Inappropriate Sinus Tachycardia: Etiology, Pathophysiology, and Management: JACC Review Topic of the Week.

Inappropriate sinus tachycardia (IST) is a clinical syndrome that generally affects young patients and is associated with distressing symptoms. Although the most common symptom is palpitations, it can be accompanied by a myriad of symptoms, including anxiety, dizziness, presyncope, and syncope. The pathogenesis of IST is not well understood and considered multifactorial, with autonomic dysfunction being the central abnormality. IST is a diagnosis of exclusion. Management presents a clinical challenge. The overall efficacy of lifestyle modifications and medical therapy may be limited. Recent advances in catheter and surgical sinus node sparing ablation techniques have led to improvement in outcomes. In addition, increased focus has led to development of multimodality team-based interventions to improve outcomes in this group of patients. In this review, we discuss the mechanistic basis of IST, review current approaches to diagnosis, and outline contemporary therapeutic approaches.

Leadless pacemaker implantation under direct visualization during valve surgery.

OBJECTIVE: The leadless cardiac pacemaker is typically implanted percutaneously and has been widely used for patients who have already undergone valve surgery. We sought to determine the feasibility and safety of implanting the leadless pacemaker under direct visualization during valve surgery. METHODS: We performed a retrospective analysis of consecutive adult patients (n = 15) who underwent implantation of a leadless pacemaker under direct visualization at the time of valve surgery. Indications for single-chamber pacing were sick sinus syndrome with pauses (53.3%), atrial fibrillation with slow ventricular rates (13.3%) or complete heart block (6.6%), and elevated risk for postoperative heart block (26.6%). Leadless pacemaker performance and pacing percentage were assessed. RESULTS: Patients' age was 67.5 ± 17 years, 6 patients (40%) were male, and 14 patients (93%) had atrial fibrillation. Isolated tricuspid valve replacement was performed in 5 patients (33.3%), and the remainder underwent multivalve surgery that included concomitant tricuspid valve repair/replacement. In 93% of the patients (n = 14), the immediate post-cardiopulmonary bypass pacing thresholds were normal (≤2.0 V at 0.24 ms) and normalized in the remaining patient by the next morning. The impedance/sensing values were normal and stable through follow-up (151 ± 119 days) in all patients. Reliable leadless pacemaker performance allowed for deferral of temporary epicardial wires in 11 patients (73%). There were no procedural complications or device malfunction. CONCLUSIONS: Leadless cardiac pacemaker implantation during valve surgery is feasible and safe. This hybrid approach to pacing may simplify the perioperative management of patients undergoing valve surgery who have an indication for single-chamber pacing.

Sinus Node Sparing Hybrid Thoracoscopic Ablation Outcomes in Patients with Inappropriate Sinus Tachycardia (SUSRUTA-IST) Registry.

BACKGROUND: Medical treatment of inappropriate sinus tachycardia (IST) remains suboptimal. Radiofrequency sinus node (RF-SN) ablation has poor success and higher complication rates. OBJECTIVE: We aimed to compare clinical outcomes of the novel SN sparing hybrid ablation technique with those of RF-SN modification for IST management. METHODS: This is a multicenter prospective registry comparing the SN sparing hybrid ablation strategy with RF-SN modification. The hybrid procedure was performed using an RF bipolar clamp, isolating superior vena cava/inferior vena cava with the creation of a lateral line across the crista terminalis while sparing the SN region (identified by endocardial 3-dimensional mapping). RF-SN modification was performed by endocardial and/or epicardial mapping and ablation at the site of earliest atrial activation. RESULTS: Of the 100 patients (hybrid ablation group, n = 50; RF-SN group, n = 50), 82% were women, and the mean age was 22.8 years. Normal sinus rhythm and rate were restored in all patients in the hybrid group (vs 84% in the RF-SN group; P = .006). Hybrid ablation was associated with significantly better improvement in mean daily heart rate and peak 6-minute walk heart rate compared with RF-SN ablation. The RF-SN group had a significantly higher rate of redo procedures (100% vs 8%; P < .001), phrenic nerve injury (14% vs 0%; P = .012), lower acute pericarditis (48% vs 92%; P < .0001), permanent pacemaker implantation (50% vs 4%; P < .0001) than did the hybrid ablation group. CONCLUSION: The novel sinus node sparing hybrid ablation procedure appears to be more efficacious and safer in patients with symptomatic drug-resistant IST with long-term durability than RF-SN ablation.

