Conduction system pacing, a European survey: insights from clinical practice.

AIMS: The field of conduction system pacing (CSP) is evolving, and our aim was to obtain a contemporary picture of European CSP practice. METHODS AND RESULTS: A survey was devised by a European CSP Expert Group and sent electronically to cardiologists utilizing CSP. A total of 284 physicians were invited to contribute of which 171 physicians (60.2%; 85% electrophysiologists) responded. Most (77%) had experience with both His-bundle pacing (HBP) and left bundle branch area pacing (LBBAP). Pacing indications ranked highest for CSP were atrioventricular block (irrespective of left ventricular ejection fraction) and when coronary sinus lead implantation failed. For patients with left bundle branch block (LBBB) and heart failure (HF), conventional biventricular pacing remained first-line treatment. For most indications, operators preferred LBBAP over HBP as a first-line approach. When HBP was attempted as an initial approach, reasons reported for transitioning to utilizing LBBAP were: (i) high threshold (reported as >2 V at 1 ms), (ii) failure to reverse bundle branch block, or (iii) > 30 min attempting to implant at His-bundle sites. Backup right ventricular lead use for HBP was low (median 20%) and predominated in pace-and-ablate scenarios. Twelve-lead electrocardiogram assessment was deemed highly important during follow-up. This, coupled with limitations from current capture management algorithms, limits remote monitoring for CSP patients. CONCLUSIONS: This survey provides a snapshot of CSP implementation in Europe. Currently, CSP is predominantly used for bradycardia indications. For HF patients with LBBB, most operators reserve CSP for biventricular implant failures. Left bundle branch area pacing ostensibly has practical advantages over HBP and is therefore preferred by many operators. Practical limitations remain, and large randomized clinical trial data are currently lacking.

Worldwide survey on implantation of and outcomes for conduction system pacing with His bundle and left bundle branch area pacing leads.

BACKGROUND: Adoption and outcomes for conduction system pacing (CSP), which includes His bundle pacing (HBP) or left bundle branch area pacing (LBBAP), in real-world settings are incompletely understood. We sought to describe real-world adoption of CSP lead implantation and subsequent outcomes. METHODS: We performed an online cross-sectional survey on the implantation and outcomes associated with CSP, between November 15, 2020, and February 15, 2021. We described survey responses and reported HBP and LBBAP outcomes for bradycardia pacing and cardiac resynchronization CRT indications, separately. RESULTS: The analysis cohort included 140 institutions, located on 5 continents, who contributed data to the worldwide survey on CSP. Of these, 127 institutions (90.7%) reported experience implanting CSP leads. CSP and overall device implantation volumes were reported by 84 institutions. In 2019, the median proportion of device implants with CSP, HBP, and/or LBBAP leads attempted were 4.4% (interquartile range [IQR], 1.9-12.5%; range, 0.4-100%), 3.3% (IQR, 1.3-7.1%; range, 0.2-87.0%), and 2.5% (IQR, 0.5-24.0%; range, 0.1-55.6%), respectively. For bradycardia pacing indications, HBP leads, as compared to LBBAP leads, had higher reported implant threshold (median [IQR]: 1.5 V [1.3-2.0 V] vs 0.8 V [0.6-1.0 V], p = 0.0008) and lower ventricular sensing (median [IQR]: 4.0 mV [3.0-5.0 mV] vs. 10.0 mV [7.0-12.0 mV], p < 0.0001). CONCLUSION: In conclusion, CSP lead implantation has been broadly adopted but has yet to become the default approach at most surveyed institutions. As the indications and data for CSP continue to evolve, strategies to educate and promote CSP lead implantation at institutions without CSP lead implantation experience would be necessary.

Outcomes of left atrial appendage occlusion using the AtriClip device: a systematic review.

