Definition and management of arrhythmia-induced cardiomyopathy: findings from the European Heart Rhythm Association survey.

AIMS: Arrhythmia-induced cardiomyopathy (AiCM) represents a subtype of acute heart failure (HF) in the context of sustained arrhythmia. Clear definitions and management recommendations for AiCM are lacking. The European Heart Rhythm Association Scientific Initiatives Committee (EHRA SIC) conducted a survey to explore the current definitions and management of patients with AiCM among European and non-European electrophysiologists. METHODS AND RESULTS: A 25-item online questionnaire was developed and distributed among EP specialists on the EHRA SIC website and on social media between 4 September and 5 October 2023. Of the 206 respondents, 16% were female and 61% were between 30 and 49 years old. Most of the respondents were EP specialists (81%) working at university hospitals (47%). While most participants (67%) agreed that AiCM should be defined as a left ventricular ejection fraction (LVEF) impairment after new onset of an arrhythmia, only 35% identified a specific LVEF drop to diagnose AiCM with a wide range of values (5-20% LVEF drop). Most respondents considered all available therapies: catheter ablation (93%), electrical cardioversion (83%), antiarrhythmic drugs (76%), and adjuvant HF treatment (76%). A total of 83% of respondents indicated that adjuvant HF treatment should be started at first HF diagnosis prior to antiarrhythmic treatment, and 84% agreed it should be stopped within six months after LVEF normalization. Responses for the optimal time point for the first LVEF reassessment during follow-up varied markedly (1 day-6 months after antiarrhythmic treatment). CONCLUSION: This EHRA Survey reveals varying practices regarding AiCM among physicians, highlighting a lack of consensus and heterogenous care of these patients.

Treatment with catheter ablation for patients with arrhythmia-induced cardiomyopathy caused by atrial fibrillation promises a good prognosis.

Clinical outcomes after catheter ablation in patients with reduced left ventricular (LV) ejection fraction (EF) and atrial fibrillation (AF) remain unclear. This study aimed to explore the clinical outcomes of patients with arrhythmia-induced cardiomyopathy (AIC) and the influence of pharmacological treatment on clinical outcomes in patients with AIC after the procedure. Ninety-six patients with AF with a reduced LVEF (LVEF < 50%, 66.7 ± 10.9 years; 72 males) underwent AF ablation. AIC was defined as patients whose LVEF recovered ≥ 50% after catheter ablation (n = 67) and patients whose LVEF remained reduced were defined as non-AIC (n = 29). During a median follow-up of 25 (13-40) months, Kaplan-Meier analysis demonstrated that patients with AIC were associated with less frequent cardiovascular death (p = 0.025) and hospitalization for worsening heart failure (p < 0.001) than those without AIC. Freedom from AF recurrence was similar between the two groups (p = 0.47). In multivariate analysis, the LV end-diastolic diameter (p = 0.0002) and the CHA2DS2-VASc scores (p = 0.0062) were independent predictors of AIC. Among the 67 patients with AIC, no significant differences in baseline characteristics, except for LV chamber size and cryoballoon use, were observed between patients with AIC with (n = 31) and without renin-angiotensin system (RAS) inhibitors (n = 36). In the Kaplan-Meier analysis, cardiovascular death, hospitalization for worsening heart failure, and AF recurrence after catheter ablation did not differ between patients treated with and without RAS inhibitors (all p > 0.05). Catheter ablation in patients with AIC due to AF is associated with a good post-procedural prognosis.IRB information The study was approved by the Research Ethics Committee of the University of Fukui (No. 20220151) and clinical trial registration (UMIN000050391).

Atrial arrhythmias and heart failure: A "modern view" of an old paradox.

