3.5 Cardiac Inflammatory Disease, Tamponade & Post-Cardiac-Surgery Care

Cardiac Inflammatory Disease, Tamponade & Post-Cardiac-Surgery Care

This final cardiovascular section covers infections and inflammation of the heart's three layers — myocardium, endocardium, and pericardium — along with the emergency that can follow any of them, cardiac tamponade, and the specialized surveillance required after cardiac surgery.

Myocarditis

Myocarditis is inflammation of the heart muscle, most often triggered by a viral infection (Coxsackievirus is classic), though autoimmune disease and certain medications can also cause it. It can mimic acute coronary syndrome — chest pain, ECG changes, and elevated troponin — but coronary arteries are typically normal on angiography. Management is largely supportive: rest, treatment of heart failure symptoms if they develop, and avoidance of strenuous activity during recovery. Severe or unresolved myocarditis can progress to dilated cardiomyopathy.

Infective Endocarditis

Endocarditis is an infection of the endocardium, typically forming vegetations (masses of platelets, fibrin, and organisms) on heart valves. Risk factors include IV drug use, prosthetic heart valves, structural heart disease, and recent invasive or dental procedures. Diagnosis uses the Duke criteria, combining blood culture, echocardiographic, and clinical findings.

Classic clinical findings (many from septic emboli or immune complex deposition):

• Persistent fever and a new or changed heart murmur
• Osler nodes — tender, raised nodules on fingers/toes
• Janeway lesions — painless, flat, hemorrhagic macules on palms/soles
• Splinter hemorrhages — thin, dark streaks under the nails
• Roth spots — retinal hemorrhages with pale centers, seen on fundoscopic exam

Because organisms embed in fibrin, at least three sets of blood cultures from separate sites are drawn before starting antibiotics, and treatment requires prolonged IV antibiotic therapy (often 4–6 weeks). Vegetations can embolize to the brain, lungs, spleen, or extremities, so the nurse must monitor closely for signs of stroke, limb ischemia, or other embolic events. Patients at highest risk — those with prosthetic valves, a prior history of endocarditis, or certain congenital heart defects — require antibiotic prophylaxis before selected dental and invasive procedures, an important patient-education point on discharge.

Pericarditis

Pericarditis is inflammation of the pericardial sac, producing sharp, pleuritic chest pain that classically worsens when lying flat or with inspiration and improves when sitting up and leaning forward. Auscultation may reveal a scratchy pericardial friction rub. The ECG shows diffuse ST-segment elevation with PR-segment depression across most leads — a pattern distinct from the localized ST elevation of an MI. First-line treatment is NSAIDs plus colchicine, which reduces the risk of recurrence.

Cardiac Tamponade

Tamponade occurs when fluid accumulates in the pericardial sac faster than it can stretch to accommodate, compressing the heart and impairing ventricular filling. It can complicate pericarditis, trauma, malignancy, or cardiac surgery.

Beck's triad is the classic exam finding:

1. Hypotension
2. Jugular venous distension
3. Muffled or distant heart sounds

Additional findings include pulsus paradoxus — an exaggerated drop in systolic blood pressure (> 10 mmHg) during inspiration — and electrical alternans on ECG (a beat-to-beat alternation in QRS amplitude from the heart swinging within the fluid-filled sac). Tamponade is a medical emergency requiring urgent pericardiocentesis or surgical drainage to relieve the compression; delay can rapidly progress to obstructive shock and cardiac arrest.

Post-Cardiac-Surgery ICU Care

Patients returning from CABG, valve replacement/repair, or other open cardiac procedures require intensive, structured surveillance during the immediate postoperative period:

• Hemodynamic monitoring — continuous arterial pressure, CVP, and often pulmonary artery pressures; titrate vasoactive drips to maintain perfusion while avoiding excessive afterload on fresh suture lines.
• Chest tube output — monitor hourly for excessive bleeding (generally more than 100–150 mL/hr sustained, or a sudden large volume) suggesting surgical bleeding, and conversely, a sudden decrease or cessation of chest tube drainage accompanied by hypotension, JVD, and muffled heart sounds should raise immediate suspicion for cardiac tamponade from a clot obstructing the tube.
• Dysrhythmia surveillance — new-onset atrial fibrillation is extremely common after cardiac surgery (postoperative afib), typically within the first few days, and is managed with rate or rhythm control per standard protocols.
• Temperature management — patients often return hypothermic from bypass; rewarming is done gradually to avoid shivering, which increases oxygen demand.
• Pain control and early mobility — adequate analgesia supports deep breathing and early ambulation, reducing pulmonary complications.
• Sternal wound surveillance — monitor for signs of mediastinitis or sternal wound infection (increasing pain, drainage, sternal instability or "click" with movement, or fever), a serious complication requiring prompt evaluation; strict sterile technique during dressing changes and glucose control (hyperglycemia is a major risk factor) help prevent it.
• Neurologic and renal surveillance — cardiopulmonary bypass carries a risk of postoperative stroke and acute kidney injury; baseline and serial neurologic checks and monitoring of urine output and creatinine trend are standard for the first 24–48 hours.

Across this whole section, the unifying exam skill is pattern recognition: matching a cluster of findings (positional chest pain plus a friction rub, or hypotension plus JVD plus muffled heart sounds) to the correct inflammatory or compressive process, and knowing which of these findings demands emergent intervention rather than supportive monitoring.