Paradoxical interatrial conduction recovery after cavotricuspid isthmus ablation: A case report.

We present a case of a patient with advanced interatrial block who was admitted for cavotricuspid isthmus ablation as treatment of typical atrial flutter. A baseline advanced interatrial block pattern turned into partial interatrial block pattern and prolonged PR interval after the procedure. We discuss the mechanism underlying that change.

Symptom burden guiding invasive electrophysiological study in paroxysmal supraventricular tachycardia: The believe SVT registry.

BACKGROUND AND OBJECTIVE: Patients with palpitations clinically suggestive of paroxysmal supraventricular tachycardia (PSVT) are often managed conservatively until ECG-documentation of the tachycardia, leading to high impact on life quality and healthcare resource utilization. We evaluated results of electrophysiological study (EPS), and ablation when appropriate, among these patients, with special focus on gender differences in management. METHODS: BELIEVE SVT is a European multicenter, retrospective registry in tertiary hospitals performing EPS in patients with palpitations, without ECG-documentation of tachycardia or preexcitation, and considered highly suggestive of PSVT by a cardiologist or cardiac electrophysiologist. We analyzed clinical characteristics, results of EPS and ablation, complications, and clinical outcomes during follow-up. RESULTS: Six-hundred eighty patients from 20 centers were included. EPS showed sustained tachycardia in 60.9% of patients, and substrate potentially enabling AVNRT in 14.7%. No major/permanent complications occurred. Minor/transient complications were reported in 0.84% of patients undergoing diagnostic-only EPS and 1.8% when followed by ablation. During a 3.4-year follow-up, 76.2% of patients remained free of palpitations recurrence. Ablation (OR: 0.34, P < .01) and male gender (OR: 0.58, P = .01) predicted no recurrence. Despite a higher female proportion among patients with recurrence, (77.2% vs 63.5% among those asymptomatic during follow-up, P < .01), 73% of women in this study reported no recurrence of palpitations after EPS. CONCLUSIONS: EPS and ablation are safe and effective in preventing recurrence of nondocumented palpitations clinically suggestive of PSVT. Despite a lower efficacy, this strategy is also highly effective among women and warrants no gender differences in management.

Impacto de la fracción de eyección del ventrículo izquierdo en el consumo de recursos, los costes y el pronóstico en pacientes con insuficiencia cardiaca / Differences in clinical outcomes, health care resource utilization and costs in heart failure patients according to left ventricular ejection fraction

Introducción y objetivos: No se conoce bien el impacto de la fracción de eyección del ventrículo izquierdo (FEVI) en el coste y la utilización de recursos sanitarios (URS) en la insuficiencia cardiaca (IC). El objetivo de nuestro trabajo es comparar el consumo de costes, la URS y el pronóstico según grupos de FEVI. Métodos: Estudio observacional retrospectivo que incluyó a todos los pacientes con diagnóstico principal de IC en urgencias o en una hospitalización en un centro terciario español durante 2018. Se excluyó la IC de nuevo diagnóstico. Se compararon los resultados clínicos, los costes y la URS según la FEVI (reducida [IC-FEr], ligeramente reducida [IC-FElr] y conservada [IC-FEc]) a 1 año. Resultados: De 1.287 pacientes con diagnóstico de IC en urgencias, 365 (28,4%) fueron dados de alta (grupo de urgencias [GU]) y 919 (71,4%), hospitalizados (GH). En total, 190 pacientes (14,7%) tenían IC-FEr; 146 (11,4%), IC-FElr y 951 (73,9%), IC-FEc. La media de edad fue 80,1±10,7 años, y el 57,1% eran mujeres. La mediana [intervalo intercuartílico] del coste por paciente-año fue de 1.889 [259-6.269] euros en el GU y 5.008 [2.747-9.589] euros en el GH (p <0,001). Los pacientes con IC-FEr del GU sufrieron más hospitalizaciones. El coste de la IC-FEr por paciente-año fue superior en ambos grupos: en el GU, 4.763 [2.076-17.155] euros con IC-FEr frente a 3.900 [590-8.013] euros con IC-FElr frente a 3.812 [259-5.486] euros con IC-FEc; en el GH, 6.321 [3.335-796] frente a 6.170 [3.189-10.484] frente a 4.636 [2.609-8.977] euros respectivamente; todos, p <0,001). Esta diferencia se debió a que los pacientes con IC-FEr ingresaron con mayor frecuencia en unidades de cuidados críticos y recibieron más pruebas diagnóstico-terapéuticas. Conclusiones: La FEVI influye significativamente en los costes y URS en la IC. Los pacientes con IC-FEr, especialmente los hospitalizados, concentran un mayor coste que aquellos con IC-FEc.(AU)