Diagnostic Utility of Smartwatch Technology for Atrial Fibrillation Detection - A Systematic Analysis.

BACKGROUND: Smartphone technologies have been recently developed to assess heart rate and rhythm, but their role in accurately detecting atrial fibrillation (AF) remains unknown. OBJECTIVE: We sought to perform a meta-analysis using prospective studies comparing Smartwatch technology with current monitoring standards for AF detection (ECG, Holter, Patch Monitor, ILR). METHODS: We performed a comprehensive literature search for prospective studies comparing Smartwatch technology simultaneously with current monitoring standards (ECG, Holter, and Patch monitor) for AF detection since inception to November 25th, 2019. The outcome studied was the accuracy of AF detection. Accuracy was determined with concomitant usage of ECG monitoring, Holter monitoring, loop recorder, or patch monitoring. RESULTS: A total of 9 observational studies were included comparing smartwatch technology, 3 using single-lead ECG monitoring, and six studies using photoplethysmography with routine AF monitoring strategies. A total of 1559 patients were enrolled (mean age 63.5 years, 39.5% had an AF history). The mean monitoring time was 75.6 days. Smartwatch was non-inferior to composite ECG monitoring strategies (OR 1.06, 95% CI 0.93 - 1.21, p=0.37), composite 12 lead ECG/Holter monitoring (OR 0.90, 95% CI 0.62 - 1.30, p=0.57) and patch monitoring (OR 1.28, 95% CI 0.84 - 1.94, p=0.24) for AF detection. The sensitivity and specificity for AF detection using a smartwatch was 95% and 94%, respectively. CONCLUSIONS: Smartwatch based single-lead ECG and photoplethysmography appear to be reasonable alternatives for AF monitoring.

How does the level of pulmonary venous isolation compare between pulsed field ablation and thermal energy ablation (radiofrequency, cryo, or laser)?

AIMS: We studied the extent/area of electrical pulmonary vein isolation (PVI) after either pulsed field ablation (PFA) using a pentaspline catheter or thermal ablation technologies. METHODS AND RESULTS: In a clinical trial (NCT03714178), paroxysmal atrial fibrillation (PAF) patients underwent PVI with a multi-electrode pentaspline PFA catheter using a biphasic waveform, and after 75 days, detailed voltage maps were created during protocol-specified remapping studies. Comparative voltage mapping data were retrospectively collected from consecutive PAF patients who (i) underwent PVI using thermal energy, (ii) underwent reablation for recurrence, and (iii) had durably isolated PVs. The left and right PV antral isolation areas and non-ablated posterior wall were quantified. There were 20 patients with durable PVI in the PFA cohort, and 39 in the thermal ablation cohort [29 radiofrequency ablation (RFA), 6 cryoballoon, and 4 visually guided laser balloon]. Pulsed field ablation patients were younger with shorter follow-up. Left atrial diameter and ventricular systolic function were preserved in both cohorts. There was no significant difference between the PFA and thermal ablation cohorts in either the left- and right-sided PV isolation areas, or the non-ablated posterior wall area. The right superior PV isolation area was smaller with PFA than RFA, but this disappeared after propensity score matching. Notch-like normal voltage areas were seen at the posterior aspect of the carina in the balloon sub-cohort, but not the PFA or RFA cohorts. CONCLUSION: Catheter-based PVI with the pentaspline PFA catheter creates chronic PV antral isolation areas as encompassing as thermal energy ablation.

Atrial Fibrillation in Patients Hospitalized With COVID-19: Incidence, Predictors, Outcomes, and Comparison to Influenza.

