Long-term results of ablation index guided atrial fibrillation ablation: insights after 5+ years of follow-up from the MPH AF Ablation Registry

Background

Catheter ablation (CA) for symptomatic atrial fibrillation (AF) offers the best outcomes for patients. Despite the benefits of CA, a significant proportion of patients suffer a recurrence; hence, there is scope to potentially improve outcomes through technical innovations such as ablation index (AI) guidance during AF ablation. We present real-world 5-year follow-up data of AI-guided pulmonary vein isolation.

Methods

We retrospectively followed 123 consecutive patients who underwent AI-guided CA shortly after its introduction to routine practice. Data were collected from the MPH AF Ablation Registry with the approval of the institutional research board.

Results

Our patient cohort was older, with higher BMI, greater CHA2DS2-VASc scores, and larger left atrial sizes compared to similar previously published cohorts, while gender balance and other characteristics were similar. The probability of freedom from atrial arrhythmia with repeat procedures is as follows: year 1: 0.95, year 2: 0.92, year 3: 0.85, year 4: 0.79, and year 5: 0.72. Age >75 years (p = 0.02, HR: 2.7, CI: 1.14-6.7), BMI >35 kg/m2 (p = 0.0009, HR: 4.6, CI: 1.8-11.4), and left atrial width as measured on CT in the upper quartile (p = 0.04, HR: 2.5, CI: 1-5.7) were statistically significant independent predictors of recurrent AF.

Conclusion

AI-guided CA is an effective treatment for AF, with 95.8% of patients remaining free from atrial arrhythmia at 1 year and 72.3% at 5 years, allowing for repeat procedures. It is safe with a low major complication rate of 1.25%. Age >75 years, BMI >35 kg/m2, and markedly enlarged atria were associated with higher recurrence rates.

Comparing Left Atrial Low Voltage Areas in Sinus Rhythm and Atrial Fibrillation Using Novel Automated Voltage Analysis: A Pilot Study

BACKGROUND

Low voltage areas (LVAs) have been proposed as surrogate markers for left atrial (LA) scar. Correlation between voltages in sinus rhythm (SR) and atrial fibrillation (AF) have previously been measured via point-by-point analysis. We sought to compare LA voltage composition measured in SR to AF, utilizing a high-density automated voltage histogram analysis (VHA) tool in those undergoing pulmonary vein isolation (PVI) for persistent AF (PeAF).

METHODS

We retrospectively analyzed patients with PeAF undergoing de novo PVI. Maps required ≥ 1,000 voltage points in each rhythm and had a standardized procedure (mapped in AF then remapped in SR post-PVI). We created six anatomical segments (AS) from each map: anterior, posterior, roof, floor, septal and lateral AS. These were analyzed by VHA, categorizing atrial LVAs into 10 voltage aliquots 0 - 0.5 mV. Data were analyzed using SPSS v.26.

RESULTS

We acquired 58,342 voltage points (n = 10 patients, mean age: 67 ± 13 years, three females). LVA burdens of ≤ 0.2 mV, designated as "severe LVAs", were comparable between most AS (except on the posterior wall) with good correlation. Mapped voltages between the ranges of 0.21 and 0.5 mV were labeled as "diseased LA tissue", and these were found significantly more in AF than SR. Significant differences were seen on the roof, anterior, posterior, and lateral AS.

CONCLUSIONS

Diseased LA tissue (0.21 - 0.5 mV) burden is significantly higher in AF than SR, mainly in the anterior, roof, lateral, and posterior wall. LA "severe LVA" (≤ 0.2 mV) burden is comparable in both rhythms, except with respect to the posterior wall. Our findings suggest that mapping rhythm has less effect on the LA with voltages < 0.2 mV than 0.2 - 0.5 mV across all anatomical regions, excluding the posterior wall.

Ablation Index Outcome in Redo Persistent Atrial Fibrillation Ablation: Results of a Short-Term Study

Background

Ablation index (AI) is a novel catheter-based parameter that has improved the outcome and safety of radiofrequency (RF) ablation of pulmonary vein isolations (PVIs). This index incorporates contact force (CF) (g), time (s), and power (W) parameters. The role of AI in redo ablations for persistent atrial fibrillation (peAF) has not been fully investigated. Hence, the impact of AI on the success of the redo PVI during the short-term follow-up period is the aim of this study.

Methods

A retrospective analysis of 39 consecutive patients who underwent redo PVI ablations for peAF was carried out between January 2016 and December 2018. Target values for AI were 500 - 550 for anterior and roof and 400 - 380 for posterior and inferior regions. We compared outcomes between AI-guided and catheter CF ablations (i.e., forced time integral (FTI) of more than 400 g/s) during a follow-up of 24 months.

Results

Pulmonary vein reconnections at redo procedure were similar in both groups (P = 0.1). AF free burden period was non-significant (mean 15.53 ± 2.4 months in AI group vs. 15.22 ± 1.9 months in CF group, P = 0.79) at 24 months. The AI group demonstrated greater numbers of patients for whom anti-arrhythmic therapy could be de-escalated over 1 year (n = 11 (65%) in AI vs. n = 6 (27%) in CF, P = 0.02). Fewer patients underwent escalation of their anti-arrhythmic therapy (n = 2 (12%) in AI vs. n = 7 (32%) in CF, P = 0.15). The AI group trended towards a shorter procedure time (111.6 ± 27 min) compared to the CF group (133 ± 40 min) (P = 0.06). Other procedural details were comparable.

Conclusion

Redo PVI interventions using AI lead to a significant de-escalation in medication during follow-up. Procedure time and radiation dose using AI tends to be shorter. Both techniques are safe with minimal complications.

