Mapping the Coronary Sinus Veins Using an Active Fixation Lead to Overcome Phrenic Nerve Stimulation

History

A 69-year-old man had underlying complete heart block and chronic atrial fibrillation, diabetes mellitus, and hypertension. He had a single-chamber pacemaker implanted in 2003 for complete heart block. He developed ventricular tachycardia 8 years previously, which required cardioversion. He was referred for further management.

Current Medications

The patient was taking bisoprolol 5 mg daily, atorvastatin 10 mg daily, perindopril 4 mg daily, warfarin 2 mg daily, and subcutaneous insulin injection. Mixtard 48 units in the morning and 20 units at night.

Current Symptoms

The patient was breathless on moderate exertion.

Physical Examination

• BP/HR: 120/80 mm Hg/72 bpm

• Height/weight: 160 cm/60 kg

• Heart: Cardiomegaly

Laboratory Data

• Hemoglobin: 11.3 g/dL

• Hematocrit/packed cell volume: 34%

• Mean corpuscular volume: 77.8 fL

• Platelet count: 177 × 10 ³ /µL

• Sodium: 143 mmol/L

• Potassium: 4.2 mmol/L

• Creatinine: 108 mmol/L

• Blood urea nitrogen: 6.7 mmol/L

Electrocardiogram