Resynchronization Therapy and Sudden Death Management in Congenitally Corrected Transposition: Submitted by Damien Cullington, MBChB (Hons), MD, MRCP, FESC

History of Presenting Medical Complaint

A 38-year-old man presented to his local hospital with a 9-month history of expectorating small volumes of hemoptysis preceded by exertional dyspnoea for 4–5 months. He also gave a history of two brief episodes of dizziness but no syncope. He was referred following a recording of his 12 lead ECG which showed complete heart block (CHB) ( Fig. 8.1 ).

Echo demonstrated that he had congenitally corrected transposition of the great arteries (ccTGA) with a mildly dilated systemic right ventricle (RV) with severely impaired function and moderate systemic tricuspid valve (TV) regurgitation into a dilated left atrium. The subpulmonic, morphologic left ventricle (LV) was also severely impaired with trivial mitral regurgitation. There was no ventricular septal defect. There was a small atrial shunt with left to right flow.

He initially underwent implantation of dual chamber pacemaker. A transesophageal echo was performed under general anesthesia at the same time as pacemaker implantation and cardiac catheterization. This showed that there was moderate systemic right ventricular impairment, moderate-to-severe systemic tricuspid regurgitation, and severely impaired subpulmonic left ventricular function.

He was then readmitted with decompensated heart failure. This admission was preceded by 10 days of worsening shortness of breath, abdominal discomfort, and anorexia. He had hepatorenal decompensation with ALT 830 iu/L (<40) (normal values in brackets); ALP 119 iu/L (30–130); Bilirubin 53 umol/L (2–21); Urea 19 mmol/L (2.5–7.8); Creatinine 179 umol/L (64–104); and eGFR 37 mL/min/1.73 m ² . He was diuresed and commenced on dobutamine. His clinical condition marginally improved. Symptomatically he remained in NYHA III off inotropes, but he was accepted for an assessment at our local cardiac transplant center due to our concerns of his declining status. After continued diuresis and further optimization of his medical therapy, he continued to improve, with a reduction in his pulmonary artery pressure (PAP) and was deemed too fit for cardiac transplantation.

He is now stable on medical treatment and is symptomatically NYHA class II. He has had no further admissions due to decompensated heart failure for over 12 months. His hemoptysis has entirely resolved with reduction in his pulmonary pressures. A recent cardiopulmonary exercise test (Jan 2017) using bike ergometry at 15 W ramp staging remeasured his peak VO ₂ at 19.7 mL/kg/min at an respiratory exchange ratio (RER) of 1.56. He exercised for 13 min 2 s.

Admission Blood Tests (Normal Values Given in Brackets)

Hb 173 g/L (135–180); WCC 8.7 10 ⁹ /L (4.00–11.00); Plt 197 10 ⁹ /L (150–400)

NTproBNP levels

2013 ng/L (11/01/16)

157 ng/L (25/10/16)

Current

Hb 115 g/L (135–180);

Sodium 140 mmol/L (133–146);

Potassium 4.9 mmol/L (3.5–5.3);

Urea 10.9 mmol/L (2.5–7.8);

Creatinine 123 umol/L (64–104).

Observations

On initial presentation:

Blood pressure 147/100;

Heart rate 60 per minute;

Saturations in room air 97%.

Past Medical History and Medication (Prior to Initial Admission)

Gout—treated with allopurinol

Current Medications (2017)

Spironolactone 25 mg od

Digoxin 125 mcg od

Bumetanide 2 mg twice daily

Entresto 50 mg twice daily

Carvedilol 12.5 mg twice daily

Metformin 500 mg od

Edoxaban 30 mg od