Heart Failure and Sudden Death in Patients With Tachycardia-Induced Cardiomyopathy and Recurrent Tachycardia

Decreased plasma cell-free mitochondrial DNA may be a new biomarker of tachycardia-induced cardiomyopathy in patients with atrial fibrillation

OBJECTIVES

To determine cell-free mitochondrial DNA (mt-cfDNA) levels in tachycardia-induced cardiomyopathy (TIC) and non-TIC among atrial fibrillation (AF) cases.

BACKGROUNDS

TIC is a reversible cardiomyopathy resulting from tachyarrhythmias, such as AF. The exact cause of TIC is not fully understood, but mitochondrial dysfunction has been reported in a variety of cardiomyopathies and may be involved in TIC as well. AF is recognized to be associated with systemic inflammation, and studies have shown that in patients with AF have elevated levels of mt-cfDNA increased, and this increase is linked to systemic inflammation.

METHODS

We enrolled 67 patients with TIC (TIC group) and 671 patients without TIC (non-TIC group), who underwent catheter ablation for AF at our hospital between November 2009 and September 2016 and did not meet the exclusion criteria. We performed quantitative PCR analysis of plasma mt-cfDNA and nuclear-cfDNA and compared clinical factors and these measurements between the two groups.

RESULTS

Levels of mt-cfDNA were significantly lower in the TIC group than in the non-TIC group (1110.01 vs. 1918.71 copies/μg plasma, P = 0.027), while levels of nuclear-cfDNA were comparable between these two groups. In particular, mt-cfDNA (P = 0.0003, odds ratio [OR] 2.54), non-paroxysmal AF (P < 0.0001, OR 3.07), and diabetes mellitus (P = 0.006, OR 2.36) were identified as independent factors associated with TIC.

CONCLUSION

There are lower mt-cfDNA in TIC, and decreased plasma levels of circulating mt-cfDNA may be a new biomarker and involve in related mechanisms for AF associated TIC.

CONDENSED ABSTRACT

Tachycardia-induced cardiomyopathy (TIC) is a reversible cardiomyopathy caused by tachyarrhythmias, such as atrial fibrillation (AF) tachycardia. The pathogenesis of TIC remains incompletely understood, and there is currently no method to predict its development in patients. In this study, we show that cell-free mitochondrial DNA (mt-cfDNA) levels were significantly lower in the TIC group than in the non-TIC group. Persistent AF, coexisting diabetes mellitus, and decreased mt-cfDNA levels were independently associated with TIC. Decreased mt-cfDNA levels may serve as a novel biomarker for predicting TIC in patients with AF.

Clinical Features of Tachycardia-induced Cardiomyopathy in Patients with Atrial Fibrillation

Objective Atrial fibrillation (AF) is the most common cause of tachycardia-induced cardiomyopathy (TIC). However, which patients with AF are prone to developing TIC remains unclear. In this study, we investigated the clinical features of AF patients with TIC. Methods This single-center study included 722 patients with AF (average age, 63.1±10.2 years old; 191 women) who underwent radiofrequency catheter ablation. We defined TIC as an initial left ventricular ejection fraction (LVEF) of <40% and a >20% recovery of the LVEF after successful AF ablation and compared the clinical characteristics between the TIC and control groups. Results The proportions of type 2 diabetes (30.5% vs. 14.7%), renal dysfunction (34.2% vs. 23.8%), hypertension (67.1% vs. 54.8%), and persistent AF (62.2% vs. 32.2%) were significantly higher in the TIC group (n=82) than in the control group (n=640). The atrioventricular nodal effective refractory period (AVNERP) (303±72 ms vs. 332±86 ms; p=0.017) was significantly shorter in the TIC group than in the control group. A multivariable analysis found that persistent AF [odds ratio (OR), 3.19; 95% confidence interval (CI), 1.94-5.24], renal dysfunction (OR, 1.87; 95% CI, 1.06-3.32), and type 2 diabetes (OR, 2.30; 95% CI, 1.31-4.05) were significantly associated with TIC. Conclusion Comorbid renal dysfunction and type 2 diabetes were clinical features of AF patients with TIC. Persistent AF, and short AVNERP may be involved in the development of TIC.

Role of artificial intelligence in critical care nutrition support and research

Nutrition plays a key role in the comprehensive care of critically ill patients. Determining optimal nutrition strategy, however, remains a subject of intense debate. Artificial intelligence (AI) applications are becoming increasingly common in medicine, and specifically in critical care, driven by the data-rich environment of intensive care units. In this review, we will examine the evidence regarding the application of AI in critical care nutrition. As of now, the use of AI in critical care nutrition is relatively limited, with its primary emphasis on malnutrition screening and tolerance of enteral nutrition. Despite the current scarcity of evidence, the potential for AI for more personalized nutrition management for critically ill patients is substantial. This stems from the ability of AI to integrate multiple data streams reflecting patients' changing needs while addressing inherent heterogeneity. The application of AI in critical care nutrition holds promise for optimizing patient outcomes through tailored and adaptive nutrition interventions. A successful implementation of AI, however, necessitates a multidisciplinary approach, coupled with careful consideration of challenges related to data management, financial aspects, and patient privacy.

Arrhythmia-Induced Cardiomyopathy: JACC State-of-the-Art Review

Arrhythmias frequently accompany heart failure and left ventricular dysfunction. Tachycardias, atrial fibrillation, and premature ventricular contractions can induce a reversible form of dilated cardiomyopathy (CM) known as arrhythmia-induced CM (AiCM). The intriguing question is why certain individuals are more susceptible to AiCM, despite similar arrhythmia burdens. The primary challenge is determining the extent of arrhythmias' contribution to left ventricular systolic dysfunction. AiCM should be considered in patients with a mean heart rate of >100 beats/min, atrial fibrillation, or a PVC burden of >10%. Confirmation of AiCM occurs when CM reverses upon eliminating the responsible arrhythmia. Therapy choice depends on the specific arrhythmia, patient comorbidities, and preferences. After left ventricular function is restored, ongoing follow-up is essential if an abnormal myocardial substrate persists. Accurate diagnosis and treatment of AiCM have the potential to enhance patients' quality of life, improve clinical outcomes, and reduce hospital admissions and overall health care costs.

Tachycardia-Induced Cardiomyopathy in an Infant with Atrial Flutter and Prolonged Recovery of Cardiac Function

Background: Tachycardia-induced cardiomyopathy (TIC) is caused by prolonged tachycardia, leading to left ventricular dilatation and systolic dysfunction with heart failure. Although TIC is more common in adults, it is rare in early infancy. Methods: Clinical testing was performed as part of medical evaluation and management. Next-generation sequencing (NGS) was conducted for a patient with TIC. A literature review on TIC was also conducted. Results: The case involved a 5-month-old infant referred to the hospital due to symptoms of heart failure lasting at least two months. The infant's heart rate was 200 beats per minute, the left ventricular ejection fraction fell below 14%, and electrocardiograms showed atrial flutter, suggesting TIC. After cardioversion, there was no recurrence of atrial flutter, and cardiac function improved 98 days after tachycardia arrest. The NGS did not identify any pathogenic variants. The literature review identified eight early infantile cases of TIC. However, no previous reports described a case with such a prolonged duration of TIC as ours. Conclusions: This is the first report of a case of prolonged TIC in a child with the documented time to recover normal cardiac function. The improvement of cardiac function depends on the duration of TIC. Early recognition and intervention in TIC are essential to improve outcomes for infantile patients, as timely treatment offers the potential for recovery.

