Catheter ablation of atrial arrhythmias in cardiac amyloidosis: Impact on heart failure and mortality.

BACKGROUND: Atrial arrhythmias (AA) commonly affect patients with cardiac amyloidosis (CA) and are a contributing risk factor for the development of heart failure (HF). This study sought to investigate the long-term efficacy and impact of catheter ablation on HF progression in patients with CA and AA. METHODS: Thirty-one patients with CA and AA undergoing catheter ablation were retrospectively included (transthyretin-ATTR CA 61% and light chain-AL CA 39%). AA subtypes included atrial fibrillation (AFib) in 22 (paroxysmal in 10 and persistent in 12), atrial flutter (AFl) in 17 and atrial tachycardia (AT) in 11 patients. Long-term AA recurrence rates were evaluated along with the impact of sinus rhythm (SR) maintenance on HF and mortality. RESULTS: AA recurrence was observed in 14 patients (45%) at a median of 3.5 months (AFib n = 8, AT n = 6, AFl = 0). Post-cardioversion, medical therapy or catheter ablation, 10 patients (32%) remained in permanent AA. Over a median follow-up of 19 months, all-cause mortality was 39% (n = 12): 3 with end-stage HF, 5 due to late complications of CA, 1 sudden cardiac death, 1 stroke, 1 COVID 19 (and one unknown). With maintenance of SR following catheter ablation, significant reductions in serum creatinine and natriuretic peptide levels were observed with improvements in NYHA class. Two patients required hospitalization for HF in the SR maintenance cohort compared to 5 patients in the AA recurrence cohort (p = 0.1). All 3 patients with deaths secondary to HF had AA recurrence compared to 11 out of the 28 patients whom were long-term survivors or deaths not related to HF (p = 0.04). All-cause mortality was not associated with AA recurrence. CONCLUSION: This study demonstrates moderate long-term efficacy of SR maintenance with catheter ablation for AA in patients with CA. Improvements in clinical and biological status with positive trends in HF mortality are observed if SR can be maintained.

The real incidence of sudden death: Fair estimations or futile speculations?

BACKGROUND: The true incidence of sudden death remains undetermined, with controversial results from various publications over time and countries. AIM: To investigate if different estimations would reach the values usually reported for France. METHODS: Three different kinds of estimations were used. First, the number of resuscitated sudden deaths and necropsies for sudden death in the Haute-Garonne French administrative department (i.e. county) over the last 10years was expanded to the national level. Second, sudden death coding of death certificates was collected at the national level. Third, the total number of out-of-hospital cardiac arrests leading to any emergency call (with/without intervention) in Haute-Garonne over the last 10years was expanded to the national level. RESULTS: There was a mean of 26 resuscitated sudden deaths and 145 necropsies for sudden death each year in Haute-Garonne, i.e. 12 to 14 sudden deaths for 100,000 inhabitants, and 7700 to 9400 sudden deaths yearly when related to the whole French population, according to the year of inclusion. Based on death certificates, a mean of 6584 sudden deaths was registered each year in France. Finally, there were about 600 yearly calls/interventions for out-of-hospital cardiac arrests in Haute-Garonne, i.e. 40 to 50 sudden deaths for 100,000 inhabitants, and 16,000 to 27,000 sudden deaths yearly for the whole French territory, according to the year of inclusion. CONCLUSIONS: The incidence of sudden death ranges from 6500 to 27,000 in France according to the calculation methods. This huge difference raises the question of the true current incidence of sudden death, which may have been overestimated previously or may be underestimated in France. More straight prospective surveys are needed to solve this question, because of relevant implications for priorities that should be given to sudden death.

Lack of temporal correlations between COVID pandemic waves and the occurrence of malignant ventricular arrhythmias.

AIMS: Correlations between malignant ventricular arrhythmias and the COVID waves have never been investigated. METHODS AND RESULTS: Prevalence of malignant ventricular arrhythmias/sudden cardiac death has been correlated to the four COVID waves between the onset of pandemic and end 2021. No significant correlation was present in the temporal evolution of both COVID patients/positive tests and incidence of malignant ventricular arrhythmias, which tended to decrease after vaccination onset. CONCLUSION: We present evidence of complex higher-order periodicities and the co-existence of such regions with stable non-chaotic areas in ex vivo human hearts. We infer that the oscillation of the calcium cycling machinery is the primary mechanism of higher-order dynamics. These higher-order regions may act as niduses of instability and may provide targets for substrate-based ablation of VF.

Systematic use of half normal saline during ablation of ventricular tachycardia in structural heart disease.

