Rate-Control or Rhythm-Contol: Where do we stand?

Atrial fibrillation is the most common sustained rhythm disturbance and its prevalence is increasing worldwide due to the progressive aging of the population. Current guidelines clearly depict the gold standard management of acute symptomatic atrial fibrillation but the best-long term approach for first or recurrent atrial fibrillation is still debated with regard to quality of life, risk of new hospitalizations, and possible disabling complications, such as thromboembolic stroke, major bleeds and death. Some authors propose that regaining sinus rhythm in all cases, thus re-establishing a physiologic cardiac function not requiring a prolonged antithrombotic therapy, avoids the threat of intracranial or extracranial haemorrhages due to Vitamin K antagonists or aspirin. On the contrary, advocates of a rate control approach with an accurate antithrombotic prophylaxis propose that such a strategy may avoid the risk of cardiovascular and non cardiovascular side effects related to antiarrhythmic drugs. This review aims to explore the state of our knowledge in order to summarize evidences and issues that need to be furthermore clarified

Generalized Langevin equation with shear flow and its fluctuation-dissipation theorems derived from a Caldeira-Leggett Hamiltonian

We provide a first-principles derivation of the Langevin equation with shear flow and its corresponding fluctuation-dissipation theorems. Shear flow of simple fluids has been widely investigated by numerical simulations. Most studies postulate a Markovian Langevin equation with a simple shear drag term \`a la Stokes. However, this choice has never been justified from first principles. We start from a particle-bath system described by a classical Caldeira-Leggett Hamiltonian modified by adding a term proportional to the strain-rate tensor according to Hoover's DOLLS method, and we derive a generalized Langevin equation for the sheared system. We then compute, analytically, the noise time-correlation functions in different regimes. Based on the intensity of the shear-rate, we can distinguish between close-to-equilibrium and far-from-equilibrium states. According to the results presented here, the standard, simple and Markovian form of the Langevin equation with shear flow postulated in the literature is valid only in the limit of extremely weak shear rates compared to the effective vibrational temperature of the bath. For even marginally higher shear rates, the (generalized) Langevin equation is strongly non-Markovian and non-trivial fluctuation-dissipation theorems are derived

Pentamidine rescues contractility and rhythmicity in a Drosophila model of myotonic dystrophy heart dysfunction

Up to 80% of individuals with myotonic dystrophy type 1 (DM1) will develop cardiac abnormalities at some point during the progression of their disease, the most common of which is heart blockage of varying degrees. Such blockage is characterized by conduction defects and supraventricular and ventricular tachycardia, and carries a high risk of sudden cardiac death. Despite its importance, very few animal model studies have focused on the heart dysfunction in DM1. Here, we describe the characterization of the heart phenotype in a Drosophila model expressing pure expanded CUG repeats under the control of the cardiomyocyte-specific driver GMH5-Gal4. Morphologically, expression of 250 CUG repeats caused abnormalities in the parallel alignment of the spiral myofibrils in dissected fly hearts, as revealed by phalloidin staining. Moreover, combined immunofluorescence and in situ hybridization of Muscleblind and CUG repeats, respectively, confirmed detectable ribonuclear foci and Muscleblind sequestration, characteristic features of DM1, exclusively in flies expressing the expanded CTG repeats. Similarly to what has been reported in humans with DM1, heart-specific expression of toxic RNA resulted in reduced survival, increased arrhythmia, altered diastolic and systolic function, reduced heart tube diameters and reduced contractility in the model flies. As a proof of concept that the fly heart model can be used for in vivo testing of promising therapeutic compounds, we fed flies with pentamidine, a compound previously described to improve DM1 phenotypes. Pentamidine not only released Muscleblind from the CUG RNA repeats and reduced ribonuclear formation in the Drosophila heart, but also rescued heart arrhythmicity and contractility, and improved fly survival in animals expressing 250 CUG repeats

Rate-Control or Rhythm-Control: Where do we stand?

Atrial fibrillation is the most common sustained rhythm disturbance and its prevalence is increasing worldwide due to the progressive aging of the population. Current guidelines clearly depict the gold standard management of acute symptomatic atrial fibrillation but the best-long term approach for first or recurrent atrial fibrillation is still debated with regard to quality of life, risk of new hospitalizations, and possible disabling complications, such as thromboembolic stroke, major bleeds and death. Some authors propose that regaining sinus rhythm in all cases, thus re-establishing a physiologic cardiac function not requiring a prolonged antithrombotic therapy, avoids the threat of intracranial or extracranial haemorrhages due to Vitamin K antagonists or aspirin. On the contrary, advocates of a rate control approach with an accurate antithrombotic prophylaxis propose that such a strategy may avoid the risk of cardiovascular and non cardiovascular side effects related to antiarrhythmic drugs. This review aims to explore the state of our knowledge in order to summarize evidences and issues that need to be furthermore clarified

Characteristics and Outcome of Patients with or without Previous Implantable Cardioverter Defibrillator Interventions Undergoing Ablation for Ventricular Tachycardia

