Distal Versus Proximal Radial Artery Access for Cardiac Catheterization: 1-Year Outcomes.

Proximal radial artery (PRA) access for cardiac catheterization is safe but can jeopardize subsequent use of the artery because of occlusion. Distal radial artery (DRA) access in the anatomical snuffbox preserves the RA but safety and potential detrimental effects on hand function are unknown. We aimed to assess hand function and complications after DRA and PRA. In this single-center trial, 300 patients were randomly allocated 1:1 to cardiac catheterization through DRA or PRA. The primary end point of change in hand function from baseline to 1 year was a composite of the Quick Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, hand grip test, and thumb-forefinger pinch test. The secondary end points included access feasibility and complications. Of 216 patients with 1-year completed follow-up, 112 were randomly allocated to DRA and 104 to PRA, with balanced demographics and procedural characteristics. Both groups had similar access site bleeding rates (DRA 0% vs PRA 1.4%, p = 0.25). Radial artery occlusion occurred in 1 PRA patient versus 2 in DRA. There was no significant difference in change of hand function, median (interquartile range) hand grip (DRA 0.7 [-3 to 4.5] vs PRA 1.3 [-2 to 4.3] kg, p = 0.57), pinch grip (DRA -0.1 [-1.1 to 1] vs PRA -0.3 [-1 to 0.7] kg, p = 0.66), and Quick DASH (DRA 0 [-6.6 to 2.3] vs PRA 0 [-4.6 to 2.9] points, p = 0.58). The composite of hand function was comparable between PRA and DRA. In conclusion, DRA is a safe strategy for cardiac catheterization, with a low complication rate. Compared with PRA, there is no increased risk of hand dysfunction or radial artery occlusion at 1 year.

Impact of iodinated contrast shortage on contrast-associated acute kidney injury: a single center experience.

Background: In March 2022, a COVID-19 outbreak disrupted the global supply of iodine contrast media (ICM). Healthcare systems implemented contrast-saving strategies to maintain their remaining ICM supplies. This study sought to determine the impact of contrast shortage on the incidence of contrast-associated acute kidney injury (CA-AKI). Methods: This was a retrospective study of 265 patients undergoing 278 percutaneous coronary interventions (PCI) during 4-month periods prior to (9/1/2021 to 12/31/2021) and during (5/1/2022 to 8/31/2022) contrast shortage at a single center. The primary endpoint was the incidence of CA-AKI between study periods. Results: A total of 148 and 130 PCIs were performed before and during contrast shortage, respectively. The incidence of CA-AKI significantly decreased from 11.5% to 4.6% during contrast shortage (P = 0.04). During the shortage, average contrast volume per PCI was significantly lower (123 ± 62 mL vs 88 ± 46 mL, P < 0.001), while coronary imaging was significantly higher (34.3% vs 50%, P = 0.009) compared to preshortage. All-cause mortality at discharge was comparable between study periods (2.8% vs 3.3%, respectively; P = 0.90). Conclusion: The scarcity of ICM for PCI procedures in this single-center experience was associated with a significant increase in the utilization of intravascular imaging and a significant reduction in CA-AKI.

Prospective Multicenter International Registry of Ultrasound-Facilitated Catheter-Directed Thrombolysis in Intermediate-High and High-Risk Pulmonary Embolism (KNOCOUT PE).

BACKGROUND: Prior clinical trials have demonstrated the efficacy of ultrasound-facilitated catheter-directed thrombolysis (USCDT) for the treatment of acute intermediate-risk pulmonary embolism (PE) using reduced thrombolytic doses and shorter infusion durations. However, utilization and safety of such strategies in broader PE populations remain unclear. The KNOCOUT PE (The EKoSoNic Registry of the Treatment and Clinical Outcomes of Patients With Pulmonary Embolism) registry is a multicenter international registry designed to study the treatment of acute PE with USCDT, with focus on safety outcomes. METHODS: The KNOCOUT PE prospective cohort included 489 patients (64 sites internationally) with acute intermediate-high or high-risk PE treated with USCDT between March 2018 and June 2020. Principal safety outcomes were independently adjudicated International Society on Thrombosis and Haemostasis major bleeding at 72 hours post-treatment and mortality within 12 months of treatment. Additional outcomes included change in right ventricular/left ventricular ratio and quality of life measures over 12 months. RESULTS: Mean alteplase (r-tPA [recombinant tissue-type plasminogen activator]) infusion duration was 10.5 hours. Mean total r-tPA dose was 18.1 mg, with 31.0% of patients receiving ≤12 mg. Major bleeding events within 72 hours occurred in 1.6% (8/489) of patients. One patient experienced worsening of a preexisting subdural hematoma after USCDT and therapeutic anticoagulation, which ultimately required surgery. All-cause mortality at 30 days was 1.0% (5/489). Improvement in PE quality of life score was observed with a 41.1% (243/489, 49.7%) and 44.2% (153/489, 31.3%) mean relative reduction by 3 and 12 months, respectively. CONCLUSIONS: In a prospective observational cohort study of patients with intermediate-high and high-risk PE undergoing USCDT, mean r-tPA dose was 18 mg, and the rates of major bleeding and mortality were low. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03426124.

