Efficacy and safety of same-day discharge after atrial fibrillation ablation compared with post-procedural overnight stay: a systematic review and meta-analysis.

AIMS: Catheter ablation for atrial fibrillation (AF) has historically required inpatient admission post-procedure, but same-day discharge (SDD) has recently been reported. We aimed to assess the efficacy and safety of SDD compared with overnight stay (OS) post-ablation. METHODS AND RESULTS: We performed a systematic search of the PubMed database. Random-effects meta-analysis was performed to assess the efficacy (successful SDD) and safety (24 h complications, 30-day complications, 30-day re-admissions, and 30-day mortality) of a SDD AF ablation strategy. Fourteen non-randomized observational studies met criteria for inclusion, encompassing 26488 patients undergoing AF ablation, of whom 9766 were SDD. The mean age of participants was 61.9 years, and 67.9% were male. Around 61.7% underwent ablation for paroxysmal AF. The pooled success rate of SDD was 83.2% [95% confidence intervals (CIs): 61.5-97.0%, I2 100%]. The risk of bias was severe for all effect estimates due to confounding, as most cohorts were retrospectively identified without appropriately matched comparators. There was no significant difference in 30-day complications [odds ratio (OR): 0.95, 95% CI: 0.65-1.40, I2 53%] or 30-day re-admission (OR 0.96, 95% CI: 0.49-1.89, I2 82%) between groups. There were insufficient data for meta-analysis of 24 h complications and 30-day mortality. Where reported, no re-admissions occurred due to 24 h complications after SDD. Two deaths (0.04%) were reported in both SDD and OS groups. CONCLUSION: Same-day discharge after AF ablation appears to be an effective and safe strategy in selected patients. However, the available evidence is of low quality, and more robust prospective studies comparing SDD to OS are needed.

Point-by-Point Radiofrequency Ablation Versus the Cryoballoon or a Novel Combined Approach: A Randomized Trial Comparing 3 Methods of Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation (The Cryo Versus RF Trial).

INTRODUCTION: Catheter ablation of paroxysmal AF using the Cryoballoon (CRYO) has yielded similar success rates to conventional wide encirclement using radiofrequency catheter ablation (RFCA), but randomized data are lacking. Pilot data suggested a high success rate with a combined approach (COMBINED) using wide encirclement with RFCA followed by 2 CRYO applications to each vein. We compared these 3 strategies in a randomized controlled trial. METHODS AND RESULTS: Patients undergoing first time paroxysmal AF ablation were randomized to RFCA, CRYO, or COMBINED. Patients were followed up at 3, 6, and 12 months with 7 days of ambulatory ECG monitoring. Success was defined as freedom from arrhythmia without antiarrhythmic drugs after a single procedure. A total of 237 patients were randomized. Success at 1 year was achieved in 47% in the RFCA group, 67% in the CRYO group, and 76% in the COMBINED group (P < 0.001 for RFCA vs. CRYO, P<0.001 for RFCA vs. COMBINED, and P = 0.220 for CRYO vs. COMBINED). Procedure time was 211 (IQR 174-256) minutes for RFCA compared to 167 (136-202) minutes for CRYO and 278 (243-327) minutes for COMBINED (P < 0.001 for RFCA vs. COMBINED, RFCA vs. CRYO, and CRYO vs. COMBINED groups). CONCLUSIONS: Pulmonary vein isolation for paroxysmal AF is faster with CRYO and results in a higher single procedure success rate than conventional point by point RFCA. The COMBINED approach was not superior to CRYO alone.

A comparison of left ventricular endocardial, multisite, and multipolar epicardial cardiac resynchronization: an acute haemodynamic and electroanatomical study.