BACKGROUND: Heart failure (HF) and atrial arrhythmias (AAs) are two clinical conditions that characterize the daily clinical practice of cardiologists. In this perspective review, we analyze the shared etiopathogenetic pathways of atrial arrhythmias, which are the most common cause of atrial arrhythmias-induced cardiomyopathy (AACM) and HF. HYPOTHESIS: The aim is to explore the pathophysiology of these two conditions considering them as a "unicum", allowing the definition of a cardiovascular continuum where it is possible to predict the factors and to identify the patient phenotype most at risk to develop HF due to atrial arrhythmias. METHODS: Potentially eligible articles, identified from the Electronic database (PubMed), and related references were used for a literature search that was conducted between January 2022 and January 2023. Search strategies were designed to identify articles that reported atrial arrhythmias in association with heart failure and vice versa. For the search we used the following keywords: atrial arrhythmias, atrial fibrillation, heart failure, arrhythmia-induced cardiomyopathy, tachycardiomyopathy. We identified 620 articles through the electronic database search. Out of the 620 total articles we removed 320 duplicates, thus selecting 300 eligible articles. About 150 titles/abstracts were excluded for the following reasons: no original available data, no mention of atrial arrhythmias and heart failure crosstalk, very low quality analysis or evidence. We excluded also non-English articles. When multiple articles were published on the same topic, the articles with the most complete set of data were considered. We preferentially included all papers that could provide the best evidence in the field. As a result, the present review article is based on a final number of 104 references. RESULTS: While the pathophysiology of AACM and Heart Failure with reduced ejection fraction (HFrEF) has been studied in detail over the years, the causal link between atrial arrhythmias and heart failure with Preserved Ejection Fraction (HFpEF) has been often subject of interest. HFpEF is strictly related to AAs, which has always been considered significant risk factor. In this review we described the pathophysiological links between atrial fibrillation and heart failure. Furthermore, we illustrated and discussed the preclinical and clinical predicting factors of AF and HFpEF, and the corresponding targets of the available therapeutic agents. Finally, we outlined the patient phenotype at risk of developing AF and HFpEF (Central Illustration). CONCLUSIONS: In this review, we underline how these two clinical conditions (AF and HFpEF) represent a "unicum" and, therefore, should be considered as a single disease that can manifest itself in the same phenotype of patients but at different times. Furthermore, considering that today we have few therapeutic strategies to treat these patients, it would be good to make an early diagnosis in the initial stages of the disease or intervene even before the development of signs and symptoms of HF. This is possible only by paying greater attention to patients with predisposing factors and carrying out a targeted screening with the correct diagnostic methods. A systemic approach aimed at improving the immuno-metabolic profile of these patients by lowering the body mass index, threatening the predisposing factors, lowering the mean heart rate and reducing the sympathetic nervous system activation is the key strategy to reduce the clinical impact of this disease.

Low troponin I levels predict the presence of arrhythmia-induced cardiomyopathy in patients with atrial fibrillation and left ventricular systolic dysfunction.

Successful atrial fibrillation (AF) ablation can improve reduced left ventricular ejection fraction (LVEF) with AF, which is defined as arrhythmia-induced cardiomyopathy (AIC). However, it is difficult to pre-procedurally predict the presence of AIC. We aimed to explore the pre-procedural predictors of AIC in patients with AF and reduced LVEF. This study included 60 patients with a reduced LVEF (LVEF < 50%; 69.1 ± 8.8 years; 45 men) who underwent successful AF ablation. Responders were defined as patients whose LVEF post-procedurally improved to the normal range (≥ 50%). Multivariate analysis revealed that the log-transformed pre-procedural troponin I (TnI) levels (odds ratio [OR] = 0.059; 95% confidence interval [CI] = 0.0052-0.42, p = 0.003) and age (OR = 0.91; 95% CI = 0.82-1.00, p = 0.044) were independent predictors of post-procedural LVEF recovery; further, low TnI levels (< 11.1 pg/ml) predicted LVEF recovery (sensitivity, 79.1%; specificity, 76.5%; positive predictive value, 89.5%; and negative predictive value, 59.1%). There were no significant differences in TnI levels between the baseline and 1 month after the procedure. However, four patients with high baseline TnI levels showed a > 50% reduction in the TnI levels post-procedurally, with three of these patients showing LVEF recovery. Low pre-procedural TnI levels can predict LVEF recovery after successful AF ablation in patients with reduced LVEF.

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.

Utility of Routine Transthoracic Echocardiographic Parameters to Predict Functional Recovery after Catheter Ablation Therapy in Patients with Atrial Fibrillation and Left Ventricular Systolic Dysfunction.