QT Prolongation and Torsade De Pointes After Catheter Ablation for Persistent Atrial Fibrillation in a Patient With Tachycardia-Induced Cardiomyopathy: A Case Report

Atrial fibrillation (AF) is the most common cause of tachycardia-induced cardiomyopathy (TIC). A 75-year-old woman was referred to our hospital for catheter ablation for persistent AF. On admission, transthoracic echocardiography (TTE) revealed diffuse left ventricular (LV) hypokinesis, which was suspected to be due to TIC. Catheter ablation was performed on the fifth day of hospitalization, and Torsade de Pointes (TdP) appeared on the sixth day. The serum concentration of bepridil and potassium was below the reference level. An electrocardiogram revealed marked QT prolongation, giant-negative T waves, and T-wave alternans on the seventh day of hospitalization. Cardiac magnetic resonance imaging with no contrast indicated diffuse mild LV hypokinesis, mild prolonged native T1, and no evidence of myocardial edema at T2. Coronary angiography revealed normal coronary arteries, and the ergonovine stress test results were negative. The results for five long QT syndrome susceptibility genes, including the three major genes, were negative. Subsequently, QT prolongation, giant-negative T waves, and LV dysfunction improved without treatment. This case report highlights the importance of risk management for AF patients with TIC scheduled for catheter ablation and carefully evaluating the risks of QT prolongation. Moreover, patients with TIC can experience marked QT prolongation and TdP during the perioperative period of catheter ablation. Therefore, caution should be required.

Tachycardia-induced metabolic rewiring as a driver of contractile dysfunction

Prolonged tachycardia-a risk factor for cardiovascular morbidity and mortality-can induce cardiomyopathy in the absence of structural disease in the heart. Here, by leveraging human patient data, a canine model of tachycardia and engineered heart tissue generated from human induced pluripotent stem cells, we show that metabolic rewiring during tachycardia drives contractile dysfunction by promoting tissue hypoxia, elevated glucose utilization and the suppression of oxidative phosphorylation. Mechanistically, a metabolic shift towards anaerobic glycolysis disrupts the redox balance of nicotinamide adenine dinucleotide (NAD), resulting in increased global protein acetylation (and in particular the acetylation of sarcoplasmic/endoplasmic reticulum Ca2+-ATPase), a molecular signature of heart failure. Restoration of NAD redox by NAD+ supplementation reduced sarcoplasmic/endoplasmic reticulum Ca2+-ATPase acetylation and accelerated the functional recovery of the engineered heart tissue after tachycardia. Understanding how metabolic rewiring drives tachycardia-induced cardiomyopathy opens up opportunities for therapeutic intervention.

Tachycardia and Atrial Fibrillation-Related Cardiomyopathies: Potential Mechanisms and Current Therapies

Atrial fibrillation (AF) is associated with an increased risk of new-onset ventricular contractile dysfunction, termed arrhythmia-induced cardiomyopathy (AIC). Although cardioembolic stroke remains the most feared and widely studied complication of AF, AIC is also a clinically important consequence of AF that portends significant morbidity and mortality to patients with AF. Current treatments are aimed at restoring sinus rhythm through catheter ablation and rate and rhythm control, but these treatments do not target the underlying molecular mechanisms driving the progression from AF to AIC. Here, we describe the clinical features of the various AIC subtypes, discuss the pathophysiologic mechanisms driving the progression from AF to AIC, and review the evidence surrounding current treatment options. In this review, we aim to identify key knowledge gaps that will enable the development of more effective AIC therapies that target cellular and molecular mechanisms.

Predictors of improvement in left ventricular systolic function after catheter ablation in patients with persistent atrial fibrillation complicated with heart failure

AIMS

The current management of patients with atrial fibrillation (AF) and concomitant heart failure (HF) remains a significant challenge. Catheter ablation (CA) has been shown to improve left ventricular ejection fraction (LVEF) in these patients, but which patients can benefit from CA is still poorly understood. The aim of our study was to determine the predictors of improved ejection fraction in patients with persistent atrial fibrillation (PeAF) complicated with HF undergoing CA.

METHODS AND RESULTS

A total of 435 patients with persistent AF underwent an initial CA between January 2019 and March 2023 in our hospital. We investigated consecutive patients with left ventricular systolic dysfunction (LVEF < 50%) measured by transthoracic echocardiography (TTE) within one month before CA. According to the LVEF changes at 6 months, these patients were divided into an improved group (fulfilling the '2021 Universal Definition of HF' criteria for LVEF recovery) and a nonimproved group. Eighty patients were analyzed, and the improvement group consisted of 60 patients (75.0%). In the univariate analysis, left ventricular end-diastolic diameter (P = 0.005) and low voltage zones in the left atrium (P = 0.043) were associated with improvement of LVEF. A receiver operating characteristic analysis determined that the suitable cutoff value for left ventricular end-diastolic diameter (LVDd) was 59 mm (sensitivity: 85.0%, specificity: 55.0%, area under curve: 0.709). A multivariate analysis showed that LVDd (OR = 0.85; 95% CI: 0.76-0.95, P = 0.005) and low voltage zones (LVZs) (OR = 0.26; 95% CI: 0.07-0.96, P = 0.043) were significantly independently associated with the improvement of LVEF. Additionally, parameters were significantly improved regarding the left atrial diameter, LVDd and ventricular rate after radiofrequency catheter ablation (all p < 0.05).

CONCLUSIONS

The improvement of left ventricular ejection fraction (LVEF) occurred in 75.0% of patients. Our study provides additional evidence that LVDd < 59 mm and no low voltage zones in the left atrium can be used to jointly predict the improvement of LVEF after atrial fibrillation ablation.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

Left atrial appendage peak flow velocity predicts improvement in mitral regurgitation after atrial fibrillation ablation

BACKGROUND

Mitral regurgitation (MR) is associated with an increased risk of developing atrial fibrillation (AF) and high AF recurrence ratio after ablation. Left atrial appendage (LAA) is involved in left atrium (LA) pressure modulation and LAA peak flow velocity (LAAV) is validated as an indicator of LA contractile and reservoir function. LA function is related to the MR pathology, but the relationship between LAAV and improvement in MR after ablation remains unknown.

METHODS

The present study included AF patients with moderate or severe MR from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry. We evaluated MR severity one-year post-ablation and assigned the patients based on MR improvement (at least a one-grade improvement in MR over one year) and investigated the impact of the relevant factors, including LAAV, on MR improvement.

RESULTS

This study population included a total of 289 patients [paroxysmal AF (PAF), 112 patients; persistent AF (PerAF), 177 patients]. Kaplan-Meier analysis demonstrated that the patients with MR improvement had a significantly lower risk of late arrhythmia recurrence than those without (log-rank p < 0.001). MR improvement was observed in 56.3 % (63/112) of PAF patients and 55.4 % (98/177) of PerAF patients. Multiple regression analysis showed that LAAV was an independent and significant determinant of MR improvement post-ablation in both PAF and PerAF patients (p = 0.037 and p = 0.018, respectively), in addition to age and hemoglobin in PerAF patients (p = 0.045 and p = 0.048, respectively).

