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American Journal of Physiology. Heart... Jun 2024Atrial fibrillation (AFib) is the most common cardiac rhythm disturbance, often treated via electrical cardioversion. Following rhythm restoration, a period of depressed...
Atrial fibrillation (AFib) is the most common cardiac rhythm disturbance, often treated via electrical cardioversion. Following rhythm restoration, a period of depressed mechanical function known as atrial stunning occurs, suggesting that defects in contractility occur in AFib and are revealed upon restoration of rhythm. This project aims to define the contractile remodeling that occurs in AFib. To assess contractile function, we used a canine atrial tachypacing model of induced AFib. Mass spectrometry analysis showed dysregulation of contractile proteins in samples from AFib compared to sinus rhythm atria. Atrial cardiomyocytes showed reduced force of contraction, decreased resting tension, and increased calcium sensitivity in skinned single cardiomyocyte studies. These alterations correlated with degradation of myofilament proteins including myosin heavy chain altering force of contraction, titin altering resting tension, and TnI altering calcium sensitivity. We measured degradation of other myofilament proteins including cMyBP-C and actininshowing significant degradation in the AFib samples compared to sinus rhythm atria. Many of the protein degradation products appeared as discrete cleavage products that are generated by calpain proteolysis. We assessed calpain activity and found it to be significantly increased. These results provide an understanding of the contractile remodeling that occurs in AFib and provide insight into the molecular explanation for atrial stunning and the increased risk of atrial thrombus and stroke in AFib.
PubMed: 38940916
DOI: 10.1152/ajpheart.00148.2024 -
Europace : European Pacing,... Jun 2024To describe the rationale, design, delivery and baseline characteristics of STEEER-AF (Stroke prevention and rhythm control Treatment: Evaluation of an Educational...
Design and deployment of the STEEER-AF trial to evaluate and improve guideline adherence: A cluster-randomised trial by the European Society of Cardiology and European Heart Rhythm Association.
AIMS
To describe the rationale, design, delivery and baseline characteristics of STEEER-AF (Stroke prevention and rhythm control Treatment: Evaluation of an Educational programme of the European Society of Cardiology [ESC] in a cluster-Randomised trial in patients with Atrial Fibrillation).
METHODS & RESULTS
STEEER-AF is a pragmatic trial designed to objectively and robustly determine whether guidelines are adhered to in routine practice, and evaluate a targeted educational programme for healthcare professionals. Seventy centres were randomised in 6 countries (France, Germany, Italy, Poland, Spain and United Kingdom; 2022-2023). STEEER-AF centres recruited 1732 patients with a diagnosis of atrial fibrillation (AF), with mean age 68.9 years (SD 11.7), CHA2DS2-VASc score 3.2 (SD 1.8) and 647 (37%) women. 843 patients (49%) were in AF and 760 (44%) in sinus rhythm at enrolment. Oral anticoagulant therapy was prescribed in 1,543 patients (89%), with the majority receiving direct oral anticoagulants (1,378; 89%). Previous cardioversion, antiarrhythmic drug therapy or ablation was recorded in 836 patients (48.3%). 551 patients (31.8%) were currently receiving an antiarrhythmic drug, and 446 (25.8%) were scheduled to receive a future cardioversion or ablation. The educational programme engaged 195 healthcare professionals across centres randomised to the intervention group, consisting of bespoke interactive online learning and reinforcement activities, supported by national expert trainers.
CONCLUSION
The STEEER-AF trial was successfully deployed across six European countries to investigate guideline adherence in real-world practice, and evaluate if a structured educational programme for healthcare professionals can improve patient-level care.
REGISTRATION
Clinicaltrials.gov NCT04396418.
PubMed: 38940494
DOI: 10.1093/europace/euae178 -
Journal of Arrhythmia Jun 2024A 26-year-old man with long QT syndrome (LQTS) underwent subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. The patient exhibited sinus...