Distal Versus Proximal Radial Artery Access for Cardiac Catheterization: 30-Day Outcomes of the DIPRA Study.

Background Proximal radial artery (pRA) access for cardiac catheterization is safe but can jeopardize subsequent use of the artery because of occlusion. Distal radial artery (dRA) access in the anatomical snuffbox preserves the radial artery, but safety and potential detrimental effects on hand function are unknown. Methods and Results In the DIPRA (Distal Versus Proximal Radial Artery Access for Cardiac Catheterization and Intervention) study, a single-center trial, 300 patients were randomized 1:1 to cardiac catheterization through dRA or pRA. The primary end point of change in hand function from baseline to 30 days was a composite of the QuickDASH (Quick Disabilities of the Arm, Shoulder and Hand) questionnaire, hand-grip test, and thumb forefinger pinch test. Secondary end points included access feasibility and complications; 254 of 300 patients completed follow-up at 30 days; of these, 128 were randomized to dRA and 126 to pRA with balanced demographic and procedural characteristics. Both groups had similar rates of access site bleeding (dRA 0% versus pRA 1.4%; P=0.25). Six patients with dRA failed access compared with 2 patients with pRA. Radial artery occlusion occurred in 2 pRA versus none in dRA. There were no significant differences in change in hand function, median hand-grip (dRA 0 [-3.2, 3.3] versus pRA 0.7 [-2.3, 3.3] kg; P=0.21), pinch-grip (dRA -0.3 [-1.2, 0.5] versus pRA 0 [-0.9, 0.9] kg; P=0.09), and QuickDASH (dRA 0 [-4.6, 2.3] versus pRA 0 [-4.6, 2.3] points, P=0.96). There was no significant difference in the composite of hand function between pRA and dRA. Conclusions dRA is a safe strategy for cardiac catheterization with a low complication rate. Compared with pRA, there is no increased risk of hand dysfunction at 30 days. Registration URL: https://www.ClinicalTrials.gov. Unique identifier: NCT04318990.

Comparative Outcomes of Interventions for Femoropopliteal Chronic Total Occlusion Versus Non-Chronic Total Occlusion Lesions From the Multicenter XLPAD Registry.

Background Endovascular intervention of femoropopliteal chronic total occlusions (CTOs) is technically more complex. However, there is lack of comparative analysis between CTO and non-CTO femoropopliteal interventions. Methods and Results We report procedural details and outcomes of patients treated for femoropopliteal CTO and non-CTO lesions in the XLPAD (Excellence in Peripheral Artery Disease) registry (NCT01904851) between 2006 and 2019. Primary outcomes were procedural success and 1-year major adverse limb events, a composite of all-cause death, target limb revascularization, or major amputation. Analysis included 2895 patients (CTO: n=1516 patients; non-CTO: n=1379 patients) with 3658 lesions (CTO: n=1998 lesions; non-CTO: n=1660 lesions). Conventional balloon angioplasty (20.86% versus 33.48%, P<0.001) or drug-coated balloon angioplasty (1.26% versus 2.93%, P<0.001) were more frequent in the non-CTO group, whereas bare-metal stents (28.09% versus 20.22%, P<0.001) or covered stents (4.08% versus 1.83%, P<0.001) were more frequent in the CTO group. Debulking procedures were more commonly performed in the non-CTO group (41.44% versus 53.13%, P<0.001), despite a similar degree of calcification between the 2 groups. Procedural success was higher in the non-CTO group (90.12% versus 96.79%, P<0.001). Procedural complications were higher in the CTO group (7.21% versus 4.66%, P=0.002), mainly due to excess distal embolization (1.5% versus 0.6%, P=0.015). Adjusted 1-year major adverse limb events were higher in the CTO group (22.47% versus 18.77%, P=0.019), driven mainly by target limb revascularization (19.00% versus 15.34%, P=0.013). Conclusions Procedural success is lower for endovascular treatment of femoropopliteal CTO compared with non-CTO lesions. CTO lesions are associated with higher rates of periprocedural complications and reinterventions after 1 year.