Atrial fibrillation increases lifetime stroke risk. The left atrial appendage (LAA) is thought to be the source of embolic strokes in up to 90% of cases, and occlusion of the LAA may be safer than the alternative of oral anticoagulation. Occlusion devices, such as the AtriClipTM (AtriCure, Mason, OH, USA) enable safe and reproducible epicardial clipping of the LAA. A systematic review was performed in May 2018, based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, using the keyword 'AtriClip'. A total of 68 papers were identified and reviewed; 11 studies were included. Data including demographics, medical history intervention(s) performed, periprocedural outcomes and follow-up were assessed and analysed. A total of 922 patients were identified. LAA occlusion was achieved in 902 out of 922 patients (97.8%). No device-related adverse events were reported across the studies. The reported incidence of stroke or transient ischaemic attack post-clip placement ranged from 0.2 to 1.5/100 patient-years. Four hundred and seventy-seven of 798 patients (59.7%) had ceased anticoagulation on follow-up. The AtriClip device is safe and effective in the management of patients with atrial fibrillation, either as an adjunct in patients undergoing cardiac surgery or as a stand-alone thoracoscopic procedure.

CMR Guidance for Recanalization of Coronary Chronic Total Occlusion.

OBJECTIVES: This study explored whether cardiac magnetic resonance (CMR) could help select patients who could benefit from revascularization by identifying inducible myocardial ischemia and viability in the perfusion territory of the artery with chronic total occlusion (CTO). BACKGROUND: The benefit of revascularization using percutaneous coronary intervention (PCI) in CTO is controversial. CMR offers incomparable left ventricular (LV) systolic function assessment in addition to potent ischemic burden quantification and reliable myocardial viability analysis. Whether CMR guided CTO revascularization would be helpful to such patients has not yet been explored fully. METHODS: A prospective study of 50 consecutive CTO patients was conducted. Of 50 patients undergoing baseline stress CMR, 32 (64%) were selected for recanalization based on the presence of significant inducible perfusion deficit and myocardial viability within the CTO arterial territory. Patients were rescanned 3 months after successful CTO recanalization. RESULTS: At baseline, myocardial perfusion reserve (MPR) in the CTO territory was significantly reduced compared with the remote region (1.8 ± 0.72 vs. 2.2 ± 0.7; p = 0.01). MPR in the CTO region improved significantly after PCI (to 2.3 ± 0.9; p = 0.02 vs. baseline) with complete or near-complete resolution of CTO related perfusion defect in 90% of patients. Remote territory MPR was unchanged after PCI (2.5 ± 1.2; p = NS vs. baseline). The LV ejection fraction increased from 63 ± 13% to 67 ± 12% (p < 0.0001) and end-systolic volume decreased from 65 ± 38 to 56 ± 38 ml (p < 0.001) 3 months after CTO PCI. Importantly, despite minimal post-procedural infarction due to distal embolization and side branch occlusion in 8 of 32 patients (25%), the total Seattle Angina Questionnaire score improved from a median of 54 (range 45 to 74) at baseline to 89 (range 77 to 98) after CTO recanalization (p < 0.0001). CONCLUSIONS: In this small group of patients showing CMR evidence of significant myocardial inducible perfusion defect and viability, CTO recanalization reduces ischemic burden, favors reverse remodeling, and ameliorates quality of life.

The safety and efficacy of trans-baffle puncture to enable catheter ablation of atrial tachycardias following the Mustard procedure: a single centre experience and literature review.

BACKGROUND: Targets for catheter ablation of atrial tachyarrhythmias (AT) in post-Mustard procedure patients are often located in the pulmonary venous atrium (PVA). Traditional access to this chamber is retrograde via the aorta. However trans-baffle puncture may be a key determinant of successful ablation in many cases. METHODS: All AT ablations performed in patients late after Mustard and Senning operations by a single operator from 2007 to 2012 were reviewed. RESULTS: Nine procedures were identified. In total, 12 ATs were treated, seven persistent, the remainder induced, consisting of counterclockwise cavotricuspid isthmus dependent flutter (5), macroreentrant with isthmus in the systemic venous atrium (SVA) (2), macroreentrant with isthmus in the PVA (1), focal from the PVA (3), and focal from the SVA (1). Ablation within the PVA was required in all procedures to treat AT. Retrograde access in one patient was impossible due to the presence of a Bjork-Shiley tricuspid valve replacement; retrograde access in another two patients was attempted but catheter manipulation was ineffective and AT could not be mapped and ablated. Trans-baffle puncture was performed with transoesophageal echocardiographic guidance in all cases without complications and resulted in successful ablation of AT. CONCLUSIONS: Access to the pulmonary venous atrium is essential for successful ablation of AT in many Mustard patients. Trans-baffle puncture remains a relevant technique to modern practice and can be performed safely and effectively.