BACKGROUND: Efficiency and safety of ablation using half normal saline (HNS) has been shown in refractory ventricular tachycardia (VT), but no evaluation in unselected larger populations has been made. OBJECTIVE: To evaluate the efficiency and safety of systematic HNS ablation in VT ablation. METHODS: All successive VT ablations in patients with structural heart disease from 2018 to 2021 used HNS in our center and were retrospectively included. RESULTS: One hundred seventy-seven successive VT ablation procedures using HNS have been performed in 148 patients (91% males, mean 64 ± 12 years, ischemic cardiomyopathy 64%, left ventricular ejection fraction 38 ± 13%). A mean of 19 ± 7.5 min of RF was delivered, with a mean power of 44 ± 7 W. Relevant complications happened in 9% (strokes 2%, tamponades 3%, atrioventricular block during septal ablations 5%). Over a mean follow-up of 15 ± 9 months, VT recurred in 46%. Final recurrence rate after one or several procedures was 36% (18 months follow-up). Number of VT episodes decreased from 14 ± 35 before to 2.5 ± 10 after ablation (p < .0001) and number of ICD shocks decreased from 4.8 ± 6.8 to 1.5 ± 0.8 (p = .027). CONCLUSION: Systematic use of HNS during VT ablations in patients with structural heart disease leads to long-term recurrences rates and complications in the range of what is reported using normal saline. Although controlled studies are needed for demonstrating the superiority of such attitude, the use of HNS in every scar-related VT ablation seems safe for standard cases and may be furthermore useful in case of refractory arrhythmias due to difficult-to-ablate substrates.

Development and validation of machine learning algorithms to predict posthypertensive origin in left ventricular hypertrophy.

BACKGROUND: Left ventricular hypertrophy is often associated with hypertension, which is not necessarily the cause of hypertrophy. Non-hypertension-related aetiologies often have a strong impact on patient management, and therefore require a thorough and careful workup. When considering all left ventricular hypertrophies, even the mild ones, the number of patients who need a workup increases drastically. This raises the need for a tool to evaluate the pretest probability of the origin of left ventricular hypertrophy. AIM: To predict the hypertensive origin of left ventricular hypertrophy using machine learning on first-line clinical, laboratory and echocardiographic variables. METHODS: We used a retrospective single-centre population of 591 patients with left ventricular hypertrophy, starting at 12mm maximal left ventricular wall thickness. After splitting data in a training and testing set, we trained three different algorithms: decision tree; random forest; and support vector machine. Model performances were validated on the testing set. RESULTS: All models exhibited good areas under receiver operating characteristic curves: 0.82 (95% confidence interval: 0.77-0.88) for the decision tree; 0.90 (95% confidence interval 0.85-0.94) for the random forest; and 0.90 (95% confidence interval: 0.85-0.94) for the support vector machine. After threshold selection, the last model had the best balance between its specificity of 0.96 (95% confidence interval: 0.91-0.99) and its sensitivity of 0.31 (95% confidence interval: 0.17-0.44). All algorithms relied on similar most influential predictor variables. Online calculators were developed and made publicly available. CONCLUSIONS: Machine learning models were able to determine the hypertensive origin of left ventricular hypertrophy with good performances. Implementation in clinical practice could reduce the number of aetiological workups needed in patients presenting with left ventricular hypertrophy.

Hemodynamical consequences and tolerance of sustained ventricular tachycardia.

AIMS: Factors underlying clinical tolerance and hemodynamic consequences of monomorphic sustained ventricular tachycardia (VT) need to be clarified. METHODS: Intra-arterial pressures (IAP) during VT were collected in patients admitted for VT ablation and correlated to clinical, ECG and baseline echocardiographical parameters. RESULTS: 114 VTs from 58 patients were included (median 67 years old, 81% ischemic heart disease, median left ventricular ejection fraction 30%). 61 VTs were untolerated needing immediate termination (54%). VT tolerance was tightly linked to the evolution of IAPs. Faster VT rates (p<0.0001), presence of resynchronization therapy (p = 0.008), previous anterior myocardial infarction (p = 0.009) and more marginally larger baseline QRS duration (p = 0.1) were independently associated with VT tolerance. Only an inferior myocardial infarction was more often present in patients with only tolerated VTs vs patients with only untolerated VTs in multivariate analysis (OR 3.7, 95% CI 1.4-1000, p = 0.03). In patients with both well-tolerated and untolerated VTs, a higher VT rate was the only variable independently associated with untolerated VT (p = 0.02). Two different patterns of hemodynamic profiles during VT could be observed: a regular 1:1 relationship between electrical (QRS) and mechanical (IAP) events or some dissociation between both. VT with the second pattern were more often untolerated compared to the first pattern (78% vs 29%, p<0.0001). CONCLUSION: This study helps to explain the large variability in clinical tolerance during VT, which is clearly related to IAP. VT tolerance may be linked to resynchronization therapy, VT rate, baseline QRS duration and location of myocardial infarction.

