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.

The applications of Wearable Cardioverter Defibrillators in Heart Failure and beyond

Abstract

Wearable cardioverter defibrillator has revealed a crucial device both in patients with a clear indication of ICD implantation but with temporary contraindications or in expectation of a diagnosis, considering that its use should be individualized.

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.

Gender differences in arrhythmias and psychological discomfort management

Funding Acknowledgements

Type of funding sources: None.

Background

Palpitations and/or syncope are common in patients with psychoneurological disorders [1]. Arrhythmias may be associated to psychological discomfort as well [2]. Psychiatrics, epidemiology and commonplace agree that gender may lead to difference in symptom perception, and management [3-4]

Purpose

To investigate the abovementioned association we realized a retrospective multicentric registry including, after definite instrumental diagnosis, patients with previous mental disorder diagnosis, referring to arrhythmology ambulatories.

Results

64 pts (48 F, 75%), mean age 54±18y, were enrolled in 7 centers. Psychiatric diagnoses were: anxiety-depression disorder (N=50), panic attack (N=5), behavioural disorder (N=4), epilepsy (N=3), psychosis (N=1), diagnosed in 83% by General Practitioners and in 14% by Psychiatrists. 55 pts (86%) were on drug therapy: benzodiazepines (67%), SSRI (22%), neuroleptics (3%), antidepressants (2%), and natural products (5%). Among these, 89% reported no symptoms relief. 57 pts complained palpitations, 17 extrasystoles and 19 reported syncope. EPS study was performed in 48%, 24 h Holter ECG in 28%, and LR implantation in 5% of patients. We diagnosed AF (N=11), typical AFL (N=4), AT (N=8), AVNRT (N=16), AVRT (N=4), PAC (N=1), PVC (N=10), AV block (N=4), VT (N=3) and unspecified SVT (N=3). 44 pts underwent ablation. 62 pts (96,8) experienced strong symptoms reduction or resolution, and 42 psychiatric drugs withdrawal. One pt underwent PMK implantation.

Conclusions

In our series of cardiac symptoms ascribed to psychiatric disorders, women markedly prevailed. Psychologic discomfort could be caused by arrhythmias, as resolved or dramatically ameliorated by diagnosis and treatment. Further investigation in Psychiatric context is warranted.

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 potential impact of acute coronary syndromes on automatic sensing system in Subcutaneous-ICDs

•

75 patients with ACS or CCS underwent S-ICD screening upon arrival and after PCI.

•

Before PCI, STEMI patients had lower screening pass rates than NSTE-ACS ones

•

STEMI was the only predictor of screening failure at multivariate regression analysis.

•

Patient selection and dynamic device programming are fundamental in ischemic subjects

Background

The Subcutaneous-ICD (S-ICD) is emerging as a suitable option for most ICD candidates, however some open issues regarding the sensing algorithm still remain.

Objectives

We aimed to examine the performance of the S-ICD sensing algorithm in patients hospitalized for ST elevation myocardial infarction (STEMI), non ST elevation acute coronary syndrome (NSTE-ACS) or chronic coronary syndrome (CCS), before and after revascularization.

Methods

We performed a S-ICD automated screening on 75 patients, 21 hospitalized for STEMI, 23 for NSTE-ACS and 31 for CCS, before and after percutaneous revascularization, regardless their eligibility to ICD implantation.

Results

Patients did not differ in clinical, electrocardiographic and echocardiographic parameters. Rates of screening pass were significantly lower in STEMI patients compared to NSTE-ACS and CCS (5% vs 56.7% vs 81% respectively, p < .0001). The viability of the primary vector was lower in STEMI patients compared to NSTE-ACS and CCS (33% vs 56% vs 71%, p .027 respectively). After revascularization, there were no more significant differences between groups. Pairing subjects at baseline and after revascularization, STEMI subjects percentages of screening success were respectively 5% and 81% (p < .001) and the rates of primary vector viability were 33% and 81% (p .002). STEMI was the only independent predictor of screening failure at multivariate logistic regression analysis (odds ratio 10.68 confidence interval 2.77–41.38, p = .001)

Conclusion

The performance of the S-ICD and possible malfunction detections in the context of an acute ischemic event deserve further evaluation. Adequate patient selection and the development of dynamic device programming are warranted.

