Five waves of COVID-19 pandemic in Italy: results of a national survey evaluating the impact on activities related to arrhythmias, pacing, and electrophysiology promoted by AIAC (Italian Association of Arrhythmology and Cardiac Pacing)

BACKGROUND

The subsequent waves of the COVID-19 pandemic in Italy had a major impact on cardiac care.

METHODS

A survey to evaluate the dynamic changes in arrhythmia care during the first five waves of COVID-19 in Italy (first: March-May 2020; second: October 2020-January 2021; third: February-May 2021; fourth: June-October 2021; fifth: November 2021-February 2022) was launched.

RESULTS

A total of 127 physicians from arrhythmia centers (34% of Italian centers) took part in the survey. As compared to 2019, a reduction in 40% of elective pacemaker (PM), defibrillators (ICD), and cardiac resynchronization devices (CRT) implantations, with a 70% reduction for ablations, was reported during the first wave, with a progressive and gradual return to pre-pandemic volumes, generally during the third-fourth waves, slower for ablations. For emergency procedures (PM, ICD, CRT, and ablations), recovery from the initial 10% decline occurred in most cases during the second wave, with some variability. However, acute care for atrial fibrillation, electrical cardioversions, and evaluations for syncope showed a prolonged reduction of activity. The number of patients with devices which started remote monitoring increased by 40% during the first wave, but then the adoption of remote monitoring declined.

CONCLUSIONS

The dramatic and profound derangement in arrhythmia management that characterized the first wave of the COVID-19 pandemic was followed by a progressive return to the volume of activities of the pre-pandemic periods, even if with different temporal dynamics and some heterogeneity. Remote monitoring was largely implemented during the first wave, but full implementation is needed.

Detectable reentrant circuits in localized microreentrant tachycardias in the era of ultra high-density mapping

Funding Acknowledgements

Type of funding sources: None.

Background

Optimal criteria in clinical practice differentiating microreentrant atrial tachycardias (mAT) from macroreentrant atrial arrhythmias (MAT) have not yet been clarified. The use of multielectrode catheters and the recent development of ultra high-density mapping (UHDM) with automated features has improved our knowledge of mAT circuits and foci location.

Purpose

In the present study, we systematically evaluated AT mechanisms in a large consecutive cohort of patients with MAT identifying the precise mAT circuits using the Rhythmia mapping system.

Methods

Consecutive patients indicated for MAT ablation from January 2021 to November 2021 at 33 centers were prospectively included. All MATs were completely mapped in the left or right atrium by means of the Rhythmia mapping system and the 64-poles Orion basket catheter. For study purpose, a mAT was defined as an AT with slow continuous low fragmented potentials covering at least 50% of tachycardia cycle length (CL) in a small area (set as a circuit within < 1 cm2) and in a couple of closed splines of the Orion catheter and a centrifugal activation pattern to the remainder of the atria. The Lumipoint tool was systematically used to confirm EGM fragmentation inside this area. Data are reported as mean±SD.

Results

One-hundred eighty-seven MATs were analyzed: 100 (53.7%) atypical left atrial flutter, 27 (14.3%) left AT and 60 (32%) right AT. A total of 7 MAT (prevalence of 3.7%) was identified as mATs (6 atypical left atrial flutter and 1 AT), with 5 out 7 with a previous history of AF ablation procedure. The percentage of atrial surface with a voltage level below 0.1 mV was 19±17%. The CL was 329±78ms. The electrical activity spanning the whole CL was detected by 2±0.6 pairs of close bipoles of the Orion catheter, and was actually confined to a region of 0.4±0.2cm2 with continuous highly fractionated potential covering 68±10% of the CL (longest component of fractionated EGM per spline=74±18% of the CL). Voltage level was 0.3±0.1mV at RF delivery site and 0.2±0.1mV at the site of longest duration of the fragmented potential, respectively. Targeted mAT activity was identified closer to PVs in three cases and at the mid portion of the anterior wall and at the roof in two cases each, respectively. In all cases a single shot RF delivery terminated each arrhythmia at targeted location. Consolidative RF ablations were then delivered in the adjacent area. No complication occurred. At three months follow-up all patients remained free from any AT recurrence.