Effect of a pulmonary embolism response team on the management and outcomes of patients with acute pulmonary embolism.

OBJECTIVE: We aimed to evaluate the effects of a multidisciplinary pulmonary embolism (PE) response team (PERT) on the management and outcomes of patients with acute PE. METHODS: We retrospectively reviewed all patients presenting to our institution with a diagnosis of PE from July 2020 to April 2022. The primary outcome measures were in-hospital mortality, major bleeding events defined by the International Society on Thrombosis and Haemostasis, and use of catheter-directed interventions (CDIs). The secondary outcome measures included 30-day and 12-month mortality, hospital and intensive care unit (ICU) lengths of stay, vasopressor requirement, and cardiac arrest. Continuous variables were assessed using the Mann-Whitney U test and categorical variables using the χ2 or Fisher exact test, as appropriate. RESULTS: A total of 279 patients with acute PE were identified, of whom 79 (28%), 173 (62%), and 27 (10%) were considered to have low risk, intermediate risk, and high risk, respectively. The PERT was activated for 133 patients (47.7%). Saddle and main pulmonary artery embolisms (P < .001), right ventricular strain (P= .001), right ventricular dysfunction (P < .001), coexisting deep vein thrombosis (P < .001), and dyspnea as a presenting symptom (P = .008) were significantly associated with PERT activation. Patients evaluated by the PERT were more likely to undergo CDI (49% vs 27%; P < .001) across all risk groups and less likely to have an inferior vena cava filter placed (1% vs 5%; P = .04). PERT consultation showed numerical, but nonstatistically significant, trends toward reduced in-hospital (2% vs 5%; P = .2) and 30-day (2% vs 8%; P = .06) mortality but similar rates of 12-month mortality (7% vs 8%; P = .7). PERT activation was also associated with a trend toward reduced rates of major bleeding (2% vs 7%), cardiac arrest (2% vs 7%), and vasopressor requirement (9% vs 18%). PERT consultations decreased the median number of ICU days by one half; however, we did not observe any differences in the total hospital length of stay between the groups. CONCLUSIONS: At our institution, PERT consultations were associated with significantly higher usage of CDIs and improved clinical outcomes, including reduced mortality and a lower rate of major bleeding events. PERT consultations were also associated with fewer ICU days, suggesting a possible economic benefit for implementing PERTs, although further research is needed to confirm that conclusion.

Extracorporeal membrane oxygenation for large pulmonary emboli.

Massive and submassive pulmonary emboli (PE) are increasingly being treated with percutaneous lytic and embolectomy procedures. While these procedures are overwhelmingly safe, patients with significant right ventricular strain are at risk for hemodynamic compromise requiring extracorporeal membrane oxygenation (ECMO). We conducted a retrospective study of all patients requiring ECMO support for PE from 2014 through 2022. The primary outcome was survival. Secondary outcomes included commonly encountered ECMO complications. From 2014 to 2022, 10 patients with submassive or massive PE required ECMO support. All 10 patients (100%) had right ventricular strain on echocardiography, 7 (70%) had a saddle PE, and 3 (30%) had extensive bilateral PE. Six (60%) patients required cardiopulmonary resuscitation prior to ECMO cannulation, and 4 (40%) were undergoing cardiopulmonary resuscitation while being cannulated. Nine (90%) patients were placed on venoarterial ECMO through the femoral vessels, while 1 (10%) was cannulated with right atrial to pulmonary artery ECMO. The median duration of support was 4 [3-8] days. During their course, 5 patients underwent percutaneous embolectomy, 1 underwent surgical embolectomy, and 4 underwent percutaneous lytic therapy. All patients (100%) survived to ECMO decannulation, and 6 (60%) survived to discharge. With a mean follow-up of 496 days, there were no postdischarge mortalities. In conclusion, although therapy for large PE is well tolerated, a small number of patients will experience periprocedural hemodynamic collapse requiring ECMO support. ECMO for PE patients is associated with acceptable morbidity and mortality. Further investigation is warranted to better characterize which patients are likely to require ECMO support.