Correlations Between Endocardial Voltage Mapping, Diagnosis, and Genetics in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy.

The relations between endocardial voltage mapping and the genetic background of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) have not been investigated so far. A total of 97 patients with proved or suspected ARVC who underwent 3-dimensional endocardial mapping and genetic testing have been retrospectively included. Presence, localization, and size of scar areas were correlated to ARVC diagnosis and the presence of a pathogenic variant. A total of 78 patients (80%) presented with some bipolar or unipolar scar on endocardial voltage mapping, whereas 43 carried pathogenic variants (44%). Significant associations were observed between presence of endocardial scars on voltage mapping and previous or inducible ventricular tachycardia, right ventricular function and dimensions, or electrocardiogram features of ARVC. A total of 60 of the 78 patients (77%) with an endocardial scar fulfilled the criteria for a definitive arrhythmogenic right ventricular dysplasia diagnosis versus 8 of 19 patients (42%) without scar (p = 0.003). Patients with a definitive diagnosis of ARVC had more scars from any location and the scars were larger in patients with ARVC. In the 68 patients with a definitive diagnosis of ARVC, the presence of any endocardial scar was similar whether an ARVC-causal mutation was present or not. Only scar extent was significantly greater in patients with pathogenic variants. There was no difference in the presence and characteristics of scars in PKP2 mutated versus other mutated patients. The 3-dimensional endocardial mapping could have an important role for refining ARVC diagnosis and may be able to detect minor forms with otherwise insufficient criteria for diagnosis. The trend for larger scar extent were observed in mutated patients, without any difference according to the mutated genes.

Externalized Reusable Permanent Pacemaker for Prolonged Temporary Cardiac Pacing in Critical Cardiac Care Units: An Observational Monocentric Retrospective Study.

INTRODUCTION: The use of temporary cardiac pacing is frequent in critical care units for severe bradycardia or electrical storm, but may be associated with frequent and potentially severe complications, especially when indwelling for several days. In some cases, transient indication or ongoing contraindication for a permanent pacemaker justifies prolonged temporary pacing. In that case, the implantation of an active-fixation lead connected to an externalized pacemaker represents a valuable option to increase safety and patient comfort. Yet, evidence remains scarce. We aimed to describe the population receiving prolonged temporary cardiac pacing (PTCP) and their outcomes. METHODS: We retrospectively included all consecutive patients, admitted to our hospital from 2016 to 2021, who underwent PTCP. We collected in-hospital and six-month outcomes. RESULTS: Forty-six patients (median age of 73, 63% male) were included, and twenty-nine (63%) had prior heart disease. Indications for PTCP were found: seventeen (37%) potentially reversible high-grade conduction disorders, fourteen (30%) indications for permanent pacemaker but ongoing infection, seven (15%) cardiac implantable electronic device infections requiring extraction in pacing-dependent patients, seven (15%) severe vagal hyperreactivity in prolonged critical care hospitalizations, and one (2%) recurrent sustained ventricular tachycardia requiring overdrive pacing. The median PTCP duration was nine (5-13) days. Ten (22%) patients exhibited at least one complication during hospitalization. Twenty-six (56.5%) patients required definite device implantation (twenty-five pacemakers and one cardioverter-defibrillator) and twenty (43.5%) did not (fifteen PTCP device removal for recovery and five deaths under PTCP). At six months, two (5%) deaths and two (5%) new infections of a definite implanted device occurred, all in patients with initial active infection. CONCLUSION: The use of prolonged temporary cardiac pacing, with an active -fixation lead connected to an externalized pacemaker, is possible and reasonable; this would allow for the possible recovery or resolution of contraindication for definite device implantation.

Ventricular tachycardia ablation as an alternative to implantable cardioverter-defibrillators in patients with preserved ejection fraction: current status and future prospects.

