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Cardiac Review Notes

General Information

• Heart Rate: 98 bpm

• Cardiac Axis: Normal cardiac axis presented in various leads including I, II, III, aVR, aVL, aVF.

• Measurements:   - 2D: 57% ejection fraction   - 2D dimensions:     - RVOT proximal: normal 21 - 35 mm     - Peak velocity in the Pulmonic Valve (PV) and Right Ventricular Outflow Tract (RVOT)     - Maximum PG: 113 mmHg     - Vmax: 532 cm/s

Pulmonic Stenosis

Definition

• Pulmonic Stenosis (PS): Narrowing/thickening/obstruction of the Pulmonic Valve (PV) which impedes systolic flow from Right Ventricle (RV) to the Pulmonary Artery (PA).   - Classified by location:     - Subvalvular PS     - Valvular PS     - Supravalvular PS

• Etiology: Usually congenital.

Murmur Characteristics

• Murmur: Harsh systolic ejection murmur heard best at the left upper sternal border.

2D & M-Mode ECHO Findings

• Findings:   - Thickened cusps   - Systolic doming of the PV   - Right Ventricular Hypertrophy (RVH)   - IVS (Interventricular Septum) flattening   - D-shaped Left Ventricle (LV)   - Right Atrial Enlargement (RAE)   - Later stages may lead to right heart failure.   - Post-stenotic PA dilation.

• M-Mode Evaluation:   - Evaluate "a" wave dip in the pressure gradients.   - Severe PS indicated by "a" wave depth >= 8 mm.

Doppler Evaluation

• Key Measurements:   - Acquire peak velocity, maximum PG, mean PG, & Pulmonary Velocity-Area (PVA):     $ext{PVA} = rac{(VTIRVOT) imes (CSARVOT)}{(VTIPV)}$

• Severity Scale:   - Mild PS: Peak PG < 36 mmHg, Peak Velocity < 3 m/s   - Moderate PS: Peak PG 36 - 64 mmHg, Peak Velocity 3 - 4 m/s   - Severe PS: Peak PG > 64 mmHg, Peak Velocity > 4 m/s

Pulmonic Regurgitation

Definition

• Pulmonic Regurgitation (PR): Incompetent Pulmonic Valve allows backward diastolic flow from PA to RV.

Murmur Characteristics

• Murmur: Low-pitched diastolic murmur, may increase with inspiration.   - High-pitched blowing diastolic murmur known as Graham-Steele Murmur when Pulmonary Hypertension (PH) is present.

Causes

• Incomplete closure of PV, Infective Endocarditis (IE), Rheumatic Heart Disease (RHD), congenital anomalies, carcinoid heart disease.

Complications

• Usually well tolerated for years but risks include:   - Increased risk of IE.   - Dyspnea.   - Severe PR leading to right heart failure.

2D ECHO Findings

• Common Observations:   - Trivial/mild PR.   - Anatomic defects.   - RV Volume Overload (RVVO).   - Tricuspid Variable Diastolic Flutter (TVDF).   - Turbulent diastolic flow from PA to closed PV to RVOT.

Echocardiographic Doppler Findings

• Evaluate antegrade spectral waveform for PR; measure PHT slope.

Pulmonary Hypertension

Definition

• Pulmonary Hypertension (PHTN): Begins when the small arteries in the lungs become narrowed, blocked, or destroyed.

• Classification: Five groups including:   1. Pulmonary Arterial Hypertension (PAH)   2. PAH caused by left-sided heart disease   3. PAH caused by lung disease   4. PAH caused by chronic blood clots   5. PAH due to other health conditions.

Pulmonary Arterial Hypertension (PAH)

• Pathophysiology: Blood vessels in lungs become narrowed or blocked leading to:   - Right Ventricular Hypertrophy (RVH)   - Right Ventricular Dysfunction (RVD) and potential right heart failure due to increased right ventricular pressure (RVP) flattened IVS.

Complications

• Right-sided heart enlargement and heart failure (cor pulmonale).

• Advanced lung diseases may lead to significant pulmonary hypertension.

• Elevated pressures on the right ventricle eventually lead to right heart failure.

Assessing Right Ventricular Function

• Parameters to Consider:   - Right Ventricular Diameter, Fractional Area Change, TAPSE (Tricuspid Annular Plane Systolic Excursion), and Tissue Doppler Imaging.