OBJECTIVES: The goal of this study is to determine the incidence, predictors, and outcomes of atrial fibrillation (AF) or atrial flutter (AFL) in patients hospitalized with coronavirus disease-2019 (COVID-19). BACKGROUND: COVID-19 results in increased inflammatory markers previously associated with atrial arrhythmias. However, little is known about their incidence or specificity in COVID-19 or their association with outcomes. METHODS: This is a retrospective analysis of 3,970 patients admitted with polymerase chain reaction-positive COVID-19 between February 4 and April 22, 2020, with manual review performed of 1,110. The comparator arm included 1,420 patients with influenza hospitalized between January 1, 2017, and January 1, 2020. RESULTS: Among 3,970 inpatients with COVID-19, the incidence of AF/AFL was 10% (n = 375) and in patients without a history of atrial arrhythmias it was 4% (n = 146). Patients with new-onset AF/AFL were older with increased inflammatory markers including interleukin 6 (93 vs. 68 pg/ml; p < 0.01), and more myocardial injury (troponin-I: 0.2 vs. 0.06 ng/ml; p < 0.01). AF and AFL were associated with increased mortality (46% vs. 26%; p < 0.01). Manual review captured a somewhat higher incidence of AF/AFL (13%, n = 140). Compared to inpatients with COVID-19, patients with influenza (n = 1,420) had similar rates of AF/AFL (12%, n = 163) but lower mortality. The presence of AF/AFL correlated with similarly increased mortality in both COVID-19 (relative risk: 1.77) and influenza (relative risk: 1.78). CONCLUSIONS: AF/AFL occurs in a subset of patients hospitalized with either COVID-19 or influenza and is associated with inflammation and disease severity in both infections. The incidence and associated increase in mortality in both cohorts suggests that AF/AFL is not specific to COVID-19, but is rather a generalized response to the systemic inflammation of severe viral illnesses.

Does pulsed field ablation regress over time? A quantitative temporal analysis of pulmonary vein isolation.

BACKGROUND: The tissue specificity of pulsed field ablation (PFA) makes it an attractive energy source for pulmonary vein (PV) isolation (PVI). However, beyond each PFA lesion's zone of irreversible electroporation and cell death, there may be a surrounding zone of reversible electroporation and cell injury that could potentially normalize with time. OBJECTIVE: The purpose of this study was to assess whether the level of electrical PVI that is observed acutely after PFA regresses over time. METHODS: In a clinical trial, patients with paroxysmal atrial fibrillation underwent PVI using a biphasic PFA waveform delivered through a dedicated, variably deployable multielectrode basket/flower catheter. Detailed voltage maps were created using a multispline diagnostic catheter immediately after PFA and again ∼3 months later in a prospective, protocol-specified reassessment procedure. We analyzed 20 patients who underwent PFA with durable PVI and available maps from both time points. To compare the ablated zones, the left- and right-sided PV antral isolation areas and nonablated posterior wall area were quantified and the distances between left and right PV low-voltage edges were measured. RESULTS: A comparison of voltage maps immediately after PFA and at a median of 84 days (interquartile range 69-90 days) later revealed that there was no significant difference in either the left- and right-sided PV antral isolation areas or nonablated posterior wall area. The distances between low-voltage edges on the posterior wall were also not significantly different between the 2 time points. CONCLUSION: This study demonstrates that the level of PV antral isolation after PFA with a multielectrode PFA catheter persists without regression.

Transcatheter embolic coils to treat peridevice leaks after left atrial appendage closure.

BACKGROUND: Left atrial appendage closure (LAAC) has proven to be an effective alternative to long-term oral anticoagulation in the prevention of thromboembolic events in patients with atrial fibrillation. In a minority of patients, inadequate seal may result in persistent peridevice flow and inability of the appendage to fully thrombose, thereby representing a potential source for thromboembolism. OBJECTIVE: The purpose of this study was to study the use of endovascular coiling of the appendage to address persistent peridevice leak in patients undergoing LAAC with the Watchman device. METHODS: This is a retrospective single-center analysis involving patients who underwent placement of a LAAC device and returned for endovascular coiling to address persistent device leak between 2018 and 2020. Baseline characteristics, procedural outcomes, and follow-up echocardiograms were analyzed to demonstrate the feasibility and safety of this technique. RESULTS: Patients (N = 20) were identified with a mean leak size of 3.8 ± 1.3 mm (range 2.5-7 mm), all of whom had a non-thrombosed appendage. Acute procedural success was achieved in 95% of patients. Complete or significant reduction in flow beyond the LAAC device was achieved in 61% and 33% of patients, respectively. The 1 procedure-related adverse event was a pericardial effusion before coil deployment, requiring percutaneous drainage. CONCLUSION: The clinical impact of residual peridevice leak post-Watchman implantation is a matter of continuing investigation. However, appendage coiling represents a new therapeutic tool to address this potential source for thromboembolism. Further studies should address the clinical impact of this technique, including the safety of discontinuing anticoagulation after successful coiling.

Malignant Arrhythmias in Patients With COVID-19: Incidence, Mechanisms, and Outcomes.

