Impact of simple electrocardiographic markers as predictors for deterioration of left ventricular function in patients with frequent right ventricular apical pacing.

Several trials demonstrated that frequent right ventricular apical pacing (RVAP) was associated with cardiac dysfunction and an increased rate of heart failure hospitalization. However, there are few reports about the 12-lead electrocardiogram (12-ECG) parameters at the time of device implantation to predict deterioration of LVEF in patients with frequent RVAP. We retrospectively studied 115 consecutive patients undergoing pacemaker or implantable cardioverter-defibrillator implantation with RVAP, with rate of ventricular pacing ≥ 40% and LVEF ≥ 50% at the time of implantation. We compared the 12-ECG characteristics at the time of device implantation between patients with deterioration of LVEF (≥ 10% reduction) and those without. Twenty-nine patients (25%) had deteriorated LVEF with a decrease in mean LVEF from 59 to 40% during a median follow-up period of 8.9 [4.6-13.7] years. Multivariate logistic regression analysis showed that cumulative % of ventricular pacing [odds ratio (OR) 1.04 per 1% increase, 95% confidence interval (CI) 1.01-1.09, p = 0.04], notching of baseline paced QRS in limb leads (OR 5.04, 95% CI 1.59-19.6, p = 0.005) and the QS pattern in all precordial leads (OR 3.56, 95% CI 1.21-10.8, p = 0.02) were independently associated with deterioration of LVEF. The QS pattern of baseline paced QRS in all precordial leads had 58% sensitivity, 93% specificity for the RV lead position at the tip of RV apex. In conclusion, considering OR by multivariate analysis, notching of baseline paced QRS in limb leads and the QS pattern in all precordial leads at device implantation may be simple and useful predictors to identify patients who are at risk for deterioration of cardiac function during long-term RVAP. 12-ECG monitoring at device implantation and avoidance of the RVAP site showing a QS pattern may be important to prevent deterioration of cardiac function in patients with frequent RVAP.

The utility of T-wave alternans during the morning in the summer for the risk stratification of patients with Brugada syndrome.

The prognostic value of the seasonal variations of T-wave alternans (TWA) and heart rate variability (HRV), and the seasonal distribution of ventricular fibrillation (VF) in Brugada syndrome (Br-S) is unknown. We assessed the utility of seasonal variations in TWA and HRV for risk stratification in Br-S using a 24-h multichannel Holter electrocardiogram (24-M-ECG). We enrolled 81 patients with Br-S (grouped according to their history of VF, n = 12; syncope, n = 8; no symptoms, n = 61) who underwent 24-M-ECG in all four seasons. Precordial electrodes were attached to the third (3L-V2) and fourth (4L-V2, 4L-V5) intercostal spaces. We determined the maximum TWA (max-TWA) values and calculated HRV during night and morning time periods for all seasons. During a follow-up period of 5.8 ± 2.8 years, 11 patients experienced new VF episodes and there was a peak in new VF episodes in the summer. The VF group had the greatest 3L-V2 max-TWA value during morning time in the summer among the three groups and showed higher 3L-V2 max-TWA value than in the other seasons. The cutoff value for the 3L-V2 max-TWA during morning time in the summer was determined to be 42 µV using ROC analysis (82 % sensitivity, 74 % specificity; p = 0.0006). Multivariate analysis revealed that a 3L-V2 max-TWA value ≥42 µV during morning time in the summer and previous VF episodes were predictors of future VF episodes. The 3L-V2 max-TWA value during morning time in the summer may be a useful predictor of future VF episodes in Br-S.

Safety and efficacy of high-rate cutoff and long detection interval ICD programming in secondary prevention patients.

