Evolution of the impact of the COVID-19 pandemic on heart transplant recipients: Decreasing risk, improving perspective.

BACKGROUND AND METHODS: Heart transplant recipients (HTr) have a higher probability of suffer from severe coronavirus disease-2019 (COVID-19) in comparison to general population, but their risk has changed over the course of the pandemic in relation to various factors. We conducted a prospective study including all HTr at risk of COVID-19 in a tertiary center between February 2020 and October 2022. The aim was to analyze how the prognosis (incidence of pneumonia and mortality) of COVID-19 in HTr has evolved over time, contextualizing variants, vaccination, and other treatments. RESULTS: Of 308 HTr included, 124 got the infection (39.2%). COVID and non-COVID HTr had similar baseline characteristics. COVID-19 patients with pneumonia had a poorer prognosis than those with less severe presentations, with a higher rate of hospitalization (93.3 vs. 14.1%, p < .001) and death (41.0 vs. 1.2%, p < .001). Multivariate analysis identified age ≥60 years (odds ratio [OR] 3.65, 95% confidence interval [CI] 1.16-11.49, p = .027), and chronic kidney disease ≥3a (OR 4.95, 95% CI 1.39-17.54, p = .014) as predictors of pneumonia. Two-dose vaccination (OR 0.20, CI 95% 0.05-0.72, p = .02) and early remdesivir administration (OR 0.17, CI 0.03-0.90, p = .037) were protective factors. Over the course of the pandemic considering three periods in the follow-up (prevaccination February-December 2020, postvaccination January-December 2021, and post early remdesivir indication January-October 2022), we observed a reduction in pneumonia incidence from 62% to 19% (p < .001); and mortality (from 23% to 4%, p < .001). CONCLUSIONS: The prognosis of COVID-19 in HTr has improved over time, likely due to vaccination and early administration of remdesivir.

Bayesian analysis of the Substrate Ablation vs. Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia trial.

BACKGROUND AND AIMS: Bayesian analyses can provide additional insights into the results of clinical trials, aiding in the decision-making process. We analysed the Substrate Ablation vs. Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia (SURVIVE-VT) trial using Bayesian survival models. METHODS AND RESULTS: The SURVIVE-VT trial randomized patients with ischaemic cardiomyopathy and monomorphic ventricular tachycardia (VT) to catheter ablation or antiarrhythmic drugs (AAD) as a first-line strategy. The primary outcome was a composite of cardiovascular death, appropriate implantable cardioverter-defibrillator shocks, unplanned heart failure hospitalizations, or severe treatment-related complications. We used informative, skeptical, and non-informative priors with different probabilities of large effects to compute the posterior distributions using Markov Chain Monte Carlo methods. We calculated the probabilities of hazard ratios (HR) being <1, <0.9, and <0.75, as well as 2-year survival estimates. Of the 144 randomized patients, 71 underwent catheter ablation and 73 received AAD. Regardless of the prior, catheter ablation had a >98% probability of reducing the primary outcome (HR < 1) and a >96% probability of achieving a reduction of >10% (HR < 0.9). The probability of a >25% (HR < 0.75) reduction of treatment-related complications was >90%. Catheter ablation had a high probability (>93%) of reducing incessant/slow undetected VT/electric storm, unplanned hospitalizations for ventricular arrhythmias, and overall cardiovascular admissions > 25%, with absolute differences of 15.2%, 21.2%, and 20.2%, respectively. CONCLUSION: In patients with ischaemic cardiomyopathy and VT, catheter ablation as a first-line therapy resulted in a high probability of reducing several clinical outcomes compared to AAD. Our study highlights the value of Bayesian analysis in clinical trials and its potential for guiding treatment decisions. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03734562.

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.

Clinical relevance of adding intravascular ultrasound to coronary angiography for the diagnosis of extrinsic left main coronary artery compression by a pulmonary artery aneurysm in pulmonary hypertension.

