scholarly journals Cardiac Synchronization

2020 ◽  
Author(s):  
Keyword(s):  
Cardiac Synchronization

scholarly journals Morphometric Characterization of Human Coronary Veins and Subvenous Epicardial Adipose Tissue—Implications for Cardiac Resynchronization Therapy Leads

2020 ◽  
Vol 7 ◽  
Author(s):  
Jonas Keiler ◽  
Felix G. Meinel ◽  
Jasmin Ortak ◽  
Marc-André Weber ◽  
Andreas Wree ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Cardiac Computed Tomography ◽  
Cardiac Resynchronization ◽  
Coronary Veins ◽  
Lead Placement ◽  
Section Technique ◽  
Left Posterior ◽  
Epicardial Fat Tissue ◽  
Venous Diameter ◽  
Cardiac Synchronization

Subvenous epicardial fat tissue (SEAT), which acts as an electrical insulation, and the venous diameter (VD) both constitute histomorphological challenges for optimal application and lead design in cardiac synchronization therapy (CRT). In this study, we characterized the morphology of human coronary veins to improve the technical design of future CRT systems and to optimize the application of CRT leads. We retrospectively analyzed data from cardiac computed tomography (CT) of 53 patients and did studies of 14 human hearts using the postmortem freeze section technique and micro CT. Morphometric parameters (tributary distances, offspring angles, luminal VD, and SEAT thickness) were assessed. The left posterior ventricular vein (VVSP) had a mean proximal VD of 4.0 ± 1.4 mm, the left marginal vein (VMS) of 3.2 ± 1.5 mm and the anterior interventricular vein (VIA) of 3.9 ± 1.3 mm. More distally (5 cm), VDs decreased to 2.4 ± 0.6 mm, 2.3 ± 0.7 mm, and 2.4 ± 0.6 mm, respectively. In their proximal portions (15 mm), veins possessed mean SEAT thicknesses of 3.2 ± 2.4 (VVSP), 3.4 ± 2.4 mm (VMS), and 4.2 ± 2.8 mm (VIA), respectively. More distally (20–70 mm), mean SEAT thicknesses decreased to alternating low levels of 1.3 ± 1.1 mm (VVSP), 1.7 ± 1.1 mm (VMS), and 4.3 ± 2.6 mm (VIA), respectively. In contrast to the VD, SEAT thicknesses alternated along the further distal vein course and did not display a continuous decrease. Besides the CRT responsiveness of different areas of the LV myocardium, SEAT is a relevant electrophysiological factor in CRT, potentially interfering with sensing and pacing. A sufficient VD is crucial for successful CRT lead placement. Measurements revealed a trend toward greater SEAT thickness for the VIA compared to VVSP and VMS, suggesting a superior signal-to-noise-ratio in VVSP and VMS.

High frequency irreversible electroporation (H-FIRE) as a novel method of targeted cell death.

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 277-277
Author(s):  
Imran A Siddiqui ◽  
Russell C. Kirks ◽  
Erin H Baker ◽  
Eduardo Latouche ◽  
Matt Dewitt ◽  
...  
Keyword(s):  
Cell Death ◽  
High Frequency ◽  
Irreversible Electroporation ◽  
Vital Signs ◽  
Cardiac Monitoring ◽  
Vascular Integrity ◽  
Cancer Cell Death ◽  
Novel Method ◽  
Vascular Structures ◽  
Cardiac Synchronization