Several trials demonstrated that a long detection interval and a high-rate cutoff reduced implantable cardioverter-defibrillator (ICD) therapy in primary prevention patients. However, only a few data are available for secondary prevention (SP) patients. The aim of this study was to evaluate whether these ICD programming would be effective in reducing ICD therapies in SP patients. We enrolled 65 SP patients under ICD or cardiac resynchronization therapy with the defibrillator programmed with the same setting (conventional setting). During follow-up, we changed detection rates in each zone; cycle length (CL) ≤400 to ≤370 ms for ventricular tachycardia (VT) zone, CL ≤350 to ≤320 ms for fast VT zone, CL ≤300 to ≤270 ms for ventricular fibrillation (VF) zone, and number of intervals to detect ventricular tachyarrhythmia in VF zone: 12-24. We retrospectively compared the incidences of ICD therapies, syncope, and hospitalization due to slow VT under the detection rate between both settings. Median follow-up periods were 5.0 (interquartile range 2.5-7.8) and 2.5 years (interquartile range 2.3-2.7) in conventional and strategic settings, respectively. The incidence of appropriate ATP and shock significantly decreased in strategic setting (conventional and strategic settings: 21.2 and 4.8 ATPs per year, respectively, OR 0.18, 95 % CI 0.06-0.54, p = 0.002, 26.1 and 7.8 shocks per year, respectively, OR 0.29, 95 % CI 0.09-0.88, p = 0.03). The incidence of overall inappropriate therapy significantly decreased (conventional and strategic settings: 17.6 and 2.8 therapies per year, respectively, OR 0.14, 95 % CI 0.05-0.44, p = 0.01). The incidence of syncope and slow VT was not significantly different between both settings. In conclusion, ICD programming-combined long detection interval with high-rate cutoff was effective in reducing appropriate shock and inappropriate therapy without increasing the incidence of syncope and slow VT in SP patients.

Utility of T-wave alternans during night time as a predictor for ventricular fibrillation in patients with Brugada syndrome.

The prognostic value of T-wave alternans (TWA) during the night time in patients with Brugada syndrome (Br-S) remains unknown. We assessed TWA for risk stratification using 24-h multichannel Holter electrocardiogram (24-M-ECG) in Br-S. We enrolled 129 patients with Br-S [grouped according to histories of ventricular fibrillation (VF), n = 16; syncope, n = 10; or no symptoms (asymptomatic), n = 103] and 11 controls. Precordial electrodes were attached to the third (3L-V1, 3L-V2) and fourth (4L-V1, 4L-V2 and 4L-V5) intercostal spaces. We measured the values of maximum TWA (max-TWA) during the night time (12 a.m.-6 a.m.) and the day time (12 p.m.-6 p.m.) and calculated parameters of heart rate variability. Compared to the asymptomatic and control groups, the VF and syncope groups showed significantly greater 3L-V2 max-TWA during the night time. The cutoff value for the 3L-V2 max-TWA during the night time was determined as 20 µV (sensitivity 94 % and specificity 48 %; p = 0.01). Multivariate analysis revealed that 3L-V2 max-TWA during the night time ≥20 µV and previous VF episodes were independent predictors of future VF episodes. During a mean follow-up period of 68 ± 37 months, 16 patients experienced VF episodes. The incidence of VF episodes was the highest during the night time (p < 0.001). The 3L-V2 max-TWA during the night time may be a useful predictor for VF episodes in patients with Br-S.

Monitoring of multiple fish species by quantitative environmental DNA metabarcoding surveys over two summer seasons.

