Implantation of a Biventricular Implantable Cardioverter-Defibrillator Followed by Catheter Ablation in a Patient with Dilated Cardiomyopathy and Permanent Atrial Fibrillation

History

The patient has dilated cardiomyopathy with an initial left ventricular ejection fraction (LVEF) of 25%, permanent atrial fibrillation (AF), and the cardiovascular risk factors of obesity (body mass index 32 kg/m²) and arterial hypertension.

The diagnosis of nonischemic dilated cardiomyopathy was established 1 year previously after angiographic exclusion of significant coronary artery disease, and medical heart failure therapy was initiated. Additionally, an antiarrhythmic treatment with amiodarone and an oral anticoagulation with phenprocoumon were initiated because of highly symptomatic paroxysmal AF mainly manifesting as debilitating palpitations. The amiodarone therapy, however, had to be terminated as a result of drug-induced hyperthyroidism after 3 months of treatment. Over the past several months, paroxysmal AF progressed to less symptomatic persistent AF, and after recent electrical cardioversion had failed to restore sinus rhythm, AF was considered permanent because the decision was made to cease further attempts of rhythm control interventions and to continue with a rate control strategy with metoprolol and digitoxin.

The patient arrived for treatment with slowly progressive breathlessness, fatigue, marked limitation of physical activity corresponding to New York Heart Association (NYHA) functional class III, and ankle swelling despite optimal medical heart failure treatment. He also reports recurrent episodes of irregular heart action.

Current Medications

The patient’s current medications are metoprolol 95 mg twice daily; phenprocoumon with a target international normalized ratio of 2.5 (range 2.0 to 3.0); digitoxin 0.07 mg once daily; torasemide 10 mg twice daily; ramipril 10 mg once daily; and spironolactone 25 mg once daily.

Current Symptoms

The patient demonstrated progressive breathlessness, marked limitation of physical activity (NYHA functional class III), fatigue, severely reduced exercise capacity, mildly symptomatic irregular heart action, and recurrent ankle swelling. Anginal pain, dizziness, and syncopal events were denied.

Physical Examination

• BP/HR: 110/70 mm Hg/70 bpm

• Height/weight: 184 cm/107 kg

• Neck veins: Not distended

• Lungs/chest: Slight fine crackles over both lung bases during inspiration, no decrease in breath sounds, no dullness during percussion of the lungs

• Heart: Irregular heart beat, heart rate about 60 bpm, no murmur, no third heart sound (S ₃ ) or fourth heart sound (S ₄ )

• Abdomen: Soft, adipose, nontender, nondistended, no hepatosplenomegaly, bowel sounds present in all four quadrants

• Extremities: No cyanosis, mild peripheral edema

Laboratory Data

• Hemoglobin: 9.4 mmol/L

• Hematocrit/packed cell volume: 45%

• Mean corpuscular volume: 90.6 fL

• Platelet count: 254/nL

• Sodium: 137 mmol/L

• Potassium: 4.5 mmol/L

• Creatinine: 101 µmol/L

• Blood urea nitrogen: 7.5 mmol/L

Electrocardiogram

Findings

The electrocardiogram recorded atrial fibrillation with a heart rate of about 55 bpm, normal QRS axis, left bundle branch block with a QRS duration of 150 ms, QT interval duration of 440 ms, and secondary repolarization abnormalities ( Figure 2-1 ).