Background: Catheter ablation (CA) is a well-established treatment in patients with ventricular tachycardia and appropriate implantable cardioverter defibrillator (ICD) therapies. Methods: We enrolled 57 consecutive carriers of ICD undergoing CA for electrical storm (ES). Our aim was to investigate differences in clinical, device-related, and electroanatomic features among patients who had history of appropriate ICD interventions before the ES compared to those who had not. The primary endpoint was a composite of death from any cause and recurrences of sustained VT, ventricular fibrillation, appropriate ICD therapy, or ES. Results: During a median follow up of 39 months, 28 patients (49%) met the primary endpoint. Those with previous ICD interventions had a higher prevalence of late potentials and a greater unipolar low-voltage area at electroanatomic mapping. Patients who met the primary endpoint had a higher prevalence of ATP/shock episodes preceding the ES event. At Cox regression analysis, non-ischemic dilated cardiomyopathy (NIDCM), QRS duration, and previous ATP and/or shock before the ES were associated with arrhythmic recurrences and/or death. At multivariate analysis, NIDCM and previous shock were associated with arrhythmic recurrences and/or death. Conclusions: A history of recurrent ICD therapies predicts worse outcomes when CA is needed because of ES. Although more studies are needed to definitively address this question, our data speak in support of an early referral for CA of ES

Cardiac pacemaker battery discharge after external electrical cardioversion for broad QRS Complex Tachycardia

External electrical cardioversion or defibrillation may be necessary in patients with implanted cardiac pacemaker (PM) or implantable cardioverter defibrillator (ICD). Sudden discharge of high electrical energy employed in direct current (DC) transthoracic countershock may damage the PM/ICD system resulting in a series of possible device malfunctions. For this reason, when defibrillation or cardioversion must be attempted in a patient with a PM or ICD, some precautions should be taken, particularly in PM dependent patients, in order to prevent damage to the device. We report the case of a 76-year-old woman with a dual chamber PM implanted in the right subclavicular region, who received two consecutive transthoracic DC shocks to treat haemodynamically unstable broad QRS complex tachycardia after cardiac surgery performed with a standard sternotomic approach. Because of the sternal wound and thoracic drainage tubes together with the severe clinical compromise, the anterior paddle was positioned near the pulse generator. At the following PM test, a complete battery discharge was detected

Cardiac Pacemaker Battery Discharge After External Electrical Cardioversion for Broad QRS Complex Tachycardia

External electrical cardioversion or defibrillation may be necessary in patients with implanted cardiac pacemaker (PM) or implantable cardioverter defibrillator (ICD). Sudden discharge of high electrical energy employed in direct current (DC) transthoracic countershock may damage the PM/ICD system resulting in a series of possible device malfunctions. For this reason, when defibrillation or cardioversion must be attempted in a patient with a PM or ICD, some precautions should be taken, particularly in PM dependent patients, in order to prevent damage to the device. We report the case of a 76-year-old woman with a dual chamber PM implanted in the right subclavicular region, who received two consecutive transthoracic DC shocks to treat haemodynamically unstable broad QRS complex tachycardia after cardiac surgery performed with a standard sternotomic approach. Because of the sternal wound and thoracic drainage tubes together with the severe clinical compromise, the anterior paddle was positioned near the pulse generator. At the following PM test, a complete battery discharge was detected

Long-term clinical impact of permanent pacemaker implantation in patients undergoing transcatheter aortic valve implantation: a systematic review and meta-analysis

AIMS: The aims of this study is to assess by an updated meta-analysis the clinical outcomes related to permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI) at long-term (≥12 months) follow-up (LTF). METHODS AND RESULTS: A comprehensive literature research was performed on PubMed and EMBASE. The primary endpoint was all-cause death. Secondary endpoints were rehospitalization for heart failure, stroke, and myocardial infarction. A subgroup analysis was performed according to the Society of Thoracic Surgeon-Predicted Risk of Mortality (STS-PROM) score. This study is registered with PROSPERO (CRD42021243301). A total of 51 069 patients undergoing TAVI from 31 observational studies were included. The mean duration of follow-up was 22 months. At LTF, PPI post-TAVI was associated with a higher risk of all-cause death [risk ratio (RR) 1.18, 95% confidence interval (CI) 1.10-1.25; P < 0.001] and rehospitalization for heart failure (RR 1.32, 95% CI 1.13-1.52; P < 0.001). In contrast, the risks of stroke and myocardial infarction were not affected. Among the 20 studies that reported procedural risk, the association between PPI and all-cause death risk at LTF was statistically significant only in studies enrolling patients with high STS-PROM score (RR 1.25, 95% CI 1.12-1.40), although there was a similar tendency of the results in those at medium and low risk. CONCLUSION: Patients necessitating PPI after TAVI have a higher long-term risk of all-cause death and rehospitalization for heart failure as compared to those who do not receive PPI

Should we perform systematic electrophysiological study in Steinert's disease?

Myotonic dystrophy type 1 (Steinert's disease) is a multisystem disorder with autosomal dominant inheritance. This disease is associated with the presence of an abnormal expansion of a cytosine thymine-guanine (CTG) trinucleotide repeat on chromosome 19q13.3. Because of rhythmic complications, the place for systematic electrophysiological study (EPS) has to be discussed

Atrial High-Rate Episodes and Subclinical Atrial Fibrillation: State of the Art and Clinical Questions with Complex Solutions

Atrial high-rate episodes (AHREs) and subclinical atrial fibrillation (AF) are frequently registered in asymptomatic patients with cardiac implantable electronic devices (CIEDs) and insertable cardiac monitors (ICMs). While an increased risk of thromboembolic events (e.g., stroke) and benefits from anticoagulation have been widely assessed in the setting of clinical AF, concerns persist about optimal clinical management of subclinical AF/AHREs. As a matter of fact, an optimal threshold of subclinical episodes’ duration to predict stroke risk is still lacking and recently published randomized clinical trials assessing the impact of anticoagulation on thromboembolic events in this specific setting have shown contrasting results. The aim of this review is to summarize current evidence regarding classification and clinical impact of subclinical AF/AHREs and to discuss the latest evidence regarding the potential benefit of anticoagulation in this setting, highlighting which clinical questions are still unanswered