Successful Revascularization of Critical Limb Ischemia: A Challenging Case of a Unilateral Tibial-to-Tibial Intervention.

Critical limb ischemia requires urgent diagnosis and intervention. Limitations to percutaneous revascularization therapy stem from multilevel diseased vasculature. Retrograde revascularization utilizing anterior tibial artery access in complex and proximal lesions is an alternative route for intervention that can lead to limb salvage and symptom resolution.

Drug-Coated Balloon Angioplasty for Carotid Artery In-Stent Restenosis: Case Series.

OBJECTIVES: Few case reports have demonstrated promising results of drug-coated balloons (DCBs) as an emerging management for carotid artery in-stent restenosis (CAISR). Herein, we report 6 cases of CAISR which were treated with a DCB with or without new stent deployment. BACKGROUND: Carotid artery in-stent restenosis is a high-risk condition with an estimated incidence rate that varies widely from 6% to 40%. Several strategies are available now for the management of the CAISR including conventional balloon angioplasty, plaque modification balloon angioplasty, and new stent placement. METHODS: A retrospective review of consecutive patients with a diagnosis of severe CAISR at Baylor Scott & White The Heart Hospital Plano from 2011 to 2021 was performed. This study was approved by the Baylor Scott & White Research Institute institutional review board. RESULTS: Six patients underwent DCB angioplasty with or without stent placement under an embolic protection device. Resolution of CAISR was achieved in all cases with 0% to 10% residual stenosis in all cases. Following the procedure, 1 patient had a brief episode of syncope with balloon inflation with immediate recovery on deflation of the balloon. There were otherwise no significant neurological or cardiac events prior to discharge. All patients were asymptomatic at their follow-up visit with no neurological or cardiac events reported at 12, 24, and 36 months following the procedure. CONCLUSION: While CAISR treatment remains a challenging condition, our study shows that the use of DCB with or without stent placement is a feasible and promising treatment option when compared with other conventional treatment options. CLINICAL IMPACT: Carotid artery in-stent restenosis treatment remains a challenging condition. Our study shows that the use of drug coated balloon with or without stent placement is a feasible and promising treatment option when compared with current conventional treatment options.

Distal Versus Proximal Radial Artery Access for Cardiac Catheterization and Intervention: Design and Rationale of the DIPRA Trial.

BACKGROUND: Radial artery (RA) catheterization is the access of choice over femoral artery access for most interventional vascular procedures given its safety and faster patient recovery. There has been growing interest in distal radial artery (dRA) access as an alternative to the conventional proximal radial artery (pRA) access. Preserving the RA is important which serves as a potential conduit for future coronary artery bypass surgery, dialysis conduit or preserve the artery for future cardiovascular procedures. The dRA runs in close proximity to the radial nerve, which raises the concern of potential detrimental effects on hand function. STUDY DESIGN: The Distal versus Proximal Radial Artery Access for cardiac catheterization and intervention (DIPRA) trial is a prospective, randomized, parallel-controlled, open-label, single center study evaluating the outcomes of hand function and effectiveness of dRA compared to pRA access in patients undergoing cardiac catheterization. The eligible subjects will be randomized to dRA and pRA access in a (1:1) fashion. The primary end point is an evaluation of hand function at one and twelve months follow-up. Secondary end points include rates of access site hematoma, access site bleeding, other vascular access complications, arterial access success rate, and RA occlusion at one and twelve months follow up. CONCLUSION: Effects of dRA on hand function remains unknown and it's use questionable in the presence of a widely accepted pRA. DIPRA trial is designed to determine the safety and effectiveness of dRA for diagnostic and interventional cardiovascular procedures compared to the standard of care pRA.

The Vici venous stent for treatment of renal vein entrapment.

The nutcracker syndrome results from compression of the left renal vein between the superior mesenteric artery and the aorta. We present the first reported case of symptomatic left renal vein compression treated with balloon angioplasty and stenting with the Vici stent system.

Takotsubo cardiomyopathy and acute manic attack.