OBJECTIVES: We sought to assess the clinical value of adding intravascular ultrasound (IVUS) evaluation to coronary angiography (CA) to guide extrinsic left main coronary artery (LMCA) compression diagnosis and treatment in pulmonary hypertension (PH). BACKGROUND: LMCA compression due to a pulmonary artery aneurysm (PAA) is a severe complication of PH. Although guidelines encourage the use of IVUS for LMCA disease evaluation, it has hardly been used in this scenario. METHODS: We analyzed morbimortality of type 1 and 4 PH patients with clinically suspected LMCA compression by a PAA between 2010 and 2018 in a reference unit. LMCA compression was prospectively assessed with CA ± IVUS. Angiographic-LMCA compression was considered conclusive when LMCA stenosis>50% was present in four predetermined projections; inconclusive, when LMCA stenosis>50% was present in <4 projections and negative if no stenosis>50% was present. Patients with conclusive and inconclusive CA underwent IVUS. IVUS-LMCA compression was defined as systolic minimum lumen area < 6 mm2 . RESULTS: LMCA compression was suspected in 23/796 patients (3%). CA was conclusive for compression in 7(30.5%), inconclusive in 9(39%), and negative in 7(30.5%). IVUS confirmed LMCA compression in 6/7(86%) patients with conclusive CA and in 2/9(22%) with inconclusive CA. Patients fulfilling IVUS criteria for LMCA compression underwent stent implantation. At 20 months follow-up a composite end-point of death, stent restenosis/thrombosis, or lung transplant was reported in three patients (13%). CONCLUSIONS: CA can misdiagnose LMCA extrinsic compression. IVUS discriminates better whether significant compression by a PAA exists or not, avoiding unnecessary LMCA stenting. Patients treated following this strategy show a low rate of major clinical events at 20 months follow-up.

Paroxysmal and persistent atrial fibrillation ablation outcomes with the pulmonary vein ablation catheter GOLD duty-cycled phased radiofrequency ablation catheter: quality of life and 12-month efficacy results from the GOLD Atrial Fibrillation Registry.

AIMS: The GOLD AF Registry has been designed to prospectively assess the population, indications, and outcomes using second-generation phased radiofrequency (RF) ablation (pulmonary vein ablation catheter GOLD) in a global examination of standard-of-care use for the treatment of paroxysmal and persistent atrial fibrillation (AF). METHODS AND RESULTS: GOLD AF (NCT02433613) is a prospective, observational, multi-centre registry designed to characterize efficacy and safety of phased RF ablation in patients with AF. The primary endpoint was freedom from AF recurrence at 12-month follow-up after a 90-day blanking period. Ancillary objectives include safety, procedural efficiency, and quality of life (QoL). The QoL assessment using the Atrial Fibrillation Effect on QualiTy-of-Life (AFEQT) and the European Heart Rhythm Association (EHRA) Score of AF-related symptoms was collected at baseline and 12 months. In total, 1054 patients were included in this analysis (age 60.6, 67.6% male, 26.5% PersAF). Kaplan-Meier estimate of freedom from AF recurrence was 77.7% at 12 months. Peri-procedural device or procedure-related complications were observed in 26 (2.5%) patients, with a low stroke rate of 0.3%. One-year post-ablation, the EHRA AF Symptom score decreased in 68% of patients. The AFEQT score improvement was observed in 88.4% and 90.4% of patients who completed the questionnaire in-person or interviewed by phone at 12 month follow-up, respectively. CONCLUSION: Phased RF ablation for the treatment of paroxysmal and persistent AF demonstrated a 77.7% freedom from AF recurrence at 12 months in addition to a significant reduction in arrhythmia symptoms and clinically meaningful improved QoL. Low peri-procedural complication rate of <3% was reported.

Multiple ICD shocks in a patient with dilated cardiomyopathy: What is the mechanism?

We present the case of a 45-year-old male patient with dilated cardiomyopathy who suffers from multiple implantable cardioverter defibrillator (ICD) shocks. The analysis of the ICD tracing and the electrophysiological study allows to conclude that bundle branch re-entrant tachycardia is the most likely diagnosis, even in absence of conduction abnormalities in his basal electrocardiography.

Fibroblast growth factor-23 promotes rhythm alterations and contractile dysfunction in adult ventricular cardiomyocytes.

BACKGROUND: Cardiac dysfunction and arrhythmia are common and onerous cardiovascular events in end-stage renal disease (ESRD) patients, especially those on dialysis. Fibroblast growth factor (FGF)-23 is a phosphate-regulating hormone whose levels dramatically increase as renal function declines. Beyond its role in phosphorus homeostasis, FGF-23 may elicit a direct effect on the heart. Whether FGF-23 modulates ventricular cardiac rhythm is unknown, prompting us to study its role on excitation-contraction (EC) coupling. METHODS: We examined FGF-23 in vitro actions on EC coupling in adult rat native ventricular cardiomyocytes using patch clamp and confocal microscopy and in vivo actions on cardiac rhythm using electrocardiogram. RESULTS: Compared with vehicle treatment, FGF-23 induced a significant decrease in rat cardiomyocyte contraction, L-type Ca2+ current, systolic Ca2+ transients and sarcoplasmic reticulum (SR) load and SR Ca2+-adenosine triphosphatase 2a pump activity. FGF-23 induced pro-arrhythmogenic activity in vitro and in vivo as automatic cardiomyocyte extracontractions and premature ventricular contractions. Diastolic spontaneous Ca2+ leak (sparks and waves) was significantly increased by FGF-23 via the calmodulin kinase type II (CaMKII)-dependent pathway related to hyperphosphorylation of ryanodine receptors at the CaMKII site Ser2814. Both contraction dysfunction and spontaneous pro-arrhythmic Ca2+ events induced by FGF-23 were blocked by soluble Klotho (sKlotho). CONCLUSIONS: Our results show that FGF-23 reduces contractility and enhances arrhythmogenicity through intracellular Ca2+ mishandling. Blocking its actions on the heart by improving sKlotho bioavailability may enhance cardiac function and reduce arrhythmic events frequently observed in ESRD.