Assessment of Radiation-Induced Malfunction in Cardiac Implantable Electronic Devices

Background

Radiation therapy (RT) is a standard cancer treatment modality, and an increasing number of patients with cardiac implantable electronic devices (CIEDs) are being referred for RT. The goals of this study were as follows: (i) to determine the incidence of CIED malfunction following RT; (ii) to characterize the various types of malfunctions that occur; and (iii) to identify risk factors associated with CIED malfunction following RT.

Methods

A retrospective study of patients with CIEDs who received RT between 2007 and 2018 at 4 Canadian centres (Sunnybrook Health Sciences Centre, Kingston General Hospital, Hamilton Health Sciences Centre, and University of Ottawa Heart Institute) was conducted. Patients underwent CIED interrogation after completion of RT, to assess for late damage to the CIEDs. Data on demographics, devices, and RT were compared for the primary outcome of device malfunction.

Results

Of 1041 patients with CIEDs who received RT, 811 patients with complete data were included. Device malfunctions occurred in 32 of 811 patients (4%). The most common device malfunctions were reduced ventricular/atrial sensing (in 13 of 32 [41%]), an increase in lead threshold (in 9 of 32 [22%]), lead noise (in 5 of 32 [16%]), and electrical reset (in 2 of 32 [6%]). Higher beam energy (≥ 10 MV) was associated with malfunction (P < 0.0001). Radiation dose was not significantly different between the malfunction and non-malfunction groups (58.3 cGy vs 65 cGy, respectively, P = 0.71).

Conclusions

Although RT-induced CIED malfunctions are rare (occurring in 4% of patients with a CIED who undergo RT), collaborative efforts between radiation oncologists and cardiac rhythm device clinics to optimize CIED monitoring are needed, to detect and manage CIED malfunctions. Malfunctions are more common in patients receiving higher–beam energy (≥10MV)RT.

Left atrial scar burden in sinus rhythm differs from atrial fibrillation using automated voltage analysis during radiofrequency ablation for atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Scar burden in atrial fibrillation (AF) can be overestimated due to many factors. Scar burden has prognostic value and substrates considered for ablation by some electrophysiologists. We compared left atrial (LA) scar voltage in AF to sinus rhythm (SR) using voltage histogram analysis (VHA) of those undergoing pulmonary vein isolation (PVI) for persistent AF (PeAF). We believe this is the first study analysing LA scar location in SR and AF using VHA.

Methods

We retrospectively analysed 120 anatomical segments (AS) and whole LA voltages (N= 10 patients, mean age 68 ± 7, 4 females) in SR and AF. Fast anatomical maps (FAM) were grouped into 6 AS in AF and SR: Anterior, Posterior, Roof, Floor, Septal and Lateral AS, which were analysed via VHA (Figure 1) in 10 voltage ranges between 0mV-0.5mV. Total LA area in each voltage aliquot was recorded in SR and AF, taking diseased LA as 0.2-0.5mV and dense LA scar as &lt;0.2mV. The pulmonary veins, mitral annulus and trans-septal puncture sites were excluded from analyses. We included patients over age 18 with PeAF who had de novo PVI with no extra ablation lines, maps with &gt;1000 voltage points in both rhythms and uniform procedure involving initial mapping in AF then remapping in SR after PVI. Statistical analyses conducted with IBM SPSS v.26.

Results

Total LA scar burden was greater in AF (Mean 142.76 mm², SD ± 138.78mm²) than SR (Mean 109mm², SD ± 107.8mm²), p= &lt;0.0001, Table 1. Scar correlation in SR and AF had a good relationship, R = 0.416 (p= &lt;0.001). Every 1mm² of scar identified during SR yielded a mean of 1.54mm² in AF, (p= &lt;0.001).

Conclusions

AF was associated with higher scar burden in the Roof, Anterior, Lateral and Posterior AS. Dense LA scar (≤ 0.2mV) on the Posterior AS was significantly higher in AF, while in other AS was comparable to SR. Mapping substrate in AF, especially the posterior wall, may be misleading as scar burden may be overestimated when compared to SR. Table 1Voltage&lt; 0.02 mV (mean area ± SD mm2)0.2-0.5mV (mean area mm2)RhythmSRAFp-valueSRAFp-valueEntire LA115.89 ± 113.61143.41 ± 144.230.02*105.78 ± 103.73144.00 ± 135.24&lt;0.0001*Roof82.72 ± 117.3283.68 ± 113.560.95115 ± 77.14150.61 ± 93.170.01*Anterior131.8 ± 169.53126.5 ± 154.570.85158.53 ± 99.22220.87 ± 173.070.002*Lateral70.5 ± 80.0090.57 ± 117.990.3687.52 ± 66.82137.05 ± 104.990.0002*Septal80.99 ± 89.0380.99 ± 89.030.6899.123 ± 73.62115.37 ± 84.830.18Floor105.1 ± 134.91106.42 ± 148.670.96117.62 ± 85.41151.2 ± 110.070.052Posterior102.14 ± 157.47159.03 ± 194.650.02*138.27 ± 112.28234 ± 150.45&lt;0.0001*LA scar distribution in SR and AF, *denotes significant results.Abstract Figure 1

Predictors of appropriate shock after generator replacement in patients with an implantable cardioverter defibrillator

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are indicated for the primary prevention of sudden cardiac death in patients with reduced left ventricular ejection fraction (LVEF). The ongoing risk/benefit profile of an ICD at generator replacement is unknown. This study aimed to identify predictors of appropriate ICD shocks and therapies after first ICD generator replacement, and its procedure-related complications.

METHODS

We conducted a multicenter, retrospective cohort study including patients with primary prevention ICDs who underwent generator replacement between April 2005 and July 2015 at three Canadian centers. The primary and secondary outcomes were appropriate ICD shock and any appropriate ICD therapy, respectively. Procedure-related complication rates were also reported.

