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Background: This meta-analysis assessed the relationship between obstructive sleep apnea (OSA) and echocardiographic parameters of diastolic dysfunction (DD), which are used in the assessment of heart failure with preserved ejection fraction. Methods: We searched the databases including Ovid MEDLINE, Ovid Embase, Scopus, Web of Science, Google Scholar, and EBSCO CINAHL from inception up to December 26, 2020. The search was not restricted to time, publication status, or language. Two independent investigators screened the identified studies and extracted the data in duplicate. We conducted a meta-analysis using RevMan v.5. The risk of bias was assessed using Cochrane collaboration tools. Comparisons were made between patients with OSA, diagnosed in-laboratory polysomnography or home sleep apnea testing, and patients without OSA in relation to established markers of DD. Results: Primary search identified 2,512 studies. A total of 18 studies including 2,509 participants were included. The two groups were free of conventional cardiovascular risk factors. Significant structural changes were observed between the two groups. Patients with OSA exhibited greater left atrial volume index (LAVI) (3.94 95% CI [0.8, 7.07]; p = 0.000) and left ventricular mass index (11.10 95% CI [2.56, 19.65]; p = 0.000) as compared to control group. The presence of OSA was also associated with more prolonged deceleration time (10.44 ms 95% CI [0.71, 20.16]; p = 0.04), isovolumic relaxation time (IVRT) (7.85 ms 95% CI [4.48, 11.22]; p = 0.000), and a lower ratio of early to late mitral inflow velocities (E/A) ratio (−0.62 95% CI [−1, −0.24]; p = 0.001) suggestive of early DD. The early mitral inflow velocity to mitral annular early diastolic velocity (E/e′) ratio (0.94 95% CI [0.44, 1.45]; p = 0.000) was increased. Linear correlation between severity of OSA and LAVI and IVRT parameters was observed but this association did not sustain for the E/A and E/e′. The ejection fraction was not significantly different between patients with OSA and healthy controls (−0.48 95% CI [−1.18, 0.23]; p = 0.18). Conclusion: An association between OSA and echocardiographic parameters of DD was detected that was independent of conventional cardiovascular risk factors. OSA may be independently associated with DD perhaps due to higher LV mass. Investigating the role of continuous positive airway pressure therapy in reversing or ameliorating DD is recommended.

Introduction Although ablation of typical atrial flutter (AFL) can be easily achieved with radiofrequency energy (RF), there are no studies that compare effectiveness of different ablation catheters. Our study aimed to compare the effectiveness of various types of ablation catheters in the treatment of AFL. Methods We analysed patients with AFL who underwent RF ablation by a single operator at our institution. Successful ablation was evidenced by presence of bidirectional conduction block (trans-isthmus conduction time ≥130 ms, or doubling of baseline conduction time, or presence of double potentials ≥90ms). Logistic regression was used to compare success rate and linear regression to compare lesion time. Results Out of the 222 patients, only 6 patients did not meet success criteria (2.7%). Catheters used were 8 mm tip in 16 patients, internally irrigated (Chili II Boston Scientific) in 47 patients, externally irrigated (non-force sensing) catheters (CoolPath, Abbott) in 40 patients. Externally irrigated force sensing catheter (Tacticath, Abbott) was used with >10 gm of force and (LPLD) setting (30W-45°C-60 sec) in 50 patients, and high-power short duration (HPSD) setting (50W-43°C −12 sec,) in 70 patients. No complications were encountered. Catheter type had no statistically significant association with ablation success. In terms of lesion time, HPSD catheter statistically significantly shortened lesion time by 758.3s, [CI −1128.29, −388.35s] followed by LPLD by 419.0s [CI −808.49, −29.47s]. Table 1 shows the lesion time difference for the catheters used as compared with 8 mm tip. Conclusions Typical atrial flutter radiofrequency ablation procedure had a high success rate, not influenced by type of ablation catheter. Contact force ablation catheter on HPSD is associated with shorter total lesion time. Funding Acknowledgement Type of funding sources: None.

Introduction Atrioventricular node (AVN) radiofrequency ablation is a highly effective treatment of atrial tachycardias resistant to other management modalities. There are limited studies that compare different radiofrequency ablation catheters. Our study aimed to compare the effectiveness of several types of ablation catheters in AVN ablation. Methods We identified patients who underwent AVN ablation for different indications at our institution. Data related to patients and procedures were collected through retrospective chart review. The radiofrequency catheters used were: plain non irrigated, externally irrigated (EI), and contact force sensing with 10-20 gm of force in two different settings: low power long duration (LPLD) (30W, 45°C, and 60 sec) and high-power short duration (HPSD) (50W, 43°C, and 12 sec). We compared the different catheters in terms of success rate using logistic regression and lesion time using linear regression. Results We identified 66 patients who underwent AVN ablation, out of which 31 were female (47%). The patients were elderly, with a mean age of 73.27 years. The indications were resistant atrial fibrillation in 74%, atrial flutter in 18%, and other atrial tachycardias in 8% of patients. Types of catheters used were plain non irrigated in 48%, EI in 2%, LPLD in 16%, and HPSD in 34% of patients. All ablation procedures were successful with no immediate post-procedure complications. Regarding lesion time, HPSD was significantly shorter compared to plain catheters by 403.42s[-631.67, -175.17]. Conclusions Radiofrequency ablation of AVN is a highly effective treatment modality for atrial tachyarrhythmias that failed other management methods. While plain catheter, LPLD, and HPSD were equally safe and effective, HPSD catheter had significantly shorter lesion time and thus procedure time.