Optimization of initial energy for cardioversion of atrial tachyarrhythmias with biphasic shocks

Impact of Defibrillator Electrode Placement on Outcome of Electrical Cardioversion of Atrial Fibrillation: A Pilot Observational Study

BACKGROUND

Anterior-posterior electrode placement is preferred in electrical cardioversion of atrial fibrillation. However, the optimal anterior-posterior electrode position in relation to the heart is not studied.

METHODS AND RESULTS

We performed a prospective observational study on patients presenting for cardioversion of atrial fibrillation. Electrodes were placed in the anterior-posterior position and shock was delivered in a step-up approach (100 J→200 J→360 J). Fluoroscopic images were obtained, and distances were measured from points A, midanterior electrode; and B, midposterior electrode, to midpoint of the cardiac silhouette. Patients requiring one 100 J shock for cardioversion success (group I) were compared with those requiring >1 shock/100 J (group II). Logistic regression was used to determine the impact of electrode distance on low energy (100 J) cardioversion success. Computed tomography scans from this cohort were analyzed for anatomic landmark correlation to the cardiac silhouette. Of the 87 patients included, 54 (62%) comprised group I and 33 (38%) group II. Group I had significantly lower distances from the mid-cardiac silhouette to points A (5.0±2.4 versus 7.4±3.3 cm; P<0.001) and B (7.3±3.0 versus 10.0±3.8 cm; P=0.002) compared with group II. On multivariate analysis, higher distances from the mid-cardiac silhouette to point A (odds ratio, 1.33 [95% CI, 1.07-1.70]; P=0.01) and B (odds rsatio, 1.24 [95% CI, 1.05-1.50]; P=0.01) were independent predictors of low energy (100 J) cardioversion failure. Based on review of computed tomography scans, we suggest that the xiphoid process may be an easy landmark to guide proximity to the myocardium.

CONCLUSIONS

In anterior-posterior electrode placement, closer proximity to the cardiac silhouette predicts successful 100 J cardioversion irrespective of clinical factors.

Wide QRS complex tachycardia with a mysterious mask-Tricuspid isthmus-dependent atrial flutter with preexcitation syndrome and dual atrioventricular nodal pathway conduction

Key Clinical Message

Atrial flutter (AFL) and supraventricular tachycardia (SVT) are common arrhythmias in clinic. However, some AFL cases may present additional complexities, such as both accessory pathways (AP) and dual atrioventricular node pathways, putting on a mysterious mask and making it challenging to distinguish on electrocardiograms (ECGs).

Abstract

A 60-year-old male patient had a sudden syncope, and an ECG showed wide QRS complex tachycardia. This diagnostic ambiguity is further compounded by the fact that SVT via AP conduction can exhibit wide QRS complex tachycardia characteristics resembling ventricular tachycardia (VT). Consequently, a definitive diagnosis through electrophysiological (EP) examination becomes imperative, as it dictates subsequent ablation strategies. In this article, we present a rare case involving three distinct arrhythmias including AFL, AP, and dual atrioventricular node pathways, and successfully treated through ablation.

[Atrial fibrillation on the intensive care unit : The special prognostic importance of the first manifestation]

Atrial fibrillation (AF) is the most common arrhythmia in the intensive care unit (ICU) and is associated with increased mortality. The AF is classified into five different forms, initially diagnosed AF, paroxysmal AF, persistent AF, long-standing persistent AF and permanent AF. Studies could confirm that the first manifestation of AF (new onset AF) is of particular importance in intensive care patients. The mortality and costs are much higher than for patients with chronic AF. This important clinical difference of the AF pattern should be taken into consideration in the treatment of intensive care patients. The treatment of comorbidities is essential in the treatment concept on the ICU. In patients with an increased risk of thromboembolic complications, therapeutic anticoagulation is indicated, although the greatly increased risk of bleeding during intensive care treatment should be considered in individual cases. In cases of hemodynamic instability electrical cardioversion should immediately be carried out. Otherwise, pharmacological cardioversion can also be carried out. Apart from a few exceptions, amiodarone is the antiarrhythmic drug of choice for rhythm control due to the contraindications for other drugs.

[Adult advanced life support]

These European Resuscitation Council Advanced Life Support guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the prevention of and ALS treatments for both in-hospital cardiac arrest and out-of-hospital cardiac arrest.

European Resuscitation Council Guidelines 2021: Adult advanced life support

These European Resuscitation Council Advanced Life Support guidelines, are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the prevention of and ALS treatments for both in-hospital cardiac arrest and out-of-hospital cardiac arrest.

Management of tachyarrhythmias in pregnancy - A review

The most common arrhythmias detected during pregnancy include sinus tachycardia, sinus bradycardia, and sinus arrhythmia, identified in 0.1% of pregnancies. Isolated premature atrial or ventricular arrhythmias are observed in 0.03% of pregnancies. Arrhythmias may become more frequent during pregnancy or may manifest for the first time.

The effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter: a protocol for a systematic review with meta-analysis and Trial Sequential Analysis

BACKGROUND

Atrial fibrillation is the most common arrhythmia of the heart with a prevalence of approximately 2% in the western world. Atrial flutter, another arrhythmia, occurs less often with an incidence of approximately 200,000 new patients per year in the USA. Patients with atrial fibrillation and atrial flutter have an increased risk of death and morbidities. The management of atrial fibrillation and atrial flutter is often based on interventions aiming at either a rhythm control strategy or a rate control strategy. The evidence on the comparable effects of these strategies is unclear. This protocol for a systematic review aims at identifying the best overall treatment strategy for atrial fibrillation and atrial flutter.