RESULTS

Of the 219 patients in the cohort, 61 (28%) experienced an appropriate shock while 40 (18%) experienced appropriate antitachycardia pacing over a median follow up of 2.2 years. Independent predictors of appropriate ICD shocks included: LVEF at time of replacement (adjusted odds ratio [OR] 0.4 per 10% increase in LVEF, P < .001), a history of appropriate ICD shocks prior to replacement (OR 4.9, P < .001), and a history of inappropriate ICD shocks (OR 4.2, 95%, P < .002). Similar predictors were identified for the secondary outcome of any appropriate ICD therapy. Device-related complications were reported in 25 (11%) patients, with 1 (0.5%) resulting in death, 14 (6.3%) requiring site re-operation, and 6 (2.7%) requiring cardiac surgical management.

CONCLUSION

Not all primary prevention ICD patients undergoing generator replacement will require appropriate device therapies afterwards. Generator replacement is associated with several risks that should be weighed against its anticipated benefit. A comprehensive assessment of the risk-benefit profile of patients undergoing generator replacement is warranted.

Left atrial scar identification and quantification in sinus rhythm and atrial fibrillation

Identification and quantification of low voltage areas (LVA) in atrial fibrillation (AF), identified by their bipolar voltages (BiV) via electro-anatomical voltage mapping is an area of interest to prognosis of AF free burden. LVAs have been linked to diseased left atrial (LA) tissue which results in pro-fibrillatory potentials. These LVAs are dominantly found within the pulmonary veins, however, as the disease progresses other areas of the LA show low voltage. The scar burden of the LA is linked to recurrence of the arrhythmia and can be a target of further modification. This burden is classically assessed once sinus rhythm (SR) is attained, but this is susceptible to operator variability with overestimated dense LA scar (<0.2 mV) and underestimated diseased LA tissue (<0.5 mV). The novel automated voltage histogram analysis (VHA) tool may increase accuracy, however, is yet to be fully validated. A recent study indicates that LVAs can be assessed just as reliably in AF as SR, but BiV is lower with linear correlation to SR values (0.24-0.5 mV respectively). In this paper, we review current data as well as review current methods of identifying, quantifying, and grading LA scar. We also compared AF vs SR voltages of a patient undergoing catheter ablation in our site using our VHA tool to compare the results. In keeping with the cited papers, we found lower voltages in our patient measured in AF. This area warrants further study to assess correlation in more patients, with view to developing prognostic and therapeutic grading systems.

Dynamic Local Activation Time Mapping in Heavily Scarred Left Atrium and Persistent Atrial Fibrillation: A proof of concept case report

We report the case of a 68-year-old male, presenting with persistent atrial fibrillation (Pe AF) refractory to anti arrhythmic medications and cardioversion, on a background history of ischaemic heart disease. Pre and post standard pulmonary vein isolation (PVI), left atrial (LA) voltageanalyses wereperformed, followed by dynamic local activation time (DLAT) mapping in addition to focal activity identification.Thisdemonstrated a heavily scarred LA, and a number ofareas of focal activity. The patient remained in atrial fibrillation (AF) post rotor (focal activity) targeting,howevernotable changes in AF cycle length (CL)werenotedandslowed by an average of 25.3 milliseconds. Comparison between DLAT mappingpre and post PVI were anatomically similar but not identical. The anatomical distribution of heavy scar areas in the LA did not correspond to the DLAT areas of interest. The patient subsequentlyremained in normal sinus rhythm (SR) for 6 monthson a low dose Beta blockade in a short follow up period. DLAT mapping and its characteristics in heavily scarred LA are reported in this case.

Double Anomalies: Brugada Syndrome Presenting with a Persistent Left Superior Vena Cava

BACKGROUND The presentation of Brugada syndrome (BrS) with a persistent left superior vena cava (PLSVC) is expected to be a rare entity. It is unknown if this venous anomaly is linked to the arrhythmogenesis seen in BrS, or it is coincidental. This case describes a clinical presentation of the 2, in tandem, and displays the anomaly in association with BrS. CASE REPORT A 54-year-old female presented to the Emergency Department with non-prodromal syncope. This was on a background of a number of similar episodes in the past, and a current suspected viral illness comprising fever and diarrhea. Her resting electrocardiogram was suggestive of BrS. The later was confirmed with an ajmaline provocation test after ECG normalization in the subsequent 24 hours post admission. Pre-intracardiac defibrillator (ICD) procedure imaging displayed the PLSVC. An ICD was implanted, and the advancement of the guidewires displayed the venous anomaly. Post-procedure echocardiography confirmed appropriate positioning of the leads. The patient recovered well and is currently symptom free. CONCLUSIONS PLSVC presenting with BrS is a rare occurrence. It is unknown whether or not the PLSVC and BrS are linked in their presentation, or merely a coincidence.

Indications of Cardiac Resynchronization in Non-Left Bundle Branch Block: Clinical Review of Available Evidence

Cardiac resynchronization therapy (CRT) benefits have been firmly established in patients with heart failure and reduced left ventricular ejection fraction (HFrEF), who remain in New York Heart Association (NYHA) functional classes II and III, despite optimal medical therapy, and have a wide QRS complex. An important and consistent finding in published systematic reviews and in subgroup analyses is that the benefits of CRT are maximum for patients with a broader QRS durations, typically described as QRS duration > 150 ms, and for patients with a typical left bundle branch block (LBBB) QRS morphology. It remains uncertain whether patients with non-LBBB QRS complex morphology clearly benefit from CRT or only modestly respond.