AIMS: Alternative forms of cardiac resynchronization therapy (CRT), including biventricular endocardial (BV-Endo) and multisite epicardial pacing (MSP), have been developed to improve response. It is unclear which form of stimulation is optimal. We aimed to compare the acute haemodynamic response (AHR) and electrophysiological effects of BV-Endo with MSP via two separate coronary sinus (CS) leads or a single-quadripolar CS lead. METHODS AND RESULTS: Fifteen patients with a previously implanted CRT system received a second temporary CS lead and left ventricular (LV) endocardial catheter. A pressure wire and non-contact mapping array were placed into the LV cavity to measure LVdP/dtmax and perform electroanatomical mapping. Conventional CRT, BV-Endo, and MSP were then performed (MSP-1 via two epicardial leads and MSP-2 via a single-quadripolar lead). The best overall AHR was found using BV-Endo pacing with a 19.6 ± 13.6% increase in AHR at the optimal endocardial site over baseline (P < 0.001). There was an increase in LVdP/dtmax with MSP-1 and MSP-2 compared with conventional CRT, but this was not statistically significant. Biventricular endocardial pacing from the optimal site was significantly superior to conventional CRT (P = 0.039). The AHR achieved when BV-Endo pacing was highly site specific. Within individuals, the best pacing modality varied and was affected by the underlying substrate. Left ventricular activation times did not predict the optimal haemodynamic configuration. CONCLUSION: Biventricular endocardial pacing and not MSP was superior to conventional CRT, but was highly site specific. Within individuals, however, different methods of stimulation are optimal and may need to be tailored to the underlying substrate.

Multi-site left ventricular pacing as a potential treatment for patients with postero-lateral scar: insights from cardiac magnetic resonance imaging and invasive haemodynamic assessment.

AIMS: Multi-site left ventricular (LV) pacing may be superior to single-site stimulation in correcting dyssynchrony and avoiding areas of myocardial scar. We sought to characterize myocardial scar using cardiac magnetic resonance imaging (CMR). We aimed to quantify the acute haemodynamic response to single-site and multi-site LV stimulation and to relate this to the position of the LV leads in relation to myocardial scar. METHODS: Twenty patients undergoing cardiac resynchronization therapy had implantation of two LV leads. One lead (LV1) was positioned in a postero-lateral vein, the second (LV2) in a separate coronary vein. LV dP/dtmax was recorded using a pressure wire during stimulation at LV1, LV2, and both sites simultaneously (LV1 + 2). Patients were deemed acute responders if ΔLV dP/dtmax was ≥ 10%. Cardiac magnetic resonance imaging was performed to assess dyssynchrony as well as location and burden of scar. Scar anatomy was registered with fluoroscopy to assess LV lead position in relation to scar. RESULTS: LV dP/dtmax increased from 726 ± 161 mmHg/s in intrinsic rhythm to 912 ± 234 mmHg/s with LV1, 837 ± 188 mmHg/s with LV2, and 932 ± 201 mmHg/s with LV1 and LV2. Nine of 19 (47%) were acute responders with LV1 vs. 6/19 (32%) with LV2. Twelve of 19 (63%) were acute responders with simultaneous LV1 + 2. Two of three patients benefitting with multi-site pacing had the LV1 lead positioned in postero-lateral scar. CONCLUSION: Multi-site LV pacing increased acute response by 16% vs. single-site pacing. This was particularly beneficial in patients with postero-lateral scar identified on CMR.

Relationship between endocardial activation sequences defined by high-density mapping to early septal contraction (septal flash) in patients with left bundle branch block undergoing cardiac resynchronization therapy.

