Is electrical cardioversion independently associated with infarcts on brain magnetic resonance imaging or clinical outcomes in patients with atrial fibrillation?

BACKGROUND: Electrical cardioversion (ECV) is frequently performed in symptomatic atrial fibrillation. OBJECTIVE: This study aimed to assess the association of ECV with infarcts on brain magnetic resonance imaging (bMRI) and clinical outcomes. METHODS: The Swiss Atrial Fibrillation Cohort Study included 2386 patients; 1731 patients were evaluated by bMRI. ECVs were recorded by questionnaire. Patients were assigned to categories by number of ECVs performed before enrollment (0, 1, ≥2). A bMRI study was conducted at baseline and after 2 years (n = 1227) and analyzed for large noncortical or cortical infarcts and small noncortical infarcts. Clinical outcomes were recorded during follow-up. Associations of ECV and outcome measures were assessed by multivariate analyses. RESULTS: There was no independent association between the number of ECVs and infarct prevalence (large noncortical or cortical infarcts and small noncortical infarcts) on baseline bMRI (ECV 1 vs 0: odds ratio [OR], 0.95 [95% CI, 0.68-1.24]; ECV ≥2 vs 0: OR, 1.04 [0.72-1.44]) or between ECVs performed during follow-up and new infarcts on bMRI at 2 years (OR, 1.46 [0.54-3.31]). ECVs were not associated with overt stroke or transient ischemic attack (ECV 1 vs 0: hazard ratio [HR], 1.36 [0.88-2.10]; ECV ≥2 vs 0: HR, 1.53 [0.94-2.48]), hospitalization for heart failure (ECV 1 vs 0: HR, 1.06 [0.82-1.37]; ECV ≥2 vs 0: HR, 1.03 [0.77-1.38]), or death (ECV 1 vs 0: HR, 0.90 [0.70-1.15]; ECV ≥2 vs 0: HR, 0.91 [0.69-1.20]). CONCLUSION: There was no association between ECV performed before enrollment and cerebral infarcts on baseline bMRI or between ECV performed during follow-up and new infarcts at 2 years. Moreover, ECV was not associated with clinical events.

Impact of comorbidity on complication rates and life expectancy in patients with a leadless pacemaker.

BACKGROUND: Knowledge about impact of age and comorbidities on outcome in patients with leadless pacemakers (LPM) is limited. OBJECTIVES: To analyse outcome in LPM patients according to age and comorbidities. METHODS: This Swiss, multi-centre, retrospective analysis includes all patients with LPM implanted between 2015 and 2022. Charlson-Comorbidity-Index (CCI) was determined and patients were divided into a low- (CCI ≤ 5) and high- comorbidity (CCI > 5) group. Peri-procedural complications, in-hospital death, and all-cause mortalities were assessed. Finally, all-cause mortality according to three groups (CCI ≤ 3, 4-5, >5) was compared to age and sex-adjusted mortality in the general Swiss population. RESULTS: 863 patients (median age 81 years, 65% male, 42% with CCI > 5) were included. Peri-procedural/long-term complication rates did not differ between the low- vs. high-comorbidity groups (2.6% vs. 1.7%, p = 0.48 and 1.2% vs. 2.8%, p = 0.12, respectively). In-hospital (3.6% vs. 0.6%, p = 0.002) and all-cause mortality (HR 2.9, 95%CI 2.2-3.8, p < 0.001) were significantly higher in the high-comorbidity group resulting in a three-year mortality of 58% (95%CI 51-65%) vs. 22% (95%CI 17-27%) in the low-comorbidity group. In patients with a CCI ≤ 3, all-cause mortality was comparable to the age- and sex-adjusted mortality of the general Swiss population. CONCLUSIONS: In elderly patients with high comorbidity, LPM implantation was not associated with increased peri-procedural/long-term complications. All-cause mortality in LPM patients with a CCI ≤ 3 was comparable to age- and sex-adjusted mortality in the general Swiss population. Despite a relatively high three-year mortality due to competing risk factors, LPM implantation is safe, even in elderly patients with high comorbidity. CONDENSED ABSTRACT: In this Swiss, multi-centre, retrospective cohort analysis, 863 patients implanted with a leadless pacemaker were included and divided into a high-comorbidity (with a CCI > 5) and low-comorbidity (with a CCI ≤ 5) group. There was no between group difference in terms of implantation outcomes and peri-operative or long-term complications. Furthermore, all-cause mortality during follow-up in patients with a CCI ≤ 3 was comparable to age- and sex-adjusted mortality in the general Swiss population. These data indicate that LPM implantation is a safe procedure, even in elderly patients with high comorbidity.

[Arrhythmias in thyroid dysfunction]. / Arrhythmien bei Schilddrüsenerkrankungen.