Introduction and objectives: The impact of left ventricular ejection fraction (LVEF) on health care resource utilization (HCRU) and cost in heart failure (HF) patients is not well known. We aimed to compare outcomes, HCRUs and costs according to LVEF groups. Methods: Retrospective, observational study of all patients with an emergency department (ED) visit or admission to a tertiary hospital in Spain 2018 with a primary HF diagnosis. We excluded patients with newly diagnosed heart failure. One-year clinical outcomes, costs and HCRUs were compared according to LVEF (reduced [HFrEF], mildly reduced [HFmrEF], and preserved [HFpEF]). Results: Among 1287 patients with a primary diagnosis of HF in the ED, 365 (28.4%) were discharged to home (ED group), and 919 (71.4%) were hospitalized (hospital group [HG]). In total, 190 patients (14.7%) had HFrEF, 146 (11.4%) HFmrEF, and 951 (73.9%) HFpEF. The mean age was 80.1±10.7 years; 57.1% were female. The median [interquartile range] of costs per patient/y was €1889 [259-6269] in the ED group and €5008 [2747-9589] in the HG (P <.001). Hospitalization rates were higher in patients with HFrEF in the ED group. The median costs of HFrEF per patient/y were higher in patients in both groups: €4763 [2076-17 155] vs €3900 [590-8013] for HFmrEF vs €3812 [259-5486] for HFpEF in the ED group, and €6321 [3335-796] vs €6170 [3189-10484] vs €4636 [2609-8977], respectively, in the hospital group (all P <.001). This difference was driven by the more frequent admission to intensive care units, and greater use of diagnostic and therapeutic tests among HFrEF patients. Conclusions: In HF, LVEF significantly impacts costs and HCRU. Costs were higher in patients with HFrEF, especially those requiring hospitalization, than in those with HFpEF.(AU)

Conduction system pacing and atrioventricular node ablation in heart failure: The PACE-FIB study design.

AIMS: Atrial fibrillation (AF) worsens the prognosis of patients with heart failure (HF). Successful treatments are still very scarce for those with permanent AF and preserved (HFpEF) or mildly reduced (HFmrEF) ejection fraction. In this study, the long-term benefits and safety profile of heart rate regularization through left-bundle branch pacing (LBBP) and atrioventricular node ablation (AVNA) will be explored in comparison with pharmacological rate-control strategy. METHODS AND RESULTS: The PACE-FIB trial is a multicentre, prospective, open-label, randomized (1:1) clinical study that will take place between March 2022 and February 2027. A total of 334 patients with HFpEF/HFmrEF and permanent AF will receive either LBBP followed by AVNA (intervention arm) or optimal pharmacological treatment for heart rate control according to European guideline recommendations (control arm). All patients will be followed up for a minimum of 36 months. The primary outcome measure will be the composite of all-cause mortality, HF hospitalization, and worsening HF at 36 months. Other secondary efficacy and safety outcome measures such as echocardiographic parameters, functional status, and treatment-related adverse events, among others, will be analysed too. CONCLUSION: LBBP is a promising stimulation mode that may foster the clinical benefit of heart rate regularization through AV node ablation compared with pharmacological rate control. This is the first randomized trial specifically addressing the long-term efficacy and safety of this pace-and-ablate strategy in patients with HFpEF/HFmrEF and permanent AF.

Sex differences in patterns of referral and resource utilization in the cardiology clinic: an outpatient analysis.

Aims: Women may have different management patterns than men in specialised care. Our aim was to assess potential sex differences in referral, management and outcomes of patients attending outpatient cardiac consultations. Methods and results: Retrospective observational analysis of patients ≥18 years referred for the first time from primary care to a tertiary hospital cardiology clinic in 2017-2018, comparing reasons for referral, decisions and post-visit outcomes by sex.A total of 5,974 patients, 2,452 (41.0%) men aged 59.2 ± 18.6 years and 3,522 (59.0%) women aged 64.5 ± 17.9 years (P < 0.001) were referred for a first cardiology consultation. The age-related referral rates were higher in women. The most common reasons for consultation were palpitations in women (n = 676; 19.2%) and ECG abnormalities in men (n = 570; 23.2%). Delays to cardiology visits and additional tests were similar. During 24 months of follow-up, women had fewer cardiology hospitalisations (204; 5.8% vs. 229; 9.3%; P = 0.003) and lower mortality (65; 1.8% vs. 66; 2.7%; P = 0.028), but those aged <65 years had more emergency department visits (756; 48.5% vs. 560; 39.9%, P < 0.001) than men. Conclusion: There are substantial sex differences in primary care cardiology referral patterns, including causes, rates, decisions and outcomes, which are only partially explained by age differences. Further research is needed to understand the reasons for these differences.