CONCLUSION

LAAV can predict an improvement in MR after catheter ablation in both PAF and PerAF patients.

State-of-the-art document on optimal contemporary management of cardiomyopathies

Cardiomyopathies represent significant contributors to cardiovascular morbidity and mortality. Over the past decades, a progress has occurred in characterization of the genetic background and major pathophysiological mechanisms, which has been incorporated into a more nuanced diagnostic approach and risk stratification. Furthermore, medications targeting core disease processes and/or their downstream adverse effects have been introduced for several cardiomyopathies. Combined with standard care and prevention of sudden cardiac death, these novel and emerging targeted therapies offer a possibility of improving the outcomes in several cardiomyopathies. Therefore, the aim of this document is to summarize practical approaches to the treatment of cardiomyopathies, which includes the evidence-based novel therapeutic concepts and established principles of care, tailored to the individual patient aetiology and clinical presentation of the cardiomyopathy. The scope of the document encompasses contemporary treatment of dilated, hypertrophic, restrictive and arrhythmogenic cardiomyopathy. It was based on an expert consensus reached at the Heart Failure Association online Workshop, held on 18 March 2021.

Catheter Ablation for the Management of Atrial Fibrillation: An Update of the Literature

Catheter ablation has been shown to be more effective at maintaining sinus rhythm and improving quality of life when compared to antiarrhythmic drugs. Radiofrequency and cryoablation are two effective methods. However, catheter-only ablation strategies have not consistently produced high success rates in treating longstanding and persistent AF patients. The emerging treatment of choice for such cases is hybrid ablation, which involves a multidisciplinary and minimally invasive approach to achieve surgical ablation of the direct posterior left atrial wall in combination with endocardial catheter ablation. Studies have shown promising results for the hybrid approach when compared with catheter ablation alone, but it is not without risks. Large and randomised studies are necessary to further evaluate these strategies for managing AF.

Sinus Node Dysfunction

Sinus node dysfunction (SND) is a multifaceted disorder most prevalent in older individuals, but may also occur at an earlier age. In most cases, the SND diagnosis is ultimately established by documenting its ECG manifestations. EPS has limited utility. The treatment strategy is largely dictated by symptoms and ECG manifestations. Not infrequently, both bradycardia and tachycardia coexist in the same patients, along with other diseases common in the elderly (e.g., hypertension, coronary artery disease), thereby complicating treatment strategy. Prevention of the adverse consequences of both bradyarrhythmia and tachyarrhythmia is important to reduce susceptibility to syncope, falls, and thromboembolic complications.

Ventricular rate in atrial fibrillation and the risk of heart failure and death

AIMS

While clinical trials have suggested that a high ventricular rate is associated with increased risk of heart failure (HF) and mortality, all-comers studies are warranted.

OBJECTIVE

To assess 1-year risk of new-onset diagnosed HF and all-cause mortality among rate-control treated patients presenting with atrial fibrillation (AF) on an electrocardiogram (ECG) according to ventricular rate.

METHODS AND RESULTS

ECGs recorded at the Copenhagen General Practitioners Laboratory (2001-15) were used to identify patients with AF. Multivariate Cox proportional hazard regression models were used to compare risk of new-onset HF and all-cause mortality after first ECG presenting with AF according to ventricular rate on ECG [<60, 60-79, 80-99, and 100-110, > 110 beats per minute (bpm)]. We identified 7408 patients in treatment with rate control drugs at time of first ECG presenting with AF [median age 78 years (Q1,Q3 = 70-85 years)], 45.8% male, median ventricular rate 83 bpm, (Q1,Q3 = 71-101 bpm)]. During 1-year follow-up, 666 (9.0%) of all patients with AF developed HF and 858 (11.6%) died. Patients with AF ventricular rates 100-110 bpm and >110 bpm had a hazard ratio (HR) of 1.46 (CI: 1.10-1.95) and 2.41 (CI: 1.94-3.00) respectively for new-onset HF, compared with 60-79 bpm. Similarly, patients with AF ventricular rates 100-110 bpm and >110 bpm had a HR of 1.44 (CI: 1.13-1.82) and 1.34 (CI: 1.08-1.65) respectively for all-cause mortality, compared with 60-79 bpm.

CONCLUSIONS

Ventricular rates ≥100 bpm among patients presenting with AF on ECG in treatment with rate control drugs were associated with greater risk of both new-onset HF and all-cause mortality.

Efficacy of intravenous magnesium for the management of non-post operative atrial fibrillation with rapid ventricular response: A systematic review and meta-analysis

BACKGROUND

Intravenous magnesium (IV Mg), a commonly utilized therapeutic agent in the management of atrial fibrillation (AF) with rapid ventricular response, is thought to exert its influence via its effect on cellular automaticity and prolongation of atrial and atrioventricular nodal refractoriness thus reducing ventricular rate. We sought to undertake a systematic review and meta-analysis of the effectiveness of IV Mg versus placebo in addition to standard pharmacotherapy in the rate and rhythm control of AF in the nonpostoperative patient cohort given that randomized control trials (RCTs) have shown conflicting results.

METHODS

Randomized controlled trials comparing IV Mg versus placebo in addition to standard of care were identified via electronic database searches. Nine RCTs were returned with a total of 1048 patients. Primary efficacy endpoints were study-defined rate control and rhythm control/reversion to sinus rhythm. The secondary endpoint was patient experienced side effects.

RESULTS

Our analysis found IV Mg in addition to standard care was successful in achieving rate control (odd ratio [OR] 1.87, 95% confidence interval [CI] 1.13-3.11, p = .02) and rhythm control (OR 1.45, 95% CI 1.04-2.03, p = .03). Although not well reported among studies, there was no significant difference between groups regarding the likelihood of experiencing side effects.

CONCLUSIONS

IV Mg, in addition to standard-of-care pharmacotherapy, increases the rates of successful rate and rhythm control in nonpostoperative patients with AF with rapid ventricular response and is well tolerated.

Echocardiographic changes and heart failure hospitalizations following rhythm control for arrhythmia-induced cardiomyopathy: results from a multicenter, retrospective study

BACKGROUND

The incidence and prevalence of arrhythmia-induced cardiomyopathy (AIC) are unclear but likely underrecognized. LV dysfunction is common among patients with atrial fibrillation (AF), atrial flutter (AFL), and frequent premature ventricular contractions (PVC). The hallmark of AIC is the improvement of left ventricular ejection fraction (LVEF) following arrhythmia treatment. Changes in echocardiographic parameters and their effect on outcomes after rhythm control for AIC are not well understood. We aimed to study echocardiographic parameters and outcomes following rhythm control for AIC.

METHODS

A multicenter, retrospective study was conducted at 4 different medical centers involving patients with AIC. Clinical, echocardiographic, and outcome (mortality and heart failure hospitalizations [HFH]) parameters were extracted from the medical record.

