Etiology, Pathophysiology and Diagnosis of CCF
Definition
- Inability of heart to maintain adequate output for metabolic needs at rest or during exercise (systolic failure).
- Inability to receive blood into ventricular cavities at low pressure during diastole (diastolic failure).
Etiology
Causes by Age
| Age Group | Causes |
|---|---|
| Infants | - Congenital heart disease (CHD) - Myocarditis and primary myocardial disease - Tachyarrhythmias, bradyarrhythmias - Kawasaki disease with coronary occlusion - Pulmonary hypertension (persistent pulmonary hypertension of newborn, primary, airway obstruction hypoxia) - Miscellaneous: Anemia, hypoglycemia, infections, hypocalcemia, neonatal asphyxia. |
| Children | - Rheumatic fever, rheumatic heart disease (typically >5 years) - CHD complicated by anemia, infection, or endocarditis - Systemic hypertension - Myocarditis, primary myocardial disease - Pulmonary hypertension (primary, secondary). |
Time of Onset of CCF in CHD
| Time of Onset | Specific Cardiac Lesions |
|---|---|
| Birthβ1 week | Duct-dependent systemic circulation (hypoplastic left heart syndrome, critical aortic stenosis, severe coarctation, interrupted aortic arch); obstructed total anomalous pulmonary venous return (TAPVR); congenital mitral/tricuspid valve regurgitation; neonatal Ebstein anomaly. |
| 1β4 weeks | Patent ductus arteriosus (PDA) in preterms; ventricular septal defect (VSD) with coarctation; persistent truncus arteriosus; transposition of great arteries (TGA) with large VSD/PDA; critical aortic stenosis; congenital mitral/tricuspid regurgitation; single ventricle with unrestrictive pulmonary flow. |
| 1β2 months | TGA with VSD/PDA; endocardial cushion defects; VSD; PDA; severe coarctation; anomalous left coronary artery from pulmonary artery (ALCAPA); single ventricle with unrestrictive flow. |
| 2β6 months | VSD; PDA; endocardial cushion defect; ALCAPA; coarctation; single ventricle with unrestrictive pulmonary flow. |
Correctable/Subtle Causes of CCF
- Sustained tachyarrhythmias (ectopic atrial tachycardia, permanent junctional re-entrant tachycardia).
- Severe bradycardia (complete heart block).
- Severe anemia (Hemoglobin < 5 g/dL) causing high-output failure.
- Coarctation of aorta.
- Anomalous left coronary artery from pulmonary artery (ALCAPA).
- Metabolic: Hypocalcemia, hypoglycemia.
Pathophysiology
Hemodynamic Mechanisms
- Decreased cardiac function elevates atrial and ventricular filling pressures.
- Elevated capillary pressure induces pulmonary edema.
- Poor cardiac output decreases end-organ blood flow.
- Triggers sympathetic nervous system activation.
- Results in poor peripheral perfusion and decreased urine output.
- Severe left-sided lesions precipitate acute hemodynamic overload, increasing left atrial and pulmonary venous pressures.
Shunt vs. Obstructive Physiology
- Left-to-Right Shunts: Intrinsic cardiac muscle contractility remains normal or increased. Heart failure develops at 6β8 weeks of life as pulmonary vascular resistance physiologically declines, exacerbating pulmonary overcirculation.
- Congenital Valve Regurgitation: Mitral or tricuspid leakage precipitates early heart failure. Tricuspid regurgitation severity exacerbated by elevated neonatal pulmonary artery pressures.
- Increased Pressure Load: Obstruction to ventricular outflow (valvular pulmonic stenosis, aortic stenosis, coarctation). Heart compensates via wall hypertrophy. Progressive obstruction leads to fibrosis, chamber dilation, and eventual ventricular failure.
Myocardial Failure
- Cardiomyopathies compromise systolic contractility (dilated) or diastolic relaxation (restrictive).
- Viral myocarditis initiates inflammatory myocardial damage, leading to ventricular enlargement and poor function.
