker, 60–100 bpm) → AV node (delays impulse) → bundle of His → right and left bundle branches → Purkinje fibers.

Heart valves: atrioventricular (tricuspid, mitral) prevent backflow during systole; semilunar (pulmonary, aortic) prevent backflow during diastole; the mitral valve has anterior and posterior leaflets.

Cardiac output is influenced by preload, afterload, contractility, and heart rate; afterload is the resistance the ventricle must overcome to eject blood (related to systemic vascular resistance).

The thoracic cavity contains the lungs, heart, great vessels, esophagus, trachea, and thymus; the mediastinum is divided into superior, anterior, middle, and posterior compartments.

The right lung has three lobes (upper, middle, lower) and two fissures (oblique, horizontal); the left lung has two lobes (upper, lower) and one fissure (oblique).

Pleural space: visceral pleura covers the lung, parietal pleura lines the thoracic wall; the potential space contains a thin film of fluid for lubrication and surface tension.

The diaphragm is the primary muscle of inspiration (phrenic nerve, C3–C5); accessory muscles include external intercostals, scalenes, and sternocleidomastoids.

The trachea bifurcates at the carina (level of T4–T5) into right and left main bronchi; the right main bronchus is wider and more vertical, making it more susceptible to aspiration.

Pulmonary circulation is low-pressure (25/8 mmHg) and high-flow; bronchial circulation is high-pressure and supplies oxygenated blood to lung tissue.

The thoracic aorta gives off intercostal arteries; the superior vena cava drains the upper body, the inferior vena cava drains the lower body into the right atrium.

Normal tidal volume is about 500 mL; vital capacity is the maximum amount of air exhaled after a maximal inhalation; residual volume is air remaining after maximal exhalation.

Ultrasound frequency and resolution: higher frequency (e.g., 5–10 MHz) improves resolution but reduces penetration; lower frequency (2–5 MHz) improves penetration for deeper structures.

The Doppler equation: frequency shift (Δf) = (2 × f₀ × v × cosθ) / c, where f₀ is transmitted frequency, v is blood velocity, θ is the angle between the beam and flow, and c is the speed of sound in tissue (~1540 m/s).

Continuous-wave (CW) Doppler measures high velocities without aliasing but lacks depth specificity; pulsed-wave (PW) Doppler provides depth specificity but is limited by the Nyquist limit (aliasing when velocity exceeds PRF/2).

Color flow Doppler maps direction (red toward, blue away) and velocity; variance maps (e.g., green/yellow) indicate turbulence.

Tissue Doppler imaging (TDI) measures myocardial velocities (e.g., e' for diastolic function) with high amplitude and low velocity; it is less angle-dependent than blood flow Doppler.

Harmonic imaging uses the second harmonic frequency to improve endocardial border definition and reduce artifact; it is commonly used in 2D echocardiography.

Frame rate is affected by sector width, depth, and line density; reducing sector width or depth increases frame rate, which is important for temporal resolution.

M-mode provides high temporal resolution for measuring chamber dimensions and timing of valve motion, but only along a single line.

Standard transthoracic echocardiography (TTE) views include parasternal long-axis (PLAX), parasternal short-axis (PSAX), apical four-chamber, apical two-chamber, apical three-chamber, and subcostal views.

In the apical four-chamber view, the left ventricle is on the right side of the screen, and the right ventricle is on the left; the apex is at the top.

Left ventricular ejection fraction (LVEF) can be estimated visually or by the Simpson's method of disks (biplane) using end-diastolic and end-systolic volumes.

Mitral inflow pulsed-wave Doppler: E wave (early diastolic filling) and A wave (atrial contraction); E/A ratio >1 is normal in young adults, but reverses with impaired relaxation.

Tissue Doppler e' velocity <8 cm/s (septal) or <10 cm/s (lateral) suggests diastolic dysfunction; E/e' ratio >14 indicates elevated left ventricular filling pressures.

Tricuspid regurgitant (TR) jet velocity >2.8 m/s suggests pulmonary hypertension; peak TR velocity plus right atrial pressure estimates systolic pulmonary artery pressure.

Aortic stenosis severity by Doppler: peak velocity >4 m/s, mean gradient >40 mmHg, and aortic valve area <1.0 cm² indicate severe stenosis.

Thoracic ultrasound: the presence of B-lines (comet-tail artifacts) indicates interstitial fluid; lung sliding absence suggests pneumothorax.

Heart failure with reduced ejection fraction (HFrEF): LVEF <40%; with preserved EF (HFpEF): LVEF ≥50% and evidence of diastolic dysfunction.

Myocardial infarction: regional wall motion abnormality (hypokinesis, akinesis, dyskinesis) in the distribution of the affected coronary artery; complications include papillary muscle rupture, ventricular septal defect, and pericardial effusion.

Aortic stenosis: calcific degeneration in elderly or bicuspid valve in younger; echocardiographic findings include thickened leaflets, reduced opening, and increased transvalvular velocity.

Mitral regurgitation: primary (leaflet pathology) or secondary (ventricular dilation); color Doppler shows a systolic jet into the left atrium; severe MR may show pulmonary vein flow reversal.

Pericardial effusion: anechoic space around the heart; cardiac tamponade shows right ventricular diastolic collapse, right atrial systolic collapse, and respiratory variation in mitral inflow.

Hypertrophic cardiomyopathy (HCM): asymmetric septal hypertrophy (≥15 mm) with dynamic left ventricular outflow tract obstruction; systolic anterior motion (SAM) of the mitral valve may be present.

Infective endocarditis: echocardiography may show vegetations (mobile echogenic masses on valves); complications include abscess, fistula, and valve destruction.

Pulmonary embolism: echocardiography may show right ventricular dilation and dysfunction, McConnell's sign (apical sparing), and elevated right ventricular systolic pressure.

Ultrasound safety: use the ALARA principle (As Low As Reasonably Achievable) to minimize exposure; mechanical index (MI) and thermal index (TI) should be monitored.

The acoustic output of diagnostic ultrasound is regulated by the FDA; the TI indicates potential for tissue heating, and the MI indicates potential for cavitation.

Patient privacy and confidentiality are protected by HIPAA; only authorized personnel should access patient information.

Informed consent is required before invasive or transesophageal echocardiography procedures; the patient must understand risks, benefits, and alternatives.

Standard precautions (hand hygiene, gloves, masks, eye protection) are used for all patients to prevent infection transmission.

Proper ergonomics (adjusting bed height, monitor position, and using support) reduces musculoskeletal strain during scanning.

Scope of practice: sonographers perform examinations but do not interpret or diagnose; final interpretation is the responsibility of the supervising physician.

Documentation must be accurate, complete, and timely; errors should be corrected according to institutional policy without altering the original record.