Arrhythmia-induced cardiomyopathy (AIC) occurring in patients with atrial fibrillation (AF) is a reversible form of cardiomyopathy characterized by LV systolic dysfunction. However, it is difficult to predict the reversibility before rhythm control therapy. We performed this study to develop a parameter for the identification of AIC in routine transthoracic echocardiography (TTE) in patients with presumptive AIC due to AF.We retrospectively studied 72 patients treated with catheter ablation therapy for persistent AF, and LV ejection fraction (LVEF) ≤ 45%. The patients were divided into 2 groups by follow-up TTE performed within 12 ± 6 months postoperatively. Patients with ≥ 15% improvement in LVEF or ≥ 10% improvement and ≥ 50% in LVEF were classified as the AIC group, and the others were classified as the non-AIC group.A total of 57 (79%) patients were classified as the AIC group. In the stepwise multivariate logistic regression model, LV end-diastolic dimension (LVDd) and e' (septal) were independent predictors of AIC. The sensitivities of LVDd ≤ 53 mm and e' (septal) ≥ 6.3 cm/second were 60% and 75%, respectively. Their specificities were 80% and 67%, respectively. The presence of either LVDd ≤ 53 mm or e' (septal) ≥ 6.3 cm/second had a higher sensitivity (90%); their co-occurrence had a higher specificity (93%) in predicting AIC.The functional recovery in patients with AIC can occur in LV systolic dysfunction without remodeling and impairment of relaxation. The combination of LVDd and e' (septal) is useful in predicting AIC due to AF with routine TTE.

Cardiovascular magnetic resonance-based predictors of complete left ventricular systolic functional recovery after rhythm restoration in patients with atrial tachyarrhythmia.

AIMS: To establish a cardiovascular magnetic resonance (CMR)-based prediction model for complete systolic left ventricular ejection fraction (LVEF) recovery for the distinction of 'arrhythmia-induced' from 'arrhythmia-mediated' cardiomyopathy in patients with atrial tachyarrhythmias. METHODS AND RESULTS: Two hundred and fifty-three tachyarrhythmia patients referred for catheter ablation were enrolled and underwent CMR baseline imaging; patients with a reduced LVEF <50% at baseline and CMR imaging at 3-month follow-up after successful rhythm restoration constituted the final study population (n = 134). CMR at baseline consisted of standard functional cine imaging, determination of extracellular volume, and late gadolinium enhancement (LGE) imaging; follow-up CMR comprised standard functional cine imaging. Left ventricular end-diastolic volume index (LVEDVI) measurements were categorized in 'opposite', 'normal', and 'enlarged'. At follow-up, 80% (107/134) presented with complete LVEF recovery, while in 20% (27/134) persistent LVEF impairment was observed. LVEDVI and LGE were independent predictors of complete LVEF recovery with LGE adding significant incremental value on logistic regression modelling. Model-derived probabilities for complete LVEF recovery in LVEDVI categories of opposite, normal, and enlarged for LGE negativity and positivity were 94%, 85%, and 29% and 77%, 55%, and 8%, respectively. CONCLUSION: CMR-derived assessment of LVEDVI category and LGE allowed for identification of arrhythmia-induced cardiomyopathy with acceptable discriminative performance. Probabilities for complete LVEF recovery for the combination of opposite LVEDVI/LGE negativity and enlarged LVEDVI/LGE positivity were 94% and 8%, respectively. The CMR-based prediction model of complete LVEF recovery can be used to perform upfront stratification in atrial tachyarrhythmia-related LVEF impairment.

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.

[Arrhythmogenic right ventricular cardiomyopathy associated with arrhythmia-induced cardiomyopathy: A case report].