Remote-controlled magnetic navigation and ablation with 3D image integration as an alternative approach in patients with intra-atrial baffle anatomy.

BACKGROUND: Improvement in outcome of infants born with congenital heart defects has been accompanied by an increasing frequency of late arrhythmias. Ablation is difficult because of multiple tachycardias in the presence of complex anatomy with limited accessibility. We report on remote-controlled ablation using magnetic navigation in conjunction with 3D image integration in patients with previous intra-atrial baffle procedures. METHODS AND RESULTS: Thirteen patients (8 male; age, 30.5±8 years) with supraventricular tachycardia (SVT) underwent catheter ablation. Group A had a medical history of a Mustard or Senning operation, whereas group B had undergone total cavopulmonary connection. A total of 26 tachycardias were treated in 17 procedures (median cycle length of 280 ms). Group A patients had more inducible SVTs than group B, and all index SVTs were located in the remainder of the morphological right atrium in all but 1 patient. Retrograde access through the aorta was performed and led to successful ablation, using magnetic navigation with a very low total radiation exposure (median of 3.8 minutes in group A versus 5.9 minutes in group B). Only 1 of 13 patients continued to have short-lasting SVTs despite 3 ablation procedures during a median follow-up time of >200 days. CONCLUSIONS: Remote-controlled catheter ablation by magnetic navigation in combination with accurate 3D image integration allowed safe and successful elimination of SVTs, using an exclusively retrograde approach, resulting in low radiation exposure for patients after intra-atrial baffle procedures (Mustard, Senning, or total cavopulmonary connection).

Ablation of ventricular fibrillation in an orthotopic heart lung transplant.

Arrhythmia is well described following cardiac transplantation. We report a case of recurrent ventricular fibrillation (VF) originating from an orthotopic cardiac allograft. VF was consistently initiated on each occasion by a relatively early-coupled monomorphic ventricular ectopic. Antiarrhythmic agents failed to suppress the arrhythmia. Electrophysiological testing with noncontact mapping showed a high-frequency potential at the earliest activation site. Radiofrequency ablation resulted in abolition of ventricular ectopy with no further VF recurrence. Although there is substantial experience with ablation of atrial tachycardias in this setting, experience with ablation for ventricular arrhythmias is limited and ablation of VF not described.

Role of cardiovascular magnetic resonance as a gatekeeper to invasive coronary angiography in patients presenting with heart failure of unknown etiology.

BACKGROUND: In patients presenting with new-onset heart failure of uncertain etiology, the role of coronary angiography (CA) is unclear. Although conventionally performed to differentiate underlying coronary artery disease from dilated cardiomyopathy, CA is associated with a risk of complications and may not detect an ischemic cause resulting from arterial recanalization or an embolic episode. In this study, we assessed the diagnostic accuracy of a cardiovascular magnetic resonance (CMR) protocol incorporating late gadolinium enhancement (LGE) and magnetic resonance CA as a noninvasive gatekeeper to CA in determining the etiology of heart failure in this subset of patients. METHODS AND RESULTS: One hundred twenty consecutive patients underwent CMR and CA. The etiology was ascribed by a consensus panel that used the results of the CMR scans. Similarly, a separate consensus group ascribed an underlying cause by using the results of CA. The diagnostic accuracy of both strategies was compared against a gold-standard panel that made a definitive judgment by reviewing all clinical data. The study was powered to show noninferiority between the 2 techniques. The sensitivity of 100%, specificity of 96%, and diagnostic accuracy of 97% for LGE-CMR were equivalent to CA (sensitivity, 93%; specificity, 96%; and diagnostic accuracy, 95%). As a gatekeeper to CA, LGE-CMR was also found to be a cheaper diagnostic strategy in a decision tree model when United Kingdom-based costs were assumed. The economic merits of this model would change, depending on the relative costs of LGE-CMR and CA in any specific healthcare system. CONCLUSION: This study showed that LGE-CMR is a safe, clinically effective, and potentially economical gatekeeper to CA in patients presenting with heart failure of uncertain etiology.

