What is the meaning and treatment of abnormal heart sounds after heart surgery?

Management of Abnormal Heart Sounds After Heart Surgery

Abnormal heart sounds after cardiac surgery require prompt evaluation and management based on the specific type of abnormality, as they may indicate significant cardiovascular dysfunction that affects morbidity and mortality.

Types of Abnormal Heart Sounds and Their Significance

Valvular Abnormalities

• A new systolic murmur may indicate mitral regurgitation, which can result from myxomatous degeneration or post-infarction left ventricular remodeling 1
• Aortic regurgitation presents with a diastolic murmur and requires attention to volume control and afterload reduction 1
• Mitral stenosis, though increasingly rare, presents with a diastolic flow rumble and requires heart rate control to prevent pulmonary congestion 1
• Prosthetic valve dysfunction may present with muffled heart sounds or new murmurs, requiring immediate evaluation 1

Abnormal Heart Sounds

• A third heart sound (S3) may indicate heart failure and is associated with substantially increased risk 1
• Pericardial closure during surgery can cause abnormal interventricular septal motion, altering heart sounds 2
• Post-CABG surgery, heart sounds typically shift toward lower frequencies, which can be objectively measured and subjectively perceived by patients 3

Evaluation of Abnormal Heart Sounds

Initial Assessment

• Perform thorough auscultation to detect new murmurs or muffling of prosthetic heart sounds 1
• Obtain an ECG to identify arrhythmias, ischemic changes, or conduction abnormalities 4
• Use echocardiography to evaluate ventricular function, valve function, and presence of pericardial effusion 4
• Consider chest X-ray to assess cardiac silhouette and pulmonary status 4

Further Diagnostic Workup

• For suspected prosthetic valve thrombosis, transoesophageal echocardiography and cinefluoroscopy can detect restricted leaflet movement 1
• Serial ECGs and cardiac-specific enzyme analyses should be obtained for suspected perioperative myocardial ischemia 1
• For arrhythmias, continuous ECG monitoring is essential to identify the specific type and guide management 4

Management Based on Specific Abnormalities

Valvular Issues

• For mitral regurgitation, consider afterload reduction and diuretics to achieve hemodynamic stabilization 1
• For mitral stenosis, ensure control of heart rate during the perioperative period to prevent pulmonary congestion 1
• For aortic regurgitation, focus on volume control and afterload reduction; avoid unusually slow heart rates 1
• For prosthetic valve thrombosis in hemodynamically stable patients with recent subtherapeutic anticoagulation, a short course of intravenous heparin should be used first 1

Arrhythmias

• Beta-blockers are recommended as first-line therapy for rate control in supraventricular arrhythmias, including atrial fibrillation 1
• For hemodynamically unstable patients with arrhythmias, electrical cardioversion is indicated 4
• Correct underlying causes of arrhythmias, including electrolyte abnormalities and optimizing oxygenation 4
• For postoperative atrial fibrillation prophylaxis, beta-blockers are strongly recommended 1
• Consider amiodarone in patients for whom beta-blockers are contraindicated 1

Conduction Abnormalities

• For new postoperative sinus node dysfunction or atrioventricular block with persistent symptoms or hemodynamic instability after coronary artery bypass surgery, permanent pacing is recommended before discharge 1
• Temporary epicardial pacing wires placed during surgery can manage transient bradyarrhythmias 1
• Routine placement of temporary epicardial pacing wires during coronary artery bypass surgery is reasonable 1

Heart Failure

• For myocardial dysfunction, consider low-to-moderate doses of dobutamine, epinephrine, milrinone, or levosimendan 1
• For vasoplegia-induced hypotension, use norepinephrine to maintain adequate perfusion pressure 1
• Exclude hypovolemia in patients under vasopressors through repeated volume assessments 1
• For heart failure with suspected coronary hypoperfusion, an intra-aortic balloon pump is highly recommended 1

Follow-up and Long-term Management

• Schedule the first post-operative visit within 6 weeks of discharge 4
• Establish baselines for continued follow-up, including assessment of symptomatic status and physical signs 4
• Evaluate heart rhythm and ECG abnormalities at follow-up visits 4
• Implement long-term cardiovascular risk reduction strategies, including statin therapy, blood pressure control, and antiplatelet therapy as appropriate 4

Common Pitfalls to Avoid

• Do not ignore even mild reduction of left ventricular ejection fraction in patients with mitral regurgitation, as it may indicate reduced ventricular reserve 1
• Avoid unusually slow heart rates in patients with severe aortic regurgitation, as this can increase the volume of regurgitation 1
• Do not overlook the need for endocarditis prophylaxis in patients with prosthetic valves undergoing procedures that may result in bacteremia 1
• Avoid calcium channel antagonists for prevention of atrial fibrillation/flutter following cardiac surgery 1
• Do not use digitalis as monotherapy for reducing the incidence of postsurgical atrial fibrillation 1