INTRODUCTION: The occurrence of a sustained monomorphic ventricular tachycardia in patients with structural heart disease is a class 1 indication for ICD because of the expected relevant risk of sudden death. However, if this concerns selected patients with preserved left ventricular function and well-tolerated arrhythmias is still poorly known. AREAS COVERED: In this article, we review the available data about the natural history of nonimplanted patients with structural heart disease and sustained ventricular tachycardia and the possible role of catheter ablation alone in this population. EXPERT OPINION: In structural heart disease patients with well-tolerated sustained ventricular tachycardia and preserved LVEF, catheter ablation alone, without ICD implantation, does not seem to carry an important risk of sudden death and the prognosis of these patients is mainly nonarrhythmic. Randomized prospective trials are urgently needed for evaluating the place of first choice ablation without ICD implantation in these populations.

Prevalence, management, and outcomes of haemorrhagic events in left ventricular assist device recipients.

AIMS: Left ventricular assist devices (LVADs) have reduced the mortality of patients with advanced heart failure both as bridge-to-transplant and as destination therapy. However, LVADs are associated with various complications, including bleedings, which affect the prognosis. The aim of the study was to explore the prevalence, management, and outcomes of haemorrhagic adverse events in LVAD recipients. METHODS AND RESULTS: We conducted a retrospective, single-centre, cohort study including all patients who received an LVAD from January 2008 to December 2019 in our tertiary centre (Rangueil University Hospital, Toulouse, France). Bleeding events, death, and heart transplantation were collected from electronic medical files. Eighty-eight patients were included, and 43 (49%) presented at least one bleeding event. Gastrointestinal (GI) bleeding was the most frequent (n = 21, 24%), followed by epistaxis (n = 12, 14%) and intracranial haemorrhage (n = 9, 10%). Bleeding events were associated with increased mortality [hazard ratio (HR) 3.8, 95% confidence interval (CI) 1.5-9.3, P < 0.01], particularly in case of intracranial haemorrhage (HR 14.6, 95% CI 4.2-51.1, P < 0.0001). GI bleedings were associated with a trend towards increased mortality (HR 3.0, 95% CI 0.9-9.3, P = 0.05). Each bleeding episode multiplied the risk of death by 1.8 (95% CI 1.2-2.7, P < 0.01). Finally, only early bleedings (<9 months post-implantation) had an impact on mortality (HR 4.2, 95% CI 1.6-11.1, P < 0.01). Therapeutic management was mainly based on temporary interruption of anticoagulation and permanent interruption of antiplatelet therapy. Invasive management was rarely performed. CONCLUSIONS: Haemorrhagic events in LVAD recipients are frequent and associated with increased mortality. GI bleedings are the most frequent, and intracranial haemorrhages the most associated with mortality. Management remains empirical requiring more research.

Radiation dose during catheter ablation in children using a low fluoroscopy frame rate.

BACKGROUND: Catheter ablation (CA) in children using fluoroscopy carries risks inherent to ionizing radiation exposure. AIMS: The objective of this study was to demonstrate the feasibility of using low frames rate during ablation in children to maximally decrease radiation dose. METHODS: Hundred sixty eight successive patients<18 years of age undergoing CA performed under a 3.75 frames/second rate were retrospectively included. Demographics, procedural and dosimetry data were analysed. The effective dose (ED) was evaluated in a subgroup of 14 patients. RESULTS: Median age and weight were 15 years and 54kg, 72% had WPW, 10% AV node reentrant tachycardia, 10% ventricular tachycardia (atrial tachycardia, flutter and atrial fibrillation for the other cases). Acute success was achieved in 98.5% without any complication. Median procedure and fluoroscopy duration were 120 and 16minutes. Median Dose Area Product (DAP) and Air Kerma were 2.46Gy.cm2 and 18 mGy respectively (2Gy.cm2 and 15 mGy for WPW ablation). A significant reduction of median DAP was noted over the years for WPW, from 3.1Gy.cm2 in 2011 to 1.4 in 2019. Median estimated ED was 0.19 mSv (0.03 to 1.64), falling into the range of yearly normal natural irradiation or caused by leasure or professional activity. CONCLUSION: Low frame rate fluoroscopy is a highly effective and safe approach in decreasing radiation exposure during CA in children without altering the success rate of the procedure. ED is low, similar to natural/leisure irradiation. This approach can be considered a good alternative to 3D-based procedures in terms of efficiency and radiation issues, at least for WPW ablations.

Relationships between left ventricular mass and QRS duration in diverse types of left ventricular hypertrophy.

