Is T-Wave Alternans a Repolarization Abnormality Marker in COVID-19? An Investigation on the Potentialities of Portable Electrocardiogram Device.

Background: Cardiac arrhythmias are significantly associated with poor outcomes in coronavirus disease 2019 (COVID-19) patients. Microvolt T-wave alternans (TWA) can be automatically quantified and has been recognized as a representation of repolarization heterogeneity and linked to arrhythmogenesis in various cardiovascular diseases. This study aimed to explore the correlation between microvolt TWA and COVID-19 pathology. Methods: Patients suspected of COVID-19 in Mohammad Hoesin General Hospital were consecutively evaluated using Alivecor® Kardiamobile 6L™ portable electrocardiogram (ECG) device. Severe COVID-19 patients or those who are unable to cooperate in active ECG self-recording were excluded from the study. TWA was detected and its amplitude was quantified using the novel enhanced adaptive match filter (EAMF) method. Results: A total of 175 patients, 114 COVID-19 patients (polymerase chain reaction (PCR)-positive group), and 61 non-COVID-19 patients (PCR-negative group) were enrolled in the study. PCR-positive group was subdivided according to the severity of COVID-19 pathology into mild and moderate severity subgroups. Baseline TWA levels were similar between both groups during admission (42.47 ± 26.52 µV vs. 44.72 ± 38.21 µV), but higher TWA levels were observed during discharge in the PCR-positive compared to the PCR-negative group (53.45 ± 34.42 µV vs. 25.15 ± 17.64 µV, P = 0.03). The correlation between PCR-positive result in COVID-19 and TWA value was significant, after adjustment of other confounding variables (R2 = 0.081, P = 0.030). There was no significant difference in TWA levels between mild and moderate severity subgroups in patients with COVID-19, both during admission (44.29 ± 27.14 µV vs. 36.75 ± 24.46 µV, P = 0.34) and discharge (49.47 ± 33.62 µV vs. 61.09 ± 35.99 µV, P = 0.33). Conclusions: Higher TWA values can be observed on follow-up ECG obtained during discharge in the PCR-positive COVID-19 patients.

The Association of Obstructive Sleep Apnea in Ischemia with No Obstructive Coronary Artery Disease - A Pilot Study.

Obstructive sleep apnea (OSA) is increasingly recognized to be a risk factor for cardiovascular disease. This pilot study assessed the association of OSA and invasive coronary microvascular function in patients with ischemia with no obstructive coronary artery disease (INOCA). Forty-two patients with angina, were prospectively screened at a single tertiary centre covering the northern metropolitan area of South Australia, from February 2018 to December 2020 (ACTRN12618000149268). Forty patients were invited into to this observational study after coronary angiography demonstrated INOCA and functional coronary vasomotor disorder (n = 40). Twenty one participants subsequently underwent a sleep study for OSA diagnosis while 9 participants had prior formal diagnosis of OSA (ACTRN12618000227291). Of the 30 participants with OSA data, 87% (n = 26) had a diagnosis of OSA. Accordingly, 11 with mild severity, 7 with moderate severity and 8 with severe OSA. No OSA was observed in 4 participants. Participants with OSA were older [61.4±8.7 vs 49.9±9.7, P = 0.002] with similar clinical characteristics for the pattern and severity of angina and other co-morbidities. 73.3% (n = 22) had abnormal functional disorders of the epicardial coronary arteries and/or coronary microcirculation. On multivariate analysis, OSA was the only statistically significant association with functional coronary microvascular disorders [OR 53.95, 1.41 -2065.01, P = 0.032]. This study provided an observation of a significant correlation between INOCA with abnormal coronary vasomotor function and OSA in an Australian cohort. This correlation supports a possible pathophysiological interplay between these two conditions that needs to be further evaluated. The benefit of treatment of OSA in this subset remains unknown.

A Simple Percutaneous Retrieval Technique for an Embolized Watchman Left Atrial Appendage Closure Device in the Thoracic Aorta Using a Homemade Snare.

A 60-year old male with paroxysmal atrial fibrillation underwent a combined procedure of left atrial appendage occlusion and pulmonary vein isolation. However, an acute intraprocedural 24-mm Watchman device dislodgement occurred, and thus a decision for urgent surgery was made. However, it was noted during the surgery that the device had migrated further to the descending aorta, just distal to the left subclavian artery. Since a right sternotomy access for retrieval was not feasible, a percutaneous approach was justified. A homemade snare was created using a combination of a long sheath, J-wire, and a regular snare, and the device was successfully retrieved without significant difficulty.

Role of Indices Incorporating Power, Force and Time in AF Ablation: A Systematic Review of Literature.

INTRODUCTION: Successful pulmonary vein isolation (PVI) for atrial fibrillation (AF) depends on the formation of durable transmural lesions. Recently, novel indices have emerged to guide lesion delivery. The aim of the systematic review of literature was to determine AF recurrence following ablation guided by indices incorporating force, power and time, and compare acute procedural outcomes and 12-month AF recurrence with ablation guided by contact force (CF) guided only. METHODS: PubMed, EMBASE, and Web of Science Core Collection databases were searched on 27 January 2020 using the keywords; catheter ablation, ablation index (AI), lesion size index (LSI), contact force, atrial fibrillation. RESULTS: After exclusions, seven studies were included in the analysis. AI-guided catheter ablation was associated with a 91% (n=5, 0.91 95% CI; 0.88-0.93) and 80% (n=5, 0.80, 95% CI; 0.77-0.84) freedom from AF at 12 months with and without the use of anti-arhythmic drugs respectively. As compared to CF guided ablation, AI-guided catheter ablation was associated with a 49% increase in successful first pass isolation (n=3; RR: 1.49, 95% CI; 1.38, 1.61), a 50% decrease in number of acute reconnections (n=4; RR: 0.50, 95% CI; 0.39-0.65) and a 22% (n=4, RR: 1.22, 95% CI; 1.10-1.35) increase in AF freedom without anti-arrhythmic drugs at 12 months. CONCLUSIONS: Radiofrequency ablation guided by AI was associated with higher successful first pass isolation and lower rates of acute reconnection which translates to greater freedom from AF at 12 months [CRD42019131469].

Left ventricular lead positioning in cardiac resynchronization therapy: an innovative retrograde approach without using snare.

AIMS: Ideal positioning of left ventricular (LV) pacing lead in cardiac resynchronization therapy (CRT) is technically demanding. This case aims to place LV lead in anterolateral branch of coronary sinus (CS) using collateral route blindly. METHODS AND RESULTS: Externalization via the CS ostium using collaterals retrogrogradely, which was not visible in initial balloon occlusion venography, through one delivery sheath with the support of commonly used micro-guide catheter and subsequent successful LV lead placement in anterolateral branch of CS. CONCLUSION: This innovative retrograde approach for LV pacing lead implantation in anterolateral branch of CS obviated the need for snare technique to capture the distal end of the wire when antegrade route was not successful.