Thyroid dysfunction is associated with characteristic changes in heart rate and arrhythmias. Thyroid hormones act through genomic and non-genomic effects on myocytes and influence contractility, relaxation and action potential duration through a variety of mechanisms. Atrial fibrillation is the most common arrhythmia associated with thyroid dysfunction, it occurs in both euthyroidism and hyperthyroidism in clear association with T4 levels. Mechanistically, in the hyperthyroid state, increased automaticity and triggered activity, together with a shortened refractory period and slowing of the conduction speed, lead to the initiation and maintenance of multiple intraatrial reentry circuits. Influences from the autonomic nervous system and hemodynamics controlled by thyroid hormones act as modulators for arrhythmias, which are promoted by a corresponding substrate (significant impact of comorbidities). Concerning therapy, in addition to treating hyperthyroidism, the initial therapeutic focus is on adequate rate control and anticoagulation in patients with a high risk of thromboembolism. Ablation of atrial fibrillation can be considered later on, although there is an increased likelihood of recurrence compared to patients without hyperthyroidism.Prolongation of the QT interval and increase in QT dispersion are involved in the formation of ventricular arrhythmias. Epidemiological data suggest an association of elevated T4 levels with ventricular arrhythmias and sudden cardiac death. However, this seems to be mainly relevant for patients with underlying cardiac disease (e.g. ICD users).

Prevalence and outcomes of heart failure phenotypes in patients with atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is common in patients with heart failure (HF). Real-world data about long-term outcomes and rhythm control interventions use in AF patients with and without HF remain scarce. METHODS: AF patients from two prospective, multicentre studies were classified based on the HF status at baseline into: HF with preserved ejection fraction (HFpEF), HF with reduced or mildly reduced ejection fraction (HFrEF/HFmrEF), and no HF. The prespecified primary outcome was risk of HF hospitalisation. Other outcomes of interest included mortality, cardiovascular events, AF progression, and quality of life. RESULTS: A total of 1265 patients with AF were analysed (mean age 69.6 years, women 27.4%) with a median follow-up of 5.98 years. Patients with HFpEF (n = 126) had a 2.69-fold and patients with HFrEF/HFmrEF (n = 308) had a 2.12-fold increased risk of HF hospitalisation compared to patients without HF (n = 831, p < 0.001). Similar results applied for all-cause and cardiovascular mortality. The risk for AF progression was higher for patients with HFpEF and HFrEF/HFmrEF (6.30 and 6.79 per 100 patient-years, respectively) compared to patients without HF (4.20). The use of rhythm control strategies during follow-up was least in the HFpEF population (4.56 per 100 patient-years) compared to 7.74 in HFrEF/HFmrEF and 8.03 in patients with no HF. With regards to quality of life over time, this was worst among HFpEF patients. CONCLUSIONS: The presence of HFpEF among patients with AF carried a high risk of HF hospitalisations and AF progression, and worse quality of life. Rhythm control interventions were rarely offered to HFpEF patients. These results uncover an unmet need for enhanced therapeutic interventions in patients with AF and HFpEF.

Heart rate variability and stroke or systemic embolism in patients with atrial fibrillation.

BACKGROUND: Stroke remains one of the most serious complications in atrial fibrillation (AF) patients and has been linked to disturbances of the autonomic nervous system. OBJECTIVE: The purpose of this study was to test the hypothesis that impaired cardiac autonomic function might be associated with an enhanced stroke risk in AF patients. METHODS: A total of 1922 AF patients who were in either sinus rhythm (SR group; n = 1121) or AF (AF group; n = 801) on a 5-minute resting electrocardiographic (ECG) recording were enrolled in the study. Heart rate variability triangular index (HRVI), standard deviation of normal-to-normal intervals, root mean square root of successive differences of normal-to-normal intervals, mean heart rate, 5-minute total power, and power in the high-frequency, low-frequency, and very-low-frequency ranges were calculated. Cox regression models were constructed to examine the association of heart rate variability (HRV) parameters with the composite endpoint of stroke or systemic embolism. RESULTS: Mean age was 71 ± 8 years in the SR group and 75 ± 8 years in the AF group. Thirty-seven patients in the SR group (3.4%) and 60 patients in the AF group (8.0%) experienced a stroke or systemic embolism during follow-up of 5 years. In patients with SR, HRVI <15 was the strongest HRV parameter to be associated with stroke or systemic embolism (hazard ratio 3.04; 95% confidence interval 1.3-7.0; P = .009) after adjustment for multiple confounders. In the AF group, no HRV parameter was found to be associated with the composite endpoint. CONCLUSION: HRVI measured during SR on a single 5-minute ECG recording is independently associated with stroke or systemic embolism in AF patients. HRV analysis in SR may help to improve risk stratification in AF patients.

