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Cardiology Research Apr 2014Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. Cardioversion for AF may be performed by either using direct current (DC) shock (electrical...
Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. Cardioversion for AF may be performed by either using direct current (DC) shock (electrical cardioversion) or using drugs (chemical cardioversion). Here we report a case of a patient with heart failure and AF, who reverted to the normal sinus rhythm on correction of hyperkalemia (electrogenic cardioversion). The patient maintained sinus rhythm during follow-up. We highlight the importance of serum potassium in patients with AF.
PubMed: 28392880
DOI: 10.14740/cr334w -
F1000Research 2017Atrial fibrillation (AF) remains a difficult management problem. The restoration and maintenance of sinus rhythm-rhythm control therapy-can markedly improve symptoms and... (Review)
Review
Atrial fibrillation (AF) remains a difficult management problem. The restoration and maintenance of sinus rhythm-rhythm control therapy-can markedly improve symptoms and haemodynamics for patients who have paroxysmal or persistent AF, but some patients fare well with rate control alone. Sinus rhythm can be achieved with anti-arrhythmic drugs or electrical cardioversion, but the maintenance of sinus rhythm without recurrence is more challenging. Catheter ablation of the AF triggers is more effective than anti-arrhythmic drugs at maintaining sinus rhythm. Whilst pulmonary vein isolation is an effective strategy, other ablation targets are being evaluated to improve sinus rhythm maintenance, especially in patients with chronic forms of AF. Previously extensive ablation strategies have been used for patients with persistent AF, but a recent trial has shown that pulmonary vein isolation without additional ablation lesions is associated with outcomes similar to those of more extensive ablation. This has led to an increase in catheter-based technology to achieve durable pulmonary vein isolation. Furthermore, a combination of anti-arrhythmic drugs and catheter ablation seems useful to improve the effectiveness of rhythm control therapy. Two large ongoing trials evaluate whether a modern rhythm control therapy can improve prognosis in patients with AF.
PubMed: 29043080
DOI: 10.12688/f1000research.11061.1 -
Heart Rhythm O2 Jun 2022Atypical left atrial flutter (AFL) may be macroreentrant or spatially localized. The relationship between the critical isthmus (CI) for localized reentry with sinus...
BACKGROUND
Atypical left atrial flutter (AFL) may be macroreentrant or spatially localized. The relationship between the critical isthmus (CI) for localized reentry with sinus rhythm (SR) conduction slowing has not been systematically examined.
OBJECTIVE
To examine the correlation between CI sites for localized AFL (L-AFL) and deceleration zones (DZ) identified by isochronal late activation mapping (ILAM) during baseline rhythm.
METHODS
Patients with localized AFL who underwent high-density activation mapping of both SR and AFL were retrospectively analyzed. L-AFL was defined as reentry restricted to 2 wall segments of the left atrium. CI was defined by activation mapping and sites of successful termination during ablation. DZ, defined as >3 isochrones within 1 cm radius during baseline rhythm, were correlated to the locations of the CI.
RESULTS
Thirty-one consecutive patients that underwent detailed sinus rhythm and AFL high-density activation maps were analyzed at 3 centers. A mean 4060 ± 3275 and 6209 ± 8656 points were collected in ILAM and AFL activation maps, respectively. At least 1 DZ (1.7 ± 0.77) was identified in all patients. ILAM showed 3.27 ± 0.52 isochrones per DZ (168 ± 32 ms), and co-localized to CI sites at a distance of 6.7 ± 3 mm. A total of 34% ± 14% of the AFL cycle length was contained within 0.5 cm of the DZ.
CONCLUSIONS
In patients with L-AFL, CI co-localized with DZ during baseline rhythm, suggesting that DZ mapping during SR may yield candidate targets for ablation as an adjunct to pulmonary vein isolation to prevent a subtype of AFL.