277 Background: Irreversible electroporation unlike ablation is excellent in inducing cell death via apoptosis. It, however, has disadvantages of electrical conduction via cardiac and nervous tissue. This results in requiring cardiac monitoring and general anesthesia and paralytics while performing electroporation. We hypothesized a novel high-frequency IRE (H-FIRE) system employing ultra-short bipolar pulses would obviate the need for cardiac synchronization and paralytics while maintaining measurable effect on cell death. Methods: Female swine (55-65Kg) were used. Two H-FIRE electrodes were inserted into the liver (1.5-cm spacing). In the absence of paralytics H-FIRE pulses were delivered (2250V, 2-5-2 pulse configuration) at different on times (100 vs. 200μs) or number of pulses (100 vs. 300). Next electrodes were placed across major hepatic vascular structures and H-FIRE performed. At conclusion tissue was resected and analyzed histologically. Results: 24 H-FIREs were performed (mean ablation time 275 secs). No EKG abnormalities or changes in vital signs were measured during H-FIRE procedures. In 1/24 H-FIREs minor twitching of the rectus abdominis was recorded coinciding with pulse delivery. Histologically, tissues had effective electroporation as evidenced by cell death and caspase activity. Blinded scoring was performed for necrosis and apoptosis. Areas of cell death were predictable. No significant vascular damage or coagulated/thermally-desiccated blood was detected within major vessels following H-FIRE. Conclusions: H-FIRE is a novel way of liver electroporation. It produces predictable cell apoptosis without the requirement of paralytics and alteration of electrocardiographic signals as compared to traditional electroporation, while preserving underlying vascular integrity. Its application in cancer cell death needs to be further studied, but it has a potential for clinical use in targeting tumors with minimal morbidity and associated cardiac and neurologic side effects.

Novel left ventricular cardiac synchronization: left ventricular septal pacing or left bundle branch pacing?

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii10-ii18 ◽  
Author(s):  
Shengjie Wu ◽  
Parikshit S Sharma ◽  
Weijian Huang
Keyword(s):  
Left Ventricular ◽  
Widespread Application ◽  
Right Ventricular Pacing ◽  
Septal Pacing ◽  
Cardiac Synchronization ◽  
Lead Location ◽  
Transvenous Approach ◽  
Long Term Performance ◽  
Term Performance

Abstract It is well recognized that a high burden of right ventricular pacing results in deleterious clinical outcomes over the long term. His bundle pacing can achieve optimal ventricular synchronization; however, relatively high pacing thresholds, low R-wave amplitudes, and the long-term performance have been concerns. Recently, left ventricular (LV) septal endocardium pacing (LVSP) has demonstrated improved acute haemodynamics. Another novel technique of intraseptal left bundle branch pacing (LBBP) via transvenous approach has been adopted rapidly and has demonstrated its feasibility and effectiveness. This article reviews the clinical application and differences between LVSP and LBBP. Compared with LVSP, LBBP has strict criteria for left conduction system capture and lead location. In addition to LV septal capture it also stimulates the proximal left bundle branch, resulting in rapid and physiological LV activation. With a uniformity and standardization of the implant procedure and definitions, it may be possible to achieve widespread application of this form of physiological pacing.

scholarly journals Comparison of self-gated cine MRI retrospective cardiac synchronization algorithms

2008 ◽  
Vol 28 (3) ◽  
pp. 767-772 ◽  
Author(s):  
Grace M. Nijm ◽  
Alan V. Sahakian ◽  
Steven Swiryn ◽  
James C. Carr ◽  
John J. Sheehan ◽  
...  
Keyword(s):  
Cine Mri ◽  
Cardiac Synchronization

P603Cardiac Magnetic Resonance evaluation and risk stratification of patients with unexplained or suspected arrhythmias

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
M Carrington ◽  
R Santos ◽  
J Pais ◽  
B Picarra ◽  
R Rocha ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Risk Stratification ◽  
Interventricular Septum ◽  
Structural Heart Disease ◽  
Ventricular Ejection Fraction ◽  
Cardiac Evaluation ◽  
Study Population ◽  
Lv Volume ◽  
Cardiac Synchronization ◽  
The Impact