Early rhythm-control ablation therapy in preventing AF recurrences: insight from the CHARISMA Registry

Funding Acknowledgements

Type of funding sources: None.

Background

An early and comprehensive rhythm-control therapy emerges as a need to treat AF in an effective way and to improve the ablation outcomes, in terms of arrhythmia-free survival.

Purpose

We aimed to investigate the importance of timing of ablation in preventing AF recurrences.

Methods

153 consecutive patients (pts) undergoing AF ablation from the CHARISMA registry at 8 Italian centres were included. Ablations were guided by a novel radiofrequency ablation catheter with local impedance (LI)-sensing capability through a dedicated algorithm (DirectSense, Boston Scientific). Pts were grouped as early treated (ET) if the procedure was performed within 1 year after the first AF episode and as delayed treated (DT) if admitted for ablation after more than 1 year. The ablation endpoint was PVI as assessed by entrance and exit block. Post-ablation follow-up was scheduled at 3, 6 and 12 months. AF and atrial tachycardia (AT) recurrences were considered as long-term endpoint.

Results

Of the 153 pts enrolled (69.9% male, 59 ± 10 years, 61.4% paroxysmal AF, 38.6% persistent AF), 123 (80.4%) met Class I indications, 23 (15%) Class IIa indications and 7 (4.6%) Class IIb indications according to current ESC AF guidelines. The mean time to ablation procedure from the first AF episode was 1034 ± 1483 days. Eighty pts (52.3%) were included in ET group, whereas 73 pts (47.7%) in DT group. No differences were found between AF type in terms of ablation strategy (53.3% of the cases -52 out 94- were classified as ET for paroxysmal AF vs 47.5% of the cases -28 out 59- were ET for persistent AF, p = 0.4346). At the end of the procedures, all PVs had been successfully isolated in all study pts. During a mean follow-up of 366 ± 130 days, 18 pts (11.8%) suffered an AF/AT recurrence after the 90-day blanking period. Recurrences occurred mostly in the DT group compared to the ET one (13 out 73 -17.8%- vs 5 out 80 -6.3%-, p = 0.042) and the time to AT/AF recurrence was longer in the ET group (HR = 0.2876, 95%CI: 0.1029 to 0.8038; p = 0.0181). On multivariate logistic analysis adjusted for baseline confounders, only hypertension (HR = 4.66, 95%CI: 1.5 to 14.48, p = 0.0081) was independently associated with recurrences. An early rhythm-control therapy was associated with a low risk of recurrences beyond the hypertension risk factor, ranging from 2% (no hypertension and an ET ablation therapy) to 30.3% (with hypertension and a DT procedure) (Figure 1).

Conclusion

A LI-guided ablation strategy for PVI proved to be safe and effective and resulted in a very high recurrence-free rate. An early rhythm-control therapy in the absence of common risk factors was associated with the lowest rate of recurrences. Abstract Figure. AT/AF Recurrence

Impact of channels identification and ablation in ventricular tachycardia patients through high-density mapping: preliminary experience from an Italian registry

Funding Acknowledgements

Type of funding sources: None.

Background

Ventricular tachycardia (VT) ablation techniques in ischemic cardiomyopathy have evolved during the recent years. However, the long-term success rate remains disappointing. A technique based on channel identification and ablation through a novel automated algorithm may limit the extent of ablation needed and possibly lead to higher successful rate.

Purpose

To report preliminary data on feasibility and safety of a channel identification approach and to characterize late potentials (LPs) features using an ultra-high density mapping system with a novel analysis tool in ischemic VT procedures.