BACKGROUND: Patients with coronavirus disease 2019 (COVID-19) who develop cardiac injury are reported to experience higher rates of malignant cardiac arrhythmias. However, little is known about these arrhythmias-their frequency, the underlying mechanisms, and their impact on mortality. METHODS: We extracted data from a registry (NCT04358029) regarding consecutive inpatients with confirmed COVID-19 who were receiving continuous telemetric ECG monitoring and had a definitive disposition of hospital discharge or death. Between patients who died versus discharged, we compared a primary composite end point of cardiac arrest from ventricular tachycardia/fibrillation or bradyarrhythmias such as atrioventricular block. RESULTS: Among 800 patients with COVID-19 at Mount Sinai Hospital with definitive dispositions, 140 patients had telemetric monitoring, and either died (52) or were discharged (88). The median (interquartile range) age was 61 years (48-74); 73% men; and ethnicity was White in 34%. Comorbidities included hypertension in 61%, coronary artery disease in 25%, ventricular arrhythmia history in 1.4%, and no significant comorbidities in 16%. Compared with discharged patients, those who died had elevated peak troponin I levels (0.27 versus 0.02 ng/mL) and more primary end point events (17% versus 4%, P=0.01)-a difference driven by tachyarrhythmias. Fatal tachyarrhythmias invariably occurred in the presence of severe metabolic imbalance, while atrioventricular block was largely an independent primary event. CONCLUSIONS: Hospitalized patients with COVID-19 who die experience malignant cardiac arrhythmias more often than those surviving to discharge. However, these events represent a minority of cardiovascular deaths, and ventricular tachyarrhythmias are mainly associated with severe metabolic derangement. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04358029.

Syncope and presyncope in patients with COVID-19.

INTRODUCTION: Recent studies have described several cardiovascular manifestations of COVID-19 including myocardial ischemia, myocarditis, thromboembolism, and malignant arrhythmias. However, to our knowledge, syncope in COVID-19 patients has not been systematically evaluated. We sought to characterize syncope and/or presyncope in COVID-19. METHODS: This is a retrospective analysis of consecutive patients hospitalized with laboratory-confirmed COVID-19 with either syncope or presyncope. This "study" group (n = 37) was compared with an age and gender-matched cohort of patients without syncope ("control") (n = 40). Syncope was attributed to various categories. We compared telemetry data, treatments received, and clinical outcomes between the two groups. RESULTS: Among 1000 COVID-19 patients admitted to the Mount Sinai Hospital, the incidence of syncope/presyncope was 3.7%. The median age of the entire cohort was 69 years (range 26-89+ years) and 55% were men. Major comorbidities included hypertension, diabetes, and coronary artery disease. Syncopal episodes were categorized as (a) unspecified in 59.4% patients, (b) neurocardiogenic in 15.6% patients, (c) hypotensive in 12.5% patients, and (d) cardiopulmonary in 3.1% patients with fall versus syncope and seizure versus syncope in 2 of 32 (6.3%) and 1 of 33 (3.1%) patients, respectively. Compared with the "control" group, there were no significant differences in both admission and peak blood levels of d-dimer, troponin-I, and CRP in the "study" group. Additionally, there were no differences in arrhythmias or death between both groups. CONCLUSIONS: Syncope/presyncope in patients hospitalized with COVID-19 is uncommon and is infrequently associated with a cardiac etiology or associated with adverse outcomes compared to those who do not present with these symptoms.

Validation of scoring system predicting permanent pacemaker implantation after transcatheter aortic valve replacement.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is being increasingly performed in patients with severe aortic stenosis. Despite newer generation valves, atrioventricular (AV) conduction disturbance is a common complication, necessitating permanent pacemaker (PPM) implantation in about 10% of patients. Hence, it is imperative to improve periprocedural risk stratification to predict PPM implantation after TAVR. The objective of this study was to externally validate a novel risk-stratification model derived from the National Inpatient Sample (NIS) database that predicts risk of PPM from TAVR. METHODS: Components of the score included pre-TAVR left and right bundle branch block, sinus bradycardia, second-degree AV block, and transfemoral approach. The scoring system was applied to 917 patients undergoing TAVR at our institution from November 2011 to February 2017. We assessed its predictive accuracy by looking at two components: discrimination using the C-statistic and calibration using the Hosmer-Lemeshow goodness of fit test. RESULTS: Ninety patients (9.8%) required PPM. The scoring system showed good discrimination with C-statistic score of 0.6743 (95% CI: 0.618-0.729). Higher scores suggested increased PPM risk, that is, 7.3% with score ⩽3, 19.23% with score 4-6, and 37.50% with score ≥7. Patients requiring PPM were older (81.4 versus 78.7 years, P = .002). Length of stay and in-hospital mortality was significantly higher in PPM group. CONCLUSIONS: The NIS database derived PPM risk prediction model was successfully validated in our database with acceptable discriminative and gradation capacity. It is a simple but valuable tool for patient counseling pre-TAVR and in identifying high-risk patients.