RESULTS

Two hundred fifty-five patients (age 66 ± 11 years, 73% male) with AIC caused by AF (51%), atrial tachycardia/AFL (20%), and PVCs (29%) were included and followed for a median period of 6 months after successful rhythm control. Significant improvements in left ventricular (LV) ejection fraction (P < 0.0001), LV end-systolic volume (ml) (90 ± 48 to 58 ± 30; P < 0.0001), LV internal diameter end diastole (cm) (5.5 ± 0.78 to 5.3 ± 0.64; P = 0.0001) and end systole (4.7 ± 0.95 to 4.3 ± 1.02; P < 0.0001), right atrial pressure (mmHg) (11.3 ± 5.0 to 7.4 ± 3.2; P = 0.0001), and right ventricular function (n (%)) (42 (44) to 9 (11); P < 0.0001) were noted following arrhythmia treatment. No deaths occurred during follow-up. HFH occurred in 7 patients. Arrhythmia recurrence rate was 50.5%. Neither echocardiographic parameters nor recurrence of arrhythmia correlated with HFH.

CONCLUSION

Arrhythmia treatment significantly improved echocardiographic LV dimensions, LVEF, and RAP in this multicenter AIC cohort, underscoring the need for early recognition and aggressive rhythm control in suspected AIC patients. The event rate was too low to assess for outcome predictors.

How arrhythmias weaken the ventricle: an often underestimated vicious cycle

Arrhythmia-induced cardiomyopathy (AIC) is classified as a form of dilated cardiomyopathy in which left ventricular systolic dysfunction (LVSD) is triggered by tachycardic or arrhythmic heart rates. On the one hand AIC can develop in patients without cardiac disease and on the other hand it can appear in patients with pre-existing LVSD, leading to a further reduction in left ventricular (LV) ejection fraction. A special aspect of AIC is the potential termination or partial reversibility of LVSD; thus, AIC is curatively treatable by the elimination of the underlying arrhythmia. Since arrhythmias are often seen merely as a consequence than as an underlying cause of LVSD, and due to the fact that the diagnosis of AIC can be made only after recovery of LV function, the prevalence of AIC is probably underestimated in clinical practice. Pathophysiologically, animal models have shown that continuous tachycardic pacing induces consecutive changes such as the occurrence of LVSD, increased filling pressures, LV dilatation, and decreased cardiac output. After termination of tachycardia, reversibility of the described pathologies can usually be observed. Studies in human ventricular myocardium have recently demonstrated that various cellular structural and functional mechanisms are activated even by normofrequent atrial fibrillation, which may help to explain the clinical AIC phenotype.

Long-Term Outcomes of Tachycardia-Induced Cardiomyopathy Compared with Idiopathic Dilated Cardiomyopathy

BACKGROUND

data on the natural course and prognosis of tachycardia-induced cardiomyopathy (TICMP) and comparison with idiopathic dilated cardiomyopathies (IDCM) are scarce.

OBJECTIVE

To compare the clinical presentation, comorbidities, and long-term outcomes of TICMP patients with IDCM patients.

METHODS

a retrospective cohort study of patients hospitalized with new-onset TICMP or IDCM. The primary endpoint was a composite of death, myocardial infarction, thromboembolic events, assist device, heart transplantation, and ventricular tachycardia or fibrillation (VT/VF). The secondary endpoint was recurrent hospitalization due to heart failure (HF) exacerbation.

RESULTS

the cohort was comprised of 64 TICMP and 66 IDCM patients. The primary composite endpoint and all-cause mortality were similar between the groups during a median follow-up of ~6 years (36% versus 29%, p = 0.33 and 22% versus 15%, p = 0.15, respectively). Survival analysis showed no significant difference between TICMP and IDCM groups for the composite endpoint (p = 0.75), all-cause mortality (p = 0.65), and hospitalizations due to heart failure exacerbation. Nonetheless, the incidence of recurrent hospitalization was significantly higher in TICMP patients (incidence rate ratio 1.59; p = 0.009).

CONCLUSIONS

patients with TICMP have similar long-term outcomes as those with IDCM. However, it portends a higher rate of HF readmissions, mostly due to arrhythmia recurrences.

Tachycardia-Induced Cardiomyopathy in a Young Adult: The Significance of Early Diagnosis and Treatment

Tachycardia-induced cardiomyopathy (TIC) is gradually gaining the attention it deserves as one of the most common causes of reversible cardiomyopathy. Although TIC appears common, there has been limited data, especially among young adults. Patients with tachycardia and left ventricular dysfunction should be suspected of having TIC, with or without established etiology of heart failure, because TIC can develop by itself or contribute to cardiac dysfunction. We present a case of a previously healthy 31-year-old woman with persistent nausea and vomiting, poor oral intake, fatigue, and persistent palpitations. Vital signs at presentation were significant for tachycardia of 124 beats per minute, which she reported was similar to her baseline heart rate of 120s per minute. There were no apparent signs of volume overload at the presentation. Labs were significant for microcytic anemia with hemoglobin/hematocrit of 10.1/34.4 g/dL, and mean corpuscular volume was low at 69.4 fL; other labs were unremarkable. Transthoracic echocardiography obtained at admission was significant for mild global left ventricular hypokinesis, systolic dysfunction with an estimated left ventricular ejection fraction of 45-50%, and mild tricuspid regurgitation. Persistent tachycardia was suggested as the primary cause of cardiac dysfunction. The patient was subsequently started on guideline-directed medical therapy, including beta blockers, angiotensin-converting enzyme inhibitors, and spironolactone, with eventual normalization of the heart rate. Anemia too was also treated. Follow-up transthoracic echocardiography done four weeks after was notable for significant interval improvement in left ventricular ejection fraction of 55-60%, with a heart rate of 82 beats per minute. The case illustrates the need for early identification of TIC regardless of the patient's age. It is essential that physicians consider it in the differential diagnosis of new-onset heart failure because prompt treatment leads to the resolution of symptoms and improvement of ventricular function.

Rate of atrial fibrillation and flutter induced tachycardiomyopathy in a cohort of hospitalized patients with heart failure and detection of indicators for improved diagnosis

Background

Atrial fibrillation (AF) and atrial flutter (AFL) induced tachycardiomyopathy (TCM) has been known to cause reversible heart failure (HF) for many years. However, the prevalence of the disease is unknown, and diagnosis is challenging. Therefore, the aim of the present study was (1) to assess the rate of AF/AFL induced TCM and (2) to identify indicators for diagnosis.

Methods

Consecutively, all patients with a diagnosis of HF who were hospitalized in our department within 12 months were reviewed. For the main analysis, all patients with HF with reduced ejection fraction (HFrEF) and AF or AFL were included. AF/AFL induced TCM was diagnosed when there was at least a 10% improvement in left ventricular ejection fraction under rhythm or rate control within 3 months. Patients with HFrEF with AF/AFL but without TCM served as control group.

Results

A total of 480 patients were included. AF/AFL induced TCM occurred in 26 patients (5.4%) and HFrEF with AF/AFL in 53 patients (11%). Independent indicators of AF/AFL induced TCM were age<79 years [Odds ratio 5.887, confidence interval (CI) 1.999-17.339, p < 0.001], NT-pro-BNP <5,419 pg/mL (Odds ratio 2.327, CI 1.141-4.746, p = 0.004), and a resting heart rate >112 bpm (Odds ratio 2.503, CI 1.288-4.864, p = 0.001).