A multi-purpose spiral high-density mapping catheter: initial clinical experience in complex atrial arrhythmias.

PURPOSE: There is an increasing need for catheter ablation procedures to treat complex atrial tachycardias (AT) and atrial fibrillation (AF), often requiring detailed endocardial mapping. The sequential point-to-point contact mapping of complex arrhythmias is time-consuming and may not always be feasible. We assessed the utility of a novel spiral duo-decapolar high-density (HD) mapping catheter to delineate complex arrhythmia substrates for ablation. METHODS: The patients underwent HD mapping using a spiral catheter (AFocusII) and the EnSite NavX system, during catheter ablation procedures, to treat atrial arrhythmias. RESULTS: In 26 patients, a total of 32 atrial arrhythmias were mapped and ablated, comprising of five focal AT, eight macroreentrant AT, 11 persistent AF and eight paroxysmal AF. The HD catheter was used to acquire endocardial surface geometries in all cases and to map the pulmonary veins in patients undergoing AF ablation. In persistent AF, HD catheter mapping permitted the creation of highly detailed complex fractionated electrogram maps (left atrium 449 ± 128 points in 7.2 ± 2.6 min; right atrium 411 ± 113 points in 6.7 ± 1.6 min). In AT, activation mapping was performed with the acquisition of 305 ± 158 timing points in 7.3 ± 2.6 min, guiding successful ablation in all cases. During the follow-up of 7.0 ± 2.6 months, all AT patients remained free of significant arrhythmia. CONCLUSIONS: High-density contact mapping with a novel spiral multipolar catheter allows rapid assessment of focal and macroreentrant AT, and complex fractionated electrical activity in the atria. It has further multi-functional capabilities as a pulmonary vein mapping catheter and for accurate geometry creation when used with a 3D mapping system.

Stem cell infusion into the vein of Marshall.

The vein of Marshall (VOM) and related cardiac ganglia have been clearly implicated in atrial fibrillation. Electrophysiological procedures have targeted these sites of autonomic innervation. However, targeting the exact sites has proven technically challenging. Identifying the VOM and infusing stem cells may ablate related ganglia autonomic function and offer an innovative treatment for atrial fibrillation.

Unusual scarring patterns on cardiac magnetic resonance imaging: A potentially treatable etiology not to be missed.

A case of cardiomyopathy and ventricular tachycardia previously assumed to be idiopathic in origin is described. Investigation with cardiac magnetic resonance imaging prompted the diagnosis and successful treatment of an underlying disorder based on typical scarring patterns seen with late gadolinium enhancement. The present report suggests that clinicians should have a low threshold for actively excluding this condition in patients presenting with cardiomyopathy, even in the absence of other disease features, particularly if typical scarring patterns are found on cardiac magnetic resonance imaging because disease-specific therapy appears to significantly improve both symptoms and prognosis.

Validation of magnetic resonance myocardial perfusion imaging with fractional flow reserve for the detection of significant coronary heart disease.

BACKGROUND: Magnetic resonance myocardial perfusion imaging (MRMPI) has a number of advantages over the other noninvasive tests used to detect reversible myocardial ischemia. The majority of previous studies have generally used quantitative coronary angiography as the gold standard to assess the accuracy of MRMPI; however, only an approximate relationship exists between stenosis severity and functional significance. Pressure wire-derived fractional flow reserve (FFR) values <0.75 correlate closely with objective evidence of reversible ischemia. Accordingly, we have compared MRMPI with FFR. METHODS AND RESULTS: One hundred three patients referred for investigation of suspected angina underwent MRMPI with a 1.5-T scanner. The stress agent was intravenous adenosine (140 microg . kg(-1) . min(-1)), and the first-pass bolus contained 0.1 mmol/kg gadolinium. In the following week, coronary angiography with pressure wire studies was performed. FFR was recorded in all patent major epicardial coronary arteries, with a value <0.75 denoting significant stenosis. MRMPI scans, analyzed by 2 blinded observers, identified perfusion defects in 121 of 300 coronary artery segments (40%), of which 110 had an FFR <0.75. We also found that 168 of 179 normally perfused segments had an FFR > or = 0.75. The sensitivity and specificity of MRMPI for the detection of functionally significant coronary heart disease were 91% and 94%, respectively, with positive and negative predictive values of 91% and 94%. CONCLUSIONS: MRMPI can detect functionally significant coronary heart disease with excellent sensitivity, specificity, and positive and negative predictive values compared with FFR.