Methods

Consecutive patients (pts) indicated for ischemic VT ablation were enrolled in the CHARISMA study. A complete map of the left ventricle was performed prior and after ablation through the Rhythmia mapping system. For our purpose channels were defined as any signal activity bounded by anatomic and functional barriers and characterized through a novel map analysis tool (Lumipoint-LM-) that automatically identifies fragmented late potentials (LPs) and continuous activation was used on the whole ventricular substrate. Procedural endpoint was the elimination of all identified conducting channels (CCs) by ablation at the CC entrance and exit followed by abolition of any residual LPs inside the CC. The ablation endpoint was noninducibility.

Results

A total of 18 channels were identified through LM from 14 pts: 71.4% of the pts had 1 CC, 28.6% had 2 CCs. In the majority of the cases LPs where identified only inside CCs (57.1%), whereas in 6 cases (42.9%) LPs were present both inside and outside. The mean conduction time inside CCs was 50.3 ± 30ms, the mean CC length was 32.6 ± 17mm and the conduction velocity was 0.8 ± 0.5 mm/ms. LPs covered a mean area of 7.0 ± 5mm2 (ratio between LPs area and CCs’ area = 52.4 ± 33.7%). At voltage map analysis 1 CC was present in 78.6% of the cases (2 CCs in 21.4%). LPs were identified only inside CCs in 42.9% of the cases, both inside and outside in 50% and only outside in 7.1%. Healthy tissue (voltage level≥0.5mV) was prevalent (61.2 ± 13.8%), followed by intermediate voltage areas (0.5-0.05mV; 37.5 ± 13.7%) and very low voltage areas (&lt;0.05mV; 1.2 ± 2%). LPs were found mostly at intermediate voltage areas (54.1 ± 31.7% of the covered area; 39.1 ± 28.4% at healthy tissue and 6.8 ± 17.8% at very low voltage areas). Agreement in CCs identification between advanced analysis through LM and voltage map was fair (9/14 with complete agreement). In 3 cases voltage map overestimated LPs areas, in 2 cases failed to fully identify LPs. All CCs’ entrance and exit were successfully ablated and abolition of any residual LPs inside the CC was achieved in all pts. No complication occurred. Noninducibility was achieved in all the cases.

Conclusions

In our preliminary experience, a new channel identification approach through the advanced Lumipoint algorithm seems to be safe, feasible and effective at least in the acute setting of ischemic VT ablation.

A novel local impedance algorithm to guide effective pulmonary vein isolation in AF patients: 1-year outcome from the CHARISMA Study

Background

Recently, a novel technology able to measure local tissue impedance (LI) providing a measure of tissue characteristics aimed at validating confidently ablation endpoints has become available for clinical use.

Purpose

We report the outcomes of our acute and long-term clinical evaluation of this algorithm in consecutive atrial fibrillation ablation cases.

Methods

Consecutive patients (pts) undergoing AF ablation at 6 Italian centers were included in the CHARISMA registry. A novel RF ablation catheter and a dedicated algorithm were used to measure LI through the distal catheter's electrode. The ablation was guided by looking at the magnitude and time course of impedance drop during RF delivery. The maximum distance between each ablation spot (center-to-center) was suggested to be ≤4 mm. RF applications were targeted to a LI drop of 10 Ω and RF applications were stopped when a maximum cutoff LI drop of &lt;40 Ω was observed. Successful single RF ablation was defined according with a reduction of signal voltage (RedV) by at least 50% and inability to capture local tissue on pacing. Ablation endpoint was PVI as assessed by entrance and exit block. Post-ablation, all pts were monitored with ambulatory event monitoring, as well as Holter monitoring at 3, 6, and 12 months post-ablation. Additional ECG monitoring was performed as indicated by patient symptoms.