Ventricular Tachycardia Storm After Standard Radiofrequency Pulmonary Vein Isolation

Patient: Male, 69

Final Diagnosis: Ventricular tachycardia storm post PVI ablation

Symptoms: Recurrent premature ventricular contractions at 180–200 bpm rate that progressed into a VT storm

Medication: —

Clinical Procedure: Radiofrequency PVI ablation

Specialty: Cardiology

Coronary Sinus Electrograms May Predict New-onset Atrial Fibrillation After Typical Atrial Flutter Radiofrequency Ablation (CSE-AF)

Background

Complex fractionated electrograms (EGMs) of the coronary sinus electrograms (CSEs) are employed as a target during radiofrequency ablations (RFA) of atrial fibrillation (AF). Anatomically, CSEs includes both of left atrium (LA), coronary sinus musculature and right atrium (RA) electrograms.

Aim

To determine the significance of fractionated CSE and delayed potentials as a predictor of new-onset AF after radiofrequency ablation (RFA) of isolated atrial flutter (AFL).

Methods

Consecutive patients underwent AFL ablation. Fractionated and/or continuous discrete activities were recorded from coronary sinus electrograms during sinus rhythm and during pacing. Earliest CSE to the S nadir or peak R in milliseconds was recorded and considered as propagation delay for EGMs.

Results

Forty patients were included during a mean follow-up period of 55.1± 15.8 months. Twenty patients (50 %) developed AF while the remaining 20 patients maintained sinus rhythm(SR) during the follow-up period. Proximal and mid CSEs were significantly fractionated in AF group compared to group with no AF development (65 % and 60% Vs. 35 % and 30 %, p = 0.03, respectively). However, during pacing from distal duo-decapolar catheter (pole 1-2), distal CSEs alone were significantly fractionated (p < 0.05) compared to SR group. Significant delayed propagation of proximal CSE during pacing and in sinus rhythm were observed in AF group (12.3 ± 9.2 ms vs 7.1 ± 3.6 ms, p = 0.03) and (7.2 ± 2.9 ms Vs 8.1 ± 4.6 ms, p= 0.02) in the same order.

Conclusion

Incidence of AF is associated with fractionated proximal and mid CSE in sinus rhythm and distal CSE during paced rhythm after isolated AFL ablation. Delayed proximal CSE propagation is correlated with AF incidence.

Gold-tip versus contact-sensing catheter for cavotricuspid isthmus ablation: A comparative study

OBJECTIVE

Radiofrequency (RF) ablation is a highly successful procedure for the management of typical atrial flutter (AFL), an abnormal heart rhythm originating within the atria. There is no strong evidence that the use of contact force (CF) has any impact on procedural duration or acute success in the management of cavotricuspid isthmus (CTI)-dependent AFL. The aim of this study was to compare acute procedural parameters using a non-CF, 4-mm, gold-tip, irrigated catheter and a CF-sensing catheter in patients with AFL.

METHODS

This was a retrospective cohort study. Consecutive patients who underwent typical AFL catheter ablation with either a gold-tip or CF-sensing catheter were enrolled. The procedural parameters obtained were: time to achieve bidirectional block, time to terminate AFL, total duration of RF application, procedure duration, fluoroscopy time, acute reconnection within 20 minutes following the last RF application, and procedural complications.

RESULTS

Of the 40 patients screened, 37 were included in the study. The procedural endpoint of bidirectional isthmus block was achieved in all patients. The use of gold-tip catheters was associated with a shorter length of time to achieve bidirectional block (median time: 20.0 minutes [interquartile range {IQR}: 12.0-28.0 minutes]) compared with a median time of 36.0 minutes (IQR: 12.0-53.0 minutes; p=0.048) in the CF group. Furthermore, there was a trend toward reduced procedural duration in favor of the gold-tip catheter (median goldtip: 74.0 minutes [IQR: 57.0-84.0 minutes]; median CF: 85.0 minutes [IQR: 57.0-107.0 minutes]; p=0.171). A greater requirement for the use of long sheaths was observed in cases where the CF catheter was employed for the procedure (CF: 11, 57.9 %; non-CF: 1, 5.6%; p=0.005).

CONCLUSION

The time required to achieve bidirectional block, which is also reflected in the procedural time, was less when using a gold-tip catheter, and there was less need for the use of a long sheath. Further studies may be useful to evaluate this finding.

Ineffective Shock Deliveries in a Patient with Ischemic Cardiomyopathy: Shock Vector Matters

A 56-year-old male who had previously received an implantable cardioverter-defibrillator for primary prevention was admitted to the hospital with frequent shocks. Device interrogation revealed ineffective shock deliveries. Possible explanations for failed treatment are discussed herein.

Contact-Force Guided Pulmonary Vein Isolation does not Improve Success Rate in Persistent Atrial Fibrillation Patients and Severe Left Atrial Enlargement: A 12-month Follow-Up Study

Background

Catheter ablation is a cornerstone treatment strategy in atrial fibrillation (AF). Left atrial (LA) size is one of the contributors in development of AF recurrences. The impact of contact-forced (CF) guided catheter ablation on the success rate of persistent AF patients with severe enlarged LA has not been investigated yet.

Methods

Sixty-six patients with diagnosis of longstanding persistent AF undergoing catheter ablation were enrolled. All patients underwent a standard transthoracic echocardiography according to the guidelines. LA size was considered severely enlarged when LA diameter was ≥ 50 mm. CF catheter ablation with a Tacticath Quartz catheter (St Jude Medical, St. Paul, MN, USA) was used in all patients.

Results

The mean age was 61.9 ± 9.9 years, and LAD 47.8 ± 11.6 mm. Among 66 patients with persistent AF, 32 (48%) patients were diagnosed with AF recurrences. Twenty-eight (42%) patients had severely enlarged LA. The recurrence of AF was comparable in patients with and without severe enlarged LA (47% vs. 42%, p=0.79). The recurrence of AF was lower in patients who underwent CF-guided ablation with a normal LA dimension (36 %, p=0.54). Procedure duration was longer in patients with severely enlarged LA. LA dimension was not significantly different between patients with and without AF recurrence (49.8 ± 7.9 mm vs. 45.9 ± 7.5 mm, p=0.15). LAD and was significantly correlated with the time to recurrence of AF (r:-0.60, p=0.02).