Conclusion

Approximately 5% of all patients hospitalized for HF suffer from AF/AFL induced TCM. Improved discrimination of AF/AFL induced TCM to HFrEF with AF/AFL is possible considering age, NT-pro-BNP level, and resting heart rate >112 beats/minute. Based on these parameters, an earlier diagnosis and improved therapy might be possible.

Emerging concepts in heart failure management and treatment: focus on tachycardia-induced cardiomyopathy

Tachycardia-induced cardiomyopathy is an entity characterized by reversible dysfunction of the left ventricle, which can be induced by different types of arrhythmia such as atrial fibrillation, atrial flutter, incessant supraventricular tachycardia and ventricular arrhythmia (more frequent causes). Correct identification of the causative arrhythmia and normalization of the heart rate (e.g through medical treatment, electrical cardioversion, ablation) can lead to recovery of left ventricular function. Tachycardia-induced cardiomyopathy should be suspected in patients with tachycardia and left ventricular dysfunction (heart failure setting), especially when there is no history of previous heart disease. Its usual phenotype is that of non-ischaemic/non-valvular dilated cardiomyopathy and it can occur in both children (main cause: permanent junctional reciprocating tachycardia) and adults (main cause: atrial fibrillation). With proper treatment, most cases recover within a few months, though there is a risk of relapse, especially when the causal arrhythmia reappears or its control is lost. This is a narrative review that comprehensively addresses the pathophysiology, clinical manifestations, and therapeutic management of tachycardia-induced cardiomyopathy. This article is part of the Emerging concepts in heart failure management and treatment Special Issue: https://www.drugsincontext.com/special_issues/emerging-concepts-in-heart-failure-management-and-treatment.

Impact of cavotricuspid isthmus ablation for typical atrial flutter and heart failure in the elderly-results of a retrospective multi-center study

Introduction

While in the CASTLE-AF trial, in patients with atrial fibrillation and heart failure with reduced ejection fraction, interventional therapy using pulmonary vein isolation was associated with outcome improvement, data on cavotricuspid isthmus ablation (CTIA) in atrial flutter (AFL) in the elderly is rare.

Methods

We included 96 patients between 60 and 85 years with typical AFL and heart failure with reduced or mildly reduced ejection fraction (HFrEF/HFmrEF) treated in two medical centers. 48 patients underwent an electrophysiological study with CTIA, whereas 48 patients received rate or rhythm control and guideline-compliant heart failure therapy. Patients were followed up for 2 years, with emphasis on left ventricular ejection fraction (LVEF) over time. Primary endpoints were cardiovascular mortality and hospitalization for cardiac causes.

Results

Patients with CTIA showed a significant increase in LVEF after 1 (p < 0.001) and 2 years (p < 0.001) in contrast to baseline LVEF. Improvement of LVEF in the CTIA group was associated with significantly lower 2-year mortality (p = 0.003). In the multivariate regression analysis, CTIA remained the relevant factor associated with LVEF improvement (HR: 2.845 CI:95% 1.044-7.755; p = 0.041). Elderly patients (≥ 70 years) further benefited from CTIA, since they showed a significantly reduced rehospitalization (p = 0.042) and mortality rate after 2 years (p = 0.013).

Conclusions

CTIA in patients with typical AFL and HFrEF/HFmrEF was associated with significant improvement of LVEF and reduced mortality rates after 2 years. Patient age should not be a primary exclusion criterion for CTIA, since patients ≥70 years also seem to benefit from intervention in terms of mortality and hospitalization.

Inappropriate sinus tachycardia: an examination of existing definitions

Aims

Inappropriate sinus tachycardia (IST) is a syndrome characterized by an elevated sinus rate unassociated with known physiological, pathological, or pharmacological causes. Despite published consensus documents, IST definitions appear to vary in the literature. In this study, we reviewed IST publications to evaluate IST definition variability and ascertain the degree to which consensus definitions are being adopted.

Methods and results

English-language articles in PubMed, Ovid MEDLINE, Ovid Embase, and Google Scholar published from 1 January 1970 to 1 June 2021 with the title terms ‘inappropriate sinus tachycardia,’ ‘non-paroxysmal sinus tachycardia,’ or ‘permanent sinus tachycardia’ were searched. In each, the IST definition used, qualifying characteristics, and publications cited to support each definition were recorded. We identified 138 publications meeting the search criteria. Inappropriate sinus tachycardia definitions were provided in 114 of 138 articles (83%). A majority of definitions (92/114, 81%) used distinct heart rate (HR) thresholds. Among these, the most common threshold was ≥100 beats per minute (BPM) (75/92, 82%), mainly measured at rest (54/92, 59%). Most definitions (47/92, 51%) included a second criterion to qualify for IST; these were most often an HR threshold of 90 BPM measured over 24 h by ambulatory electrocardiogram (37/47, 79%). Diagnosis of exclusion was a common criterion (75/92, 82%) but symptom status was not (41/92, 45%). The 2015 Heart Rhythm Society IST consensus was commonly cited but adopted in only 37% of definitions published after 2015.

Conclusions

Inappropriate sinus tachycardia definitions in current literature are inconsistent, and professional society consensus IST definitions have, to date, had limited impact.

Electrocardiogram and CMR to differentiate tachycardia-induced cardiomyopathy from dilated cardiomyopathy in patients admitted for heart failure

In patients admitted for heart failure (HF) with reduced left ventricular ejection fraction (LVEF) and a concomitant supraventricular tachyarrhythmia (SVT) it is a challenge to predict LVEF recovery and differentiate tachycardia-induced cardiomyopathy (TIC) from dilated cardiomyopathy (DCM). The role of the electrocardiogram (ECG) and cardiac magnetic resonance (CMR) and in this acute setting remains unsettled. Forty-three consecutive patients admitted for HF due to SVT and LVEF < 50% undergoing CMR in the acute phase, were retrospectively included. Those who had LVEF > 50% at follow up were classified as TIC and those with LVEF < 50% were classified as DCM. Clinical, CMR and ECG findings were analyzed to predict LVEF recovery. Twenty-five (58%) patients were classified as TIC. Patients with DCM had wider QRS (121.2 ± 26 vs 97.7 ± 17.35 ms; p = 0.003). On CRM the TIC group presented with higher LVEF (33.4 ± 11 vs 26.9 ± 6.4%; p = 0.019) whereas late gadolinium enhancement (LGE) was more frequent in DCM group (61 vs 16%; p = 0.004). On multivariate analysis, QRS duration ≥ 100 ms (p = 0.027), LVEF < 40% on CMR (p = 0.047) and presence of LGE (p = 0.03) were independent predictors of lack of LVEF recovery. Furthermore, during follow-up (median 60 months) DCM patients were admitted more frequently for HF (44 vs 0%; p < 0.001) than TIC patients. In patients with reduced LVEF admitted for HF due to SVT, QRS ≥ 100 ms, LVEF < 40% and LGE are independently associated with lack of LVEF recovery and worse clinical outcome.