AIMS: Early inward motion and thickening/thinning of the ventricular septum associated with left bundle branch block is known as the septal flash (SF). Correction of SF corresponds to response to cardiac resynchronization therapy (CRT). We hypothesized that SF was associated with a specific left ventricular (LV) activation pattern predicting a favourable response to CRT. We sought to characterize the spatio-temporal relationship between electrical and mechanical events by directly comparing non-contact mapping (NCM), acute haemodynamics, and echocardiography. METHODS AND RESULTS: Thirteen patients (63 ± 10 years, 10 men) with severe heart failure (ejection fraction 22.8 ± 5.8%) awaiting CRT underwent echocardiography and NCM pre-implant. Presence and extent of SF defined visually and with M-mode was fused with NCM bull's eye plots of endocardial activation patterns. LV-dP/dt(max) was measured during different pacing modes. Five patients had a large SF, four small SF, and four no SF. Large SF patients had areas of conduction block in non-infarcted regions, whereas those with small or no SF did not. Patients with large SF had greater acute response to LV and biventricular (BIV) pacing vs. those with small/no SF (% increase dP/dt 28 ± 14 vs. 11 ± 19% for LV pacing and 42 ± 28 vs. 22 ± 21% for BIV pacing) (P < 0.05). This translated into a more favourable chronic response to CRT. The lines of conduction block disappeared with LV/BIV pacing while remaining with right ventricle pacing. CONCLUSION: A strong association exists between electrical activation and mechanical deformation of the septum. Correction of both mechanical synchrony and the functional conduction block by CRT may explain the favourable response in patients with SF.

Provocation Testing and Therapeutic Response in a Newly Described Channelopathy: RyR2 Calcium Release Deficiency Syndrome.

BACKGROUND: A novel familial arrhythmia syndrome, cardiac ryanodine receptor (RyR2) calcium release deficiency syndrome (CRDS), has recently been described. We evaluated a large and well characterized family to assess provocation testing, risk factor stratification and response to therapy in CRDS. METHODS: We present a family with multiple unheralded sudden cardiac deaths and aborted cardiac arrests, primarily in children and young adults, with no clear phenotype on standard clinical testing. RESULTS: Genetic analysis, including whole genome sequencing, firmly established that a missense mutation in RYR2, Ala4142Thr, was the underlying cause of disease in the family. Functional study of the variant in a cell model showed RyR2 loss-of-function, indicating that the family was affected by CRDS. EPS (Electrophysiological Study) was undertaken in 9 subjects known to carry the mutation, including a survivor of aborted sudden cardiac death, and the effects of flecainide alone and in combination with metoprolol were tested. There was a clear gradation in inducibility of nonsustained and sustained ventricular arrhythmia between subjects at EPS, with the survivor of aborted sudden cardiac death being the most inducible subject. Administration of flecainide substantially reduced arrhythmia inducibility in this subject and abolished arrhythmia in all others. Finally, the effects of additional metoprolol were tested; it increased inducibility in 4/9 subjects. CONCLUSIONS: The Ala4142Thr mutation of RYR2 causes the novel heritable arrhythmia syndrome CRDS, which is characterized by familial sudden death in the absence of prior symptoms or a recognizable phenotype on ambulatory monitoring or exercise stress testing. We increase the experience of a specific EPS protocol in human subjects and show that it is helpful in establishing the clinical status of gene carriers, with potential utility for risk stratification. Our data provide evidence that flecainide is protective in human subjects with CRDS, consistent with the effect previously shown in a mouse model.

Cardiac MRI to investigate myocardial scar and coronary venous anatomy using a slow infusion of dimeglumine gadobenate in patients undergoing assessment for cardiac resynchronization therapy.

PURPOSE: To evaluate a cardiac MR (CMR) examination with slow infusion of a high-relaxivity contrast agent to visualize coronary venous anatomy (CVA) and myocardial scar in heart failure patients awaiting cardiac resynchronization therapy (CRT). MATERIALS AND METHODS: Fourteen patients awaiting CRT (seven ischemic cardiomyopathy (ICM) and seven non-ICM) and two with normal LV function underwent CMR on a 1.5 Tesla (T) MR scanner. Dimeglumine-gadobenate was slowly infused. Bolus arrival in the LV was measured by a dynamic electrocardiogram (ECG) -triggered inversion recovery (IR) scan subsequent to starting an ECG-triggered respiratory-navigated three-dimensional (3D) SSFP MR scan with IR preparation to acquire systolic whole-heart anatomy for vein visualization. Delayed contrast-enhanced MR scan was performed to assess myocardial scar. CVA obtained by CMR was compared with X-ray venography in 11 patients. CVA and scar were segmented and registered for visual inspection. RESULTS: For all subjects, there was excellent visualization of the CVA. All ICM and one non-ICM patient showed scar. There was excellent correlation between veins seen by CMR and venography. CONCLUSION: We have demonstrated that slow infusion protocol of dimeglumine-gadobenate can be used to assess both CVA and myocardial scar in a single MR examination. Furthermore, an image overlay technique has been used to show the relationship of scar to the CVA.