Takotsubo cardiomyopathy predominantly occurs in women, with a high incidence in patients with psychiatric diseases. We present a 64-year-old white woman with an acute manic episode complicated by rhabdomyolysis and takotsubo cardiomyopathy.

Transcatheter closure of five atrial septal communications in the presence of severe pulmonary arterial hypertension and severe left ventricular non-compliance.

Closure of congenital atrial communications in the presence of either severe pulmonary arterial hypertension (PAH) with pulmonary-to-systemic (right-to-left) shunting, or severe left ventricular (LV) non-compliance with left-to-right shunting is often considered prohibitive. Thus, the recognition of durable reversibility of these physiologic conditions is crucial. We describe a hemodynamic conundrum in a patient with five septal communications in whom the coexistence of unmasked bidirectional physiologic shunting, severe PAH, and worsening left-sided overload dissuaded initial closure. We report our strategy for hemodynamic evaluation and successful closure of all defects.

Management of recurrent leaks following postinfarction ventricular septal defect repairs.

Ventricular septal rupture (VSR) complicates acute myocardial infarction (AMI) in less than 0.2% of cases and is usually surgically managed by endocardial patch repair with infarct exclusion. Although successful in 80% of cases, failure of patch repair (often because of patch dehiscence) results in attempts at percutaneous closure as reoperative mortality can be as high as 40%. We describe a case of an AMI in a 63-year-old male with resultant VSR that required repeat surgical patch repair secondary to recurrent leak. We discuss the management of recurrent leaks and surgical techniques aimed at decreasing residual defects.

Waist circumference and metabolic syndrome: the risk for silent coronary artery disease in males.

BACKGROUND: Waist circumference (WC) is a component used to define metabolic syndrome. However, its role as an independent predictor of silent coronary artery disease (CAD), above its contribution to metabolic syndrome, remains unknown. METHODS: Male veterans without known CAD, undergoing cardiac stress testing for indications other than typical angina or its equivalent, were evaluated for the presence of silent CAD. High WC and metabolic syndrome were defined per the revised National Cholesterol Education Program (NCEP-R) and the International Diabetes Federation (IDF) criteria. RESULTS: Data on 1,071 patients (age 61±11 years) were analyzed retrospectively. On multivariable logistic regression analysis [odds ratio (OR), 95% confidence interval (CI), P value), a WC ≥94 cm (1.42, 1.04-1.93; P=0.026), metabolic syndrome by NCEP-R (1.73, 1.29-2.33; P<0.0001), and metabolic syndrome by IDF (1.57, 1.17-2.11; P=0.003) were independent predictors of silent CAD. When comparing patients meeting criteria for metabolic syndrome defined by either NCEP-R or IDF, the prevalence of silent CAD was not statistically different (P=0.86). The prevalence of silent CAD associated with a high WC was not inferior to that seen between silent CAD and metabolic syndrome as defined by either criterion. Last, among patients with metabolic syndrome defined by NCEP-R, those with a high WC as a defining component of metabolic syndrome had a higher prevalence of silent CAD (30% vs. 20%; P=0.026). CONCLUSION: A WC ≥94 cm in males is independently associated with an increased prevalence of silent CAD. In patients with metabolic syndrome, this prevalence is increased by the presence of high WC.

A retrospective analysis of proceduralist-directed, nurse-administered propofol sedation for implantable cardioverter-defibrillator procedures.

BACKGROUND: There is controversy whether proceduralist-directed, nurse-administered propofol sedation (PDNAPS) is safe. OBJECTIVE: To assess the frequency of adverse events when PDNAPS is used for implantable cardioverter-defibrillator (ICD)-related procedures and to determine the patient and procedural characteristics associated with adverse events. METHODS: Consecutive ICD-related procedures using PDNAPS from May 2006 to July 2009 at a tertiary-care hospital were evaluated. Serious adverse events were defined as procedural death, unexpected transfer to an intensive care unit, respiratory failure requiring intubation/bag-mask ventilation, or hypotension requiring vasoconstrictor/inotrope support. Nonserious adverse events were defined as hypotension requiring fluid resuscitation or hypoxemia requiring augmented respiratory support with non-rebreather mask, oral airway, or jaw lift. RESULTS: Of 582 patients (age 64 ± 14 years, 72.3% males) undergoing ICD-related procedures using PDNAPS, 58 (10.0%) patients had serious adverse events with no procedural death and 225 (38.7%) had nonserious adverse events. Longer procedure duration (relative risk [RR] = 2.1 per hour; 95% confidence interval [CI] = 1.6-2.8; P < .001) and biventricular implant (RR = 2.7; CI = 1.4-5.3; P = .003) were independent predictors of serious adverse events. A longer procedure duration (RR = 1.4 per hour; CI = 1.1-1.7; P = .001), heart failure class (RR = 1.4 per 1 class; CI = 1.1-1.7; P = .002), and use of propofol infusion (RR = 3.5; CI = 2.2-5.7; P < .001) were independent predictors of nonserious adverse events. CONCLUSION: PDNAPS for shorter ICD procedures including single- and dual-chamber implants, generator changes, and defibrillation threshold testing have acceptable rates of serious adverse events and manageable nonserious adverse events and should be considered for further study. Biventricular implants and other complex procedures should be done with an anesthesiologist.