Pulmonary Vein Isolation for Atrial Fibrillation: Comparison of a Very High-Power Very Short-Duration (vHPvSD) Ablation Protocol versus a Hybrid Ablation Approach-Procedural and Mid-Term Outcome Data.

Background: Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is a standard-of-care treatment in the rhythm control strategy of symptomatic atrial fibrillation (AF). Ablation protocols, varying in the power and duration of energy delivery, have changed rapidly in recent years. Very high-power very short-duration ablation (vHPvSD) is expected to shorten procedural times compared to conventional ablation approaches. However, the existing data suggest that this might come at the cost of lower first-pass isolation rates, a predictor of poor ablation long-term outcomes. This study aims to compare a vHPvSD protocol to a hybrid strategy, in which the power and duration of the energy transfer are adapted depending on the anatomical location. Methods: We retrospectively analyzed procedural and outcome data from 93 patients (55 vHPvSD vs. 38 hybrid) scheduled for de novo pulmonary vein isolation. A vHPvSD ablation protocol (90 Watt (W), 4 s) was compared to a hybrid protocol using vHPvSD on the posterior wall and 50 W HPSD (high-power short-duration) ablation guided by the Ablation Index along the remaining spots. Results: Ablation times were significantly shorter in the vHPvSD cohort (5.4 min. vs. 14.2 min, p < 0.001), thus resulting in a significant reduction in the overall procedural duration (91 min vs. 106 min, p = 0.003). The non-significant slightly higher first-pass isolation rates in the vHPvSD cohort (85% vs. 76%, p = 0.262) did not affect freedom from AF 6 months after the procedure (83% vs. 87%, p = 0.622). Conclusions: vHPvSD helps in shortening the PVI procedural duration, thus neither affecting first-pass isolation rates nor freedom from atrial tachyarrhythmia recurrence at 6 months after the index procedure.

[Heart failure with preserved left ventricular ejection fraction (HFpEF)].

INTRODUCTION: Heart failure with preserved left ventricular ejection fraction (HFpEF) is a common and very important disease entity because of its association with frequent repeat hospitalization and high mortality. Hallmarks of the underlying pathophysiology include a small left ventricular cavity due to concentric remodeling, impaired left ventricular compliance and left atrial dysfunction. This leads to an increase in left atrial and pulmonary pressure on exertion and in advanced stages of the disease already at rest with consecutive exertional dyspnea and exercise intolerance. Additional cardiovascular mechanisms including atrial fibrillation, chronotropic incompetence and coronary artery disease as well as non-cardiac co-morbidities contribute to a variable extent to the clinical picture. The diagnostic work-up is demanding and complex but the concepts have significantly improved during the last years. The study results of the Sodium Glucose cotransporter-2 inhibitors (SGLT-2-inhibitors) have revolutionized the treatment of HFpEF. In the present article, we provide an overview about the current understanding of the pathophysiology of HFpEF, the principles of the diagnostic pathways and a summary of the intervention studies in the field, and we propose an approach for the treatment in clinical practice.

Pulmonary and Systemic Hemodynamics in Patients with Hyperthyroidism.

BACKGROUND: There is an association between hyperthyroidism and pulmonary hypertension. However, the prevalence of pulmonary hypertension in hyperthyroidism and the underlying mechanisms are incompletely defined. METHODS: Consecutive patients with severe hyperthyroidism, mostly due to Graves disease, were included in this single-center study. Echocardiographic assessment of pulmonary hemodynamics was performed at the time of hyperthyroidism diagnosis (baseline) and after normalization of thyroid hormones (follow-up; median 11 months). In a subset of patients, right heart catheterization and noninvasive assessment of central hemodynamics was performed. RESULTS: Among all 99 patients, 31% had pulmonary hypertension at baseline. The estimated systolic pulmonary artery pressure correlated significantly with the estimated left ventricular filling pressure (E/e'). The invasively measured systolic pulmonary artery pressure correlated well with the estimated systolic pulmonary artery pressure. Cardiac output, E/e', left and right ventricular dimensions were significantly reduced from baseline to follow-up, whereas the estimated pulmonary vascular resistance did not differ. Diastolic blood pressure was significantly higher at follow-up, with no change in systolic blood pressure. The central systolic blood pressure, however, exhibited a trend for a reduction at follow-up, while the pulse wave velocity was significantly lower at follow-up. CONCLUSIONS: Approximately one-third of patients with hyperthyroidism have evidence of pulmonary hypertension. Our data suggest that an increased cardiac output and left ventricular filling pressure are the main mechanisms underlying the elevated systolic pulmonary artery pressure in hyperthyroidism, whereas there is no evidence of significant pulmonary vascular disease.