Portentous pinball.

A 76-year-old woman presented with a six-day history of pleuritic pain, dyspnea and a swollen, tender left calf. She was dyspneic, tachypneic and tachycardic (heart rate 109 beats/min), with decreased oxygen saturation (83%) and a partial pressure of oxygen of 9 kPa. Her blood pressure was 119/79 mmHg, and she had elevated jugular venous pressure (11 mmHg). A computed tomographic pulmonary angiogram revealed extensive bilateral pulmonary artery thrombi and an ultrasound confirmed a lower limb thrombus. Echocardiography demonstrated a dilated right ventricle with pulmonary artery hypertension (75 mmHg) and a free-floating thrombus of 1.5 cm x 4 cm, which ricocheted across the right ventricular outflow tract from the tricuspid to the pulmonary valve. The left ventricle was underfilled and hyperdynamic. Following thrombolysis, the patient's clinical status improved. Echocardiography revealed improved biventricular function, no residual right ventricular thrombus, and pulmonary artery pressure normalization. The present case demonstrates the usefulness of echocardiography in submassive pulmonary embolus risk stratification and management.

Thiazolinediones and heart failure: the potential to precipitate irreversible cardiac dysfunction.

Thiazolinediones are increasingly prescribed to improve glycaemic control in patients with type 2 diabetes. Experimental evidence suggests that these agents may exert a beneficial effect on cardiac haemodynamics, and protect against the development and progression of heart failure. However, these agents have been reported to precipitate heart failure, and in all cases this has been reversed by discontinuation of thiazolinediones, implicating a reversible mechanism. We report a unique case of irreversible dilated cardiomyopathy precipitated by pioglitazone, highlighting the potential for thiazolinediones to cause irreversible cardiac dysfunction. At present the underlying mechanisms for this are unclear, but this warrants further research.

Direct comparison of myocardial perfusion cardiovascular magnetic resonance sequences with parallel acquisition.

PURPOSE: To directly compare the three main myocardial perfusion cardiovascular magnetic resonance (CMR) sequences incorporating parallel acquisition methods. MATERIALS AND METHODS: In 15 subjects (12 men, 57 +/- 15.7 years) referred for diagnostic coronary angiography, we acquired first-pass perfusion images (0.1 mmol/kg gadolinium-DTPA) at rest and during adenosine (140 microg/kg/min) on three separate occasions using three sequences incorporating parallel acquisition methods and approximately equivalent spatiotemporal resolution: hybrid echo planar imaging (hEPI), steady-state free precession (SSFP), and gradient echo imaging (GRE). We calculated the contrast-to-noise ratio (CNR) of each scan and blinded observers scored the presence and severity of artifacts (1, worst to 4, best), diagnostic confidence (0, low to 2, high), transmurality, area, and epicardial vessel territory of perfusion defects. RESULTS: CNR was greatest with SSFP and least with hEPI (13.15 vs 7.85 P < 0.001). The most artifacts were recorded with SSFP and least with hEPI (2.00 vs 3.03 P < 0.001). Observers were significantly more confident in reporting hEPI images (1.6 hEPI vs 0.9 SSFP, P < 0.001). Results for GRE were intermediate for all assessments. CONCLUSION: The hEPI sequence scored best for diagnostic performance despite the SSFP sequence having greater CNR. This trial favors hEPI for clinical myocardial perfusion CMR and suggests CNR should not be the sole criterion used to gauge the best candidate sequence.