A 26-year-old man with long QT syndrome (LQTS) underwent subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. The patient exhibited sinus bradycardia relative to his age. The heart rate decreased, and the QT interval became longer with the administration of β-blockers, the first-line therapy for LQTS. The patient experienced frequent S-ICD discharges. Subsequently, a single-chamber pacemaker was implanted, and the 12-lead electrocardiogram showed atrial pacing and ventricular sensing at 60 beats per minute with a shorter QTc interval. After converting to "double-device therapy," the patient did not experience any ventricular arrhythmia events.
PubMed: 38939789
DOI: 10.1002/joa3.13027 -
Journal of Arrhythmia Jun 2024Recent evidence suggests an elevated risk of cognitive impairment and dementia in individuals with atrial fibrillation (AF), irrespective of stroke occurrence. AF, known... (Review)
Review
BACKGROUND
Recent evidence suggests an elevated risk of cognitive impairment and dementia in individuals with atrial fibrillation (AF), irrespective of stroke occurrence. AF, known to reduce brain perfusion, particularly through silent cerebral ischemia, underscores the intricate relationship between cardiac and cerebral health. The heart plays a crucial role in supporting normal brain function, and rhythm control, a standard AF treatment, has demonstrated enhancements in brain perfusion. This systematic review aimed to examine published data concerning the influence of rhythm control on brain perfusion in patients with atrial fibrillation.
METHODS
A systematic search for relevant studies was carried out in Scopus, PubMed, Cochrane Reviews, ProQuest, and EBSCOhost, spanning from their inception until April 30, 2023. Studies that specifically examined brain perfusion following any form of rhythm control in atrial fibrillation were included in the review.
RESULTS
The review encompassed 10 studies involving 436 participants. Among these, six utilized electrical cardioversion for rhythm control. The majority (8 out of 10) demonstrated that restoring sinus rhythm markedly enhances brain perfusion. In one of the two remaining studies, notable improvement was observed specifically in a region closely linked to cognition. Additionally, both studies reporting data on the Mini-Mental State Examination (MMSE) showed a consistent and significant increase in scores following rhythm control.
CONCLUSION
Successful rhythm control in AF emerges as a significant contributor to enhanced brain perfusion, suggesting a potential therapeutic avenue for reducing cognitive impairment incidence. However, further validation through larger prospective studies and randomized trials is warranted.
PubMed: 38939785
DOI: 10.1002/joa3.13056 -
Journal of Arrhythmia Jun 2024The concept of ablation index (AI) was introduced to evaluate radiofrequency (RF) ablation lesions. It is calculated from power, contact force (CF), and RF duration....
BACKGROUND
The concept of ablation index (AI) was introduced to evaluate radiofrequency (RF) ablation lesions. It is calculated from power, contact force (CF), and RF duration. However, other factors may also affect the quality of ablation lesions. To examine the difference in RF lesions made during sinus rhythm (SR) and atrial fibrillation (AF).
METHODS
Sixty patients underwent index pulmonary vein isolation during SR ( = 30, SR group) or AF ( = 30, AF group). All ablations were performed with a power of 50 W, a targeted CF of 5-15 g, and AI of 400-450 using Thermocool Smarttouch SF. The CF, AI, RF duration, temperature rise (Δtemp), impedance drop (Δimp), and the CF stability of each ablation point quantified as the standard deviation of the CF (CF-SD) were compared between the two groups.
RESULTS
A total of 3579 ablation points were analyzed, which included 1618 and 1961 points in the SR and the AF groups, respectively. Power, average CF, RF duration per point, and the resultant AI (389 ± 59 vs. 388 ± 57) were similar for the two rhythms. However, differences were seen in the CF-SD (3.5 ± 2.2 vs. 3.8 ± 2.1 g, < .01), Δtemp (3.8 ± 1.3 vs. 4.0 ± 1.3°C, < .005), and Δimp (10.3 ± 5.8 vs. 9.4 ± 5.4 Ω, < .005).