• Normal values for RV measurements:   - Basal width: 25 - 41 mm   - Mid width: 19 - 35 mm   - Longitudinal RV length: 59 - 83 mm

TAPSE Measurement

• Procedure for TAPSE:   - Place M-mode cursor between RV free wall and tricuspid valve annulus, measure peak systolic longitudinal motion:     - TAPSE < 17 mm = decreased RV function.

Tissue Doppler Imaging

• Assessment Technique: Evaluating tissue Doppler velocities of tricuspid annulus to denote systolic velocities represented as S' wave.

• Normal S' prime value: > 10 cm/s; values less than this indicate RV systolic dysfunction.

Fractional Area Change (FAC)

• RVFAC: Represents the percentage change in RV area from end-diastole to end-systole.

• Calculation for RVFAC:     $ext{RVFAC} ( ext{ extpercent}) = rac{ ext{RVEDA} - ext{RVESA}}{ ext{RVEDA}}$

• Normal RVFAC value: >= 35% indicates good RV function.

Estimating Right Atrial Pressure

• Based on IVC size and inspiratory collapse:   - IVC size < 2.1 cm with > 50% collapse = 3 mmHg RA pressure   - IVC size < 2.1 cm with < 50% collapse = 8 mmHg RA pressure   - IVC dilated > 2.1 cm with > 50% collapse = 8 mmHg RA pressure   - IVC dilated > 2.1 cm with < 50% collapse = 15 mmHg RA pressure.

Diastolic Dysfunction

Definition

• Diastolic dysfunction refers to the inability of the heart muscle to relax normally after each heartbeat, impairing cardiac filling during diastole.

• Consequences include:   - Elevated filling pressures, leading to pulmonary congestion and symptoms of dyspnea.   - Heart failure from prolonged diastolic dysfunction.

Diastolic Dysfunction Stages

1. Grade I - Impaired Relaxation: Decreased E-wave; increased A-wave due to more blood from atrial contraction.

2. Grade II - Pseudonormal Filling Pattern: Increased left atrial pressure; E/A ratio returns to normal ranges; falsely resembles normal function.

3. Grade III - Restrictive: Elevated left atrial pressures; E/A ratio > 2.0; deceleration time < 160 ms.

4. Grade IV - Fixed Restrictive: No change in E/A with Valsalva maneuver; indicates poor prognosis.

Left Ventricular Mass

• LV mass estimation based on cavity dimension and wall thickness:   - Formula: ext{LV Mass} = 0.8 imes ext{(1.04[(LVEDD + IVSd + PWd)}^3 - LVEDD^3)]} + 0.6   - To find the left ventricular mass index, divide LV mass by body surface area (g/m²).

Electrocardiography (ECG)

Standard Lead Placements

• 12 Lead Placement: EKG leads placement (RA, LA, RL, LL, V1-V6) according to predefined anatomical landmarks.

• Limb Leads: I, II, III formed by RA, LA, and LL (Einthoven Triangle).

• Precordial Leads: V1-V6 placed along the thorax.

• Augmented leads: Unipolar leads that provide specific insights into heart activity.

Common ECG Measurements

• Normal Values:   - P Wave: 0.08 - 0.11 seconds   - PR Interval: 0.12 - 0.20 seconds   - QRS complex: 0.06 - 0.10 seconds   - QT Interval: < 0.38 seconds.

Heart Rate Determination

• Methods:   - R-R Method: Count large boxes between R waves, divide by 300.   - 1500 Method: Count small squares between R waves, divide into 1500.   - 6 Second Method: Count QRS complexes in 6-second intervals; multiply by 10.

Cardiac Rhythms

• Normal Sinus Rhythm: 60 - 100 BPM, consistent intervals between waves, regular P waves before QRS.

• Bradycardia: < 60 BPM, consistent intervals as per NSR.

• Tachycardia: > 100 BPM, other criteria consistent with NSR.

• Sinus Dysrhythmia: 60-100 BPM, irregular intervals between waves, normal P wave appearance.

Summary of Important Protocols and Measurements for Cardiac Assessment

• Use of 2D Echo and M-mode for structural and functional assessment of heart chambers; Doppler for flow evaluation.

• Reliance on categorized heart pressures and RV function metrics to assess cardiac performance and pathology.

• Continuous monitoring of volume metrics of the right atrium and right ventricle through refined ultrasound techniques and proper electrode placements for reliable ECG interpretation.

Recommended Study Material

• Refer to all 2D anatomical references and review PowerPoint presentations discussed in class.

Conclusion

• Comprehensive understanding of cardiac conditions is critical for assessment and management. Make use of all outlined measuring techniques and protocols for accurate diagnosis and treatment planning in clinical practices.