Results

A total of 1914 point by point first pass RF applications &gt;10 s performed around PVs were analyzed from 98 pts (mean age = 61±11 years, 69% male, 55% paroxysmal AF, 45% persistent AF, 60% de novo procedures, 40% redo procedures). The mean LI was 105±15Ω prior to ablation and 92±13Ω after ablation (p&lt;0.0001, mean absolute LI drop of 12.7±8Ω) during a median RF delivery time of 22 [17–31] sec. Effective ablation spots (88%) showed a higher absolute impedance drop (13.6±8Ω at effective RedV vs 6±3Ω at ineffective RedV, p&lt;0.0001) compared with ineffective sites (12%). No steam pops or complications, including atrio-esophageal fistula or tamponade were reported during or after the procedures. At the end of the procedures all PVs were successfully isolated in all study pts. During a median follow-up of 369 [287–446] days, 13 pts (13.2%) developed an AF/AT recurrence after the 90-days blanking period (9.2% with paroxysmal vs 18% with persistent AF, p=0.239; 8.5% for de novo vs 20.5% for redo procedures, p=0.127). The time to recurrence was comparable among AF type (HR=1.97; 0.66 to 5.86; log-rank p=0.2265 for persistent vs paroxysmal AF) and procedural type (HR=2.56; 0.84 to 7.82; log-rank p=0.087 for redo vs de novo procedure)

Conclusions

In our experience, the magnitude of the LI drop during RF delivery was associated with effective lesion formation. An ablation strategy for PVI guided by LI technology was safe and effective, and resulted in a very low recurrence rate of AF at 1-year follow-up irrespective of paroxysmal/persistent AF type or de novo/redo procedure.

Funding Acknowledgement

Type of funding source: None

Late gadolinium enhancement location and transcatheter ablation efficacy in a large cohort of patients affected by myocarditis with arrhythmic manifestation

Introduction

Myocarditis is a complex inflammatory disease, usually secondary to viral infections or immune system dysregulation, with extremely heterogeneous clinical manifestations. Among them, potentially life-threatening ventricular arrhythmias (VA) may present at any stage of the disease as an expression of myocardial electrical instability.

Purpose

Our aim was to evaluate the efficacy of radiofrequency catheter ablation (RFCA) of VA in our large cohort of myocarditis, trying to understand the predictors of RFCA success.

Methods and results

144 patients (61 men; age 43 [29–54] years) with history of myocarditis with arrhythmic presentation (118 biopsy-proven, 82%) composed our population. At presentation, 26% of patients suffered of ventricular tachycardia (VT) while in 17% cardiac arrest occurred: overall 49 patients (35%) were implanted with an ICD. The median left ventricular ejection fraction (LVEF) was 58% (48–61%). An intensive non-invasive and invasive work-up was performed: 104 patients underwent cardiac magnetic resonance (CMR) that showed late gadolinium enhancement (LGE) in 67 of them (63%). In 37 patients LGE was found in the anteroseptal portion of the left ventricle: this pattern showed association with major arrhythmic relapse (VT and ventricular fibrillation) during follow up (Fig. 1; OR 4.0, CI 95% 1.14–14.1, p=0.03). 95 patients underwent endocardial RFCA, using contact electroanatomic mapping. Interestingly, in patients with anteroseptal LGE RCFA didn't affect significantly the arrhythmic relapse (OR 5, CI 95% 0.9–33, p=0.06). Otherwise RFCA prevent arrhythmic relapse in patients that showed LGE in ventricular portion other than the anteroseptal one (OR 0.027, IC 95% 0.002–0.40, p&lt;0.01). During a median follow-up of 735 days (418–2168) 6 deaths occurred: logistic regression on all-cause death showed LVEF and VT at presentation as the only independent predictors for mortality (p=0.01).

Conclusions

In myocarditis patients with VA, LGE pattern predicts arrhythmic relapse during follow-up. RFCA success rate is strictly linked to scar location, being significantly higher in patients with non-anteroseptal LGE.

Figure 1

Funding Acknowledgement

Type of funding source: None

P1005Origin, distribution and timing of the slow pathway potentials recorded inside the Kock's triangle in Avnrt patients through High-density Mapping

Background

Atrial activation during typical atrioventricular nodal reentrant tachycardia (AVNRT) exhibits anatomic variability and spatially heterogeneous propagation inside the Kock's Triangle (KT). The mechanism of the reentrant circuit has not been elucidated yet.

