Cardiovascular Disorders Overview

Disorders of the Pericardium

• Acute Pericarditis: Inflammation of the pericardium causing chest pain, fever, muscle aches, and malaise. Treated with rest, salicylates, NSAIDs, and possibly colchicine.
• Constrictive (Restrictive) Pericarditis: Fibrous scarring and calcification of the pericardium restrict heart function, leading to exercise intolerance, dyspnea, fatigue, and anorexia. Treatment includes dietary sodium restriction, diuretics, anti-inflammatory drugs, and potentially surgical excision.
• Pericardial Effusion: Fluid accumulation in the pericardial cavity, a life-threatening condition. Assessment may reveal a murmur and chest pain. Treatment involves pericardiocentesis (fluid removal).

Disorders of the Myocardium

• Cardiomyopathies: Diseases affecting the myocardium, impairing the heart's pumping ability. Often idiopathic, and may result from neurohumoral responses to ischemia or hypertension.
• Dilated Cardiomyopathy: Weakening and stretching of the heart muscle, hindering blood pumping. Treatment may involve surgical closure techniques.

Congenital Heart Defects

• Atrial Septal Defect (ASD): Abnormal opening between atria, shunting blood from left to right. Often asymptomatic, diagnosed by murmur. Three types: ostium primum, ostium secundum, and sinus venosus. Surgical closure is recommended before school age.
• Ventricular Septal Defect (VSD): Abnormal opening between ventricles, shunting blood from the high-pressure left side to the low-pressure right side. Clinical manifestations vary with age and defect size, potentially causing heart failure, poor weight gain, murmur, and systolic thrill. Treatment ranges from minimal intervention to surgical repair. Blood flows from the left ventricle to the right ventricle.
• Atrioventricular Canal Defect (AVC): Results from incomplete fusion of endocardial cushions, affecting atrial and ventricular septa and AV valves. Manifests with murmur, heart failure, and respiratory infections. Complete repair is usually done between 3 and 6 months of age.

Obstructive Defects

• Coarctation of the Aorta: Narrowing of the aorta impeding blood flow. Commonly found near the ductus arteriosus but can occur elsewhere. Newborns may present with heart failure; older children might exhibit upper extremity hypertension, lower extremity pulse weakness, cool mottled skin, and leg cramps during exercise. Treatment includes prostaglandin administration, mechanical ventilation, inotropic support, and surgery.
• Truncus Arteriosus: Failure of the embryonic artery to divide into the pulmonary artery and aorta. The truncus straddles a VSD. Four types, with varying pulmonary artery origins. Clinical manifestations include cyanosis (worsening with activity) and murmur. Treatment involves surgical procedures like the modified Rastelli procedure.
• Hypoplastic Left Heart Syndrome: Underdevelopment of left-sided cardiac structures, obstructing left ventricular outflow. The left ventricle, aorta, and aortic arch are underdeveloped; mitral atresia or stenosis may be present. Clinical manifestations include decreased systemic perfusion leading to hypoxemia, acidosis, and shock. Treatment involves prostaglandin administration, acidosis correction, inotropic support, ventilatory manipulation, surgery, and potentially cardiac transplantation.

ECG Interpretations: The Cardiac Cycle and Conduction System

• The cardiac cycle has five phases.
• The heart's conduction system facilitates coordinated heartbeats.
• Electrocardiography (ECG) and Holter monitoring are used to assess myocardial ischemia, infarction, conduction defects, and dysrhythmias. The baseline is isoelectric.

ECG Interpretation: Myocardial Infarction (MI)

• Subendocardial Infarction (Non-STEMI): Involves only the inner myocardium. ECG shows ST segment depression and T-wave inversion.
• Transmural Infarction (STEMI): Involves the entire myocardial wall thickness. ECG shows ST segment elevation. STEMI patients require urgent intervention.

Arrhythmias/Dysrhythmias

• Disturbances in heart rhythm, ranging from occasional missed beats to severely impaired pumping. Caused by abnormal impulse generation or conduction.

Specific Arrhythmias

• Atrial Fibrillation: The most common arrhythmia. Rapid, irregular atrial activity (400-600 bpm) causing fibrillatory waves on ECG. No visible P-waves, irregularly irregular QRS complexes, and often a high ventricular rate.
• Atrial Flutter: Rapid, regular atrial contractions (usually 300 bpm), creating a "sawtooth" pattern on ECG. Ventricular rate is slower than atrial rate (e.g., 70 bpm if every fourth atrial impulse is conducted).
• Premature Atrial Contractions (PACs): Extra, premature P-wave with abnormal morphology, followed by a compensatory pause. May appear as atrial bigeminy.
• Premature Ventricular Contractions (PVCs): Wide, abnormal QRS complexes out of sequence with the normal rhythm, followed by a compensatory pause.
• Ventricular Tachycardia: Rapid ventricular rate (>100 bpm). Can be monomorphic (uniform QRS complexes) or polymorphic (variable QRS complexes). May require immediate medical intervention (code blue).

Explore the disorders affecting the pericardium and myocardium, including acute pericarditis, constrictive pericarditis, and various cardiomyopathies. This quiz will test your knowledge on symptoms, treatments, and complications associated with these conditions.