Invasive Right Ventricular Pressure-Volume Analysis: Basic Principles, Clinical Applications, and Practical Recommendations

Right ventricular pressure-volume (PV) analysis characterizes ventricular systolic and diastolic properties independent of loading conditions like volume status and afterload. While long-considered the gold-standard method for quantifying myocardial chamber performance, it was traditionally only performed in highly specialized research settings. With recent advances in catheter technology and more sophisticated approaches to analyze PV data, it is now more commonly used in a variety of clinical and research settings. Herein, we review the basic techniques for PV loop measurement, analysis, and interpretation with the aim of providing readers with a deeper understanding of the strengths and limitations of PV analysis. In the second half of the review, we detail key scenarios in which right ventricular PV analysis has influenced our understanding of clinically relevant topics and where the technique can be applied to resolve additional areas of uncertainty. All told, PV analysis has an important role in advancing our understanding of right ventricular physiology and its contribution to cardiovascular function in health and disease.

Catheter Ablation in Persistent AF, the Evolution towards a More Pragmatic Strategy

Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and represents a heterogeneous disorder with a complex pathological basis. While significant technological advances have taken place over the last decade in the field of catheter ablation of AF, response to ablation varies and long-term success rates in those with persistent AF remain modest. Mechanistic studies have highlighted potentially different sustaining factors for AF in the persistent AF population with substrate-driven focal and re-entrant sources in the body of the atria identified on invasive and non-invasive mapping studies. Translation to clinical practice, however, remains challenging and the application of such mapping techniques to clinical ablation has yet to demonstrate a significant benefit beyond pulmonary vein isolation (PVI) alone in the persistent AF cohort. Recent advances in catheter and ablation technology have centered on improving the durability of ablation lesions at index procedure and although encouraging results have been demonstrated with early studies, large-scale trials are awaited. Further meaningful improvement in clinical outcomes in the persistent AF population requires ongoing advancement in the understanding of AF mechanisms, coupled with continuing progress in catheter technology capable of delivering durable transmural lesions.

Comparative study of intracranial access in thrombectomy using next generation 0.088 inch guide catheter technology

BackgroundMost conventional 0.088 inch guide catheters cannot safely navigate intracranial vasculature. The objective of this study is to evaluate the safety of stroke thrombectomy using a novel 0.088 inch guide catheter designed for intracranial navigation.MethodsThis is a multicenter retrospective study, which included patients over 18 years old who underwent thrombectomy for anterior circulation large vessel occlusions. Technical outcomes for patients treated using the TracStar Large Distal Platform (TracStar LDP) or earlier generation TRX LDP were compared with a matched cohort of patients treated with other commonly used guide catheters. The primary outcome measure was device-related complications. Secondary outcome measures included guide catheter failure and time between groin puncture and clot engagement.ResultsEach study arm included 45 patients. The TracStar group was non-inferior to the control group with regard to device-related complications (6.8% vs 8.9%), and the average time to clot engagement was 8.89 min shorter (14.29 vs 23.18 min; p=0.0017). There were no statistically significant differences with regard to other technical outcomes, including time to recanalization (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2B). The TracStar was successfully advanced into the intracranial internal carotid artery in 33 cases (73.33%); in three cases (6.67%), it was swapped for an alternate catheter. Successful reperfusion (mTICI 2B-3) was achieved in 95.56% of cases. Ninety-day follow-up data were available for 86.67% of patients, among whom 46.15% had an modified Rankin Score of 0–2%, and 10.26% were deceased.ConclusionsTracstar LDP is safe for use during stroke thrombectomy and was associated with decreased time to clot engagement. Intracranial access was regularly achieved.

Impact of Micro-, Mini- and Multi-Electrode Mapping on Ventricular Substrate Characterisation

Accurate substrate characterisation may improve the evolving understanding and treatment of cardiac arrhythmias. During substrate-based ablation techniques, wide practice variations exist with mapping via dedicated multi-electrode catheter or conventional ablation catheters. Recently, newer ablation catheter technology with embedded mapping electrodes have been introduced. This article focuses on the general misconceptions of voltage mapping and more specific differences in unipolar and bipolar signal morphology, field of view, signal-to-noise ratio, mapping capabilities (density and resolution), catheter-specific voltage thresholds and impact of micro-, mini- and multi-electrodes for substrate mapping. Efficiency and cost-effectiveness of different catheter types are discussed. Increasing sampling density with smaller electrodes allows for higher resolution with a greater likelihood to record near-field electrical information. These advances may help to further improve our mechanistic understanding of the correlation between substrate and ventricular tachycardia, as well as macro-reentry arrhythmia in humans.