Relationship between intracardiac impedance and left ventricular contractility in patients undergoing cardiac resynchronization therapy.

AIMS: Cardiac resynchronization therapy (CRT) has dramatically improved the symptoms and prognosis of patients with heart failure in large randomized clinical trials. Optimization of device settings may maximize benefit on an individual basis, although the best method for this is not yet established. We evaluated the use of cardiogenic impedance measurements (derived from intracardiac impedance signals) in CRT device optimization, using invasive left ventricular (LV) dP/dtmax as the reference. METHODS AND RESULTS: Seventeen patients underwent invasive haemodynamic assessment using a pressure wire placed in the LV cavity at the time of CRT device implantation. Intracardiac impedance measurements were made at different atrioventricular (AV) and interventricular (VV) delays and compared with LV dP/dtmax. We assessed the performance of patient-specific and generic impedance-based models in predicting acute haemodynamic response to CRT. In two patients, LV catheterization with the pressure wire was unsuccessful and in two patients LV lead delivery was unsuccessful; therefore, data were acquired for 13 out of 17 patients. Left ventricular dP/dtmax was 919±182 mmHg/s at baseline and this increased acutely (by 24%) to 1121±226 mmHg/s as a result of CRT. The patient-specific impedance-based model correctly predicted the optimal haemodynamic response (to within 5% points) for AV and VV delays in 90 and 92% of patients, respectively. CONCLUSION: Cardiogenic impedance measurements are capable of correctly identifying the maximum achievable LV dP/dtmax as measured by invasive haemodynamic assessment. This study suggests that cardiogenic impedance can potentially be used for CRT optimization and may have a role in ambulatory assessment of haemodynamics.

Advanced image fusion to overlay coronary sinus anatomy with real-time fluoroscopy to facilitate left ventricular lead implantation in CRT.

BACKGROUND: Failure rate for left ventricular (LV) lead implantation in cardiac resynchronization therapy (CRT) is up to 12%. The use of segmentation tools, advanced image registration software, and high-fidelity images from computerized tomography (CT) and cardiac magnetic resonance (CMR) of the coronary sinus (CS) can guide LV lead implantation. We evaluated the feasibility of advanced image registration onto live fluoroscopic images to allow successful LV lead placement. METHODS: Twelve patients (11 male, 59 ± 16.8 years) undergoing CRT had three-dimensional (3D) whole-heart imaging (six CT, six CMR). Eight patients had at least one previously failed LV lead implant. Using segmentation software, anatomical models of the cardiac chambers, CS, and its branches were overlaid onto the live fluoroscopy using a prototype version of the Philips EP Navigator software to guide lead implantation. RESULTS: We achieved high-fidelity segmentations of cardiac chambers, coronary vein anatomy, and accurate registration between the 3D anatomical models and the live fluoroscopy in all 12 patients confirmed by balloon occlusion angiography. The CS was cannulated successfully in every patient and in 11, an LV lead was implanted successfully. (One patient had no acceptable lead values due to extensive myocardial scar). CONCLUSION: Using overlaid 3D segmentations of the CS and cardiac chambers, it is feasible to guide CRT implantation in real time by fusing advanced imaging and fluoroscopy. This enabled successful CRT in a group of patients with previously failed implants. This technology has the potential to facilitate CRT and improve implant success.

Power, Lesion Size Index and Oesophageal Temperature Alerts During Atrial Fibrillation Ablation: A Randomized Study.