Conclusions

In this standard of care clinical experience with UHDM system, the prevalence of mAT seems to be higher than previously reported in literature. A technique based on mAT identification through a novel automated algorithm and matched area of electrogram fractionation captured by the Orion catheter may limit the extent of ablation needed.

Ventricular tachycardia channels ablation incorporating automated high-density mapping guidance: data from the CHARISMA registry

Funding Acknowledgements

Type of funding sources: None.

Background

Ventricular tachycardia (VT) ablation targeting conducting channels (CC)s based on timing of late potentials (LPs) during sinus rhythm (dechanneling) may facilitate a scar homogenization strategy without the need for extensive ablation and possibly lead to higher successful rate.

Purpose

We evaluated the feasibility and safety of a CC identification and ablation approach by means of an ultra-high density mapping system with a novel automated algorithm in ischemic VT procedures.

Methods

Consecutive patients indicated for ischemic VT ablation were prospectively included. A complete map of the left ventricle was performed prior and after ablation through the Rhythmia mapping system. Channels were defined as any signal activity bounded by anatomic and functional barriers and characterized through the Lumipoint (LM) tool and continuous activation was used on the whole ventricular substrate. Procedural end point was the elimination of all identified CCs by ablation at the CC entrance and exit followed by abolition of any residual LPs inside the CC. The ablation endpoint was noninducibility. Data are reported as mean±SD.

Results

A total of 36 channels were identified through LM from 28 patients (1.2±0.5 per patient): 21 (75%) patients had 1 CC, 6 (21.4%) had 2 CCs and 1 (3.6%) had 3 CCs. LPs were identified inside CCs in 19 cases (67.9%). In 8 cases (28.6%) LPs were present both inside and outside and in 1 (3.6%) case LPs were present only outside the CC. LPs inside channels covered an area of 7.6±5 mm2 with a ratio between LPs area and CCs’ area of 67.4±31.8%. In 12 (43%) cases LPs area covered more than 90% of the CCs’ area. At voltage map analysis a total of 34 CC were identified: 1 CC was present in 75% of the cases, 2 CCs in 17.9% and 3 CCs in 3.6%. LPs were identified only inside CCs in 46.4% of the cases, both inside and outside in 42.9% and only outside in 10.7%. Healthy tissue (voltage level≥0.5mV) was prevalent (68.2±17%), followed by intermediate voltage areas (0.5-0.05 mV; 31.1±17%) and very low voltage areas (<0.05mV; 0.7±1%). LPs were found mostly at intermediate voltage areas (57.0±34% of the covered area; 39.1±33% at healthy tissue and 3.4±13% at very low voltage areas). LM was more accurate than traditional voltage mapping in identifying CCs: in 6 (21.4%) cases voltage map overestimated LPs areas, in 2 (7.1%) cases failed to fully identify LPs and only in 19 out 28 (67.8%) LM and voltage map had a complete agreement. All CCs’ entrance and exit were successfully ablated and abolition of any residual LPs inside the CC was achieved in all patients. No complication occurred. Noninducibility was achieved in all (100%) the cases.

Conclusions

In this experience, a channel identification approach through the advanced Lumipoint tool was more accurate than traditional voltage mapping and seems to be safe, feasible, and effective at least in the acute setting of ischemic VT ablation.

The magnitude and the course of local impedance drop to guide successful AF ablation: insight from an Italian registry

Funding Acknowledgements

Type of funding sources: None.

Background

It has been demonstrated that an ablation strategy based on local impedance (LI) algorithm is helpful in guiding successful ablation of atrial fibrillation (AF) cases. How the magnitude and the course of LI drop could impact the effectiveness of ablation has to be proved.

Purpose

We aimed to evaluate LI drop characteristics in predicting effective radiofrequency (RF) ablation of consecutive AF cases.