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a kind of inherited cardio-myopathy, which is characterized by fibro-fatty replacement of right ventricular myocardium, leading to ventricular arrhythmia. However, rapid atrial arrhythmias are also common, including atrial fibrillation, atrial flutter and atrial tachycardia. Long term rapid atrial arrhythmia can lead to further deterioration of cardiac function. This case is a 51-year-old male. He was admitted to Department of Cardiology, Peking University Third Hospital with palpitation and fatigue after exercise. Electrocardiogram showed incessant atrial tachycardia. Echocardiography revealed dilation of all his four chambers, especially the right ventricle, with the left ventricular ejection fraction of 40% and the right ventricular hypokinesis. Cardiac magnetic resonance imaging found that the right ventricle was significantly enlarged, and the right ventricular aneurysm had formed; the right ventricular ejection fraction was as low as 8%, and the left ventricular ejection fraction was 35%. The patients met the diagnostic criteria of ARVC, and both left and right ventricles were involved. His physical activities were restricted, and metoprolol, digoxin, spironolactone and ramipril were given. Rivaroxaban was also given because atrial tachycardia could cause left atrial thrombosis and embolism. His atrial tachycardia converted spontaneously to normal sinus rhythm after these treatments. Since the patient had severe right ventricular dysfunction, frequent premature ventricular beats and non-sustained ventricular tachycardia on Holter monitoring, indicating a high risk of sudden death, implantable cardioverter defibrillator (ICD) was implanted. After discharge from hospital, physical activity restriction and the above medicines were continued. As rapid atrial arrhythmia could lead to inappropriate ICD shocks, amiodarone was added to prevent the recurrence of atrial tachycardia, and also control ventricular arrhythmia. After 6 months, echocardiography was repeated and showed that the left ventricle diameter was reduced significantly, and the left ventricular ejection fraction increased to 60%, while the size of right ventricle and right atrium decreased slightly. According to the clinical manifestations and outcomes, he was diagnosed with ARVC associated with arrhythmia induced cardiomyopathy. According to the results of his cardiac magnetic resonance imaging, the patient had left ventricular involvement caused by ARVC, and the persistent atrial tachycardia led to left ventricular systolic dysfunction.

Exercise and Arrhythmias: A Double-Edged Sword.

Ample evidence indicates that moderate regular exercise is beneficial for both normal individuals and patients with cardiovascular (CV) disease. However, intense and strenuous exercise in individuals with evident or occult underlying CV abnormalities may have adverse effects with provocation and exacerbation of arrhythmias that may lead to life-threatening situations. Both of these aspects of exercise-induced effects are herein reviewed.

Ablation for idiopathic ventricular arrhythmia - with and without arrhythmia-induced cardiomyopathy.

OBJECTIVES: We conducted a study to assess the procedural success and long-term freedom from arrhythmia in patients treated with radiofrequency ablation (RFA) for idiopathic ventricular arrhythmia (VA) with and without arrhythmia-induced cardiomyopathy (AIC). DESIGN: We identified 131 patients treated with RFA for idiopathic VA in our institution; 16 of whom had AIC. Data were obtained from patient files. A questionnaire was used to assess the improvement in subjective symptoms late after RFA. RESULTS: At the initial RFA, any VA was abolished in 93 patients (71%), non-targeted VA still was observed in 5 patients (4%), and the targeted VA remained present in 29 (22%). In 4 patients (3%) procedural success was undeterminable. During a median follow-up time of 8 months after latest RFA, 100 patients (76%) stayed free from recurrence. We observed no difference in procedural or long-term success between patients with and without AIC. When excluding patients with fascicular ventricular tachycardia (VT), a significantly higher proportion of patients with AIC had VA originating from the left ventricle (p = 0.027). Patients with AIC had a significant improvement of ejection fraction after RFA (p < 0.001). Totally 89 of 99 patients (90%) who returned the questionnaire reported symptomatic benefit a median of 64 months after their latest procedure. CONCLUSIONS: RFA is effective for treating idiopathic VA with and without AIC, with high rates of long-term freedom from VA and symptomatic relief. We found more patients with AIC had left ventricle VA.

Clinical Characterization of Arrhythmia-Induced Cardiomyopathy in Patients With Tachyarrhythmia and Idiopathic Heart Failure.