Atrial fibrillation-induced tachycardiomyopathy and heart failure: an underappreciated and elusive condition

Many patients with persistent, chronic, or frequently recurring paroxysmal atrial fibrillation (AF) may develop a tachycardiomyopathy (TCM) with left ventricular (LV) dysfunction and heart failure (HF), which is reversible upon restoration and maintenance of sinus rhythm, when feasible, or via better and tighter ventricular rate (VR) control. Mechanisms involved in producing this leading cause of TCM (AF-TCM) include loss of atrial contraction, irregular heart rate, fast VR, neurohumoral activation, and structural myocardial changes. The most important of all mechanisms relates to optimal VR control, which seems to be an elusive target. Uncontrolled AF may also worsen preexisting LV dysfunction and exacerbate HF symptoms. Data, albeit less robust, also point to deleterious effects of slow VRs on LV function. Thus, a J-shaped relationship between VR and clinical outcome has been suggested, with the optimal VR control hovering at ~ 65 bpm, ranging between 60 and 80 bpm; VRs above and below this range may confer higher morbidity and mortality rates. A convergence of recent guidelines is noted towards a stricter rather than a more lenient VR control with target heart rate < 80 bpm at rest and < 110 bpm during moderate exercise which seems to prevent TCM or improve LV function and exercise capacity and relieve TCM-related symptoms and signs. Of course, restoring and maintaining sinus rhythm is always a most desirable target, when feasible, either with drugs or more likely with ablation. All these issues are herein reviewed, current guidelines are discussed and relevant data are tabulated and pictorially illustrated.

Arrhythmia-induced Cardiomyopathy: An Article Review

Arrhythmia is one of the significant reversible causes in patients with heart disease and left ventricular dysfunction. Tachycardia, atrial fibrillation, and premature ventricular contractions have indeed been related to arrhythmia-induced cardiomyopathy (CM), a reversible dilated CM. Effective arrhythmia suppression will entirely or partially recover ventricular function, lowering morbidity and mortality. However, the importance of arrhythmia-induced CM (ARiCM) is often underestimated in clinical practice because arrhythmia is often seen as a result rather than a cause of CM, leading in treatment delays and failure to increase the quality of life and better clinical outcomes. This article review aims to summarize the pathomechanisms, and a general approach to the management of ARiCM and its long-term outcomes. ARiCM can cause a variety of clinical signs, ranging from asymptomatic to severe heart failure symptoms. Electrocardiogram, 24 h Holter monitoring, echocardiography, and cardiac magnetic resonance are all recommended for diagnosis. More research is required to better understand the pathogenesis of ARiCM and to differentiate treatment alternatives to choose the ideal ARiCM management approach.

Atypical atrial flutter: review of mechanisms, advances in mapping and ablation outcomes

PURPOSE OF REVIEW

Atrial flutter (AFL) is the second most prevalent arrhythmia after atrial fibrillation (AF). It is a macro-reentrant tachycardia that is either cavotricuspid isthmus dependent (typical) or independent (atypical). This review aims at highlighting mechanism, diagnosis and treatment of atypical AFL and the recent developments in electroanatomic mapping.

RECENT FINDINGS

Incidence of left AFL is at an exponential rise presently with increase in AF ablation rates. The mechanism of left AFL is most often peri-mitral, roof-dependent or within pulmonary veins in preablated, in contrast to posterior or anterior wall low voltage areas in ablation naïve patients. Linear lesions, compared to pulmonary vein isolation alone, have higher incidence of atypical right or left AFL. Catheter ablation for atypical AFL is associated with lower rates of thromboembolic events, transfusions, and length of stay compared to typical AFL.

SUMMARY

Advances in mapping have allowed rapid simultaneous acquisition of automatically annotated points in the atria and identification of details of macro-reentrant circuits, including zones of conduction block, scar, and slow conduction.

Arrhythmogenic Remodeling in the Failing Heart

Chronic heart failure is a clinical syndrome with multiple etiologies, associated with significant morbidity and mortality. Cardiac arrhythmias, including ventricular tachyarrhythmias and atrial fibrillation, are common in heart failure. A number of cardiac diseases including heart failure alter the expression and regulation of ion channels and transporters leading to arrhythmogenic electrical remodeling. Myocardial hypertrophy, fibrosis and scar formation are key elements of arrhythmogenic structural remodeling in heart failure. In this article, the mechanisms responsible for increased arrhythmia susceptibility as well as the underlying changes in ion channel, transporter expression and function as well as alterations in calcium handling in heart failure are discussed. Understanding the mechanisms of arrhythmogenic remodeling is key to improving arrhythmia management and the prevention of sudden cardiac death in patients with heart failure.

Supraventricular Tachycardia Causing Left Ventricular Dysfunction

There is limited evidence on characterization and natural history of supraventricular tachycardia (SVT)-induced left ventricular (LV) dysfunction. The aim of this work was to characterize clinical features and long-term evolution of SVT-induced LV dysfunction. Patients consecutively admitted with sustained SVT and heart rate >100 bpm as the only known cause of a new onset LV systolic dysfunction (i.e., LV ejection fraction [EF] <50%) were analyzed. Patients were then revaluated periodically. Recovered LVEF (i.e., ≥50%) and a composite of death, heart transplant or first episode of major ventricular arrhythmias were evaluated as study end-points. We enrolled 83 patients. After SVT therapy, 56 (67%) showed a recovered LVEF at the last follow-up of median 54 (interquartile range 36 to 87) months. Seventeen (30%) of those patients had a temporary new drop in LVEF during follow-up associated to high-rate SVT relapse. At presentation, patients with recovered LVEF were younger (52 vs 67 years respectively, p <0.001) and had higher LVEF (34% vs 27% respectively, p = 0.005) compared to non-recovered LVEF patients. Finally, 4% of recovered LVEF patients vs 26% of nonrecovered LVEF patients experienced death/heart transplant/major ventricular arrhythmias during follow-up (p = 0.004). In conclusion, after almost 5 years of follow-up, two-thirds of patients with high-rate SVT causing a newly diagnosed LV systolic dysfunction recovered and maintained normal LV function after SVT control, with a subsequent benign outcome. Long term individual surveillance is required in those patients, as arrhythmic recurrences and new drops in LVEF are common in the long term.

Sinus Node Dysfunction

Sinus node dysfunction (SND) is a multifaceted disorder most prevalent in older individuals, but may also occur at an earlier age. In most cases, the SND diagnosis is ultimately established by documenting its ECG manifestations. EPS has limited utility. The treatment strategy is largely dictated by symptoms and ECG manifestations. Not infrequently, both bradycardia and tachycardia coexist in the same patients, along with other diseases common in the elderly (e.g., hypertension, coronary artery disease), thereby complicating treatment strategy. Prevention of the adverse consequences of both bradyarrhythmia and tachyarrhythmia is important to reduce susceptibility to syncope, falls, and thromboembolic complications.