PubMed: 35734295
DOI: 10.1016/j.hroo.2022.03.003 -
The Journal of Physiology May 2016Sudden cardiac death (SCD) is the result of a change of cardiac activity from normal (typically sinus) rhythm to a rhythm that does not pump adequate blood to the brain.... (Review)
Review
Sudden cardiac death (SCD) is the result of a change of cardiac activity from normal (typically sinus) rhythm to a rhythm that does not pump adequate blood to the brain. The most common rhythms leading to SCD are ventricular tachycardia (VT) or ventricular fibrillation (VF). These result from an accelerated ventricular pacemaker or ventricular reentrant waves. Despite significant efforts to develop accurate predictors for the risk of SCD, current methods for risk stratification still need to be improved. In this article we briefly review current approaches to risk stratification. Then we discuss the mathematical basis for dynamical transitions (called bifurcations) that may lead to VT and VF. One mechanism for transition to VT or VF involves a perturbation by a premature ventricular complex (PVC) during sinus rhythm. We describe the main mechanisms of PVCs (reentry, independent pacemakers and abnormal depolarizations). An emerging approach to risk stratification for SCD involves the development of individualized dynamical models of a patient based on measured anatomy and physiology. Careful analysis and modelling of dynamics of ventricular arrhythmia on an individual basis will be essential in order to improve risk stratification for SCD and to lay a foundation for personalized (precision) medicine in cardiology.
Topics: Animals; Arrhythmias, Cardiac; Death, Sudden, Cardiac; Heart Ventricles; Humans; Risk Factors
PubMed: 26660287
DOI: 10.1113/JP270535 -
The Egyptian Heart Journal : (EHJ) :... Nov 2023Electroconvulsive therapy (ECT) is a therapy used to treat refractory mental health conditions, ranging from depression to catatonia, and it has gained renewed... (Review)
Review
BACKGROUND
Electroconvulsive therapy (ECT) is a therapy used to treat refractory mental health conditions, ranging from depression to catatonia, and it has gained renewed prominence in practice and the literature of late. Given that ECT involves the application of direct current to the body, there exists a risk of a change in cardiac rhythm during therapy. When atrial fibrillation is induced, ECT carries a potential risk of stroke. These risks have not been previously analyzed or summarized in the literature to allow physicians to make educated decisions about periprocedural risk and anticoagulation needs.
METHODS
To better describe this risk, the authors reviewed PubMed for articles that described the post-ECT cardioversion of AF to sinus rhythm, new development of AF post-ECT, and new stroke after either rhythm change.
RESULTS
Included were 14 studies describing 19 unique patients. Most patients had no rhythm change during at least one of many ECT sessions. Five patients converted from AF to sinus rhythm during at least one session, while AF followed ECT in seventeen patients during at least one ECT session. Four patients experienced both ECT-related cardioversion from AF to sinus rhythm as well as conversion from sinus rhythm to AF. Although no patients with a rhythm change experienced a stroke, one unanticoagulated patient who remained in AF developed a stroke post-ECT.
CONCLUSIONS
Electroconvulsive therapy is demonstrated to be associated with rhythm changes-from atrial fibrillation to sinus rhythm as well as from sinus rhythm to atrial fibrillation. Thus, stroke risk during and after ECT remains a possibility. The anticoagulation of patients with AF who undergo ECT should be based on individual stroke risk factors, using validated stroke risk models, rather than prescribed routinely.
PubMed: 38010438
DOI: 10.1186/s43044-023-00409-7 -
Arrhythmia & Electrophysiology Review Apr 2022Progression of AF is accompanied by structural and electrical remodelling, resulting in complex electrical conduction disorders. This is defined as electropathology and... (Review)
Review
Progression of AF is accompanied by structural and electrical remodelling, resulting in complex electrical conduction disorders. This is defined as electropathology and it increases with the progression of AF. The severity of electropathology, thus, defines the stage of AF and is a major determinant of effectiveness of AF therapy. As specific features of AF-related electropathology are still unknown, it is essential to first quantify the electrophysiological properties of atrial tissue and then to examine the inter- and intra-individual variation during normal sinus rhythm. Comparison of these parameters between patients with and without a history of AF unravels quantified electrophysiological features that are specific to AF patients. This can help to identify patients at risk for early onset or progression of AF. This review summarises current knowledge on quantified features of atrial electrophysiological properties during sinus rhythm and discusses its relevance in identifying AF-related electropathology.
PubMed: 35846426
DOI: 10.15420/aer.2022.03 -
International Journal of Molecular... Aug 2023Atrial fibrillation (AF) is a prevalent cardiac condition predominantly affecting older adults, characterized by irregular heartbeat rhythm. The condition often leads to... (Review)
Review
Atrial fibrillation (AF) is a prevalent cardiac condition predominantly affecting older adults, characterized by irregular heartbeat rhythm. The condition often leads to significant disability and increased mortality rates. Traditionally, two therapeutic strategies have been employed for its treatment: heart rate control and rhythm control. Recent clinical studies have emphasized the critical role of early restoration of sinus rhythm in improving patient outcomes. The persistence of the irregular rhythm allows for the progression and structural remodeling of the atria, eventually leading to irreversible stages, as observed clinically when AF becomes permanent. Cardioversion to sinus rhythm alters this progression pattern through mechanisms that are still being studied. In this review, we provide an in-depth analysis of the pathophysiological mechanisms responsible for maintaining AF and how they are modified during sinus rhythm restoration using existing therapeutic strategies at different stages of clinical investigation. Moreover, we explore potential future therapeutic approaches, including the promising prospect of gene therapy.