BACKGROUND: Arrhythmia-induced cardiomyopathy (AIC) is a known entity, but prospective evidence for its characterization is limited. OBJECTIVES: This study aimed to: 1) determine the relative frequency of the pure form of AIC in the clinically relevant cohort of patients with newly diagnosed, otherwise unexplained left ventricular systolic dysfunction (LVSD) and tachyarrhythmia; 2) assess the time to recovery from LVSD; and 3) identify parameters for an early diagnosis of AIC. METHODS: Patients were prospectively included, underwent effective rhythm restoration, and were followed-up at 2, 4, and 6 months to evaluate clinical characteristics, biomarkers, and cardiac imaging including cardiac magnetic resonance imaging. Patients with recurred arrhythmia were excluded from analysis. RESULTS: 41 of 50 patients were diagnosed with AIC 6 months after rhythm restoration. Left ventricular (LV) ejection fraction increased 2 months after rhythm restoration from 35.4% ± 8.2% to 52.7% ± 8.0% in AIC patients vs 37.0% ± 9.5% to 43.3% ± 7.0% in non-AIC patients. From month 2 to 6, LV ejection fraction continued to increase in AIC patients (57.2% ± 6.1%; P < 0.001) but remained stable in non-AIC patients (44.0% ± 7.8%; P = 0.628). Multivariable logistic regression analysis revealed that lower LV end-diastolic diameter at baseline could be used for early diagnosis of AIC, whereas biomarkers and other morphological or functional parameters, including late LV gadolinium enhancement, did not show suitability for early diagnosis. CONCLUSIONS: We observed a high prevalence of AIC in patients with otherwise unexplained LVSD and concomitant tachyarrhythmia, suggesting that this condition may be underdiagnosed in clinical practice. Most patients recovered fast, within months, from LVSD. A low initial LV end-diastolic diameter may constitute an early marker for diagnosis of AIC.

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.

Echocardiographic pattern of left ventricular function recovery in tachycardia-induced cardiomyopathy patients.

AIMS: Tachycardia-induced cardiomyopathy (TCM) represents a partially reversible type of cardiomyopathy (CM) that is often underdiagnosed and cardiac chamber remodelling in TCM remains incompletely understood. We aim to explore differences in the dimensions of the left ventricle and functional recovery in patients with TCM compared with patients with other forms of CM. METHODS AND RESULTS: We identified patients with reduced ejection fraction (≤50%) and/or atrial fibrillation or flutter with a left ventricular ejection fraction that improved from baseline (≥15% in left ventricular ejection fraction at follow-up or normalization of cardiac function with at least 10% improvement). Patients were then divided into two groups: (A) TCM patients and (B) patients with other forms of CM (controls). Two hundred thirty-eight patients were included (31% female, 70 years median age), 127 patients had TCM, and 111 had other forms of CM. Patients with TCM did not significantly improve indexed left ventricular volume (LVEDVI) after treatment (60 [45, 84] mL/m2 versus 56 [45, 70] mL/m2 , P = ns) compared with controls (67 [54, 81] mL/m2 versus 52 [42, 69] mL/m2 , P < 0.001). Patients with TCM patients had significantly worse fractional shortening at baseline than controls (15.5 [12, 23] vs. 20 [13, 30], P = 0.01) and higher indexed left atrial volume (LAVI) at baseline than controls (48 [37, 58] vs. 41 [33, 51], P = 0.01) that remained dilated at follow-up (follow-up LAVI 41 [33, 52] mL/m2 ). Good predictors of TCM were: normal LVEDVI (LVEDVI < 58 mL/m2 (M) and < 52 mL/m2 (F)) (odds ratio [OR] 5.2; 95% confidence interval [CI] 2.2-13.3, P < 0.001), fractional shortening < 30% (OR 3.5; 95% CI 1.4-9.2, P = 0.009), LAVI >40 mL/m2 (OR 3.4; 95% CI 1.6-7.3, P = 0.001) and normal wall thickness left ventricle (OR 3.2; 95% CI 1.4-7.8, P = 0.008). 54% of patients with TCM demonstrated diastolic dysfunction at follow-up, without differences from controls (54% vs. 43%, P = ns). 21% of patients with TCM showed persistent heart failure symptoms at follow-up compared with 4.5% of controls, P = 0.004. CONCLUSIONS: TCM patients have a specific pattern of functional recovery with persistent remodelling of the left atria and left ventricle. Several echocardiographic parameters might help identify TCM before treatment.