AIMS: Hypertrophic cardiomyopathy (HCM) may be associated with very narrow QRS, while left ventricular hypertrophy (LVH) may increase QRS duration. We investigated the relationships between QRS duration and LV mass (LVM) in subtypes of abnormal LV wall thickness. METHODS AND RESULTS: Automated measurement of LVM on MRI was correlated to automated measurement of QRS duration on ECG in HCM, left ventricular non compaction (LVNC), left ventricular hypertrophy (LVH), and controls with healthy hearts. Uni and multivariate analyses were performed between groups including explanatory variables expected to influence LVM and QRS duration. The relationships between QRS duration and LVM were further studied within each group. Two hundred and twenty-one HCM, 28 LVNC, 16 LVH, and 40 controls were retrospectively included. Mean QRS duration was 92 ms for HCM, 104 for LVNC, 110 for LVH, and 92 for controls (P < 0.01). Mean LVM was 100, 90, 108, and 68 g/m2 (P < 0.01). QRS duration, LVM, hypertension, maximal wall thickness, and late gadolinium enhancement were significantly linked to HCM in multivariate analysis (w/wo bundle branch block). An independent negative correlation was found between LVM and QRS duration in the HCM group, while the relationship was reverse in LVNC, LVH, and controls. CONCLUSION: QRS duration increases with LVM in LVNC, LVH, or in healthy hearts, while reverse relationship is present in HCM. These relationships were independent from other parameters. These results warrant additional investigations for refining diagnosis criteria for HCM in the future.

Phase analysis for ventricular arrhythmia prediction: A retrospective monocentric cohort study.

BACKGROUND: Prediction of ventricular arrhythmias (VA) mostly relies on left ventricular ejection fraction (LVEF), but with limited performance. New echocardiographic parameters such as mechanical dispersion have emerged, but acoustic window sometimes precludes this measurement. Nuclear imaging may be an alternative. We aimed to assess the ability of mechanical dispersion, measured with phase standard deviation (PSD) on radionuclide angiocardiography (RNA), to predict VAs. METHODS: This retrospective monocentric observational study included all patients who underwent a tomographic RNA from 2015 to 2019. Phase analysis yielded PSD and follow-up was examined to identify VAs, heart transplantation, and death. RESULTS: The study population consisted of 937 patients, mainly with LVEF ≤ 35% (425, 45%). Most had ischemic (334, 36%) or dilated cardiomyopathies (245, 26%). We identified 86 (9%) VAs. PSD was strongly associated with the occurrence of VA [hazard ratio per 10 ms increase (HR10) 1.12 (1.09-1.16)], heart transplantation [HR10 1.09 (1.06-1.12)], and death [HR10 1.03 (1.00-1.05)]. The association between PSD and VA persisted after adjustment for age, sex, QRS duration, LVEF, global longitudinal strain (GLS), and echocardiography-assessed mechanical dispersion. CONCLUSION: The occurrence of ventricular arrhythmias was predicted by mechanical dispersion assessed by RNA, even after adjustment for LVEF and GLS.

Premature Ventricular Contractions and Ultra-High-Definition Mapping. Contribution and Limits.

BACKGROUND: The utility of ultra-high definition mapping (UHDM) for ablation of premature ventricular contractions (PVC) remains undetermined. The aim of this study was to investigate UHDM for PVC ablation, and additionally to compare to conventional technique. METHODS: Twenty patients investigated using UHDM were prospectively included and analyzed. Electrophysiological caracteristics and results were compared to 40 patients ablated using fluoroscopy only. RESULTS: 2541±2033 EGMs and 331±240 PVC beats were recorded for each patient. Surfaces of isochronal activations were 2.3±1.7 and 6.9±6.1 cm2 (first 10 and 20 ms). Local scar was present in 40% and local block in 65%. Areas of pace-mapping > 95, 90 and 85% concordance were 1.5±3.4, 2.1±3.9 and 3.3±5 cm2. Mean distance between the ablation site and the site of best pace-mapping or of earliest activation was 8±8 mm and 5±7 mm. Pre-potential was noted in 17% vs 26% controls (ns). QS pattern was present in 83% vs 83% controls (ns), and earliest activation was - 31±50 vs - 25±14 ms in controls (ns). Procedure (100±36 vs 190±51 min, p< 0.0001) and fluoroscopy duration (15±9 vs 24±9 min, p=0.005) were shorter in controls. Acute success was achieved in 65% patients with UHDM and in 72% controls (p=ns) with lower residual PVC burden in the control group. Over a follow-up of 19±12 months, long-term success was similar between groups (65 vs 68%). CONCLUSIONS: UHDM may reveal poorly recognized activation features and PVC mechanism. In this series, conventional mapping was quicker and did clinically as well as UHDM.

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

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