Successful Reversal of Severe Tachycardia-Induced Cardiomyopathy with Cardiogenic Shock by Urgent Rhythm or Rate Control: Only Rhythm and Rate Matter

Background and objectives Severe forms of Tachycardia-induced cardiomyopathy (TIC) with cardiogenic shock are not well described so far, and efficiency of catheter ablation in this setting is unknown. Methods We retrospectively included consecutive patients admitted to the Intensive Cardiac Care Unit for acute heart failure with cardiogenic shock associated with atrial arrhythmia and managed by ablation. Result Fourteen patients were included, each with cardiogenic shock and two needing the use of extracorporeal membrane oxygenation. Successful ablation was performed in the acute setting or over the following weeks. Two patients experienced relapses of arrhythmias and were treated by new ablation procedures. At 7.5 ± 5 months follow-up, all patient were alive with stable sinus rhythm. The left ventricular Ejection Fraction dramatically improved (21 vs. 54%, p = 0.001) as well as the end-diastolic left ventricular diameter (61 vs. 51 mm, p = 0.01) and NYHA class (class IV in all vs. median 1, p = 0.002). Conclusion Restoration and maintenance of sinus rhythm in severe TIC with cardiogenic shock and atrial arrhythmias lead to a major increase or normalization of LVEF, reduction of ventricular dimensions, and improvement in functional status. Ablation is efficient in long-term maintenance of sinus rhythm and may be proposed early in refractory cases.

Heart failure and atrial flutter: a systematic review of current knowledge and practices

While the interplay between heart failure (HF) and atrial fibrillation (AF) has been extensively studied, little is known regarding HF and atrial flutter (AFL), which may be managed differently. We reviewed the incidence, prevalence, and predictors of HF in AFL and vice versa, and the outcomes of treatment of AFL in HF. A systematic literature review of PubMed/Medline and EMBASE yielded 65 studies for inclusion and qualitative synthesis. No study described the incidence or prevalence of AFL in unselected patients with HF. Most cohorts enrolled patients with AF/AFL as interchangeable diagnoses, or highly selected patients with tachycardia‐induced cardiomyopathy. The prevalence of HF in AFL ranged from 6% to 56%. However, the phenotype of HF was never defined by left ventricular ejection fraction (LVEF). No studies reported the predictors, phenotype, and prognostic implications of AFL in HF. There was significant variation in treatments studied, including the proportion that underwent ablation. When systolic dysfunction was tachycardia‐mediated, catheter ablation demonstrated LVEF normalization in up to 88%, as well as reduced cardiovascular mortality. In summary, AFL and HF often coexist but are understudied, with no randomized trial data to inform care. Further research is warranted to define the epidemiology and establish optimal management.

Update on management of atrial fibrillation in heart failure: a focus on ablation

Atrial fibrillation is increasingly encountered in patients with heart failure. Both diseases have seen tremendous rises in incidence in recent years. In general, the treatment of atrial fibrillation is focused on relieving patients from atrial fibrillation-related symptoms and risk reduction for thromboembolism and the occurrence or worsening of heart failure. Symptomatic relief may be accomplished by either (non-)pharmacological rate or rhythm control in combination with optimal therapy of underlying cardiovascular morbidities and risk factors. Atrial fibrillation ablation has been performed in patients without overt heart failure successfully for many years. However, in recent years, attempts have been made for patients with heart failure as well. In this review, we discuss the current literature describing the treatment of atrial fibrillation in heart failure. We highlight the early rate versus rhythm control studies, the importance of addressing underlying conditions and treatment of risk factors. A critical evaluation will be performed of the catheter ablation studies that have been performed so far in light of larger (post-hoc) ablation studies. Furthermore, we will hypothesise the role of patient selection as next step in optimising outcome for patient with atrial fibrillation and heart failure.

Atrial fibrillation in patients with systolic heart failure: pathophysiology mechanisms and management

Heart failure (HF) and atrial fibrillation (AF) demonstrate a constantly increasing prevalence during the 21^st century worldwide, as a result of the aging population and the successful interventions of the clinical practice in the deterioration of adverse cardiovascular outcomes. HF and AF share common risk factors and pathophysiological mechanisms, creating the base of a constant interrelation. AF impairs systolic and diastolic function, resulting in the increasing incidence of HF, whereas the structural and neurohormonal changes in HF with preserved or reduced ejection fraction increase the possibility of the AF development. The temporal relationship of the development of either condition affects the diagnostic algorithms, the prognosis and the ideal therapeutic strategy that leads to euvolaemia, management of non-cardiovascular comorbidities, control of heart rate or restoration of sinus rate, ventricular synchronization, prevention of sudden death, stroke, embolism, or major bleeding and maintenance of a sustainable quality of life. The indicated treatment for the concomitant HF and AF includes rate or/and rhythm control as well as thromboembolism prophylaxis, while the progress in the understanding of their pathophysiological interdependence and the introduction of the genetic profiling, create new paths in the diagnosis, the prognosis and the prevention of these diseases.

MONITORIA: The start of a new era of ambulatory heart failure monitoring? Part I - Theoretical Rationale

Heart failure (HF) is a multifactorial chronic syndrome with progressive increasing incidence causing a huge financial burden worldwide. Remote monitoring should, in theory, improve HF management, but given increasing morbidity and mortality, a question remains: are we monitoring it properly? Device-based home monitoring enables objective and continuous measurement of vital variables and non-invasive devices should be first choice for elderly patients. There is no shortage of literature on the subject, however, most studies were designed to monitor a single variable or class of variables that were not properly assembled and, to the best of our knowledge, there are no large randomized studies about their impact on HF patient management. To overcome this problem, we carefully selected the most critical possible HF decompensating factors to design MONITORIA, a non-invasive device for comprehensive HF home monitoring. MONITORIA stands for MOnitoring Non-Invasively To Overcome mortality Rates of heart Insufficiency on Ambulatory, and in this paper, which is part I of a series of three articles, we discuss the theoretical basis for its design. MONITORIA and its inherent follow-up strategy will optimize HF patient care as it is a promising device, which will essentially adapt innovation not to the disease but rather to the patients.

Lenient rate control versus strict rate control for atrial fibrillation: a protocol for the Danish Atrial Fibrillation (DanAF) randomised clinical trial

INTRODUCTION

Atrial fibrillation is the most common heart arrhythmia with a prevalence of approximately 2% in the western world. Atrial fibrillation is associated with an increased risk of death and morbidity. In many patients, a rate control strategy is recommended. The optimal heart rate target is disputed despite the results of the the RAte Control Efficacy in permanent atrial fibrillation: a comparison between lenient vs strict rate control II (RACE II) trial.Our primary objective will be to investigate the effect of lenient rate control strategy (<110 beats per minute (bpm) at rest) compared with strict rate control strategy (<80 bpm at rest) on quality of life in patients with persistent or permanent atrial fibrillation.

METHODS AND ANALYSIS

We plan a two-group, superiority randomised clinical trial. 350 outpatients with persistent or permanent atrial fibrillation will be recruited from four hospitals, across three regions in Denmark. Participants will be randomised 1:1 to a lenient medical rate control strategy (<110 bpm at rest) or a strict medical rate control strategy (<80 bpm at rest). The recruitment phase is planned to be 2 years with 3 years of follow-up. Recruitment is expected to start in January 2021. The primary outcome will be quality of life using the Short Form-36 (SF-36) questionnaire (physical component score). Secondary outcomes will be days alive outside hospital, symptom control using the Atrial Fibrillation Effect on Quality of Life, quality of life using the SF-36 questionnaire (mental component score) and serious adverse events. The primary assessment time point for all outcomes will be 1 year after randomisation.

