The gender difference of utilization of cardiac implantable electronic device in China: data from Arrhythmia Interventional Therapy Data Registry.

BACKGROUND: Cardiac implantable electronic devices (CIEDs) greatly improve survival and life quality of patients. However, there are gender differences regarding both the utilization and benefit of these devices. In this prospective CIED registry, we aim to appraise the gender differences in CIED utilization in China. METHODS: Twenty centers from 14 provinces in China were included in our registry study. All patients who underwent a CIED implantation in these twenty centers between Jan 2015 and Dec 2016 were included. RESULTS: A total of 8570 patients were enrolled in the baseline cohort, including 7203 pacemaker, 664 implantable cardiac defibrillators (ICD) implants and 703 cardiac resynchronization therapy device (CRT/D). Totally, 4117 (48.0%) CIED patients were female, and more than 59% pacemaker patients were female, but women account only one third of ICD or CRT/D implantation in this registry. There were significant differences between genders at pacemaker and ICD indications. Female was more likely received a pacemaker due to sick sinus syndrome (SSS) (63.9% vs. 51.0%, P < 0.001). Female patients receiving an ICD were more likely due to cardiac ion channel disease (29.2% vs. 4.2%, P < 0.001). The percentage of utilization of dual-chamber pacemaker in female patients was significantly higher than male (85.3% vs. 81.1%, P < 0.001). But male patients were more likely received a cardiac resynchronization therapy devices with defibrillator than female (56.5% vs. 41.9%, P = 0.001). In pacemaker patient, male was more likely to have structure heart disease (31.3% vs. 28.0%, P = 0.002). In ICD patient, male patients were more likely to have ischemic heart disease (48.2% vs. 29.2%, P < 0.001). The mean age of women at the time of CRT/D implantation was older than men (P = 0.014). Nonischemic cardiomyopathy (70.9%) was the most common etiology in the patients who underwent the treatment of CRT/D, no matter male or female. CONCLUSIONS: In real-world setting, female do have different epidemiology, pathophysiology and clinical presentation of many cardiac rhythm disorders when compared with male, and all these factors may affect the utilization of CIED implantation. But it also possibility that cultural and socioeconomic features may play a role in this apparent discrimination.

The prognostic significance of fragmented QRS in patients with left ventricular noncompaction cardiomyopathy.

BACKGROUND: Fragmented QRS complexes (fQRS) were proven to be associated with the prognosis of several heart diseases. However, no data is available regarding fQRS in left ventricular noncompaction cardiomyopathy (LVNC), in which the outcome varies greatly and a simple yet practicable prognostic predictor is needed. The purpose of this study was to determine the prognostic value of fQRS in LVNC patients. METHODS: Sixty-four LVNC patients were evaluated. Fragmented narrow QRS (f-nQRS) included single or multiple notches in the R or S wave in at least 2 contiguous electrocardiogram (ECG) leads and QRS duration < 120 ms, fragmented wide QRS (f-wQRS) included more than 2 notches and QRS duration > 120 ms. RESULTS: f-nQRS and f-wQRS was present in 24 (38%) and 7 (11%) patients respectively. During follow-up, 13 patients died and 7 patients underwent heart transplantation. Kaplan-Meier analysis revealed that compared with the non-f-nQRS group, the f-nQRS group associated with a significantly lower survival (P = 0.005). The f-wQRS group also demonstrated a substantially lower survival as compared with the non-f-wQRS group (P = 0.02). Multivariate analysis indicated f-nQRS was an independent predictor of all-cause mortality (HR: 5.33; P = 0.045). CONCLUSIONS: In LVNC patients, the presence of f-nQRS has significant prognostic value and may provide a valid method of risk stratification.

Impact of automatic threshold capture on pulse generator longevity.

BACKGROUND: The automatic, threshold tracking, pacing algorithm developed by St. Jude Medical, verifies ventricular capture beat by beat by recognizing the evoked response following each pacemaker stimulus. This function was assumed to be not only energy saving but safe. This study estimated the extension in longevity obtained by AutoCapture (AC) compared with pacemakers programmed to manually optimized, nominal output. METHODS: Thirty-four patients who received the St. Jude Affinity series pacemaker were included in the study. The following measurements were taken: stimulation and sensing threshold, impedance of leads, evoked response and polarization signals by 3501 programmer during followup, battery current and battery impedance under different conditions. For longevity comparison, ventricular output was programmed under three different conditions: (1) AC on; (2) AC off with nominal output, and (3) AC off with pacing output set at twice the pacing threshold with a minimum of 2.0 V. Patients were divided into two groups: chronic threshold is higher or lower than 1 V. The efficacy of AC was evaluated. RESULTS: Current drain in the AC on group, AC off with optimized programming or nominal output was (14.33 +/- 2.84) mA, (16.74 +/- 2.75) mA and (18.4 +/- 2.44) mA, respectively (AC on or AC off with optimized programming vs. nominal output, P < 0.01). Estimated longevity was significantly extended by AC on when compared with nominal setting [(103 +/- 27) months, (80 +/- 24) months, P < 0.01). Furthermore, compared with the optimized programming, AC extends the longevity when the pacing threshold is higher than 1 V. CONCLUSION: AC could significantly prolong pacemaker longevity; especially in the patient with high pacing threshold.

Incidence and causes of inappropriate detection and therapy by implantable defibrillators of cardioversion in patients with ventricular tachyarrhythmia.

BACKGROUND: Implantable cardioverter defibrillator (ICD) is the only effective therapy in patients with life threatening ventricular arrhythmias. Inappropriate detection and therapy by ICDs are the most common causes of side effects that affect the quality of life in ICD recipients. This study evaluated the incidence and causes of inappropriate detection and therapy by ICDs in patients in our hospital. METHODS: From January 2000 to December 2005, fifty patients who received ICD implantation for ventricular arrhythmias for prevention of sudden cardiac death were evaluated in this study. Each ICD was programmed using clinical arrhythmic and cardiac data of the patient before discharge. Patients were followed up by standard schedule after implantation and all data retrieved from each device were collected and saved for further analysis. RESULTS: No arrhythmic event was detected in 12/50 (24%) patients during the period of follow-up. Among the remaining patients, 11 (22%) experienced inappropriate detections and therapies during follow-up in this study. ICD detected 383 ventricular tachyarrhythmia (VT) and 108 ventricular fibrillation (VF) episodes and delivered 678 therapies. In VT group, ICD delivered 413 antitachycardiac pacings (ATPs) and 118 shocks, among which 78 ATPs and 9 shocks were initiated by 55/383 (14.3%) inappropriate detections. In VF group ICD delivered 147 shocks, among which 56 shocks were initiated by 28/108 (26.9%) inappropriate detections. Overall, more than 50% of these episodes were caused by atrial fibrillation (AF) with rapid ventricular response, followed by electromagnetic or myopotential interference. In addition, most inappropriate therapies occurred within one year after ICD implantation. CONCLUSIONS: About one fifth of patients experienced ICD inappropriate detection and therapy after implantation. The main cause was AF with rapid ventricular response, followed by electromagnetic or myopotential interference.