Purpose

To evaluate signal characteristics and find out the origin, distribution, and timing of the slow pathway (SP) potentials recorded in the KT.

Methods

The 3-D KT geometry was created during both sinus rhythm (SR) and tachycardia (TR) from the basket mapping catheter IntellaMap Orion and the Rhythmia Mapping System (Boston Scientific). The KT was divided into 8 regions moving from an antero-septal to postero-septal areas and bounded by tricuspid annulus (TA) anteriorly and tendon of Todaro (TT) posteriorly. Each area was characterized in terms of distribution and timing of Jackman (JP) and Haissaguerre (HP) potentials and signal amplitude.

Results

20 consecutive successful SP ablation cases of AVNRT were included (mean RA acquired points = 6000±1100, 275±63 inside the KT; mean KT area=29±3mm2; mean mapping time=12±5 minutes). During SR, the site of earliest atrial activation within the KT was anterior in 80% of patients whereas a midseptal activation occurred less frequently (20%). The mid-septal regions bounded by TA anteriorly and TT posteriorly showed higher prevalence of JP as compared to antero-/mid-septal regions across TT both in SR and TR (77.4% vs 4.8% during SR, p<0.0001; 84.1% vs 0% during TR, p<0.0001, respectively). HPs seemed to have variable distribution across KT (50% of these potentials recorded in antero- to mid-septal regions across TT for SR, 52.3% for TR). The median signal voltage was 0.44 [0.2–0.9] mV during SR and 0.5 [0.22–0.895] mV during TR. The mid-septal region was the area of lowest voltage compared to other regions (0.2 [0.1–0.7] mV vs 0.5 [0.4–1.5] mV for SR, p<0.0001; 0.2 [0.15–0.6] mV vs 0.6 [0.4–1.5] mV for TR, p<0.0001, respectively).

Conclusion

JPs seem to be associated with low signal-amplitude areas whereas HPs seem to have variable distribution across KT. Although not perfectly known, the typical low-high-type double potential of JP might be therefore explained by wavefront collision in the lowest area of the KT.

Acknowledgement/Funding

None

Intracardiac echocardiography in electrophysiology

Intracardiac echocardiography (ICE) is a recent, invaluable tool which can provide real-time anatomical guidance in electrophysiological procedures. By inserting intravenously an ultrasound probe and advancing it into the heart, various different views can be obtained which allow to better visualize patient anatomy, to guide the placement of electrophysiological catheters, and to detect immediately procedural complications as they occur. In atrial fibrillation ablation, ICE proves particularly useful to achieve a safer trans-septal puncture (especially in the presence of anatomical anomalies of the interatrial septum) and to help to monitor the visualization of the mapping catheters (circular, high density), or the monitoring of the balloons catheter (Cryo, Laser) position. In ventricular tachycardia ablation, on the other hand, ICE allows for continuous correlation between electrophysiological and structural findings (such as wall motion anomalies or changes in echodensity), and helps to ensure correct catheter contact and to position it, particularly around delicate structures such as the aortic cusps. In any procedure, ICE is also useful to immediately detect procedural complications, such as thrombus formation along catheters, or pericardial effusion. Thanks to its real-time morphological information, ICE provides an ideal complement to simple fluoroscopy or to more complex electroanatomic mapping techniques and is set to gain a wider role in a broad range of electrophysiological procedures.

Rate-control or rhythm-control: where do we stand?

Atrial fibrillation is the most common sustained rhythm disturbance and its prevalence is increasing worldwide due to the progressive aging of the population. Current guidelines clearly depict the gold standard management of acute symptomatic atrial fibrillation but the best-long term approach for first or recurrent atrial fibrillation is still debated with regard to quality of life, risk of new hospitalizations, and possible disabling complications, such as thromboembolic stroke, major bleeds and death. Some authors propose that regaining sinus rhythm in all cases, thus re-establishing a physiologic cardiac function not requiring a prolonged antithrombotic therapy, avoids the threat of intracranial or extracranial haemorrhages due to Vitamin K antagonists or aspirin. On the contrary, advocates of a rate control approach with an accurate antithrombotic prophylaxis propose that such a strategy may avoid the risk of cardiovascular and non cardiovascular side effects related to antiarrhythmic drugs. This review aims to explore the state of our knowledge in order to summarize evidences and issues that need to be furthermore clarified.