Abstract Introduction The etiological diagnosis of cardiac arrhythmias is often difficult. Cardiac Magnetic Resonance (CMR) is the gold standard exam for anatomical and functional cardiac evaluation and it may be indicated in patients with ventricular arrhythmias when echocardiography does not provide an accurate assessment of left and right ventricles (LV, RV). Purpose The aim of this study was to determine the impact of CMR in the diagnosis and stratification of arrhythmic risk in patients with confirmed or suspected arrhythmias, as well as to describe the changes observed. Methods We performed a prospective registry over a 5-year period of all the patients with arrhythmias who underwent CMR for diagnostic and risk stratification purposes. We followed a protocol to evaluate both anatomically and functionally the ventricles and to look for the presence of late gadolinium enhancement (LGE). Results A total of 78 patients were included, of which 65% were male and a mean age of 46±17 years-old was observed. The indications for CMR evaluation of patients with confirmed or suspected arrhythmias were as follows: 33% (n=26) of the patients had very frequent premature ventricular complexes (PVC), 23% (n=18) had sustained ventricular tachycardia (VT), 17% (n=13) suspected structural heart disease with high arrhythmic potential, 12% (n=9) unexplained recurrent syncope, 6% (n=5) supraventricular tachycardia, 5% (n=4) non-sustained VT and 4% (n=3) aborted sudden cardiac death. Depressed ventricular ejection fraction (<50%) was present in 9% (n=7) for the LV and in 14% (n=11)for the RV. Dilation of the LV was found in 24% of the patients (n=19, mean LV volume: 115±4ml/m2) and RV dilation was present in only 1 patient who had right ventricle arrhythmogenic dysplasia (RVAD) (RV volume: 152ml/m2). Cardiac synchronization artifacts due to the presence of very frequent PVC compromised the calculation of v volumes in only 4% (n=3) of the patients. In total, 6% (n=5) had interventricular septum hypertrophy (mean 15±6g/m2), 10% (n=8) had a slight prolapse of the anterior leaflet of the mitral valve and 19% (n=15) had a dilated left auricle. LGE was present in 13% (n=10) and slight pericardium effusion was detected in 12% (n=9). CMR was considered normal in 65% (n=51), in 15% (n=12) we found nonspecific changes deserving follow-up and in 20% (n=15) it was possible to establish a diagnosis which was previously unknown: 5% (n=4) had hypertrophic cardiomyopathy, 4% (n=3) LV non-compaction, 4% (n=3) a myocarditis sequelae, 3% (n=2) RVAD, 3% (n=2) a myocardial infarction scar and 1 had non-ischemic dilated cardiomyopathy. Conclusions CMR is a technique with high spatial resolution, feasible and safe, which allowed an increase in diagnosis in 20% of the patients, thus contributing to the risk stratification of our study population with suspected high arrhythmic potential when the first-line complementary exams were inconclusive.

scholarly journals Doppler ultrasound cardiac gating of intracranial flow at 7T

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Karin Markenroth Bloch ◽  
Fabian Kording ◽  
Johannes Töger
Keyword(s):  
Blood Flow ◽  
Doppler Ultrasound ◽  
False Positive ◽  
High Field ◽  
Phase Contrast ◽  
4D Flow ◽  
Ultra High Field ◽  
2D Flow ◽  
Cardiac Synchronization ◽  
Quantitative Flow

Abstract Background Ultra-high field magnetic resonance imaging (MR) may be used to improve intracranial blood flow measurements. However, standard cardiac synchronization methods tend to fail at ultra-high field MR. Therefore, this study aims to investigate an alternative synchronization technique using Doppler ultrasound. Methods Healthy subjects (n = 9) were examined with 7T MR. Flow was measured in the M1-branch of the middle cerebral artery (MCA) and in the cerebral aqueduct (CA) using through-plane phase contrast (2D flow). Flow in the circle of Willis was measured with three-dimensional, three-directional phase contrast (4D flow). Scans were gated with Doppler ultrasound (DUS) and electrocardiogram (ECG), and pulse oximetry data (POX) was collected simultaneously. False negative and false positive trigger events were counted for ECG, DUS and POX, and quantitative flow measures were compared. Results There were fewer false positive triggers for DUS compared to ECG (5.3 ± 11 vs. 25 ± 31, p = 0.031), while no other measured parameters differed significantly. Net blood flow in M1 was similar between DUS and ECG for 2D flow (1.5 ± 0.39 vs. 1.6 ± 0.41, bias ± 1.96SD: − 0.021 ± 0.36) and 4D flow (1.8 ± 0.48 vs. 9 ± 0.59, bias ± 1.96SD: − 0.086 ± 0.57 ml). Net CSF flow per heart beat in the CA was also similar for DUS and ECG (3.6 ± 2.1 vs. 3.0 ± 5.8, bias ± 1.96SD: 0.61 ± 13.6 μl). Conclusion Gating with DUS produced fewer false trigger events than using ECG, with similar quantitative flow values. DUS gating is a promising technique for cardiac synchronization at 7T.

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