BACKGROUND: Low radiofrequency powers are commonly used on the posterior wall of the left atrium for atrial fibrillation ablation to prevent esophageal damage. Compared with higher powers, they require longer ablation durations to achieve a target lesion size index (LSI). Esophageal heating during ablation is the result of a time-dependent process of conductive heating produced by nearby radiofrequency delivery. This randomized study was conducted to compare risk of esophageal heating and acute procedure success of different LSI-guided ablation protocols combining higher or lower radiofrequency power and different target LSI values. METHODS: Eighty consecutive patients were prospectively enrolled and randomized to one of 4 combinations of radiofrequency power and target LSI for ablation on the left atrium posterior wall (20 W/LSI 4, 20 W/LSI 5, 40 W/LSI 4, and 40 W/LSI 5). The primary end point of the study was the occurrence and number of esophageal temperature alerts per patient during ablation. Acute indicators of procedure success were considered as secondary end points. Long-term follow-up data were also collected for all patients. RESULTS: Esophageal temperature alerts occurred in a similar proportion of patients in all groups. Significantly, shorter radiofrequency durations were required to achieve the target LSI in the 40 W groups. Less than 50% of the radiofrequency lesions reached the target LSI of 5 when using 20 W despite a longer radiofrequency duration. A lower rate of first-pass pulmonary vein isolation and a higher rate of acute pulmonary vein reconnection were recorded in the group 20 W/LSI 5. A lower atrial fibrillation recurrence rate was observed in the 40 W groups compared with the 20 W groups at 29 months follow-up. CONCLUSIONS: When guided by LSI, posterior wall ablation with 40 W is associated with a similar rate of esophageal temperature alerts and a lower atrial fibrillation recurrence rate at follow-up if compared with 20 W. These data will provide a basis to plan future randomized trials. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02619396.

Are conflict of interest declarations appropriate to allow sufficient consideration of potential bias in presentations?

BACKGROUND: Potential conflicts of interest (CoI) are common in medical research, necessitating the use of CoI declarations. There is currently no consensus document or external authority guiding CoI declarations in conference settings, resulting in declarations of variable quality and utility. METHODS: We explored four CoI declaration parameters (sufficient slide display time; the presence of any verbal explanation pertaining to relevant CoI; the use of an adequate font size; and whether the nature and relevance of the CoI was described). Parameters were graded from one to three points, with the sum of parameters providing an overall declaration quality out of 12. We then applied this scoring system to recordings of presentations from the British Cardiovascular Society (BCS) annual conference 2018 which were available online. RESULTS: Sixty-nine presentations were suitable for inclusion, of which 47 (68%) contained a CoI statement. Thirty-six of the 47 (77%) presentations declared that they had no CoI. In the remaining 11 (23%) with reported CoI, the median time spent displaying CoI was 1 second (interquartile range (IQR) 0.7-3.3). The median quality score for presentations was 7 (IQR 6-10). CONCLUSION: This study demonstrates utility in considering aspects of CoI declarations at conferences to improve transparency.

Endocardial left ventricular pacing across the interventricular septum for cardiac resynchronization therapy: Clinical results of a pilot study.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an effective treatment for selected patients with heart failure, but it can be limited by the inability to place the left ventricular (LV) lead via the coronary sinus. OBJECTIVE: The purpose of this study was to develop an alternative approach, placing the LV lead endocardially via an interventricular septal puncture, and to assess the feasibility and safety of this technique. METHODS: All patients were anticoagulated with warfarin (international normalized ratio 2.5-3.5). A superior approach ventricular transseptal puncture using radiofrequency energy was performed. An active fixation pacing lead was delivered to the mapped site of latest electrical activation on the endocardial LV. RESULTS: Twenty patients were recruited, 15 with failed transvenous LV lead placement and 5 nonresponders to CRT. Mean (± SD) age was 67 ± 12, with 80% male, QRS duration 157 ± 14 ms, ischemic etiology 45%, New York Heart Association functional class 2.9 ± 0.4, and LV ejection fraction 28% ± 7%. The procedure was successful in all, with no serious complications. Clinical composite score improved at 6 months in 65% and worsened in 35%. LV ejection fraction improved >5% in 88%, from 28% ± 7% to 41% ± 9%. Six-minute walking distance improved >10% in 64%, from 248 ± 125 m to 316 ± 109 m. One patient suffered a lacunar ischemic stroke after 5 months with partial neurological recovery, associated with labile international normalized ratios. After 2.0 ± 1.0 years of follow-up, 3 patients died (2 pneumonia, 1 heart failure), and 2 patients suffered transient ischemic attacks. CONCLUSION: LV endocardial pacing via interventricular septal puncture in patients for whom standard CRT is not possible is similarly effective and durable, with significant but potentially acceptable risks.