Conclusion

Our preliminary findings have demonstrated that CF guided ablation does not improve the success rate in longstanding persistent AF patients with severe LA enlargement.

Standardized programming to reduce the burden of inappropriate therapies in implantable cardioverter defibrillators - Single centre follow up results

BACKGROUND

Current algorithms and device morphology templates have been proposed in current Implantable Cardioverter-Defibrillators (ICDs) to minimize inappropriate therapies (ITS), but this has not been completely successful.

AIM

Assess the impact of a deliberate strategy of using an atrial lead implant with standardized parameters; based on all current ICD discriminators and technologies, on the burden of ITS.

METHOD

A retrospective single-centre analysis of 250 patients with either dual chamber (DR) ICDs or biventricular ICDs (CRTDs) over a (41.9 ± 27.3) month period was performed. The incidence of ITS on all ICD and CRTD patients was chronicled after the implementation of standardized programming.

RESULTS

39 events of anti-tachycardial pacing (ATP) and/or shocks were identified in 20 patients (8% incidence rate among patients). The total number of individual therapies was 120, of which 34% were inappropriate ATP, and 36% were inappropriate shocks. 11 patients of the 250 patients received ITS (4.4%). Of the 20 patients, four had ICDs for primary prevention and 16 for a secondary prevention. All the episodes in the primary indication group were inappropriate, while seven patients (43%) of the secondary indication group experienced inappropriate therapies.

CONCLUSIONS

The burden of ITS in the population of patients receiving ICDs was 4.4% in the presence of atrial leads. The proposed rationalized programming criteria seems an effective strategy to minimize the burden of inappropriate therapies and will require further validation.

Cytokine Disturbances in Coronary Artery Ectasia Do Not Support Atherosclerosis Pathogenesis

BACKGROUND

Coronary artery ectasia (CAE) is a rare disorder commonly associated with additional features of atherosclerosis. In the present study, we aimed to examine the systemic immune-inflammatory response that might associate CAE.

METHODS

Plasma samples were obtained from 16 patients with coronary artery ectasia (mean age 64.9 ± 7.3 years, 6 female), 69 patients with coronary artery disease (CAD) and angiographic evidence for atherosclerosis (age 64.5 ± 8.7 years, 41 female), and 140 controls (mean age 58.6 ± 4.1 years, 40 female) with normal coronary arteries. Samples were analyzed at Umeå University Biochemistry Laboratory, Sweden, using the V-PLEX Pro-Inflammatory Panel 1 (human) Kit. Statistically significant differences (p < 0.05) between patient groups and controls were determined using Mann-Whitney U-tests.

RESULTS

The CAE patients had significantly higher plasma levels of INF-γ, TNF-α, IL-1β, and IL-8 (p = 0.007, 0.01, 0.001, and 0.002, respectively), and lower levels of IL-2 and IL-4 (p < 0.001 for both) compared to CAD patients and controls. The plasma levels of IL-10, IL-12p, and IL-13 were not different between the three groups. None of these markers could differentiate between patients with pure (n = 6) and mixed with minimal atherosclerosis (n = 10) CAE.

CONCLUSIONS

These results indicate an enhanced systemic pro-inflammatory response in CAE. The profile of this response indicates activation of macrophages through a pathway and trigger different from those of atherosclerosis immune inflammatory response.

Evaluation of the Tp-Te Interval, QTc and P-Wave Dispersion in Patients With Coronary Artery Ectasia

Background

Coronary artery ectasia (CAE) is defined as a diffuse dilatation of the diameter of the ectatic segment of the coronary artery, 1.5 times greater than that of the adjacent segment. The Tp-Te interval, P-wave and QTc dispersions are relatively new electrocardiographic markers associated with an increased risk of developing arrhythmias. Despite CAE increasing in prevalence in recent years, there is a sparsity of data available about its arrhythmogenic effect. The aim of the study was to evaluate QTc, P-wave dispersion and Tp-Te and Tp-Te/QT ratio in patients with CAE.

Methods

A retrospective comparative study was designed for consecutive age- and sex-matched patients. Twenty patients with isolated CAE (group 1) and 20 control subjects (group 2), with normal coronary arteries, were included. All patients presented with chest pain and coronary angiogram was indicated. Outcome measures included Tp-Te interval, Tp-Te/QT ratio, QTc dispersion and P-wave dispersion. Measurement of electrocardiogram (ECG) parameters was conducted using standardized digital online software. Descriptive and inferential statistics were performed.

Results

Mean Tp-Te (95.5 ± 9.01 ms) and Tp-Te/QT ratio (0.22 ± 0.02) were significantly prolonged in CAE group (Tp-Te: 84 ± 5.62 ms, P = 0.00009; Tp-Te/QT ratio: 0.20 ± 0.01, P = 0.00004). In addition, QTc (31.2 ± 3.71 ms) and P-wave dispersion (31.9 ± 5.46 ms) were significantly increased in comparison to the control group (QTc: 27.6 ± 2.82 ms, P = 0.00532 and 20 ± 3.77 ms, P = 0.00003 respectively). However, there was no difference in ventricular activation time (VAT) between groups.

Conclusions

CAE ECGs were found to be associated with increased Tp-Te, Tp-Te/QT ratio, QTc intervals and P-wave dispersions. This may suggest that CAE existence has a pro-arrhythmogenic nature.

Left Atrial Appendage characteristics in patients with Persistent Atrial Fibrillation undergoing catheter ablation (LAAPAF Study)

Background

Despite technological and scientific efforts, the recurrence rate of persistent atrial fibrillation (AF) remains high. Several studies have shown that in addition to pulmonary vein (PV) isolation other non-PV triggers, particularly left atrial appendage may be the source of initiation and maintenance of AF. There are few studies showing the role of left atrial appendage (LAA) isolation in order to obtain higher success rate in persistent AF patients.