CONCLUSIONS
Despite similar AI, various RF parameters differed according to the underlying atrial rhythm. Ablation delivered during SR demonstrated less CF variability and temperature increase and greater impedance drop than during AF.
PubMed: 38939764
DOI: 10.1002/joa3.13025 -
JACC. Advances May 2024The prognostic impact of catheter ablation (CA) of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) patients has not yet been satisfactorily elucidated.
BACKGROUND
The prognostic impact of catheter ablation (CA) of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) patients has not yet been satisfactorily elucidated.
OBJECTIVES
The aim of the study was to assess the impact of CA of AF on clinical outcomes in a large cohort of HCM patients.
METHODS
In this retrospective multicenter study, 555 HCM patients with AF were enrolled, 140 undergoing CA and 415 receiving medical therapy. 1:1 propensity score matching led to the inclusion of 226 patients (113 medical group, 113 intervention group) in the final analysis. The primary outcome was a composite of all-cause mortality, heart transplant and acute heart failure exacerbations. Secondary outcomes included AF recurrence and transition to permanent AF. Additionally, an inverse probability weighted (IPW) model was examined.
RESULTS
At propensity score matching analysis, after a median follow-up of 58.1 months, the primary endpoint occurred in 29 (25.7%) patients in intervention group vs 42 (37.2%) in medical group ( = 0.9). Thromboembolic strokes and major arrhythmic events in intervention vs medical group were 9.7% vs 7.1% ( = 0.144) and 4.4 vs 8.0% ( = 0.779), respectively. Fewer patients in intervention vs medical group experienced AF recurrences (63.7% vs 84.1%, = 0.001) and transition to permanent AF pattern (20.4% vs 33.6%, = 0.026). IPW analysis showed consistent results. Severe complications related to CA were uncommon (0.7%).
CONCLUSIONS
After 5 years of follow-up, CA did not improve major adverse cardiac outcomes in a large cohort of patients with HCM and AF. Nevertheless, CA seems to facilitate the maintenance of sinus rhythm and slow the progression to permanent AF, without significant safety concerns.
PubMed: 38939638
DOI: 10.1016/j.jacadv.2024.100899 -
JACC. Advances May 2024
PubMed: 38939637
DOI: 10.1016/j.jacadv.2024.100902 -
Cureus May 2024Reverse takotsubo cardiomyopathy is a rare variant of the classic stress-induced takotsubo cardiomyopathy. It is associated with transient left ventricular (LV) systolic...
Reverse takotsubo cardiomyopathy is a rare variant of the classic stress-induced takotsubo cardiomyopathy. It is associated with transient left ventricular (LV) systolic dysfunction characterized by basal hypokinesis and apical hyperkinesis. We present a case of a 27-year-old woman who presented to an outside facility for a scheduled cesarean section and developed perioperative chest tightness, hypoxemia, and hypotension. Her electrocardiogram (ECG) showed sinus rhythm with marked ST segment depressions in leads V4-V6. High sensitivity troponin was elevated to 474 ng/L. Transthoracic echocardiography revealed an LV ejection fraction of 52% (Simpson's) with hypokinesis of the basal myocardial segments and hyperdynamic systolic function of the apical segments. Subsequent coronary angiography showed angiographically normal epicardial coronaries. Left ventriculography showed ballooning of the basal segments with apical hyperkinesis. She was subsequently diagnosed with reverse takotsubo cardiomyopathy and managed conservatively with beta-blockers. In this case, we highlight the need for collaboration between the cardiology and obstetric teams for tailored management strategies to ensure the well-being of both mother and baby.
PubMed: 38939286
DOI: 10.7759/cureus.61225 -
Heart Rhythm Jun 2024Heart Rate Score (HRSc), the percent of atrial depolarizations in the largest paced/sensed 10-bpm histogram bin recorded in cardiac devices, is associated with several...