Randomized trial comparing pulmonary vein isolation using the SmartTouch catheter with or without real-time contact force data.

BACKGROUND: Contact force (CF) information may improve the safety and efficacy of ablation for paroxysmal atrial fibrillation (PAF). OBJECTIVE: The purpose of this study was to assess the impact of CF data on ablation for PAF. METHODS: Patients undergoing first-time PAF ablation were randomized at 7 UK centers to ablation with (CF-on) or without (CF-off) CF data available to the operator, using the same ablation catheter and mapping system. An ablation CF of 5-40g was targeted. Pulmonary vein (PV) reconnection was assessed with adenosine at 60 minutes. Follow-up for arrhythmia recurrence was for 1 year with 7-day Holter recordings at 6 and 12 months. RESULTS: One hundred seventeen patients were studied (59 CF-on, 58 CF-off). In the CF-on group, a reduction in acute PV reconnection rates (22% vs 32%, P = .03) but no significant difference in 1-year success rates off antiarrhythmic drugs (49% vs 52%, P = .9) was observed. There was no difference in major complication rates: 2 of 59 (3%) CF-on, 3 of 58 (5%) CF-off (P = .7). Procedural and fluoroscopy times were not significantly different (P>.5). Overall mean CFs per ablation were not different between groups (13.4 [9.1-19.6]g CF-on, 13.4 [7.4-22.4]g CF-off, P = .5), but a greater proportion of readings in the CF-on group were in the target range (80% vs 68%, P<.001). CONCLUSION: This randomized multicenter study demonstrated that CF data availability was associated with reduced acute PV reconnection but not improved 1-year success rates, procedural and fluoroscopy times, or complication rates. There was a reduction in extremes of CF, above and below the study target range, suggesting greater CF control during ablation.

No Benefit of Complex Fractionated Atrial Electrogram Ablation in Addition to Circumferential Pulmonary Vein Ablation and Linear Ablation: Benefit of Complex Ablation Study.

BACKGROUND: The optimal ablation strategy for persistent atrial fibrillation (AF) remains unclear. METHODS AND RESULTS: This multicentre randomized study compared circumferential pulmonary vein ablation+linear ablation (control arm) versus circumferential pulmonary vein ablation+linear ablation+complex fractionated atrial electrogram (CFAE) ablation (CFAE arm) in patients with persistent AF. Circumferential pulmonary vein ablation was performed followed by roof and mitral isthmus ablation, before CFAE ablation in the CFAE arm. Ablation strategy was maintained at the first redo procedure. Sixty-five patients were recruited in each arm. The mean age was 61±10 years, 75% were men, median AF duration was 2 years, 42% had long-lasting persistent AF, 68% had associated cardiovascular disease, mean left atrial dimension was 46±6 mm, and median CHA2DS2-VASc score was 2. Ablation and procedure times were significantly longer in the CFAE arm (70±20 versus 55±17; 201±35 versus 152±45 minutes; P<0.005). After a mean follow-up of 35±5 months, single-procedural success off antiarrhythmic drugs at 12 months (CFAE: 30/65 [46%] versus control: 37/65 [57%]; P=0.29) and multiprocedural success (CFAE: 51/65 [78%] versus control: 52/65 [80%]; P=1.0) were not significantly different. At the first redo procedure, patients in the CFAE arm had a higher incidence of organized atrial tachycardia/flutter (24/33 [73%] versus 11/31 [35%]; P=0.005) and gap-related macro-re-entrant flutter (8/33[24%] versus 1/31[3%]; P=0.03). Early recurrence of atrial arrhythmia was an independent predictor of late recurrence. CONCLUSIONS: CFAE ablation did not confer incremental benefit when performed in addition to circumferential pulmonary vein ablation and linear ablation. It was associated with a higher incidence of gap-related flutter. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01711047.