Topics: Humans; Aged; Atrial Fibrillation; Heart Rate; Tics; Heart Diseases; Heart Atria
PubMed: 37629037
DOI: 10.3390/ijms241612859 -
Journal of the American College of... Apr 2010The goal of this study was to evaluate the relationship between the presence of sinus rhythm and outcomes in patients with a history of congestive heart failure (CHF)... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
The goal of this study was to evaluate the relationship between the presence of sinus rhythm and outcomes in patients with a history of congestive heart failure (CHF) and atrial fibrillation (AF).
BACKGROUND
The value of sinus rhythm maintenance in patients with AF and heart failure (HF) is uncertain.
METHODS
A total of 1,376 patients with AF, ejection fraction < or =35%, and heart failure symptoms were randomized to a rhythm- or rate-control strategy. Detailed efficacy analyses were used to evaluate the independent effects of treatment strategy and the presence of sinus rhythm on cardiovascular outcomes.
RESULTS
Overall, 445 (32%) patients died and 402 (29%) experienced worsening HF. The rhythm-control strategy was not predictive of cardiovascular mortality (hazard ratio [HR]: 0.90, 95% confidence interval [CI]: 0.70 to 1.16; p = 0.41), all-cause death (HR: 0.86, 95% CI: 0.69 to 1.08; p = 0.19), or worsening HF (HR: 0.86, 95% CI: 0.68 to 1.10; p = 0.23). In analyses devised to isolate the effect of underlying rhythm, sinus rhythm was not associated with cardiovascular mortality [HR: 1.22, 95% CI: 0.80 to 1.87; p = 0.35), total mortality [HR: 1.11, 95% CI: 0.78 to 1.58; p = 0.57), or worsening HF [HR: 0.62, 95% CI: 0.37 to 1.02; p = 0.059).
CONCLUSIONS
A rhythm-control strategy or the presence of sinus rhythm are not associated with better outcomes in patients with AF and CHF.
Topics: Aged; Atrial Fibrillation; Electrocardiography; Female; Heart Failure; Heart Rate; Humans; Male
PubMed: 20413028
DOI: 10.1016/j.jacc.2010.01.023 -
Heart Rhythm Apr 2024Sinus rhythm activation time is useful to assess infarct border zone substrate.
BACKGROUND
Sinus rhythm activation time is useful to assess infarct border zone substrate.
OBJECTIVE
We sought to further investigate sinus activation in ventricular tachycardia (VT).
METHODS
Canine postinfarction data were analyzed retrospectively. In each experiment, an infarct was created in the left ventricular wall by left anterior descending coronary artery ligation. At 3 to 5 days after ligation, 196-312 bipolar electrograms were recorded from the anterior left ventricular epicardium overlapping the infarct border zone. Sustained monomorphic VT was induced by premature electrical stimulation in 50 experiments and was noninducible in 43 experiments. Acquired sinus rhythm and VT electrograms were marked for electrical activation time, and activation maps of representative sinus rhythm and VT cycles were constructed. The sinus rhythm activation signature was defined as the cumulative number of multielectrode recording sites that had activated per time epoch, and its derivative was used to predict VT inducibility and to define the sinus rhythm slow/late activation sequence.
RESULTS
Plotting mean activation signature derivative, a best cutoff value was useful to separate experiments with reentrant VT inducibility (sensitivity, 42/50) vs noninducibility (specificity, 39/43), with an accuracy of 81 of 93. For the 50 experiments with inducible VT, recording sites overlying a segment of isochrone encompassing the sinus rhythm slow/late activation sequence spanned the VT isthmus location in 32 cases (64%), partially spanned it in 15 cases (30%), but did not span it in 3 cases (6%).
CONCLUSION
The sinus rhythm activation signature derivative is assistive to differentiate substrate supporting reentrant VT inducibility vs noninducibility and to identify slow/late activation for targeting isthmus location.
PubMed: 38677360
DOI: 10.1016/j.hrthm.2024.04.082