Methods

Consecutive patients undergoing AF ablation at 8 Italian centers were included in the CHARISMA registry. A RF ablation catheter equipped with mini-electrodes technology and a dedicated algorithm was used to measure LI and to guide ablation. For our purpose, we defined the time to drop (τ) as the time for the first deflection of LI drop to the plateau. RF applications were targeted to a LI drop of 10 Ω and were stopped when a maximum cut-off LI drop of <40 Ω was observed. Successful single RF ablation was defined according with a reduction of signal voltage by at least 50% and inability to capture local tissue on pacing. The ablation endpoint was PVI as assessed by entrance and exit block. Follow-up were scheduled at 3, 6 and 12 months post-ablation.

Results

153 consecutive patients (61% paroxysmal AF, 39% persistent AF) were enrolled in the study. 3556 point-by-point first-pass RF applications of >10 s duration were performed around PVs. The mean LI drop was 13 ± 8Ω, the mean τ was 18.7 ± 13s and the median LI drop/τ was 0.67 [QI-QIII, 0.37 – 1.17] Ω/s. Both absolute drops in LI and LI drop/τ were greater at successful ablation sites (n = 3122, 88%) than at ineffective ablation sites (n = 434, 12%) (14 ± 8Ω vs 6 ± 4Ω, p < 0.0001 for LI; 0.73[0.41–1.25]Ω/s vs 0.35[0.22–0.59]Ω/s for LI drop/τ, p < 0.0001). Every 5-point increment in LI drop was associated with successful ablation, with an OR of 3.13 (95%CI: 2.7 to 3.6, p < 0.0001), reaching the highest point when a value larger than 15 Ω was observed (99.9% of acute success). A significant trend was observed from lower to higher LI drop/τ values and a value greater than 0.65 Ω/s (best cut-off value on the basis of the ROC analysis) was significantly associated with successful RF delivery with an OR of 5.54 (95%CI: 4.31 to 7.11, p < 0.0001). No complications occurred during and after procedures. At 1-year follow-up, the AF recurrence rate was 12% after the 90-day blanking period.

Conclusions

The magnitude and time-course of the LI drop during RF delivery were associated with effective lesion formation. This ablation strategy for PVI guided by LI technology proved safe and effective, and resulted in a very low rate of AF recurrence over 1-year follow-up.

Prognostic role of left ventricular late gadolinium enhancement (LV-LGE) in patients who received implantable cardioverter defibrillator (ICD) for secondary prevention

Introduction

LV myocardial fibrosis detected as LGE on cardiac magnetic resonance (CMR) is a predictor of arrhythmic risk in primary prevention both in ischaemic and non-ischaemic cardiomyopathy. However, we still do not know the prognostic role of LV-LGE in patients who suffered cardiac arrest (CA).

Purpose

To evaluate the prognostic role of CMR, and in particular of LV-LGE suggesting myocardial scar, in predicting appropriate ICD interventions in secondary prevention patients.

Methods

Ninety-seven consecutive patients 1) aged ≥14 years 2) hospitalized for CA because of ventricular arrhythmias from 2009/01/01 3) who underwent/undergoing a CMR within one month from the event 4) who received/receiving an ICD for secondary prevention and 5) with at least 1 year-follow-up, were enrolled for this multicentric study.

Results

97 patients (68 males, 70%), mean age 46±16 years, were enrolled. Seventy-six percent of patients received bystander cardiopulmonary resuscitation (CPR) and ventricular fibrillation (VF) was the first rhythm in 86% of cases. ST elevation was present in 18% of cases at the admission; however, angiography was found negative in 80% of patients. Myocardial oedema and LGE were identified in 26% and 64% of patients respectively. A diagnosis was made in 83.5% of cases, while in the remaining 16.5% CA was considered idiopathic. During a four-year-follow-up, 25% of patients had appropriate ICD therapy (10% of which ATP only). A significant correlation between LGE and appropriate ICD intervention was not found (p=0.89).

Conclusions

One fourth of patients who received ICD for secondary prevention had appropriate ICD therapy during a four-year-follow-up. In this setting, LV-LGE does not provide a prognostic value.

Funding Acknowledgement

Type of funding source: None

Novel occlusion tool software for pulmonary vein occlusion verification in atrial fibrillation cryoballoon ablation

Background

Optimal pulmonary vein (PV) occlusion, checked with selective contrast injection, is mandatory to obtain an effective PV isolation with a cryoballoon.

