Cardiac Evaluation and Diagnostics

Cardiac Evaluation and Diagnostics

Cardiac Evaluation and Diagnostics

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Clinical Assessment - Heart's First Clues

  • History:
    • Feeding: Sweating, fatigue, ↓intake, poor weight gain (FTT).
    • Cyanosis: Onset, squatting. Exercise intolerance.
    • Maternal: Diabetes, infections. Family Hx of CHD.
  • General Exam:
    • Syndromic facies (e.g., Down's, Turner's, Noonan's).
    • Vitals: HR, RR, 4-limb BP (coarctation), SpO2 (pre & post-ductal).
    • Clubbing, cyanosis (central/peripheral), edema.
  • CVS Exam:
    • Palpation: Apex beat (location), thrills, heaves. Pulses: Radio-femoral delay.
    • Auscultation: Heart sounds (S1, S2 splitting, S3, S4, clicks). Murmurs: Systolic/Diastolic, Grade (1-6), location, radiation, quality. Infant with cyanosis

⭐ Differential cyanosis (lower limb SpO2 < upper limb SpO2 by >3-5%) strongly suggests Persistent Ductus Arteriosus (PDA) with right-to-left shunt or interrupted aortic arch.

Chest X-Ray - X-Ray Vision

  • CT Ratio: Neonate <0.6; Infant (<1yr) <0.55; Child (>1yr) <0.5.
  • Pulmonary Vascular Markings (PVM):
    • ↑ Plethora: L→R shunts (VSD, ASD, PDA).
    • ↓ Oligemia: ↓ Pulm. Blood Flow (TOF, Pulm. Atresia).
    • Venous Congestion: LV failure, MS.
  • Classic Cardiac Silhouettes & Signs:
    • "Boot-shaped": TOF.
    • "Egg-on-string": TGA.
    • "Snowman sign" / "Figure of 8": TAPVC (supracardiac).
    • "Box-shaped" / "Wall-to-wall": Ebstein anomaly.
    • Rib notching: Coarctation of Aorta.

⭐ "Boot-shaped" heart (Coeur en sabot) in Tetralogy of Fallot signifies RV hypertrophy & upturned cardiac apex.

Pediatric ECG - Electric Heartbeats

ECG of two-day-old infant with normal findings

  • Key Differences vs. Adult ECG:
    • Rate: Faster (Neonate 100-180 bpm, ↓ with age).
    • Rhythm: Sinus arrhythmia common.
    • Axis: Right axis deviation (RAD) normal in neonates (+90° to +180°), shifts left with age.
    • Intervals (PR, QRS): Shorter, ↑ with age. QTc normal <0.44s (<0.46s infants <1yr).
    • T waves: Inverted in V1-V3 (juvenile pattern) after 1st week until adolescence.
    • RV Dominance: Prominent R in V1, S in V6 in newborns; LV dominance by ~3 yrs.

⭐ Upright T wave in V1 beyond the first week of life (up to ~6 years) or a qR pattern in V1 can suggest Right Ventricular Hypertrophy (RVH).

Echocardiography - Ultrasound Insights

  • Non-invasive gold standard for cardiac structure, function, hemodynamics.
  • Modes:
    • 2D: Real-time anatomical views, chamber dimensions (e.g., LA/Ao ratio), wall motion, pericardial effusion.
    • M-mode: Precise measurements of wall thickness, chamber size, LVEF (e.g., Teichholz, Simpson).
    • Doppler: Assesses blood flow direction, velocity, turbulence.
      • Color Doppler: Visualizes shunts (VSD, ASD), valvular regurgitation.
      • Pulsed Wave (PW): Measures velocity at specific points (e.g., E/A ratio for diastolic function).
      • Continuous Wave (CW): Measures high velocities (e.g., aortic stenosis peak gradient).
  • Applications: Congenital heart defects (CHD), valvular heart disease, cardiomyopathies, infective endocarditis, pulmonary hypertension.
  • Transthoracic (TTE) is standard; Transesophageal (TEE) for superior views of posterior structures, LA appendage, prosthetic valves. Echocardiogram: 2D, Color Doppler, and CW Doppler

⭐ In Tetralogy of Fallot, echocardiography demonstrates an overriding aorta, VSD, RVH, and pulmonary stenosis; Doppler quantifies the PS gradient and shunt.

Advanced Diagnostics - Deeper Dives

  • Cardiac MRI (CMR): Gold standard: RV assessment (volume, function), fibrosis (LGE). For complex anatomy, ARVD, myocarditis. No radiation.

  • Cardiac CT (CCT): Coronary/vascular ring assessment, airway compression. Rapid. Radiation.

  • Cardiac Catheterization: Measures pressures, $O_2$ sats ($Q_p/Q_s$), angiography. Therapeutic: device closures, valvuloplasty.

    Oxygen step-up >7% (SVC/IVC to PA) suggests ASD; >5% (RV to PA) suggests VSD.

  • EPS: Arrhythmia evaluation/ablation.

  • Genetic Testing: Syndromic CHDs, inherited arrhythmia/cardiomyopathy_._

High‑Yield Points - ⚡ Biggest Takeaways

  • VSD is the most common CHD; ASD often shows RAD on ECG.
  • Echocardiography is the gold standard for CHD diagnosis.
  • TOF features: "boot-shaped" heart (CXR), RVH (ECG), cyanosis.
  • PGE1 maintains ductal patency in duct-dependent lesions (e.g., TGA, severe PS).
  • TGA shows "egg-on-string" (CXR); TAPVC (supracardiac) shows "snowman sign".
  • Pulse oximetry screening is vital for detecting critical CHDs in newborns.

Practice Questions: Cardiac Evaluation and Diagnostics

Test your understanding with these related questions

A 3-4 month old baby with heart rate 250/min, QRS complex less than 0.07 sec and no P wave, Diagnosis will be :

1 of 5

Flashcards: Cardiac Evaluation and Diagnostics

1/10

_____cardiac is most common but _____cardiac is the most dangerous form of TAPVR

TAP TO REVEAL ANSWER

_____cardiac is most common but _____cardiac is the most dangerous form of TAPVR

Supra::Supra/Infra; infra::Supra/Infra

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