Role of atrial arrhythmia and ventricular response in atrial fibrillation induced atrial remodelling.

AIMS: No studies have assessed the specific contributions of atrial fibrillation (AF)-related atrial vs. associated ventricular arrhythmia to remodelling. This study assessed the roles of atrial arrhythmia vs. high ventricular rate in AF-associated remodelling. METHODS AND RESULTS: Four primary dog-groups (12/group) were subjected to 3-week pacing: 600-b.p.m. atrial tachypacing maintaining AF [AF w/o- atrioventricular block (AVB)]; atrial tachypacing with atrioventricular-node ablation (AF+AVB) and ventricular-demand pacing (80 b.p.m.); 160-b.p.m. ventricular-tachypacing (V160) reproducing the response rate during AF; and sinus rhythm with AVB/ventricular-pacing at 80-b.p.m. (control group). At terminal study, left-atrial (LA) effective refractory period (ERP) was reduced equally in both AF groups (w/o-AVB and AF+AVB). AF-inducibility was increased strongly in AF groups (w/o-AVB and AF+AVB) and modestly in V160. AF duration was significantly increased in AF w/o-AVB but not in AF+AVB or V160. Conduction velocity was decreased in AF w/o-AVB, to a greater extent than in AF+AVB and V160. Atrial fibrous-tissue content was increased in AF w/o-AVB, AF+AVB and V160, with collagen-gene up-regulation only in AF w/o-AVB. Connexin43 gene expression was reduced only in AF w/o-AVB. An additional group of 240-b.p.m. ventricular tachypacing dogs (VTP240; to induce heart failure) was studied: vs. other tachypaced groups, VTP240 caused greater fibrosis, but no change in LA-ERP or AF-inducibility. VTP240 also increased AF duration, strongly decreased left ventricular ejection fraction, and was the only group with LA natriuretic-peptide activation. CONCLUSION: The atrial tachyarrhythmia and rapid ventricular response during AF produce distinct atrial remodelling; both contribute to the arrhythmogenic substrate, providing new insights into AF-related remodelling and novel considerations for ventricular rate-control.

Catheter ablation for atrial fibrillation in patients with congestive heart failure.

BACKGROUND: We evaluated the 1-year success rate of maintaining sinus rhythm after catheter ablation (CA) for atrial fibrillation (AF) in patients with or without congestive heart failure (CHF). METHODS: In this single-centre retrospective matched-pair cohort study of 3,018 AF patients who underwent initial CA between January 2012 and June 2018, 227 pairs with (CHF group) or without CHF (control group) were matched using propensity scores. In the CHF group, 108 patients were assigned to the arrhythmia-induced cardiomyopathy (AIC) group whose left ventricular systolic dysfunction was explained only by lasting AF or atrial tachycardia; the remaining 119 had organic heart diseases (non-AIC group). We evaluated the 1-year AF-free survival and changes in clinical findings before and after CA. RESULTS: The CHF and control groups showed similar AF-free survival; however, AIC patients had significantly better survival than non-AIC patients. AF recurrence was significantly related to CHF re-hospitalisation, which was significantly more frequent in the non-AIC group than in the AIC group. The clinical outcomes of left atrial dilation, brain natriuretic peptide level, and left ventricular ejection function improved significantly before and after CA in both groups. The degree of improvement was significantly better in the AIC group than in the non-AIC group. CONCLUSIONS: The 1-year success rate was not significantly different between the CHF and control groups. The 1-year success rate in the AIC group was similar to that in the AIC-control group and was better than that in the non-AIC group. CHF clinical outcomes were improved significantly.

Echocardiographic Evaluation of LV Function in Patients with Tachyarrhythmia and Reduced Left Ventricular Function in Response to Rhythm Restoration.

