What is the management approach for iatrogenic cardiomyopathy?

Management of Iatrogenic Cardiomyopathy

The management of iatrogenic cardiomyopathy should focus on identifying and discontinuing the causative agent, implementing optimal medical therapy based on the specific cardiomyopathy phenotype, and considering advanced therapies for refractory cases.

Identification and Removal of Causative Agents

• Promptly identify and discontinue potential cardiotoxic medications or treatments that may have precipitated the cardiomyopathy 1
• For patients receiving cancer therapies with cardiotoxic potential, implement regular monitoring of left ventricular function to detect early signs of cardiomyopathy 1
• In cases of iatrogenic stress cardiomyopathy (Takotsubo), identify and address the triggering stressor, which may include exogenous catecholamine administration or procedural interventions 2

Medical Management Based on Cardiomyopathy Phenotype

For Dilated Cardiomyopathy Pattern:

• Implement guideline-directed medical therapy including ACE inhibitors, beta-blockers, and mineralocorticoid receptor antagonists to reduce the risk of sudden death and progressive heart failure 3
• Evaluate for and treat arrhythmogenic factors (e.g., pro-arrhythmic drugs, electrolyte abnormalities) and comorbidities that may worsen the condition 3
• For patients with dilated cardiomyopathy and reduced ejection fraction (<35%) despite optimal medical therapy for ≥3 months, consider ICD placement for primary prevention 3

For Hypertrophic Cardiomyopathy Pattern:

• For obstructive hypertrophic cardiomyopathy with persistent symptoms despite beta-blockers or non-dihydropyridine calcium channel blockers, add a myosin inhibitor (adults only), disopyramide (with AV nodal blocking agent), or consider septal reduction therapy 3
• Avoid vasodilators, excessive diuresis, and positive inotropic agents that can worsen left ventricular outflow tract obstruction 4
• Maintain adequate preload by ensuring proper hydration, especially during exercise or hot weather 4

For Arrhythmogenic Cardiomyopathy:

• For patients with documented sustained ventricular tachycardia or ventricular fibrillation, ICD implantation is recommended 3
• Amiodarone or sotalol can be effective for treatment of sustained ventricular tachycardia or ventricular fibrillation when ICD implantation is not feasible 3
• Catheter ablation may be useful as adjunctive therapy for recurrent ventricular tachycardia despite optimal anti-arrhythmic drug therapy 3

Management of Atrial Fibrillation in Cardiomyopathy

• For acute management in hemodynamically unstable patients, direct current cardioversion is preferred 3
• For long-term antiarrhythmic drug therapy to prevent AF recurrences in HCM, sotalol and amiodarone are preferred options, with amiodarone often being the most effective despite side effects 3
• In patients with cardiomyopathy and atrial fibrillation, anticoagulation should be guided by CHA₂DS₂-VASc score, with direct oral anticoagulants preferred over vitamin K antagonists except in cases of moderate/severe mitral stenosis or mechanical valves 3
• Catheter ablation should be considered for symptomatic AF after failure of or intolerance to class I or III antiarrhythmic drugs 3

Management of Ventricular Arrhythmias

• For patients with recurrent ventricular arrhythmias despite beta-blocker therapy, antiarrhythmic drug therapy (e.g., amiodarone, mexiletine, sotalol) is recommended, with the choice guided by age, comorbidities, disease severity, and patient preferences 3
• In patients with ICDs, programming antitachycardia pacing is recommended to minimize the risk of shocks 3
• For recurrent symptomatic sustained monomorphic VT or recurrent ICD shocks despite optimal device programming and antiarrhythmic therapy, catheter ablation can be useful 3

Advanced Heart Failure Management

• For patients who develop systolic dysfunction (LVEF <50%), cardiac myosin inhibitors should be discontinued 3
• Consider interrupting or discontinuing negative inotropic agents (verapamil, diltiazem, disopyramide) in patients with worsening heart failure symptoms 3
• For patients with advanced heart failure refractory to medical therapy, evaluate for heart transplantation according to current guidelines 3
• In highly selected patients with HCM who decompensate while awaiting transplant, left ventricular assist device support may be considered, with better outcomes observed in those with larger LV cavities (>46-50 mm) 3

Special Considerations

• In iatrogenic Takotsubo cardiomyopathy, which is typically transient, focus on supportive care rather than long-term heart failure medications 2
• For iatrogenic neonatal hypertrophic cardiomyopathy (e.g., from concurrent glucocorticoid and insulin administration), regular echocardiographic monitoring is essential, and the condition typically resolves with cessation of therapy 5
• In severe cases of iatrogenic cardiomyopathy with refractory cardiogenic shock, consider mechanical circulatory support such as extracorporeal membrane oxygenation as a bridge to recovery 6

Prevention Strategies

• Implement regular cardiac monitoring for patients receiving potentially cardiotoxic therapies 1
• Ensure heart failure medications are properly restarted after intercurrent illnesses 1
• Adjust fluid administration and blood transfusion volumes based on body weight to prevent volume overload 1
• Consider appropriate pacemaker selection in patients with underlying left ventricular dysfunction 1