Compatibility of a novel temperature-controlled, irrigated radiofrequency catheter with ultra-high-density mapping.

Background: Compatibility of DiamondTemp (DT) radiofrequency (RF) catheter with the Rhythmia mapping system has not been manufacturer-reported nor its tracking accuracy reported. Methods: Consecutive patients undergoing macroreentrant atrial tachycardia ablation guided by Rhythmia and ablated using DT were prospectively enrolled. Following catheter configuration, ablation lines were performed and remapped to measure the RF tag to effective-ablation-line-center (RFT-ALC) distance. Results: Among 20 consecutive patients (54 maps), 40 ablation lines were evaluated. Overall, the RFT-ALC distance was 3.88 ± 2.95 mm, and the operator assessment of accuracy was high. No complications occurred. Conclusion: The use of DT catheter guided by the Rhythmia mapping system is feasible and accurate.

Systematic Workflow and Electrogram guidance to reduce X-ray Exposure Time during cryoballoon ablation of atrial fibrillation: the SWEET-Cryo strategy.

AIMS: Cryoballoon pulmonary vein isolation (CB-PVI) offers similar efficacy to point-by-point radiofrequency PVI for patients with atrial fibrillation (AF), but generally with higher X-ray exposure. Strategies aimed at reducing fluoroscopy mostly rely on other costly imaging techniques, limiting their applicability. We designed a Systematic Workflow and Electrogram guidance to reduce X-ray Exposure Time during CB-PVI (SWEET-Cryo) strategy and analysed its impact on fluoroscopy use and acute procedural and clinical outcomes. METHODS AND RESULTS: We enrolled 100 patients with paroxysmal or persistent AF undergoing CB-PVI by two operators with different levels of expertise. Patients treated with the SWEET-Cryo strategy (prospective cohort; n = 50) or conventional fluoroscopy (retrospective control cohort; n = 50) were compared. When applied by the senior operator, the SWEET-Cryo strategy significantly reduced the mean fluoroscopy time (FT) (2.6 ± 1.25 vs. 20.3 ± 10.8 min) and mean dose area product (DAP) (5.1 ± 3.8 vs. 35.3 ± 22.3 Gy cm2) compared with those of the control group, respectively (P < 0.001). Significant reductions in FT (6.4 ± 2.5 min vs. 32.5 ± 10.05) and DAP (13.9 ± 7.7 vs. 92.3 ± 63.8) were also achieved by the less experienced operator (P < 0.001). No difference was observed in acute and long-term complications or freedom from AF between fluoroscopy strategies during a 33-month median follow-up. Mean FT was maintained below 3 min in randomly selected cases performed during the follow-up period. CONCLUSION: In contrast to conventional protocols and regardless of the operator's experience, the optimized SWEET-Cryo strategy dramatically reduced fluoroscopy exposure during CB-PVI. The efficacy, safety, or added costs of the ablation procedure were not compromised.

Differences in clinical outcomes, health care resource utilization and costs in heart failure patients according to left ventricular ejection fraction.

INTRODUCTION AND OBJECTIVES: The impact of left ventricular ejection fraction (LVEF) on health care resource utilization (HCRU) and cost in heart failure (HF) patients is not well known. We aimed to compare outcomes, HCRUs and costs according to LVEF groups. METHODS: Retrospective, observational study of all patients with an emergency department (ED) visit or admission to a tertiary hospital in Spain 2018 with a primary HF diagnosis. We excluded patients with newly diagnosed heart failure. One-year clinical outcomes, costs and HCRUs were compared according to LVEF (reduced [HFrEF], mildly reduced [HFmrEF], and preserved [HFpEF]). RESULTS: Among 1287 patients with a primary diagnosis of HF in the ED, 365 (28.4%) were discharged to home (ED group), and 919 (71.4%) were hospitalized (hospital group [HG]). In total, 190 patients (14.7%) had HFrEF, 146 (11.4%) HFmrEF, and 951 (73.9%) HFpEF. The mean age was 80.1±10.7 years; 57.1% were female. The median [interquartile range] of costs per patient/y was €1889 [259-6269] in the ED group and €5008 [2747-9589] in the HG (P <.001). Hospitalization rates were higher in patients with HFrEF in the ED group. The median costs of HFrEF per patient/y were higher in patients in both groups: €4763 [2076-17 155] vs €3900 [590-8013] for HFmrEF vs €3812 [259-5486] for HFpEF in the ED group, and €6321 [3335-796] vs €6170 [3189-10484] vs €4636 [2609-8977], respectively, in the hospital group (all P <.001). This difference was driven by the more frequent admission to intensive care units, and greater use of diagnostic and therapeutic tests among HFrEF patients. CONCLUSIONS: In HF, LVEF significantly impacts costs and HCRU. Costs were higher in patients with HFrEF, especially those requiring hospitalization, than in those with HFpEF.