Periodic monitoring can provide important information for the protection of endangered fish, sustainable use of fishery resources and management of alien species. Previous studies have attempted to monitor fish using non-invasive environmental DNA (eDNA) technology, generally employing quantitative PCR to quantify the eDNA concentration. However, the throughput was limited. High-throughput metabarcoding technology can detect the DNA of multiple species simultaneously in a single experiment but does not provide sufficient quantification. In this study, we applied a quantitative metabarcoding approach to simultaneously quantify the eDNA concentration of an entire fish assemblage in a small reservoir over two summer seasons. Traditional surveys were also conducted to investigate the individuals of fish. The eDNA concentrations were quantified using quantitative metabarcoding, and the fish species detected using this approach were highly consistent with the results of traditional fish monitoring. A significant positive relationship was observed between the eDNA concentration and fish species abundance. Seasonal changes in fish community structure were estimated using eDNA concentrations, which may reveal the activity seasons of different fish. The eDNA concentrations of different fish species peaked at different water temperatures, reflecting the differential responses of fish species to this environmental factor. Finally, by detecting outlier eDNA concentrations, the spawning activities of 13 fish species were estimated, 12 of which were roughly consistent with the current knowledge of fish spawning periods. These results indicate that quantitative eDNA metabarcoding with dozens of sampling times is useful for the simultaneous ecological monitoring of multiple fish species.

Leadless Pacemaker Implantation in Severe Kyphosis: Challenging Implantation for Tortuous IVC and Narrow RA.

Leadless pacemaker implantation is recognized as safe and effective for treating bradycardia. However, there are limited descriptions of its use in patients with complex anatomical considerations. Here, we present a case detailing the successful implantation of a leadless pacemaker with a tortuous inferior vena cava and a narrow right atrium.

Unique Extraction of a Fractured Pacemaker Lead Adhered to the Spermatic Vein.

Transvenous lead extraction has been increasingly recognized as a safe and effective method of lead extraction, but there are only few references for extracting leads migrating outside the heart. We present a successful extraction of a fractured pacemaker lead from the spermatic vein using several approaches and multiple tools.

Successful Extraction of Guidewire Entrapped in the Tricuspid Valve Leaflet Using a Laser Sheath.

Right ventriculography is a necessary step for implantation of leadless pacemaker and is considered a safe procedure. However, an inappropriate manipulation of the guidewire can lead to serious complications. We present a case where the guide-wire was entrapped in the tricuspid valve, and its successful extraction using a laser sheath. (Level of Difficulty: Advanced.).

An Unexpected Complication of Subcutaneous ICD Implantation and its Successful Management.

Subcutaneous implantable cardioverter-defibrillator implantation is known to be a safe procedure. However, inappropriate lead insertion can lead to serious complications. We present a case where an inappropriate lead placement resulted in puncturing the lung parenchyma, and successful management of the lead-related pneumothorax through thoracoscopic lead removal and partial lung resection. (Level of Difficulty: Intermediate.).

Multiple coronary artery spasms triggering life-threatening ventricular arrhythmia associated with the radiofrequency ablation of ganglionated plexuses of the left atrium.

We report a case of multiple coronary spasms leading to life-threatening ventricular arrhythmia, during left atrium (LA) ablation. Coronary artery spasm is a rare complication during radiofrequency catheter ablation of atrial fibrillation (AF). Previous reports mention that autonomic imbalance leads to coronary artery spasm and ST-segment elevation in the inferior leads, during trans-septal LA catheterization and AF ablation procedures. However, there are few reports detailing the association between ablation sites and changes in the electrocardiogram. We encountered transient ST-segment elevation and refractory ventricular arrhythmia, associated with coronary artery spasm, during radiofrequency ablation of ganglionated plexuses (superior surface of left and right atrium). .

Life-threatening pulmonary embolism associated with multiple venous aneurysms.

Popliteal venous aneurysms (PVAs) are often reported as a cause of pulmonary embolism. Previous reports documented the association between a single PVA and pulmonary embolism. We experienced a rare case with multiple venous saccular and fusiform aneurysms resulting in a nearly fatal pulmonary embolism. Surgical ligation is usually considered the first-line treatment for PVAs. In our patient, however, we selected inferior vena cava filter implantation and anticoagulant therapy to avoid the phlegmasia cerulea dolens caused by ligation of multiple aneurysms in both legs. We report a patient with multiple venous aneurysms, including PVAs, causing a nearly fatal pulmonary embolism.