Objective

We analyzed the LAA volume, volume index and shape relative to the LA in patients with persistent AF undergoing AF ablation.

Methods

Fifty-nine consecutive patients with persistent AF who underwent catheter ablation were enrolled. Computerized tomography (CT) was performed in order to assess left atrial and PV anatomy including the LAA. Digital subtraction software (GE Advantage Workstation 4.3) was used to separate the LAA from the LA and calculate: LA volume (LAV), LA volume index (LAV/body surface area), LAA volume (LAAV), LAA volume index (LAA volume/LA volume), and LAA morphology [chicken wing (CW) or non-chicken wing (NCW)].

Results

The mean age was 64.6 ± 9.8 years, 44 % male, and LA diameter 47.6 ± 7.8 mm. Median follow-up (FU) was 13 months. All patients had antral isolation of PVs and ablation of complex fractionation ± linear ablation (roof line/superior coronary sinus/mitral line). Among 59 patients with persistent AF, 26 (44 %) patients were diagnosed with AF recurrences. Mean LAV was 145.0 ± 45.9 ml, LAVI 68.9 ± 20.0 ml/m², LAAV 10.3 ± 4.0 ml, and LAAVI 7.3 ± 2.7 ml/m². LAA shape was non-chicken wing (NCW) in the majority of patients (51 %). LAA parameters were not significantly different between patients with and without AF recurrence (LAAV 11.0 ± 4.3 ml vs. 9.7 ± 3.8 ml, p=0.26; LAAVI 7.5 ± 3.0 ml/m² vs. 7.2 ± 2.5 ml/m², p=0.71; LAA shape of NCW 50 % vs 52 %, p=0.75, respectively). LAV was significantly correlated with the LAAV (r: o.47, p=0.009). The incidence of NCW LAA was significantly higher in patients with previous stroke/TIA (80 % vs. 20 %, p=0.04).

Conclusion

The LAA anatomical characteristics (volume/volume index and the shape) were comparable in patients with/out AF recurrence post PVI. It remains to be determined if additional LAA isolation will impact outcomes in patients with persistent AF.

Lesion Size Index in Maximum Voltage-Guided Cavotricuspid Ablation for Atrial Flutter

The application of optimum contact force (CF) can be used to improve ablation procedure success and safety. The lesion size index (LSI) is a novel dimensionless contact force parameter that allows for an accurate estimation of lesion volume in real time by integrating contact force (grams), duration (seconds) and power (watts). The aim was to correlate LSI values with current contact force parameters to achieve successful and safe bidirectional block of the cavotricuspid isthmus (CTI) using a maximum voltage-guided (MVG) ablation strategy. Fifteen consecutive patients (age 69 ± 7.9 years, nine males) with symptomatic atrial flutter (AFL) were evaluated and compared with 23 control (age 66.3 ± 10.4 years, 16 males) non-contact force-guided ablation cases. Irrigated-tip force-sensing ablation catheters (TactiCath Quartz™, St. Jude Medical, St. Paul, MN, USA) were used in the CF group to achieve the primary endpoint of complete bidirectional block of the isthmus. In the CF group, a total of 233 radiofrequency (RF) applications were examined. A mean LSI of 6.4 ±1.0 correlated with a force-time integral (FTI) of 581.2 ±230.9 g/s and an average CF of 13.9 ±4.9 g concurrently. Intraprocedural, fluoroscopy time and RF time demonstrated lower trends in the CF group, but no significance with respect to these trends was observed. The secondary endpoint of no reconnection within 20 min after the procedure was equally attained in both groups, and, likewise, the level of safety was comparable. An LSI value of >5 represents a new effective parameter in MVG ablation for the cavotricuspid region that demonstrates a safe profile. Guidance of CTI ablation using LSI and other contact force parameters of CF 13.9 ±4.9 g and FTI 581.2 ±230.9 g/s demonstrated highly effective and safe outcomes.

High Voltage Guided Pulmonary Vein Isolation in Paroxysmal Atrial Fibrillation

Background

Ablation of the pulmonary vein (PV) antrum using an electroanatomic mapping system is standard of care for point-by-point pulmonary vein isolation (PVI). Focused ablation at critical areas is more likely to achieve intra-procedural PV isolation and decrease the likelihood for reconnection and recurrence of atrial fibrillation (AF). Therefore this prospective pilot study is to investigate the short-term outcome of a voltage-guided circumferential PV ablation (CPVA) strategy.

Methods

We recruited patients with a history of paroxysmal atrial fibrillation (AF). The EnSite NavX system (St. Jude Medical, St Paul, Minnesota, USA) was employed to construct a three-dimensional geometry of the left atrium (LA) and voltage map. CPVA was performed; with radiofrequency (RF) targeting sites of highest voltage first in a sequential clockwise fashion then followed by complete the gaps in circumferential ablation. Acute and short-term outcomes were compared to a control group undergoing conventional standard CPVA using the same 3D system. Follow-up was scheduled at 3, 6 and 12 months.

Results

Thirty-four paroxysmal AF patients with a mean age of 40 years were included. Fourteen patients (8 male) underwent voltage mapping and 20 patients underwent empirical, non-voltage guided standard CPVA. A mean of 54 ± 12 points per PV antrum were recorded. Mean voltage for right and left PVs antra were 1.7±0.1 mV and 1.9±0.2 mV, respectively. There was a trend towards reduced radiofrequency time (40.9±17.4 vs. 48.1±15.5 mins; p=0.22).

Conclusion

Voltage-guided CPVA is a promising strategy in targeting critical points for PV isolation with a lower trend of AF recurrence compared with a standard CPVA in short-term period. Extended studies to confirm these findings are warranted.