Diagnosis
Clinical Presentation (Symptoms)
- Inadequate feeding volumes, slow feeding, tiring easily.
- Slow weight gain (inadequate caloric intake combined with increased metabolic work of breathing).
- Irritability, excessive perspiration (forehead/occiput) during feeds.
- Breathes too fast; breathes better when held upright against shoulder (orthopnea equivalent).
- Persistent hoarse cry, cough, wheezing.
- Abdominal angina, persistent emesis (indicates poor visceral perfusion).
- Altered mental status, confusion, sleepiness (decreased cerebral perfusion).
- Decreased urine output (poor renal perfusion).
Clinical Signs
| Left-Sided Failure | Right-Sided Failure | Signs Common to Both |
|---|---|---|
| Tachypnea | Hepatomegaly | Cardiac enlargement |
| Tachycardia | Facial edema / puffiness, | Gallop rhythm (S3) |
| Cough | Jugular venous engorgement | Peripheral cyanosis |
| Wheezing | Pedal edema | Small volume pulse |
| Rales in chest | Ascites | Poor weight gain |
Clinical Assessment Matrix (Hemodynamic Profiling)
Evaluate acute decompensated heart failure classifying into four profiles based on congestion and perfusion status.
- Congestion Evidence: Tachypnea, orthopnea, ascites, hepatomegaly, elevated jugular venous pressure, peripheral edema, rales.
- Low Perfusion Evidence: Narrow pulse pressure, cool extremities, sleepy/mental confusion, hypotension, worsening kidney function.
- Profiles:
- Warm and Dry (Normal).
- Warm and Wet (Congested, good perfusion).
- Cold and Dry (Low perfusion, no congestion).
- Cold and Wet (Low perfusion, significant congestion).
Nadas' Criteria for Clinical Diagnosis of Heart Disease
Used to identify underlying heart disease in presence of CCF.
- Major Criteria:
- Systolic murmur grade III or more.
- Diastolic murmur.
- Cyanosis.
- Congestive cardiac failure.
- Minor Criteria:
- Systolic murmur grade I or II.
- Abnormal second heart sound.
- Abnormal electrocardiogram.
- Abnormal X-ray.
- Abnormal blood pressure.
Imaging Modalities
- Chest X-Ray (CXR): Reveals cardiomegaly, pulmonary venous congestion, prominent vascular markings, frank pulmonary edema, pleural effusions. Blunting of cardiophrenic angle indicates fluid.
- Electrocardiogram (ECG): Identifies tachyarrhythmias, severe bradycardia (complete heart block), ventricular hypertrophy, conduction disturbances, low QRS voltages, non-specific ST-T wave changes.
- Echocardiography: Gold standard. Confirms specific anatomic CHD diagnosis, visualizes chamber dilation, assesses systolic and diastolic ventricular function, identifies valvar regurgitation, detects pericardial effusions. Essential to exclude structural causes before diagnosing idiopathic cardiomyopathy.
Laboratory Investigations
- Complete Metabolic Panel: Screens for renal insufficiency (BUN/creatinine) and hepatic dysfunction (transaminases) related to poor perfusion and venous congestion.
- Blood Gas and Lactate: Arterial/venous blood gas with lactate detects metabolic acidosis, assessing inadequate cardiac output and poor tissue oxygen delivery.
- Complete Blood Count (CBC): Rules out severe anemia causing high-output failure. Elevated white blood cells suggest infectious/inflammatory etiologies.
- Cardiac Biomarkers: Elevated Brain Natriuretic Peptide (BNP), pro-BNP, Creatine Kinase-MB (CK-MB), and Troponin indicate myocardial stretch, ischemia, or injury.
- Inflammatory Markers: Erythrocyte Sedimentation Rate (ESR), C-Reactive Protein (CRP), procalcitonin elevation suggests active infection, acute rheumatic fever, or myocarditis.
- Specific Etiologic Testing: Viral PCR (Coxsackie, Adenovirus, Parvovirus). Blood cultures for suspected infective endocarditis. Thyroid panel, carnitine levels, urine organic acids for metabolic cardiomyopathies.