Prolonged Asystolia in a Young Athlete: A Case of Sinus Arrest During REM Sleep

A young asymptomatic male athlete came to our laboratory to be enrolled in a research protocol on physical fatigue. Routine clinical and cardiological evaluations including echocardiogram were in the normal range. Several consecutive cardiopulmonary tests showed a fairly good tolerance to exercise, with no symptoms even when the effort was abruptly arrested. On the other hand, Holter ECG recordings showed long nocturnal sinus pauses. As he was absolutely asymptomatic and free from any structural heart disease, he underwent a follow-up with repeated Holter monitorings for one year. During this period he decided on his own to stop practising sports; in spite of this sharp reduction in his overall physical activity, consecutive Holter monitorings showed that the sinus pauses were progressively increasing in duration (up to 9.2 seconds). With the hypothesis of a malignant vagotonia, he underwent a tilt test; however, we could not elicit any pauses or symptoms. The pauses grew longer over time; a endocavitary electrophysiologic test was performed, which showed no evidence of disease. To rule out the hypothesis of a sleep apnoea syndrome, he also underwent a polysomnography, including EEG, eye movement electromyography, arterial blood oxygen saturation and thoracic impedance: no alterations were detected with the exception of the sinus pauses, which appeared to be strictly linked to REM sleep, as suggested by the concurrent increase in rapid eye movements and desynchronized EEG. We hence made a diagnosis of sinus arrest during REM sleep (SAdRS), a very uncommon disease belonging to the parasomnias. Pauses were then quantified for one month by implanting a ECG loop recorder. As the patient became more and more upset and worried, and the pauses increased to nearly 12 seconds, we decided to implant a pacemaker, which is the only therapeutic option established in the literature for patients with SAdRS.

Clinical, electrocardiographic and electrophysiological predictors of atrial fibrillation development in different cardiac substrates

We performed a review of the current literature in order to evaluate clinical, electrocardiographic and electrophysiologic parameters predictive of atrial fibrillation development. Clinical parameters were obtained from two large observational studies (the Framingham heart study and the Cardiovascular health study). Different laboratoristic predictors were also reviewed: ECG-derived predictors, among which we separately evaluated those derived from the 12-lead surface ECG and those derived from the signal averaged P-wave, and other electrophysiologic predictors as atrial monophasic action potential analysis. We also evaluated the clinical value of these different parameters in atrial fibrillation in patients with no overt structural heart disease and in the most common clinical conditions known to be related to atrial fibrillation development such as hypertension, heart failure, cardiovascular surgery.

Late occurrence of heart block after radiofrequency catheter ablation of the septal region: clinical follow-up and outcome

INTRODUCTION

There are few data regarding the occurrence of delayed heart block at least 24 hours after radiofrequency catheter ablation (RFCA) of AV nodal reentry or posteroseptal accessory pathways (APs). We investigated the late occurrence of heart block in this population, the clinical outcome, and whether findings at electrophysiologic study could have predicted its development.