"Spontaneous Twiddler's" Syndrome: The Importance of the Device Shape

Twiddler's syndrome is caused by patient manipulation of the cardiac implantable device (CID) around its central axis within the pocket, resulting in retraction and dislocation of the electrodes. There are, however, some reports that Twiddler's syndrome may occur spontaneously without the patient's manipulation. This remains contentious as it may be argued that patients may not want to admit to manipulating the CID or may have been unaware of their actions. Recently, we have observed three very similar cases with a "spontaneous" Twiddler's syndrome resulting in lead displacement. All of the three patients denied device manipulation and were not prone to somnambulism or repetitive involuntary motor behaviors. It, therefore, seems highly unlikely that all patients could have manipulated the device in exactly the same way to result in the same postrotational position within the implant pocket. The fact is that the same device was implicated in all these cases in a relatively similar time sequence from implant to recognition of the implantable cardiac defibrillator rotation. We postulate that the unique elongated decision of the Fortify Assura (St. Jude Medical, Minneapolis, MN, USA) ICD makes this device prone to spontaneous rotation as is exemplified by our case series.

Interatrial block and interatrial septal thickness in patients with paroxysmal atrial fibrillation undergoing catheter ablation: Long-term follow-up study

BACKGROUND

Interatrial block (IAB) is a strong predictor of recurrence of atrial fibrillation (AF). IAB is a conduction delay through the Bachman region, which is located in the upper region of the interatrial space. During IAB, the impulse travels from the right atrium to the interatrial septum (IAS) and coronary sinus to finally reach the left atrium in a caudocranial direction. No relation between the presence of IAB and IAS thickness has been established yet.

OBJECTIVE

To determine whether a correlation exists between the degree of IAB and the thickness of the IAS and to determine whether IAS thickness predicts AF recurrence.

METHODS

Sixty-two patients with diagnosis of paroxysmal AF undergoing catheter ablation were enrolled. IAB was defined as P-wave duration ≥120 ms. IAS thickness was measured by cardiac computed tomography.

RESULTS

Among 62 patients with paroxysmal AF, 45 patients (72%) were diagnosed with IAB. Advanced IAB was diagnosed in 24 patients (39%). Forty-seven patients were male. During a mean follow-up period of 49.8 ± 22 months (range 12-60 months), 32 patients (51%) developed AF recurrence. IAS thickness was similar in patients with and without IAB (4.5 ± 2.0 mm vs. 4.0 ± 1.4 mm; p = .45) and did not predict AF. Left atrial size was significantly enlarged in patients with IAB (40.9 ± 5.7 mm vs. 37.2 ± 4.0 mm; p = .03). Advanced IAB predicted AF recurrence after the ablation (OR: 3.34, CI: 1.12-9.93; p = .03).

CONCLUSIONS

IAS thickness was not significantly correlated to IAB and did not predict AF recurrence. IAB as previously demonstrated was an independent predictor of AF recurrence.

Dysregulated fatty acid metabolism in coronary ectasia: An extended lipidomic analysis

BACKGROUND

Coronary artery ectasia (CAE) is not an uncommon clinical condition, which could be associated with adverse outcome. The exact pathophysiology of the disease is poorly understood and is commonly interpreted as a variant of atherosclerosis. In this study, we sought to undertake lipidomic profiling of a group of CAE patients in an attempt to achieve better understanding of its disturbed metabolism.

METHODS

Untargeted lipid profiling and complementary modelling strategies were employed to compare serum samples from 16 patients with CAE (mean age 63.5±10.1years, 6 female) and 26 controls with normal smooth coronary arteries (mean age 59.2±6.6years and 7 female). Sample preparation, LC-MS analysis and metabolite identification were performed at the Swedish Metabolomics Centre, Umeå, Sweden.

RESULTS

Phosphatidylcholine levels were significantly distorted in the CAE patients (p=0.001-0.04). Specifically, 16-carbon fatty acyl chain phosphatidylcholines (PC) were detected in lower levels. Similarly, 11 meioties of Sphyngomyelin (SM) species were detected at lower concentrations (p=0.000001-0.01) in the same group. However, only three metabolites were significantly higher in the pure CAE subgroup (6 patients) when compared with the 10 mixed CAE patients (two meioties of SM species and one of PC). Atherosclerosis risk factors were not different between groups.

CONCLUSION

This is the first lipid profiling study reported in coronary artery ectasia. While the lower concentration and dysregulation of sphyngomyelin suggests an evidence for premature apoptosis, that of phosphatidylcholines suggests perturbed fatty acid elongation/desaturation, thus may be indicative of non-atherogenic process in CAE.

Increased Incidence of Ventricular Arrhythmias in Patients With Advanced Cancer and Implantable Cardioverter-Defibrillators

OBJECTIVES

This study evaluated the incidence of ventricular arrhythmia and implantable cardioverter-defibrillator (ICD) therapies in patients with a diagnosis of cancer.

BACKGROUND

Cardiac disease and cancer are prevalent conditions and share common predisposing factors. No studies have assessed the impact of cancer on the burden of ventricular arrhythmia in patients with cancer and ICDs.

METHODS

Retrospective study of patients with an ICD and cancer who were followed from January 2007 to June 2015. Rates of ventricular tachycardia (VT) and ventricular fibrillation (VF) before and after patients' cancers were diagnosed were evaluated by searching device data collection systems. Rates were adjusted for length of follow-up and compared using the Wilcoxon test, and times to first therapy following diagnosis (stages I to III vs. IV) were compared using Kaplan-Meier curves and log-rank test.