The reliability of cardiogenic impedance and correlation with echocardiographic and plethysmographic parameters for predicting CRT time intervals post implantation.

AIMS: Encouraging data have been reported on the use of cardiogenic impedance (CI) in cardiac resynchronization therapy (CRT) optimization. The purposes of this study were to: evaluate the stability of certain CI vectors 24 h postimplantation, study the correlation between these CI signals and selected echocardiographic parameters, and examine the possibility of non-invasive calibration of the patient-specific impedance-based prediction model. METHODS AND RESULTS: Thirteen patients received a CRT-defibrillator device with monitor capability of the dynamic impedance between several electrodes. At implantation, a patient-specific impedance-based prediction model was created for identification of optimal atrioventricular and interventricular (VV) delays and calibrated on invasive measurements of left ventricular contractility (LV dP/dtmax). Simultaneously, non-invasive measurements of LV dP/dtmax and stroke volume (SV) were obtained using a finger plethysmograph. Patients were re-evaluated with echocardiography and new CI measurements the day after implantation. The hemodynamic benefit achieved by optimal VV setting according to the patient-specific impedance-based prediction model at follow-up was not as large as the one obtained at implantation. In a multivariate partial least square regression analysis, a correlation was found between aortic velocity time integral (VTI) and a generic linear combination of CI features (P < 0,005). No correlation was found between the patient-specific impedance-based prediction models and the non-invasive measurements of LV dP/dtmax and SV. CONCLUSION: Cardiogenic impedance signals can be used to optimize CRT settings but seem less feasible as an ambulatory tool since calibration is required. The positive correlation between aortic VTI and CI measurements seems promising, although a larger cohort is required to create an echocardiography-based patient-specific model.

Steerable sheath technology in the ablation of atrial fibrillation.

Steerable sheaths have been shown to reduce procedure time in the catheter ablation of atrial fibrillation (AF), where catheter positioning and stability is typically challenging. This review critically addresses and highlights the recent developments in design of sheaths used to manipulate the ablation catheter and how these developments may impact on the ablation procedure itself, in particular the likelihood of first-time success. Patents relating to steerable sheaths are reviewed and discussed to gauge potential future developments in this area.

Cardiac magnetic resonance-derived anatomy, scar, and dyssynchrony fused with fluoroscopy to guide LV lead placement in cardiac resynchronization therapy: a comparison with acute haemodynamic measures and echocardiographic reverse remodelling.

AIMS: Left ventricular (LV) lead positioning for cardiac resynchronization therapy (CRT) is largely empirical and operator-dependent. Our aim was to determine whether cardiac magnetic resonance (CMR)-guided CRT may improve the acute and the chronic response. METHODS AND RESULTS: CMR-derived anatomical models and dyssynchrony maps were created for 20 patients. The CMR targets (three latest activated segments with <50% scar) were overlaid on to live fluoroscopy. Acute haemodynamic response (AHR) to LV pacing was assessed using an intra-ventricular pressure wire. Chronic CRT response (end-systolic volume reduction ≥15%) was assessed 6 months post-implantation. All patients underwent successful CMR-guided LV lead placement. A CMR target segment was paced in 75% of patients. The mean change in LVdP/dtmax for the CMR target was +14.2 ± 12.5 vs. +18.7 ± 11.9% for the best AHR in any segment and +12.0 ± 13.8% for the segment based on coronary sinus (CS) venography. Using CMR guidance, the acute responder rate was 60 vs. 50% on the basis of venography. At 6 months 60% of patients were echocardiographic responders. Of the echocardiographic responders, 92% were successfully paced in a CMR target segment compared with only 50% of non-responders (P = 0.04). CONCLUSION: CMR guidance compared well when validated against the AHR. Lead placement was possible in the CMR target region in most patients with an AHR comparable with the best achieved in any CS branch. The chronic response was significantly better in patients paced in a CMR target segment. These results suggest that CMR guidance may represent a clinically useful tool for CRT.