METHODS AND RESULTS

Two of 418 patients with AV nodal reentry undergoing RFCA using a posterior approach and 1 of 54 patients with RFCA of a posteroseptal AP developed late heart block. Anterograde and retrograde AV nodal conduction before and after RFCA were normal. Patients received 12, 15, and 32 RFCA lesions, respectively, using a mean maximum power of 44 W. The RFCA sites were the posterior septum for posteroseptal AP and the posterior and mid-septum for patients with AV nodal reentry, with no His electrogram ever recorded at the ablation site. During RFCA, junctional tachycardia occurred with 1:1 VA conduction in the patient with a posteroseptal AP, but occasional intermittent single retrograde blocked complexes were present in both patients with AV nodal reentry. No rapid junctional tachycardia or >1 consecutive retrograde blocked complex was ever observed during RFCA. Persistent high-degree AV block with junctional escape developed 2 days after RFCA in the posteroseptal AP patient. A permanent pacemaker was implanted, and normal conduction was noted 16 days after RFCA. Both patients with AV nodal reentry complained of fatigue, mainly on exertion, 3 to 4 days after RFCA, and ECG-documented exercise-induced variable AV block was obtained. Because heart block resolved in our initial patient, a prolonged monitoring period was allowed. Symptoms disappeared at 13 and 8 days, and a follow-up treadmill test showed normal PR interval and no heart block. No recurrence of heart block has been seen in any of these three patients.

CONCLUSION

Late unexpected heart block after RFCA of AV nodal reentry and posteroseptal AP is rare, often resolves uneventfully in 1 to 2 weeks, and no specific electrophysiologic findings predicted its occurrence. Prolonged clinical observation is preferable to immediate pacemaker implantation in such patients.

Implantable defibrillator event rates in patients with unexplained syncope and inducible sustained ventricular tachyarrhythmias: a comparison with patients known to have sustained ventricular tachycardia

OBJECTIVES

To assess the clinical significance of inducible ventricular tachyarrhythmias among patients with unexplained syncope.

BACKGROUND

Induction of sustained ventricular arrhythmias at electrophysiology study in patients with unexplained syncope and structural heart disease is usually assigned diagnostic significance. However, the true frequency of subsequent spontaneous ventricular tachyarrhythmias in the absence of antiarrhythmic medications is unknown.

METHODS

In a retrospective case-control study, the incidence of implantable cardiac defibrillator (ICD) therapies for sustained ventricular arrhythmias among patients with unexplained syncope or near syncope (syncope group, n = 22) was compared with that of a control group of patients (n = 32) with clinically documented sustained ventricular tachycardia (VT). Sustained ventricular arrhythmias were inducible in both groups and neither group received antiarrhythmic medications. All ICDs had stored electrograms or RR intervals. Clinical variables were similar between groups except that congestive cardiac failure was more common in the syncope group.

RESULTS

Kaplan-Meier analysis of the time to first appropriate ICD therapy for syncope and control groups produced overlapping curves (p = 0.9), with 57 +/- 11% and 50 +/- 9%, respectively, receiving ICD therapy by one year. In both groups, the induced arrhythmia was significantly faster than spontaneous arrhythmias, but the cycle lengths of induced and spontaneous arrhythmias were positively correlated (R = 0.6, p < 0.0001). During follow-up, three cardiac transplantations and seven deaths occurred in the syncope group, and two transplantations and five deaths occurred in the control group (36-month survival without transplant 52 +/- 11% and 83 +/- 7%, respectively, p = 0.03).

CONCLUSIONS

In patients with unexplained syncope, structural heart disease and inducible sustained ventricular arrhythmias, spontaneous sustained ventricular arrhythmias occur commonly and at a similar rate to patients with documented sustained VT. Thus, electrophysiologic testing in unexplained syncope can identify those at risk of potentially life-threatening tachyarrhythmias, and aggressive treatment of these patients is warranted.

Electrograms for identification of the atrial ablation site during catheter ablation of accessory pathways

BACKGROUND

Catheter ablation of accessory pathways using radiofrequency current has been shown to be effective in patients with Wolff-Parkinson-White syndrome, by using either the ventricular or atrial approach. However, the unipolar electrogram criteria for identifying a successful ablation at the atrial site are not well established.

