Objective: To observe the automatic ventricular capture management (VCM) conifrmed by paced depolarization integral (PDI) evoked response detection via the follow-up study in patients with Zephyr5826 pacemaker implantation. Methods: A total of 102 relevant patients were enrolled. In order to conduct PDI calculation, pacemakers were set by bipolar sensing and bipolar pacing at immediately after implantation. VCM functions were observed at 1 day, 7 days and 1 month, 3, 6, 12 months after implantation, the ventricular threshold by VCM test and manual test were compared. The symptoms of pectoralis major stimulus, diaphragm stimulus and palpitation were observed in all follow-up patients. Results: There was 1 patient died by MI at 1 month after Zephyr5826 pacemaker implantation, the rest 101 patients were followed-up for 12 months. VCM function was successfully turned-on at immediately after implantation in all patients, no pectoralis major stimulus and diaphragm stimulus occurred. VCM function was turned-off in 6/101 (5.9%) patients at 7 days after implantation due to intolerable palpitation caused by daily automatic VCM, instead they received manual test at follow-up visit. The coincidence rate of ventricular thresholds between VCM test and manual test were 100%. Ventricular pacing output voltage by VCM was (0.99 ± 0.48) V,n=608. Compared with regular pacing output voltage (2.5V, 0.4ms), VCM function may save 84% of energy consumption; compared to high pacing output voltage (3.5V, 0.4ms), VCM may save 92%. Loss of ventricular capture and poor sensation were not found by ECG and 24 h dynamic monitoring. Conclusion: Zephyr5826 pacemaker may conduct bipolar pacing and scanning with VCM function, it can be effectively and safely operated by low energy output. A few patients may not use VCM function due to intolerable palpitation.

BACKGROUND: More than 75 million procedures with intravascular iodine-based contrast media (ICM) are performed worldwide every year, and some patients undergoing these procedures do not have normal thyroid function. The long-term effects of ICM in patients with mild thyroid dysfunction (TD) are unclear. METHODS: This prospective cohort study was conducted in China. Patients with stable angina pectoris with total triiodothyronine (TT3) reduction, normal thyroid-stimulating hormone, and reverse triiodothyronine (rT3) were enrolled and divided into high-dose (≥100 mL ICM) and low-dose groups (<100 mL ICM). We dynamically investigated the trends in thyroid function, rT3, and thyroid antibodies one year after ICM exposure. RESULTS: A total of 154 patients completed 6 months of follow-up and 149 completed 1 year of follow-up. Thyroglobulin antibody (TGAB) levels were elevated in 41 (26.6%) patients before ICM exposure, 11 (7.1%) of whom also had elevated thyroid peroxidase antibody levels. Transient subclinical TD occurred 6 months after ICM exposure; 75.5% (34/45) of post-operative TD occurred in the high-dose group. One patient developed severe hypothyroidism with myxedema, requiring drug intervention 1 year after ICM exposure. The level of rT3 showed no statistically significant changes during post-operative follow-up ( P  = 0.848). The TGAB level decreased at 6th month ( P  < 0.001), but increased at 1 year after ICM exposure ( P  = 0.002). CONCLUSIONS Patients with T3 reduction are at a risk of transient subclinical TD and hypothyroidism after a single large dose of ICM. Follow-up of this population at 9-12 months after ICM exposure is warranted.
Humans ; Contrast Media/adverse effects* ; Prospective Studies ; Hypothyroidism ; Triiodothyronine ; Iodine/adverse effects* ; Thyrotropin ; Thyroxine