Isolated hemopericardium associated with rivaroxaban: first case report.

Rivaroxaban is a novel anticoagulant approved for use in patients with atrial fibrillation for stroke prevention. It is a factor Xa inhibitor, and its activity cannot be monitored with use of the international normalized ratio. A 5.6% chance of major bleeding is associated with rivaroxaban use, including intracranial and gastrointestinal bleeds. We report the first case, to our knowledge, of isolated hemopericardium related to rivaroxaban use, which could potentially lead to death from cardiac tamponade. A 76-year-old man who was receiving rivaroxaban for atrial fibrillation presented to the emergency department with pleuritic chest pain and was found to have a hemopericardium. No signs of tamponade were evident, and his bleed remained stable after discontinuing rivaroxaban. The patient had also been taking saw palmetto, which may have contributed to the bleed by increasing rivaroxaban activity. A work-up for other causes of hemopericardium, including pacemaker lead misplacement and autoimmune disease-related pericarditis, was negative. Use of the Naranjo adverse drug reaction probability scale indicated a probable relationship (score of 5) between the patient's development of hemopericardium and rivaroxaban use. This case highlights the potential for bleeding complications associated with novel anticoagulants. Herbal products and various drugs may increase rivaroxaban levels by inhibiting P-glycoprotein and cytochrome P450 3A4 activity. Clinicians should be aware of these potential interactions with rivaroxaban and perform a review of not only the patient's drug therapy but also any herbal and food products that could alter the levels of anticoagulants. The lack of an antidote and the inability to dialyze rivaroxaban is a significant concern in situations of life-threatening bleeds. A laboratory test for monitoring rivaroxaban levels may be required for its safe use.

Acute respiratory distress syndrome in human granulocytic ehrlichiosis.

The ehrlichioses are emerging zoonotic infections. They have a very nonspecific clinical presentation. The diseases generally present as undifferentiated fever, but thrombocytopenia, leucopenia, and transaminitis are important laboratory features. Ehrlichiosis as a cause of acute respiratory distress syndrome (ARDS) has been infrequently described in the literature. Physicians should be aware of this life-threatening but treatable entity. We present a patient who developed ARDS shortly after being diagnosed with and initiating treatment for human granulocytic ehrlichiosis (HGE). A 54-year-old woman presented with fever, hypotension, and pancytopenia, with peripheral smear diagnostic of ehrlichiosis. She was started on doxycycline therapy following which she developed ARDS which resolved with methylprednisone. The fatality for HGE has been estimated as 7-10%. ARDS secondary to Ehrlichia has been shown to respond dramatically to steroids.

Beliefs regarding diet during childhood illness.

BACKGROUND: Fifty percent to 70% of the burden of childhood diarrhea and respiratory infections is attributable to undernutrition. It is compounded by food restriction during illness due to false beliefs, leading to a vicious cycle of malnutrition and infection. In the long run, it decreases the child's productivity, which is an obstacle to sustainable socioeconomic development. OBJECTIVES: To assess the dietary practices during different illnesses, to study the role of education, culture and religion in feeding an ill child and to create awareness against detrimental practices. MATERIALS AND METHODS: A cross-sectional study was undertaken among 126 caregivers of ill children using an open-ended pretested questionnaire. Statistical package for social sciences software was used for data analysis. Simple proportions, percentages and Chi-square were used. RESULTS: Caregivers believed that a child must be fed less during illness. Educational status did not play a role in maintaining beliefs, but elders and religion did. Doctors too were responsible for unwanted dietary restrictions. Media did not have an impact in spreading nutrition messages. Decreased breast feeds, initiating bottle feeds, feeding diluted milk and reducing complementary feeds during illness was widely practiced. Calorie intake during illness was very less and statistically significant. Firmly rooted beliefs about "hot" and "cold" foods lead to restriction of food available at home. CONCLUSIONS: Healthy feeding practices were few, and inappropriate ones predominant. Dietary education was overlooked. While planning community-based nutrition programs, firmly rooted beliefs should be kept in mind. Involving the elderly caregivers and mothers actively along with the health workers is the need of the hour.