METHODS AND RESULTS

One hundred patients with Wolff-Parkinson-White were treated by delivering radiofrequency energy at the atrial site. Attempts were considered successful when ablation (disappearance of the delta wave) occurred in < 10 seconds. In eight patients with concealed pathway, the accessory pathway location was obtained by measuring the shortest V-A interval either during ventricular pacing or spontaneous or induced reciprocating tachycardia. In 92 patients both atrioventricular valve annuli were mapped during sinus rhythm, in order to identify the accessory pathway (K) potential before starting the ablation procedure. When a stable filtered (30-250 Hz) "unipolar" electrogram was recorded, the following time intervals were measured: (1) from the onset of the atrial to the onset of the K potential (A-K); (2) from the onset of the delta wave to the onset of the K potential (delta-K); and (3) from the onset of the K potential to the onset of the ventricular deflection (K-V). During unsuccessful versus successful attempts, A-K (51 +/- 11 ms vs 28 +/- 8 ms, P < 0.0001 for left pathways [LPs]; and 44 +/- 8 ms vs 31 +/- 8 ms, P < 0.02 for right pathways [RPs]) and delta-K intervals (2 +/- 9 ms vs -18 +/- 10 ms, P < 0.0001 for LPs; and 13 +/- 7 ms vs 5 +/- 8 ms, P < 0.02 ms for RPs) were significantly longer.

CONCLUSIONS

Short A-K interval (< 40 ms), and a negative delta-K interval recorded from the catheter positioned in the atrium are strong predictors of successful ablation of LPs and RPs. Therefore, the identification of the K potential appears to be of paramount importance for positioning of the ablation catheter, followed by analysis of A-K and delta-K unipolar electrogram intervals. However, it appears that the mere recording of K potential is not, per se, predictive of successful outcome, but rather the A-K and delta-K interval.

[Transcatheter radiofrequency ablation in supraventricular tachycardia in children: immediate results and mid-term follow-up]

OBJECTIVES

The purpose of this study was to evaluate the efficacy and safety of radiofrequency ablation of supraventricular tachycardias due to a reentry circuit in a group of closely followed-up pediatric patients.

PATIENTS

Forty-six pediatric patients (mean age 12.6 years, range 3-18) underwent a total of 48 radiofrequency ablation procedures for reciprocating supraventricular tachycardia. Thirty-nine had an orthodromic reentry tachycardia, 6 an atrioventricular node reentry tachycardia and 1 a permanent junctional reciprocating tachycardia.

METHODS

To ablate the overt accessory pathways, the Kent potential (K) was identified and then the shortest A-K, and delta wave-K intervals were measured. The shortest V-A interval was identified for those concealed. For the left-sided accessory pathways, we used the retrograde transaortic approach in 10 procedures and the transseptal approach in 18. Atrioventricular node reentry tachycardia was ablated at the site where the slow-pathway electrogram was recorded. Follow-up clinical data, electrocardiogram, 24-hours Holter monitoring and transesophageal atrial stimulation were obtained and evaluated.

RESULTS

Early: We performed a total of 48 procedures. Among 41 procedures performed in the 39 patients with accessory pathway, 38 were successful (92,6%). Mean fluoroscopy time was 31 +/- 18 min. For left sided accessory pathways, mean fluoroscopy time of procedures with retrograde approach was 45 +/- 10 min and with transseptal 23 +/- 12 min (p < 0.01). Ablation of slow-pathway in patients with intranodal reentry tachycardia was successful in 3/6 cases (50%). The patient with permanent junctional reciprocating tachycardia was successfully ablated. Late: All patients are alive and none was lost during the follow-up after a mean time of 12.9 months (range 5-33). Success at last follow-up was 100% in patients with an accessory pathway and 33% in patients with atrioventricular node reentry. In patient with permanent junctional reciprocating tachycardia, the arrhythmia appeared again one month after the procedure, thus a second successful attempt was performed.

COMPLICATIONS

Major complications (6,5%) including a right femoral vein thrombosis (one patient), an hematoma without pulse loss (one patient) and a non-sustained monomorphic ventricular tachycardia (one patient).

CONCLUSIONS

Our data show high efficacy of radiofrequency ablation in pediatric patients with accessory pathways. The risks are low at follow-up evaluation, but might be helpful a longer-term follow-up in order to evaluate the risk of a long fluoroscopy time and the arrhythmogenic effect of the scar.