The patient was a 79-year-old Japanese woman who visited the emergency room at our hospital for presyncope and nausea in June 2019. As the monitor showed bradycardia associated with chronic AF and because the patient's subjective symptoms were persisting, she was admitted to the hospital.
The patient had undergone pulmonary vein isolation (PVI) for paroxysmal AF in 2010, which progressed to chronic AF. In addition, TVR was performed in March 2016 for tricuspid valve insufficiency. In other systems, endoscopic polypectomy for early gastric cancer and stent placement for lower extremity arteriosclerosis obliterans (ASO) were both performed in 2016. The patient's medical history included chronic heart failure, chronic obstructive pulmonary disease, hypertension, chronic renal failure, pulmonary hypertension, and diabetes.
The physical findings at the initial visit included the following: body temperature 36.7  C, blood pressure 182/80 mmHg, pulse rate 45 beats per minute (bpm), irregular; and no heart murmurs or abnormal respiratory sounds. Her blood test results showed chronic anemia (Hb 9.4 g/dL) and renal dysfunction [blood urea nitrogen (BUN) 27.7 mg/dL, Cr1 15 mg/dL]. Her thyroid function was within the normal range [thyroid-stimulating hormone (TSH), 2.32 muIU/mL; free triiodothyronine (FT) 3, 2.51 pg/mL; free thyroxine (FT) 4, 1.38 ng/dL]. There were no abnormalities in cardiac enzyme levels [creatine kinase (CK), CK-muscle brain (MB), troponin I] and no changes in markers of inflammation, and the results of liver function tests were normal. NT-proBNP was high at 8,464 pg/mL.
Electrocardiography (ECG) revealed AF [heart rate (HR): 20-50 bpm] and complete right bundle branch block (QRS=144 ms). Inverted T waves were seen in leads II, III, aVF, and V1-4 (Fig. 1). Chest X-ray showed cardiomegaly (cardiothoracic ratio: 61%) and pulmonary congestion.
Echocardiography did not exhibit clear asynergy in LV wall motion: the LV ejection fraction (LVEF) was 69%, the LV end-diastolic dimension (LVDd) was 54 mm, the LV end-systolic dimension (LVDs) was 33 mm, the interventricular septal thickness at end-diastole (IVSTd) was 10 mm, and the posterior LV wall thickness (PWTd) was 10 mm. The findings indicating valvular disease included trivial tricuspid regurgitation (TR) (post-TVR), mild to moderate pulmonary regurgitation (PR) [PR end-pressure gradient (PG): 3 mmHg], right atrial and ventricular (RA and RV) enlargement, and left atrial (LA) enlargement with a left atrial diameter (LAD) of 47 mm.
After admission to the hospital, a beta-blocker (bisoprolol fumarate, 0.625 mg) that the patient had been taking was withdrawn, and she was followed-up with diuretic dose adjustments. However, as the patient frequently had a heartbeat pause lasting 5-8 seconds associated with lightheadedness and since her bradycardia did not improve, permanent pacemaker implantation was performed. Because the patient's AF had become chronic, a VVI pacemaker was used. An LV lead for CRT - instead of an RV lead - was inserted in the coronary sinus (CS) and placed on the LV side (CS lateral branch), since the patient had previously undergone TVR, although a biological tissue valve had been used.
At the implantation, the R-wave sensing was 12.1 mV, the ventricular pacing threshold was 0.6 V at 0.4 ms, and the lead impedance was 526 Omega. All measurements were within the normal range. The pacemaker implanted this time was a model with a CLS function (Edora 8 SR-T; Biotronik, Berlin, Germany), and the settings of VVI-CLS were a lower rate of 60 ppm and sensor rate of 120 ppm. After the pacemaker implantation, the doses of the patient's oral medications, including the beta-blocker and diuretics, were adjusted once more. Her lightheadedness and heart failure signs both improved, and the patient was discharged 10 days after the implantation.
An inspection of the pacemaker and ECG Holter monitoring after the patient's pacemaker implantation indicated that even though pacing was being performed by a lead placed on the epicardial side of the coronary vein, the CLS functionality was good, as indicated by an increased pacing rate (Fig. 2) and the following data: total heart beats (/day), 100,108; maximum HR (bpm), 121; minimum HR (bpm), 59; average HR (bpm), 70; and longest RR interval (sec), 1.22 (Table). Post-pacemaker implantation chest X-ray performed after the patient's discharge did not show pulmonary congestion (Fig. 3).