Durable pulmonary vein (PV) isolation at repeat atrial fibrillation (AF) ablation procedure: a comparison between 4 ablation technologies

Background Durable PV isolation is the sought-after endpoint to obtain long term success after AF catheter ablation. Evolution in technology improves efficiency, safety and effectiveness in AF catheter ablation. Purpose To investigate the effectiveness of different catheter technologies in obtaining durable PV isolation in a real-world practice. Methods Retrospective analysis of prospectively collected data of patients undergoing repeat procedures for recurrence of AF or atrial flutter at our institution was performed. Incidence of all PVs being isolated at repeat procedure was recorded and patients 4 groups created based on catheter technology used during index AF ablation procedure (SF: multipored, irrigated catheter; ST: contact force sensor catheter; Cryo: 2nd generation cryobaloon; and STSF: multipored, irrigated, contact force sensing catheter). Results We identified 269 subjects undergoing repeat ablation from May 2014 to September 2019. Mean age was 67±9.7 years, 54.6% were males, 74.4% non-paroxysmal AF at the index procedure. The mean CHA2DS2Vasc score was 2.5±0.26, LA size 4.2±0.6 cm, EF 55.3±10%. The mean time from index to redo procedure was 374±331 days. At repeat procedure all veins were isolated in 24% (6/25) who were initially ablated using SF; 36% (8/22) with Cryo; 44% (47/108) with ST; and 74% (84/114) with STSF catheter. (Figure) Conclusion Patients undergoing index ablation with STSF catheter technology were significantly more likely to have all 4 PVs isolated at repeat procedure compared to previous generation technology. Funding Acknowledgement Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Biosense Webster

810. Resistance to the Minocycline-Rifampin-Chlorhexidine (MRCH) combination does not emerge in biofilms of Tetracycline and Rifampin resistant bacteria grown on MRCH catheters depleted below antimicrobially effective concentrations

Background Central Line Associated Bloodstream Infections (CLABSIs) remain a significant medical problem for critically ill cancer patients who required catheters for extended durations. Minocycline (M) -Rifampin (R) loaded catheters have shown the greatest impact on reducing CLABSIs; however, there is a risk for developing antibiotic resistant organisms when exposed to catheters whose concentration becomes depleted below antimicrobially effective levels due to extended indwells. Chlorhexidine (CH) and M-R combination catheters (MRCH) have been proposed as a next generation catheter with improved performance. Here we studied whether bacteria that were Tetracycline and Rifampin resistant became resistant to MRCH when allowed to form biofilms on MRCH catheters depleted below antimicrobially effective MRCH concentrations. Methods Minimum inhibitory concentrations (MICs) of Tetracycline and/or Rifampin resistant stock isolates were measured by standard microbroth dilution methods. MRCH catheters were depleted to below antimicrobially effective concentrations by soaking in serum for 6 weeks. The resistant bacteria were then allowed to form biofilm for 24 hrs on the depleted catheters in broth. Following 24 hour incubation the adherent (breakthrough) bacteria were removed by sonication and MICs were remeasured. The same organisms grown on non-antimicrobial catheters were used as controls. Results MICs (ug/mL) of the organisms against each agent and the combination are tabulated below: MICs (ug/mL) of the organisms against each agent and the combination Conclusion The M and R resistant bacteria did not develop in vitro resistance to the MRCH combination after forming biofilms on MRCH catheters depleted below antimicrobially effective concentrations. Disclosures Joel Rosenblatt, PhD, Cook Medical (Shareholder, Other Financial or Material Support, Inventor of the MRCH catheter technology which is owned by the University of Texas MD Anderson Cancer Center and has been licensed to Cook Medical)Novel Anti-Infective Technologies (Shareholder, Other Financial or Material Support, Inventor of the MRCH catheter technology which is owned by the University of Texas MD Anderson Cancer Center and has been licensed to Cook Medical) Issam I. Raad, MD, Citius (Other Financial or Material Support, Ownership interest)Cook Medical (Grant/Research Support)Inventive Protocol (Other Financial or Material Support, Ownership interest)Novel Anti-Infective Technologies (Shareholder, Other Financial or Material Support, Ownership interest)

Thrombectomy for Distal, Medium Vessel Occlusions

Endovascular thrombectomy (EVT) is well established as a highly effective treatment for acute ischemic stroke (AIS) due to proximal, large vessel occlusions (PLVOs). With iterative further advances in catheter technology, distal, medium vessel occlusions (DMVOs) are now emerging as a promising next potential EVT frontier. This consensus statement integrates recent epidemiological, anatomic, clinical, imaging, and therapeutic research on DMVO-AIS and provides a framework for further studies. DMVOs cause 25% to 40% of AISs, arising as primary thromboemboli and as unintended consequences of EVT performed for PLVOs, including emboli to new territories (ENTs) and emboli to distal territories (EDTs) within the initially compromised arterial field. The 6 distal medium arterial arbors (anterior cerebral artery [ACA], M2–M4 middle cerebral artery [MCA], posterior cerebral artery [PCA], posterior inferior cerebellar artery [PICA], anterior inferior cerebellar artery [AICA], and superior cerebellar artery [SCA]) typically have 25 anatomic segments and give rise to 34 distinct arterial branches nourishing highly differentiated, largely superficial cerebral neuroanatomical regions. DMVOs produce clinical syndromes that are highly heterogenous but frequently disabling. While intravenous fibrinolytics are more effective for distal than proximal occlusions, they fail to recanalize one-half to two-thirds of DMVOs. Early clinical series using recently available, smaller, more navigable stent retriever and thromboaspiration devices suggest EVT for DMVOs is safe, technically efficacious, and potentially clinically beneficial. Collaborative investigations are desirable to enhance imaging recognition of DMVOs; advance device design and technical efficacy; conduct large registry studies using harmonized, common data elements; and complete formal randomized trials, improving treatment of this frequent mechanism of stroke.