Percutaneous alcohol septal ablation following surgical myectomy.

BACKGROUND: The management strategy for hypertrophic obstructive cardiomyopathy generally begins with medical therapy. When this fails to control symptoms, consideration is given to mechanically eliminate the obstruction caused by a thickened and bulging interventricular septum to blood flowing out of the left ventricle. The literature is abundant with data about the safety and efficacy of both surgical myectomy and the newer and now more widely utilized percutaneous alcohol septal ablation procedure. Many cases of successful surgical myectomy performed on patients with recurrent or residual symptoms following percutaneous septal ablation have been published. However, there remains a paucity of information available to the clinician faced with a patient with recurrent or residual symptoms after undergoing surgical myectomy. METHODS: We were faced with a series of 2 such patients who presented to our institution after presumed successful myectomy. Both patients had a recurrence of symptoms and a large gradient across the left ventricular outflow tract. Both patients were offered percutaneous alcohol ablation after failure of medical therapy. RESULTS: Excellent results clinically and echocardiographically were achieved in both patients, with complete symptom relief reported at follow up. CONCLUSION: We offer a review of the literature to date and believe our experience demonstrates that percutaneous alcohol septal ablation is an acceptable option that should be offered to patients who have recurrent or incomplete relief of symptoms following presumed successful surgical myectomy.

Intrinsic cardiac nerve activity and paroxysmal atrial tachyarrhythmia in ambulatory dogs.

BACKGROUND: Little is known about the relationship between intrinsic cardiac nerve activity (ICNA) and spontaneous arrhythmias in ambulatory animals. METHODS AND RESULTS: We implanted radiotransmitters to record extrinsic cardiac nerve activity (ECNA; including stellate ganglion nerve activity and vagal nerve activity) and ICNA (including superior left ganglionated plexi nerve activity and ligament of Marshall nerve activity) in 6 ambulatory dogs. Intermittent rapid left atrial pacing was performed to induce paroxysmal atrial fibrillation or atrial tachycardia. The vast majority (94%) of ligament of Marshall nerve activity were preceded by or coactivated with ECNA (stellate ganglion nerve activity or vagal nerve activity), whereas 6% of episodes were activated alone without concomitant stellate ganglion nerve activity or vagal nerve activity. Paroxysmal atrial fibrillation and atrial tachycardia were invariably (100%) preceded (<5 seconds) by ICNA. Most paroxysmal atrial tachycardia events (89%) were preceded by ICNA and sympathovagal coactivation, whereas 11% were preceded by ICNA and stellate ganglion nerve activity-only activation. Most paroxysmal atrial fibrillation events were preceded only by ICNA (72%); the remaining 28% were preceded by ECNA and ICNA together. Complex fractionated atrial electrograms were observed during ICNA discharges that preceded the onset of paroxysmal atrial tachycardia and atrial fibrillation. Immunostaining confirmed the presence of both adrenergic and cholinergic nerve at ICNA sites. CONCLUSIONS: There is a significant temporal relationship between ECNA and ICNA. However, ICNA can also activate alone. All paroxysmal atrial tachycardia and atrial fibrillation episodes were invariably preceded by ICNA. These findings suggest that ICNA (either alone or in collaboration with ECNA) is an invariable trigger of paroxysmal atrial tachyarrhythmias. ICNA might contaminate local atrial electrograms, resulting in complex fractionated atrial electrogram-like activity.