Purpose

The purpose of this study was to verify the feasibility of a new dielectric sensing system in assessing PV occlusion during cryoballoon ablation in patients with atrial fibrillation (AF).

Methods

We enrolled 25 consecutive patients with paroxysmal or persistent AF. After transseptal access a detailed image reconstruction of left atrium and PVs was achieved with a decapolar circular mapping catheter and a novel dielectric imaging system. The degree of PV occlusion with the inflated cryoballoon catheter was verified by a new occlusion tool software of the dielectric imaging system and compared to the angiography with dye injection in each PV.

Results

A total of 114 PV cryoballoon occlusion were tested. The new occlusion tool software showed a 91.7% sensitivity and 81.5% specificity in assessing a complete PV occlusion verified with dye injection. The positive predictive value was 84.6% and the negative predictive value was 89.8%. Acute isolation was achieved in all PVs. No 30 days complications were observed.

Conclusion

This is the first study that demonstrates the feasibility of a new occlusion tool software, using the novel dielectric imaging system, in verifying the degree of PV occlusion during cryoballoon ablation.

Funding Acknowledgement

Type of funding source: None

Minimal fluoroscopy approach in current clinical practice with a novel ablation technology for supraventricular tachycardia: a large multicenter experience from an Italian registry

Background

Electrophysiological studies and ablation procedures expose both physicians and patients to a large amount of radiation. Most of 3-D mapping systems provide improved tracking of catheters, possibly allowing relevant reductions in radiation exposure. No data exists on the ability of the Rhythmia mapping system to minimize fluoroscopy time and dose.

Purpose

To report preliminary data on feasibility and safety of a minimal fluoroscopic approach using the Rhythmia mapping system in supraventricular tachycardia (SVT) procedures.

Methods

Consecutive patients indicated for arrhythmia ablation were enrolled in the CHARISMA study at 12 centers. For our purpose consecutive right-side procedures performed through a minimal fluoroscopy approach with the Rhythmia mapping system were analyzed. A 3D geometry of chambers of interest was reconstructed on the basis of the electroanatomic information taken from the mapping system. Fluoroscopy was used only if deemed necessary.

Results

This analysis included 266 patients (mean age = 57±17 years, 57% male) undergoing SVT procedures (120 AVNRT, 91 AFL, 32 AP, 11 AT and 12 other right atrial procedures). In all cases, diagnostic EP and ablation catheters were positioned using a low fluoroscopic electroanatomic guided approach. The mean fluoroscopy time needed for each procedure was 55±128 s. The median reconstructed RA volume was 92 [63–131] ml in a median mapping time of 11 [7–17] min. The median number of radiofrequency ablations to terminate each arrhythmia was 6 [3–12] (total RF delivery time of 291 [180–505] s). Sixty-five percent of the procedures (n=174) were completed with less than 10 s of fluoroscopy. Low fluoroscopy approach with less than 10 s (minimal fluoroscopy approach) was most frequently obtained in case of AVNRT (91, 76%) compared to other arrhythmias' ablation (83, 57%, p=0.001) Achievement of a minimal fluoroscopic approach was not affected by operator's experience (65% vs 66%, p=1.00, respectively within physician with more or less of 10 years of active practice), whereas it was affected by presence of a fellow in training during the procedure (72% without fellow vs 26% with fellow, p<0.0001). A 100% rate of acute success was observed, and no procedure-related complications occurred. At multivariate logistic regression analysis adjusted for baseline confounders, both the total number of RF ablations (OR: 0.93 (95% CI:0.88 to 0.96; p=0.0053) and the presence of a fellow in training during the procedure (OR: 0.29; 95% CI: 0.1 to 0.87; p=0.0278) had an inverse association to the achievement of a minimal fluoroscopic approach.

Conclusions

In our preliminary experience, arrhythmias' ablation through minimal fluoroscopy approach with the use of a novel ablation technology seems to be safe, feasible, and effective in common right atrial arrhythmias. Use of fluoroscopy can be dramatically reduced in most cases, without any reduction of the safety and acute effectiveness profile.

Funding Acknowledgement

Type of funding source: None