Benefits of endocardial and multisite pacing are dependent on the type of left ventricular electric activation pattern and presence of ischemic heart disease: insights from electroanatomic mapping.

BACKGROUND: There is considerable heterogeneity in the myocardial substrate of patients undergoing cardiac resynchronization therapy (CRT), in particular in the etiology of heart failure and in the location of conduction block within the heart. This may account for variability in response to CRT. New approaches, including endocardial and multisite left ventricular (LV) stimulation, may improve CRT response. We sought to evaluate these approaches using noncontact mapping to understand the underlying mechanisms. METHODS AND RESULTS: Ten patients (8 men and 2 women; mean [SD] age 63 [12] years; LV ejection fraction 246%; QRS duration 161 [24] ms) fulfilling conventional CRT criteria underwent an electrophysiological study, with assessment of acute hemodynamic response to conventional CRT as well as LV endocardial and multisite pacing. LV activation pattern was assessed using noncontact mapping. LV endocardial pacing gave a superior acute hemodynamic response compared with conventional CRT (26% versus 37% increase in LV dP/dt(max), respectively; P<0.0005). There was a trend toward further incremental benefit from multisite LV stimulation, although this did not reach statistical significance (P=0.08). The majority (71%) of patients with nonischemic heart failure etiology or functional block responded to conventional CRT, whereas those with myocardial scar or absence of functional block often required endocardial or multisite pacing to achieve CRT response. CONCLUSIONS: Endocardial or multisite pacing may be required in certain subsets of patients undergoing CRT. Patients with ischemic cardiomyopathy and those with narrower QRS, in particular, may stand to benefit.

A simultaneous X-Ray/MRI and noncontact mapping study of the acute hemodynamic effect of left ventricular endocardial and epicardial cardiac resynchronization therapy in humans.

BACKGROUND: Cardiac resynchronization therapy (CRT) using endocardial left ventricular (LV) pacing may be superior to conventional CRT. We studied the acute hemodynamic response to conventional CRT and LV pacing from different endocardial sites using a combined cardiac MRI and LV noncontact mapping (NCM) protocol to gain insights into the underlying mechanisms. METHODS AND RESULTS: Fifteen patients (age, 63 ± 10 years; 12 men) awaiting CRT were studied in a combined x-ray and MRI laboratory. Delayed-enhancement cardiac magnetic resonance was performed to define areas of myocardial fibrosis. Patients underwent an electrophysiological study incorporating endocardial and epicardial LV pacing. Acute hemodynamic response was measured using a pressure wire within the LV cavity to derive LV dP/dt max. NCM was used to define areas of slow conduction. There was a significant improvement in all LV pacing modes versus baseline (P<0.001). LV endocardial CRT from the best endocardial site was superior to conventional CRT, with a 79.8 ± 49.0% versus 59.6 ± 49.5% increase in LV dP/dt max of from baseline (P<0.05). The hemodynamic benefits of pacing were greater when LV stimulation was performed outside of areas of slow conduction defined by NCM (P<0.001). Delayed-enhancement cardiac magnetic resonance was able to delineate zones of slow conduction seen with NCM in ischemic patients but was unreliable in nonischemic patients. CONCLUSIONS: Endocardial LV pacing appears superior to conventional CRT, although the optimal site varies between subjects and is influenced by pacing within areas of slow conduction. Delayed-enhancement cardiac magnetic resonance was a poor predictor of zones of slow conduction in nonischemic patients.