Pathophysiology of VSD and Ventricular Hypertrophy

? Pathophysiology of VSD and Ventricular Hypertrophy ? Initial Hemodynamic Left-to-right shunt : Blood flows from the high-pressure left ventricle (LV) to the lower-pressure right ventricle (RV). This increases pulmonary blood flow , leading to volume overload in the pulmonary circulation and RV . ? RVH Development The RV adapts to the increased pressure and volume by hypertrophying . This is especially pronounced in moderate to large VSDs . ? LVH Development (Yes, it can happen!) Over time, the increased pulmonary return leads to increased preload in the left atrium and left ventricle . The LV compensates for this chronic volume overload by undergoing eccentric hypertrophy . This is more likely in: Large VSDs Delayed repair Cases with biventricular volume overload ? ECG and Imaging Clues Biventricular hypertrophy (BVH) may be seen on ECG, especially in children with congenital heart disease like VSD. The Katz-Wachtel phenomenon — large biphasic QRS complexes in V2–V5 — is a classic ECG sign of BVH in VSD. ? Clinical Takeaway RVH is more prominent early due to direct shunting and pulmonary hypertension. LVH can develop later due to chronic volume overload from increased pulmonary venous return. Both can coexist — and when they do, it’s a sign of significant hemodynamic burden and often indicates the need for surgical intervention . Eisenmenger syndrome is a late and severe complication of certain congenital heart defects, especially those that cause a long-standing left-to-right shunt like a ventricular septal defect (VSD). ? What Is Eisenmenger Syndrome? Eisenmenger syndrome occurs when a chronic left-to-right shunt (e.g., from a VSD, ASD, or PDA) leads to: Pulmonary vascular remodelling Pulmonary hypertension Reversal of the shunt to right-to-left Resulting in cyanosis and systemic hypoxemia This marks the point at which the pulmonary hypertension becomes irreversible, and surgical repair of the original defect is no longer viable. ? Pathophysiology Initial Phase : Left-to-right shunt ? ? pulmonary blood flow Progressive Phase : Pulmonary vascular damage ? ? pulmonary vascular resistance (PVR) Reversal Phase : PVR exceeds systemic vascular resistance ? shunt reverses (right-to-left) Cyanotic Phase : Deoxygenated blood bypasses lungs ? enters systemic circulation ? cyanosis ? Symptoms Common clinical features include: Cyanosis (blue lips, nail beds) Clubbing of fingers and toes Exertional dyspnea and fatigue Palpitations or arrhythmias Syncope or dizziness Hemoptysis (from ruptured pulmonary vessels) Polycythemia (compensatory ? RBCs ? hyperviscosity symptoms) ? Diagnosis Echocardiogram : Detects shunt and pulmonary pressures Cardiac catheterization : Gold standard for measuring PVR ECG/X-ray/MRI : Assess chamber enlargement and pulmonary artery dilation Oxygen saturation : Low at rest or with exertion CBC : May show elevated hematocrit due to chronic hypoxia ? Treatment There is no cure, but management focuses on: ? Symptom Control Pulmonary vasodilators : Sildenafil, bosentan Diuretics : For right heart failure Antiarrhythmics : For supraventricular arrhythmias Phlebotomy : If hyperviscosity symptoms occur (with caution) ?? Preventive Measures Infective endocarditis prophylaxis for certain procedures Avoidance of pregnancy (high maternal mortality) Oxygen therapy (in select cases) ? Transplantation Heart-lung transplant or lung transplant + cardiac repair is the only definitive option for advanced cases.