ETHICS AND DISSEMINATION

Ethics approval was obtained through the ethics committee in Region Zealand. The design and findings will be published in peer-reviewed journals as well as be made available on ClinicalTrials.gov.

TRIAL REGISTRATION NUMBER

NCT04542785.

Prognostic significance of present atrial fibrillation on a single office electrocardiogram in patients with atrial fibrillation

BACKGROUND

Evidence for the association of atrial fibrillation (AF) present on the ECG and cardiovascular outcomes in AF patients is limited.

OBJECTIVE

To investigate the prognostic significance of AF on a single surface ECG for cardiovascular outcomes in AF patients.

METHODS

A total of 3642 AF patients were prospectively enrolled. Main exclusion criteria were rhythms other than sinus rhythm (SR) or AF. The primary end-point was a composite of all-cause death and hospitalizations for congestive heart failure (CHF). Secondary end-points were all-cause death, CHF hospitalizations, cardiovascular death, myocardial infarction, any stroke and stroke subtypes. Associations were assessed with multivariable Cox proportional hazards models.

RESULTS

Mean age was 71 years, 28% were female, and mean follow-up was 3.4 years. Patients with SR on the ECG at study enrolment (56%) were younger (69 vs. 74 years, P < 0.0001), had more often paroxysmal AF (73 vs. 18%, P < 0.0001) and fewer comorbidities. The incidence of the primary end-point was 1.8 and 3.1 per 100 person-years in patients with SR and AF, respectively. The multivariable-adjusted hazard ratio was 1.4 (95% confidence intervals 1.1; 1.7; P = 0.001) for patients with AF on the ECG compared to patients with SR. The hazard ratios (95% confidence intervals) were 1.4 (1.1; 1.8; P = 0.006) for all-cause death, 1.5 (1.2; 1.9; P = 0.001) for CHF and 1.6 (1.1; 2.2; P = 0.006) for cardiovascular death. None of the other associations were statistically significant.

CONCLUSIONS

The presence of AF in a single office ECG had significant prognostic implications with regard to mortality and CHF hospitalizations in patients with AF. These patients present a high-risk group and might benefit from intensified treatment.

Predictors of myocardial recovery in arrhythmia-induced cardiomyopathy: A multicenter study

BACKGROUND

Arrhythmia-induced cardiomyopathy (AIC) is characterized by improvement in left ventricular ejection fraction (LVEF) following arrhythmia treatment. Predictors of recovery in LVEF are not well understood.

OBJECTIVE

We evaluated predictors of AIC recovery in a large multicenter cohort.

METHODS

In total, 243 patients (age 65 ± 11, 73% male) with AIC caused by atrial fibrillation (49%), atrial tachycardia (20%), and premature ventricular contractions (PVCs; 31%) were treated and included. LVEF was assessed before and after treatment. Patients were stratified by arrhythmia duration (known [KN, n = 132] vs. unknown [UKN, n = 111]), arrhythmia type, LVEF, and presence of structural heart disease (SHD).

RESULTS

Arrhythmia treatment was rhythm control in 95%. Median arrhythmia duration in the KN group was 47 months (25-75th percentile, 24-80 months). Post treatment LVEF was higher in KN group (55.9 ± 7 vs. 46.2 ± 12%; p < .0001) but the degree of LVEF improvement was similar (21.2 ± 9 vs. 19.4 ± 11; p = .16). Comparing highest quartile (longest arrhythmia duration) versus the rest of the KN group, the extent of LVEF improvement was similar (21.5 ± 8 vs. 21 ± 9%; p = .1). Patients in lowest index LVEF quartile (n = 74) had more PVC-induced AIC, greater EF improvement after treatment (24 ± 17 vs. 19 ± 7%; p < .0001) but lower post treatment EF (45 ± 14 vs. 54 ± 8%; p < .0001) versus other patients. Patients with SHD had lower index EF (28 ± 8 vs. 34 ± 8%; p < .0001) and lower final EF (47 ± 12 vs. 56 ± 7; p ≪ .0001). In multivariate regression, low index LVEF predicted myocardial recovery (odds ratio, 11.4; p < .005).

CONCLUSIONS

In this AIC cohort, LVEF improved regardless of arrhythmia duration or type but those with PVCs had lower index LVEF and had less recovery. Low index LVEF predicted LVEF recovery following arrhythmia treatment.

Atrial Fibrillation and Heart Failure: Epidemiology, Pathophysiology, Prognosis, and Management

Atrial fibrillation (AF) and heart failure (HF) have similar risk factors, frequently coexist, and potentiate each other in a vicious cycle. Evidence suggests the presence of AF in both HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF) increases the risk of all-cause mortality and stroke, particularly when AF is incident. Catheter ablation may be an effective strategy in controlling symptoms and improving quality of life in AF-HFrEF. Strong data guiding management of AF-HFpEF are lacking largely due to its challenging diagnosis. Improving outcomes associated with these coexistent conditions requires further careful investigation.

MONITORIA: The start of a new era of ambulatory heart failure monitoring? Part I - Theoretical Rationale

Heart failure (HF) is a multifactorial chronic syndrome with progressive increasing incidence causing a huge financial burden worldwide. Remote monitoring should, in theory, improve HF management, but given increasing morbidity and mortality, a question remains: are we monitoring it properly? Device-based home monitoring enables objective and continuous measurement of vital variables and non-invasive devices should be first choice for elderly patients. There is no shortage of literature on the subject, however, most studies were designed to monitor a single variable or class of variables that were not properly assembled and, to the best of our knowledge, there are no large randomized studies about their impact on HF patient management. To overcome this problem, we carefully selected the most critical possible HF decompensating factors to design MONITORIA, a non-invasive device for comprehensive HF home monitoring. MONITORIA stands for MOnitoring Non-Invasively To Overcome mortality Rates of heart Insufficiency on Ambulatory, and in this paper, which is part I of a series of three articles, we discuss the theoretical basis for its design. MONITORIA and its inherent follow-up strategy will optimize HF patient care as it is a promising device, which will essentially adapt innovation not to the disease but rather to the patients.

Revisiting Antiarrhythmic Drug Therapy for Atrial Fibrillation: Reviewing Lessons Learned and Redefining Therapeutic Paradigms

Since the clinical use of digitalis as the first pharmacological therapy for atrial fibrillation (AF) 235 years ago in 1785, antiarrhythmic drug therapy has advanced considerably and become a cornerstone of AF clinical management. Yet, a preventive or curative panacea for sustained AF does not exist despite the rise of AF global prevalence to epidemiological proportions. While multiple elevated risk factors for AF have been established, the natural history and etiology of AF remain incompletely understood. In the present article, the first section selectively highlights some disappointing shortcomings and current efforts in antiarrhythmic drug therapy to uncover reasons why AF is such a clinical challenge. The second section discusses some modern takes on the natural history of AF as a relentless, progressive fibro-inflammatory "atriomyopathy." The final section emphasizes the need to redefine therapeutic strategies on par with new insights of AF pathophysiology.