The impact of COVID-19 pandemic on pulmonary hypertension: What have we learned?

The coronavirus 2019 disease (COVID-19) pandemic threatened the Spanish health-care system. Patients with demanding conditions such as precapillary pulmonary hypertension (PH) faced a potentially severe infection, while their usual access to medical care was restricted. This prospective, unicentric study assessed the impact of COVID-19 on PH patients' outcomes and the operational changes in the PH network. Sixty-three PH patients (41 pulmonary arterial hypertension [PAH]; 22 chronic thromboembolic pulmonary hypertension [CTEPH]) experienced COVID-19. Overall mortality was 9.5% without differences when stratifying by hemodynamics or PAH-risk score. Patients who died were older (73.6 ± 5 vs. 52.2 ± 15.4; p = 0.001), with more comorbidities (higher Charlson index: 4.17 ± 2.48 vs. 1.14 ± 1.67; p = 0.0002). Referrals to the PH expert center decreased compared to the previous 3 years (123 vs. 160; p = 0.002). The outpatient activity shifted toward greater use of telemedicine. Balloon pulmonary angioplasty activity could be maintained after the first pandemic wave and lockdown while pulmonary thromboendarterectomy procedures decreased (19 vs. 36; p = 0.017). Pulmonary transplantation activity remained similar. The COVID-19 mortality in PAH/CTEPH patients was not related to hemodynamic severity or risk stratification, but to comorbidities. The pandemic imposed structural changes but a planned organization and resource reallocation made it possible to maintain PH patients' care.

Homozygous Pro1066Arg MYBPC3 Pathogenic Variant in a 26Mb Region of Homozygosity Associated with Severe Hypertrophic Cardiomyopathy in a Patient of an Apparent Non-Consanguineous Family.

MYPBC3 and MYH7 are the most frequently mutated genes in patients with hereditary HCM. Homozygous and compound heterozygous genotypes generate the most severe phenotypes. A 35-year-old woman who was a homozygous carrier of the p.(Pro1066Arg) variant in the MYBPC3 gene, developed HCM phenocopy associated with left ventricular noncompaction and various degrees of conduction disease. Her father, a double heterozygote for this variant in MYBPC3 combined with the variant p.(Gly1931Cys) in the MYH7 gene, was affected by HCM. The variant in MYBPC3 in the heterozygosis-produced phenotype was neither in the mother nor in her only sister. Familial segregation analysis showed that the homozygous genotype p.(Pro1066Arg) was located in a region of 26 Mb loss of heterozygosity due to some consanguinity in the parents. These findings describe the pathogenicity of this variant, supporting the hypothesis of cumulative variants in cardiomyopathies, as well as the modulatory effect of the phenotype by other genes such as MYH7. Advancing HPO phenotyping promoted by the Human Phenotype Ontology, the gene-disease correlation, and vice versa, is evidence for the phenotypic heterogeneity of familial heart disease. The progressive establishment of phenotypic characteristics over time also complicates the clinical description.

Clinical Utility of HeartLogic, a Multiparametric Telemonitoring System, in Heart Failure.

Telemonitoring through multiple variables measured on cardiac devices has the potential to improve the follow-up of patients with heart failure. The HeartLogic algorithm (Boston Scientific), implemented in some implantable cardiac defibrillators and cardiac resynchronisation therapy, allows monitoring of the nocturnal heart rate, respiratory movements, thoracic impedance, physical activity and the intensity of heart tones, with the aim of predicting major clinical events. Although HeartLogic has demonstrated high sensitivity for the detection of heart failure decompensations, its effects on hospitalisation and mortality in randomised clinical trials has not yet been corroborated. This review details how the HeartLogic algorithm works, compiles available evidence from clinical studies, and discusses its application in daily clinical practice.