BACKGROUND
Heart Rate Score (HRSc), the percent of atrial depolarizations in the largest paced/sensed 10-bpm histogram bin recorded in cardiac devices, is associated with several adverse outcomes but it remains uncertain if HRSc independently predicts atrial high-rate episodes (AHREs) in patients with sinus node dysfunction (SND) undergoing pacemaker (PM) implantation.
OBJECTIVE
To determine if initial HRSc post-PM implant predicts new-onset AHREs in patients with SND.
METHODS
Patients had Boston Scientific PMs implanted for SND from 2012-2021 at Cleveland Clinic, University of Occupational and Environmental Health, Japan, Kyushu Rosai Hospital, and JCHO Kyushu Hospital. Patients were excluded if they had atrial fibrillation before PM implant or AHREs within 3-months post-implant. Subsequent AHREs post-implant were evaluated and correlated with HRSc.
RESULTS
Over 48.9 (IQR 25.7-50.4) months, 130 consecutive PM patients (76±10 years, 40% male) had a median initial HRSc of 74(57-86)%. AHREs defined by >1%, >6h/day burden, and ATR events>24h developed in 27/130(21%), 15/130(12%), and 9/130(7%), respectively. For each definition, patients with HRSc≥80% had higher occurrence of AHREs than those with HRSc<80% (both p=0.008, log-rank test). After adjusting for age, race, comorbidities, left ventricular ejection fraction, left atrial diameter, and cumulative %RA/RV pacing, initial HRSc ≥80% (HR:3.33, 95% CI:1.35-8.18; P=0.009) and male sex (HR:2.59, 95% CI:1.06-6.33; P=0.04) independently predicted AHREs.
CONCLUSION
HRSc≥80% is associated with new-onset, device-determined AHREs for patients undergoing PM implant for SND. HRSc may have prognostic and therapeutic implications.
PubMed: 38936446
DOI: 10.1016/j.hrthm.2024.06.046 -
Journal of Applied Physiology... Jun 2024In a 77-year-old former world-record holding male marathoner (2:08:33.6) this study sought to investigate the impact of lifelong intensive endurance exercise on cardiac...
In a 77-year-old former world-record holding male marathoner (2:08:33.6) this study sought to investigate the impact of lifelong intensive endurance exercise on cardiac structure, function and the trajectory of functional capacity (determined by maximal oxygen consumption, V̇Omax) throughout the adult lifespan. As a competitive runner, our athlete (DC) reported performing up to 150-300 miles/wk of moderate-to-vigorous exercise, and sustained 10-15 hours/wk of endurance exercise after retirement from competition. DC underwent maximal cardiopulmonary exercise testing in 1970 (aged 27yrs), 1991 (aged 49yrs) and 2020 (aged 77yrs) to determine V̇Omax. At his evaluation in 2020, DC also underwent comprehensive cardiac assessments including resting echocardiography, and resting and exercise cardiac magnetic resonance to quantify cardiac structure and function at rest and during peak supine exercise. DC's V̇Omax showed minimal change from 27yrs (69.7mL/kg/min) to 49yrs (68.1mL/kg/min), although it eventually declined by 36% by the age of 77yrs (43.6mL/kg/min). DC's V̇Omax at 77yrs, was equivalent to the 50 percentile for healthy 20-29 year-old males and 2.4 times the requirement for maintaining functional independence. This was partly due to marked ventricular dilatation (left-ventricular end-diastolic volume: 273mLs), which facilitates a large peak supine exercise stroke volume (200mLs) and cardiac output (22.2L/min). However, at the age of 78 years, DC developed palpitations and fatigue, and was found to be in atrial fibrillation requiring ablation procedures to revert his heart to sinus rhythm. Overall, this life study of a world champion marathon runner exemplifies the substantial benefits and potential side effects of many decades of intense endurance exercise.
PubMed: 38935800
DOI: 10.1152/japplphysiol.00070.2024