Super-response to cardiac resynchronization therapy may predict late phrenic nerve stimulation.

Aims: Changes in the anatomical relationship between left phrenic nerve and coronary veins may occur due to the reverse remodelling observed in super-responders to cardiac resynchronization therapy (CRT) and might be the underlying mechanism in patients developing late-onset phrenic nerve stimulation (PNS) without evidence of lead dislodgement (LD). In this study, we sought to evaluate the role of super-response (SR) to CRT as a potential predictor of late-onset PNS. Methods and results: Consecutive patients implanted with a left ventricular (LV) lead in a single centre were retrospectively analysed. Phrenic nerve stimulation was classified as 'early' when it occurred within 3 months of implantation and 'late' for occurrences thereafter. 'Late' PNS was considered related to LD (LD-PNS) when LV threshold differed by > 1 V or impedance >250 Ω from baseline values or in case of radiological displacement. Cases not meeting the former criteria were classified as 'non-LD-PNS'. Super-response was defined as a decrease ≥30% of the left ventricluar end-systolic volume at 1-year echocardiography. At 32 ± 7 months follow-up, PNS occurred in 20 of 139 patients. Late non-LD-PNS incidence was significantly higher in the SR group (8/61; 13.1%) when compared with the non-SR (1/78; 1.3%) (P = 0.010). Super-response remained the only predictor of non-LD-PNS at multivariate analysis (odds ratio: 11.62, 95% confidence interval 1.41-95.68, P = 0.023). Conclusion: Incidence of late non-LD-PNS is higher among SR to CRT, suggesting a potential role of the changes in the anatomical relationship between left phrenic nerve and coronary veins.

Entrapment of "PV-Tracker" guidewire in the pulmonary veins during atrial fibrillation ablation with PVAC Gold.

We report the entrapment of Pulmonary Vein Ablation Catheter (Medtronic, Minneapolis, MN, USA) and its guidewire within the right pulmonary veins in two patients. The catheters could be retrieved without complications but they were disabled in both cases. This nondescribed incident should be recognized by PVAC users since it may be a source of potential severe complications during pulmonary vein isolation procedures.

Randomized comparison of intravenous procainamide vs. intravenous amiodarone for the acute treatment of tolerated wide QRS tachycardia: the PROCAMIO study.

AIMS: Intravenous procainamide and amiodarone are drugs of choice for well-tolerated ventricular tachycardia. However, the choice between them, even according to Guidelines, is unclear. We performed a multicentre randomized open-labelled study to determine the safety and efficacy of intravenous procainamide and amiodarone for the acute treatment of tolerated wide QRS complex (probably ventricular) tachycardia. METHODS AND RESULTS: Patients were randomly assigned to receive intravenous procainamide (10 mg/kg/20 min) or amiodarone (5 mg/kg/20 min). The primary endpoint was the incidence of major predefined cardiac adverse events within 40 min after infusion initiation. Of 74 patients included, 62 could be analysed. The primary endpoint occurred in 3 of 33 (9%) procainamide and 12 of 29 (41%) amiodarone patients (odd ratio, OR = 0.1; 95% confidence interval, CI 0.03-0.6; P = 0.006). Tachycardia terminated within 40 min in 22 (67%) procainamide and 11 (38%) amiodarone patients (OR = 3.3; 95% CI 1.2-9.3; P = 0.026). In the following 24 h, adverse events occurred in 18% procainamide and 31% amiodarone patients (OR: 0.49; 95% CI: 0.15-1.61; P: 0.24). Among 49 patients with structural heart disease, the primary endpoint was less common in procainamide patients (3 [11%] vs. 10 [43%]; OR: 0.17; 95% CI: 0.04-0.73, P = 0.017). CONCLUSIONS: This study compares for the first time in a randomized design intravenous procainamide and amiodarone for the treatment of the acute episode of sustained monomorphic well-tolerated (probably) ventricular tachycardia. Procainamide therapy was associated with less major cardiac adverse events and a higher proportion of tachycardia termination within 40 min.