Primary vs. Secondary Heart Failure Diagnosis: Differences in Clinical Outcomes, Healthcare Resource Utilization and Cost.

Background: There is scarce information on patients with secondary heart failure diagnosis (sHF). We aimed to compare the characteristics, burden, and outcomes of sHF with those with primary HF diagnosis (pHF). Methods: Retrospective, observational study on patients ≥18 years with emergency department (ED) visits during 2018 with pHF and sHF in ED or hospital (ICD-10-CM) diagnostic codes. Baseline characteristics, 30-day and 1-year mortality, readmission and re-ED visit rates, and costs were compared between sHF and pHF. Results: Out of the 797 patients discharged home from the ED, 45.5% had sHF, and these presented lower 1-year hospitalization, re-ED visit rates, and costs. In contrast, out of the 2,286 hospitalized patients, 55% had sHF and 45% pHF. Hospitalized sHF patients had significantly (p < 0.01) greater comorbidity, lower use of recommended HF therapies, longer length of stay (10.8 ± 10.1 vs. 9.7 ± 7.9 days), and higher in-hospital and 1-year mortality (32 vs. 25.8%) with no significant differences in readmission rates and lower 1-year re-ED visit rate. Hospitalized sHF patients had higher total costs (€12,262,422 vs. €9,144,952, p < 0.001), mean cost per patient-year (€9,755 ± 13,395 vs. €8,887 ± 12,059), and average daily cost per patient. Conclusion: Hospitalized sHF patients have a worse initial prognosis, greater use of healthcare resources, and higher costs.

The anti-aging factor Klotho protects against acquired long QT syndrome induced by uremia and promoted by fibroblast growth factor 23.

BACKGROUND: Chronic kidney disease (CKD) is associated with increased propensity for arrhythmias. In this context, ventricular repolarization alterations have been shown to predispose to fatal arrhythmias and sudden cardiac death. Between mineral bone disturbances in CKD patients, increased fibroblast growth factor (FGF) 23 and decreased Klotho are emerging as important effectors of cardiovascular disease. However, the relationship between imbalanced FGF23-Klotho axis and the development of cardiac arrhythmias in CKD remains unknown. METHODS: We carried out a translational approach to study the relationship between the FGF23-Klotho signaling axis and acquired long QT syndrome in CKD-associated uremia. FGF23 levels and cardiac repolarization dynamics were analyzed in patients with dialysis-dependent CKD and in uremic mouse models of 5/6 nephrectomy (Nfx) and Klotho deficiency (hypomorphism), which show very high systemic FGF23 levels. RESULTS: Patients in the top quartile of FGF23 levels had a higher occurrence of very long QT intervals (> 490 ms) than peers in the lowest quartile. Experimentally, FGF23 induced QT prolongation in healthy mice. Similarly, alterations in cardiac repolarization and QT prolongation were observed in Nfx mice and in Klotho hypomorphic mice. QT prolongation in Nfx mice was explained by a significant decrease in the fast transient outward potassium (K+) current (Itof), caused by the downregulation of K+ channel 4.2 subunit (Kv4.2) expression. Kv4.2 expression was also significantly reduced in ventricular cardiomyocytes exposed to FGF23. Enhancing Klotho availability prevented both long QT prolongation and reduced Itof current. Likewise, administration of recombinant Klotho blocked the downregulation of Kv4.2 expression in Nfx mice and in FGF23-exposed cardiomyocytes. CONCLUSION: The FGF23-Klotho axis emerges as a new therapeutic target to prevent acquired long QT syndrome in uremia by minimizing the predisposition to potentially fatal ventricular arrhythmias and sudden cardiac death in patients with CKD.

Remote heart failure management using the HeartLogic algorithm. RE-HEART registry.