METHODS

This protocol for a systematic review was performed following the recommendations of the Cochrane Collaboration and the eight-step assessment procedure suggested by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials assessing the effects of any rhythm control strategy versus any rate control strategy. We plan to search the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, Science Citation Index Expanded on Web of Science, and BIOSIS to identify relevant trials. Any eligible trial will be assessed and classified as either high risk of bias or low risk of bias, and our conclusions will be based on trials with low risk of bias. The analyses of the extracted data will be performed using Review Manager 5 and Trial Sequential Analysis. For both our primary and secondary outcomes, we will create a 'Summary of Findings' table and use GRADE assessment to assess the quality of the evidence.

DISCUSSION

The results of this systematic review have the potential to benefit thousands of patients worldwide as well as healthcare systems and healthcare economy.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016051433.

Cardioversion in Non-Valvular Atrial Fibrillation

BACKGROUND

Atrial fibrillation is the most common type of cardiac arrhythmia and is associated with elevated rates of stroke, heart failure, hospital admission, and death. Its prevalence in the overall population is 1.5% to 2%. To convert atrial fibrillation to sinus rhythm, cardioversion is needed.

METHODS

This review is based on pertinent articles published from 2004 to December 2014 that were retrieved by a selective PubMed search employing the terms "atrial fibrillation" and "cardioversion."

RESULTS

In electrical cardioversion, a defibrillator is used to pass a pulse of current between two electrodes. In pharmacological cardioversion, antiarrhythmic drugs are given intravenously or orally. Electrical cardioversion results in sinus rhythm in more than 85% of patients; pharmacological cardioversion results in sinus rhythm in about 70% of patients with recent-onset atrial fibrillation. As a rule, cardioversion should be carried out only under effective therapeutic anticoagulation with heparin, a vitamin K antagonist, or a new oral anticoagulant drug. If atrial fibrillation has been present for more than 48 hours, cardioversion must be preceded by transesophageal echocardiography to rule out blood clot in the left atrium, or else the patient is pretreated with an anticoagulant drug for at least 3 weeks. As cardioversion can transiently impair left atrial pumping function, anticoagulation is usually maintained for 4 weeks after the procedure. The decision whether to continue anticoagulation beyond this point is based on the risk of stroke, as assessed with the CHA2DS2-VASc score.

CONCLUSION

The main risks of cardioversion-thrombo--embolism and clinically significant hemorrhage--occur in 1% of cases or less (in the first 30 days after treatment) if the procedure is carried out as recommended in therapeutic guidelines. Serious complications still occur, but they are rare.

A South Australian registry of biphasic cardioversions of atrial arrhythmias: efficacy and predictors of success

BACKGROUND

Restoration of sinus rhythm by biphasic cardioversion is an established strategy for patients in atrial arrhythmias. This study aimed to investigate the real-life practice of cardioversions throughout a local hospital to determine frequency and predictors of success and use of high energy (> 200 joules).

METHODS

Prospective analysis of consecutive biphasic cardioversions from 2009-2013. Patient demographics, medical history and cardioversion data were collected.

RESULTS

484 cardioversions from 379 patients were included in the final analysis. The majority (73%) of cardioversions were immediately successful after a single shock; overall success was 88% (1-5 shocks). Exploratory analyses revealed that single-shock success was significantly associated with lighter weight (OR 1.19, 95% CI 1.0-1.4, p<0.05). If a second shock was required, energy escalation was significantly associated with success (OR 3.11, 95% CI 1.43-6.77, p<0.05). Increasing weight was the strongest predictor of receiving high energy (10kg increase OR 1.43, 95% CI 1.13-1.81, p<0.05).

CONCLUSIONS

This prospective analysis reflects the real-life heterogeneous practice of biphasic cardioversions of atrial arrhythmias throughout a local hospital. These findings highlight the importance of first shock energy selection with careful consideration of patient weight. We emphasise the recommendation to escalate energy, highlighting the need for high-energy defibrillators in 'hard-to-cardiovert' patients.

[Therapy of atrial fibrillation in the critically ill]

Atrial fibrillation (AF) is the most common form of arrhythmia in the intensive care unit (ICU) and is associated with increased mortality. A total of five types of AF can be distinguished: initially diagnosed, paroxysmal, persistent, long-standing persistent and permanent AF. In addition to the initial treatment, antithrombotic therapy, rate and rhythm management can be used. The treatment of comorbidities is part of the patient management and for patients with increased risk of thromboembolic events anticoagulation is recommended. The simplest risk assessment scheme is the CHADS score. In the acute setting rate control is important. Direct current cardioversion is urgently recommended for patients with AF when hemodynamic instability is present even in patients with AF and pre-excitation in Wolff-Parkinson-White syndrome. Pharmacological cardioversion may be considered in patients with AF when hemodynamic stability is present. When choosing the antiarrhythmic agent for critically ill patients only amiodarone can be considered with some exceptions due to the specific contraindications.

Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

The goal of therapy for bradycardia or tachycardia is to rapidly identify and treat patients who are hemodynamically unstable or symptomatic due to the arrhythmia. Drugs or, when appropriate, pacing may be used to control unstable or symptomatic bradycardia. Cardioversion or drugs or both may be used to control unstable or symptomatic tachycardia. ACLS providers should closely monitor stable patients pending expert consultation and should be prepared to aggressively treat those with evidence of decompensation.