AIMS: Tachyarrhythmia due to atrial fibrillation (AF) is often associated with reduced left ventricular (LV) function and has been proposed to cause arrhythmia-induced cardiomyopathy (AIC). However, the precise diagnostics of AIC and reversibility after rhythm restoration are poorly understood. Our aim was to investigate systolic LV function in tachycardic AF and to evaluate the direct effect of rhythm restoration. METHODS: We prospectively studied 24 patients (71% male, age 65 ± 9 years) with tachycardic AF and newly diagnosed reduced left ventricular ejection fraction (LVEF). Just before and immediately after electrical cardioversion (ECV), transthoracic echocardiography was performed. Geometric as well as functional data were assessed. RESULTS: Patients presented with a heart rate (HR) of 117.4 ± 21.6/min and a 2D-/3D-LVEF of 32 ± 9/31 ± 8%. ECV to sinus rhythm normalized HR to 77 ± 11/min with an increase of 2D-/3D-LVEF to 37 ± 9/37 ± 10% (p < 0.01 vs. baseline, each). Left ventricular geometry changed with an increase of end-diastolic volume (LVEDV) while end-systolic volume (LVESV) remained unchanged. Parameters concerning myocardial deformation (global longitudinal strain (GLS), strain rate (SR)) decreased whereas the RR interval-corrected GLS (GLSc) remained unchanged. In a simple linear regression model, GLS correlated with 2D- and 3D-LVEF not only before (pre) ECV, but also after (post) ECV. We demonstrate that the increase of LVEF and GLS (ratios pre/post) correlates with the change of HR (ΔHR; R2 = 0.20, 0.33 and 0.32, p < 0.05 each), whereas ratios of GLSc and SR do not significantly correlate with HR (R2 = 0.03 and 0.01, p = n.s. each). CONCLUSION: In patients with tachyarrhythmia and reduced ejection fraction, ECV leads to immediate improvement in EF and GLS while HR-corrected LV contractility remains unchanged. This suggests that the immediate effects of rhythm restoration are mostly related to changes in left ventricular volume, but not to an acute improvement of heart-rate independent contractility.

Severe Heart Failure Associated With Tachycardia-Induced Cardiomyopathy Due to Incessant Atrioventricular Re-Entrant Tachycardia.

Short RP interval atrioventricular re-entrant tachycardias do not typically present as an incessant form. We present 2 cases of incessant atrioventricular re-entrant tachycardias leading to tachycardia-induced cardiomyopathy with severe heart failure presentation in middle-aged adults. Both underwent accessory pathway ablation and recovered normal left ventricle function before hospital discharge. (Level of Difficulty: Intermediate.).

Preprocedural Troponin T Levels Predict the Improvement in the Left Ventricular Ejection Fraction After Catheter Ablation of Atrial Fibrillation/Flutter.

Background Left ventricular (LV) systolic dysfunction is reversible in some patients once the arrhythmia is controlled. However, identifying this arrhythmia-induced cardiomyopathy among patients with LV systolic dysfunction is challenging. We explored the factors predicting the reversibility of the LV ejection fraction (LVEF) after catheter ablation of atrial fibrillation and/or atrial flutter in patients with LV systolic dysfunction. Methods and Results Forty patients with a reduced LVEF (LVEF <50%; 66.2±10.7 years; 32 men) who underwent atrial fibrillation/atrial flutter ablation were included. Transthoracic echocardiography was performed before and during the early (<4 days) and late phases (>3 months) after the ablation. Responders were defined as having a normalized LVEF (≥50%) during the late phase after the ablation. The LVEF improved from 39.8±8.8 to 50.9±10.9% at 1.2±0.6 days after the procedure, and to 56.2±12.2% at 9.6±8.0 months after the procedure (both for P<0.001). Thirty (75.0%) patients were responders. The preprocedural echocardiographic parameters were comparable between the responders and nonresponders. In the multivariate analysis, the preprocedural high-sensitivity troponin T was the only independent predictor of the recovery of the LV dysfunction during the late phase after ablation (odds ratio, 1.17; 95% CI, 1.06-1.33; P=0.001), and a level of ≤12 pg/mL predicted recovery of the LV dysfunction with a high accuracy (sensitivity, 90.0%; specificity, 76.7%; positive predictive value, 56.3%; and negative predictive value, 95.8%). Conclusions Preprocedural high-sensitivity troponin T levels might be a simple and useful parameter for predicting the reversibility of the LV systolic dysfunction after atrial fibrillation/atrial flutter ablation in patients with a reduced LVEF.