INTRODUCTION AND OBJECTIVES: HeartLogic is a multiparametric algorithm incorporated into implantable cardioverter-defibrillators (ICD). The associated alerts predict impending heart failure (HF) decompensations. Our objective was to analyze the association between alerts and clinical events and to describe the implementation of a protocol for remote management in a multicenter registry. METHODS: We evaluated study phase 1 (the investigators were blinded to the alert state) and phases 2 and 3 (after HeartLogic activation, managed as per local practice and with a standardized protocol, respectively). RESULTS: We included 288 patients from 15 centers. In phase 1, the median observation period was 10 months and there were 73 alerts (0.72 alerts/patient-y), with 8 hospitalizations and 2 emergency room admissions for HF (0.10 events/patient-y). There were no HF hospitalizations outside the alert period. In the active phases, the median follow-up was 16 (95%CI, 15-22) months and there were 277 alerts (0.89 alerts/patient-y); 33 were associated with HF hospitalizations or HF death (n=6), 46 with minor decompensations, and 78 with other events. The unexplained alert rate was 0.39 alerts/patient-y. Outside the alert state, there was only 1 HF hospitalization and 1 minor HF decompensation. Most alerts (82% in phase 2 and 81% in phase 3; P=.861) were remotely managed. The median NT-proBNP value was higher within than outside the alert state (7378 vs 1210 pg/mL; P <.001). CONCLUSIONS: The HeartLogic index was frequently associated with HF-related events and other clinically relevant situations, with a low rate of unexplained events. A standardized protocol allowed alerts to be safely and remotely detected and appropriate action to be taken on them.

Zfhx3 Transcription Factor Represses the Expression of SCN5A Gene and Decreases Sodium Current Density (INa).

The ZFHX3 and SCN5A genes encode the zinc finger homeobox 3 (Zfhx3) transcription factor (TF) and the human cardiac Na+ channel (Nav1.5), respectively. The effects of Zfhx3 on the expression of the Nav1.5 channel, and in cardiac excitability, are currently unknown. Additionally, we identified three Zfhx3 variants in probands diagnosed with familial atrial fibrillation (p.M1260T) and Brugada Syndrome (p.V949I and p.Q2564R). Here, we analyzed the effects of native (WT) and mutated Zfhx3 on Na+ current (INa) recorded in HL-1 cardiomyocytes. ZFHX3 mRNA can be detected in human atrial and ventricular samples. In HL-1 cardiomyocytes, transfection of Zfhx3 strongly reduced peak INa density, while the silencing of endogenous expression augmented it (from -65.9 ± 8.9 to -104.6 ± 10.8 pA/pF; n ≥ 8, p < 0.05). Zfhx3 significantly reduced the transcriptional activity of human SCN5A, PITX2, TBX5, and NKX25 minimal promoters. Consequently, the mRNA and/or protein expression levels of Nav1.5 and Tbx5 were diminished (n ≥ 6, p < 0.05). Zfhx3 also increased the expression of Nedd4-2 ubiquitin-protein ligase, enhancing Nav1.5 proteasomal degradation. p.V949I, p.M1260T, and p.Q2564R Zfhx3 produced similar effects on INa density and time- and voltage-dependent properties in WT. WT Zfhx3 inhibits INa as a result of a direct repressor effect on the SCN5A promoter, the modulation of Tbx5 increasing on the INa, and the increased expression of Nedd4-2. We propose that this TF participates in the control of cardiac excitability in human adult cardiac tissue.

Impact of Coronavirus Disease 2019 on Cardiac Arrhythmia Care: Experience of a Spanish Tertiary Hospital During the Health Crisis Triggered by the First Wave of the Pandemic.

The coronavirus disease 2019 (COVID-19) pandemic has resulted in a deep restructuring of cardiovascular care, especially in the setting of cardiac arrhythmia units, which are characterized by a wide variety of clinical and interventional activities. We describe the experience of a large university hospital deeply hit during the COVID-19 health crisis (first outbreak of the pandemic), focusing on the exceptional measures implemented and their impact in terms of outcomes. We performed a retrospective study comparing the human and structural resources and the activity of a cardiac arrhythmia unit in a Spanish tertiary hospital for two consecutive periods: from January 12, 2020, to March 8, 2020 ("pre-COVID stage"), and from March 9, 2020, to May 2, 2020 ("COVID stage"). Data were contextualized within the number of confirmed COVID-19 cases in the region of Madrid. The measures implemented were promotion of non-face-to-face consultations, selection of urgent procedures, design of a "COVID-free" circuit for outpatient interventions, and protocolization for patients with COVID-19. A total of 3,526 consultations and 362 procedures were performed. During the COVID stage, the number of consultations remained stable, and the electrophysiology rooms' activity decreased by 55.2% with a relative increase in the number of urgent-hospitalized cases attended (11.8% COVID-19-positive patients). The electrophysiology rooms' activity returned to "normal" in the last week of the COVID stage, with no contagion being detected among patients or professionals. In conclusion, the measures implemented allowed us to respond safely and efficiently to the health care needs of patients with arrhythmias during the COVID-19 crisis and may be useful for other institutions facing similar situations.