RESULTS

Among 1,598 patients with an ICD, 209 patients (13.1%) had a pathological diagnosis of malignancy; and in 102 patients (6.4%), malignancy was diagnosed following device insertion. After the diagnosis of cancer, 32% of patients experienced VT/VF over 23.2 ± 23.6 months, and the frequency of arrhythmic events was significantly increased after the diagnosis (1.19 ± 0.32 vs. 0.12 ± 0.21 episodes per month, respectively; p = 0.03). The incidence of VT/VF was markedly higher in patients with stage IV cancer than in those with earlier stages (p = 0.03). In this group, the incidence of VT/VF was 41.2%, with an average of 7.2 ± 18.5 events per patient, all of whom received ICD shocks. The rate of ICD deactivation in stage IV patients was 35.3%. Inappropriate therapies occurred in 13.7%, and atrial fibrillation was the most frequent cause.

CONCLUSIONS

One-third of patients who had received ICDs developed ventricular arrhythmia after a diagnosis of cancer. The incidence was significantly higher in those with advanced metastatic disease. Findings underscore the need to discuss ICD management as part of end-of-life care.

Unipolar voltage threshold of 5.0 mV is optimal to localize critical isthmuses in post-infarction patients presenting with ventricular tachycardia

INTRODUCTION

Bipolar voltage mapping is useful to delineate post-infarct endocardial scar and guide ablation of ischemic VT. The role of unipolar mapping is not yet well defined. The aim of this study was to assess the correlation between electrophysiological findings in patients with ischemic VT and unipolar voltage maps using different cut-offs.

METHODS

We included 10 patients (age 67 ± 7 years, ejection fraction 33 ± 10%) with ischemic cardiomyopathy undergoing catheter ablation for recurrent VT. Patients with right-sided VTs were excluded. In all patients a unipolar voltage map was constructed during right ventricular pacing. Ablation was performed guided by activation and entrainment mapping in hemodynamically stable VTs and by pace-mapping and abnormal (late/split/fractionated) potentials in unstable VTs. Subsequently, the unipolar voltage maps were analyzed off-line using cutoffs from 1.0 to 8.0 mV and correlated with the isthmus sites.

RESULTS

A total of 17 sustained VTs were induced in the 10 patients and non-inducibility of the clinical VT was achieved in 90% of patients by endocardial ablation. The optimal cutoff was 5.0 mV. By using this value, the mean surface area of abnormal unipolar voltage was 43.8% and 95% of all VT isthmuses were located within the area of scar, as well as 81% of abnormal potentials. In addition, 71% of isthmuses were at less than 1cm from the scar border.

CONCLUSION

Unipolar voltage mapping showed good correlation with areas of isthmuses and abnormal electrograms in patients with scar-related VT, with a cut-off of 5.0 mV allowing the best delineation of ablation targets.

Coronary artery ectasia as a culprit for acute myocardial infarction: review of pathophysiology and management

Coronary artery ectasia (CAE) is defined as localized coronary dilatation, which exceeds the diameter of normal adjacent segments or the diameter of the patient's largest coronary vessel by 1.5 times. The pathophysiology of CAE remains unclear as its relationship with atherosclerosis remains only modestly established. The histological variances and conflicting reports of the role of traditional cardiovascular risk factors, also, weakens the significance of such association. The slow coronary flow (CSF) of CAE may lead to ischemic and thrombotic events, a mechanism that has never been fully elucidated, but may play a fundamental role in its pathogenesis. While pure, non-atherosclerotic, CAE is believed to have better prognosis when compared to atherosclerotic obstructive CAE, it is thought that CAE is not a simple condition but rather has an adverse clinical course. Nevertheless, long-term prognosis and outcome of CAE is similar to atherosclerotic-non-CAE. Since CAE was first described, oral anticoagulants have been considered as a valid treatment option. Dual antiplatelet therapy is widely employed in acute coronary syndrome (ACS), which also applies to CAE patients presenting with ACS. However, there is a significant uncertainty about the best treatment strategy for CAE in acute myocardial infarction. We hereby report a variety of presentations of CAE complicated with ST elevation myocardial infarction (STEMI). Pathophysiological and anatomical varieties of ectatic coronary culprit lesions represent clinical challenges in uniformly managing this condition. Our review is unique in critically showing the pathophysiology, available controversial evidence upon management and prognostic features of CAE with STEMI.

Ventricular activation time as a marker for diastolic dysfunction in early hypertension

BACKGROUND

A standard 12-lead electrocardiogram (ECG) is performed in all hypertensive patients, primarily to detect left ventricular hypertrophy. Echocardiographic assessment of hypertensive subjects reveals that abnormalities in diastolic function occur more commonly and earlier than increased left ventricular mass. However, ECG changes associated with diastolic dysfunction (DD) remain poorly defined; we assessed the ventricular activation time (VAT) (i.e., the time for the ventricle to depolarize) as a potential marker for DD in early hypertension.

METHODS

Ninety subjects (aged 46 +/- 1.3 years; 43 men) with newly diagnosed, untreated hypertension underwent ECG and comprehensive two-dimensional echocardiography. Left ventricular DD was echocardiographically assessed using Canadian Consensus Guidelines. We compared VAT, which corresponds to the QR interval in the 12-lead ECG, with echocardiographic parameters of DD.

RESULTS

VAT was prolonged in subjects with DD (46.3 +/- 0.4 vs. 39.6 +/- 0.3 ms, P < 0.01). There was a significant correlation between VAT and tissue Doppler imaging (TDI) (early diastolic velocity) e' (r = -0.53, P < 0.0001), (ratio of early and late diastolic velocities) e'/a' (r = -0.53, P < 0.0001), transmitral Doppler (TMD) (early peak filling rate, and early deceleration peak) E/A (r = -0.32, P = 0.001), and (ratio of early diastolic mitral inflow and early diastolic velocities) E/e' (r = 0.44, P < 0.0001).

CONCLUSION

Prolongation of the VAT is associated with DD in patients with newly diagnosed untreated hypertension.