3-Dimensional ventricular electrical activation pattern assessed from a novel high-frequency electrocardiographic imaging technique: principles and clinical importance

AbstractThe study introduces and validates a novel high-frequency (100–400 Hz bandwidth, 2 kHz sampling frequency) electrocardiographic imaging (HFECGI) technique that measures intramural ventricular electrical activation. Ex-vivo experiments and clinical measurements were employed. Ex-vivo, two pig hearts were suspended in a human-torso shaped tank using surface tank electrodes, epicardial electrode sock, and plunge electrodes. We compared conventional epicardial electrocardiographic imaging (ECGI) with intramural activation by HFECGI and verified with sock and plunge electrodes. Clinical importance of HFECGI measurements was performed on 14 patients with variable conduction abnormalities. From 3 × 4 needle and 108 sock electrodes, 256 torso or 184 body surface electrodes records, transmural activation times, sock epicardial activation times, ECGI-derived activation times, and high-frequency activation times were computed. The ex-vivo transmural measurements showed that HFECGI measures intramural electrical activation, and ECGI-HFECGI activation times differences indicate endo-to-epi or epi-to-endo conduction direction. HFECGI-derived volumetric dyssynchrony was significantly lower than epicardial ECGI dyssynchrony. HFECGI dyssynchrony was able to distinguish between intraventricular conduction disturbance and bundle branch block patients.

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3-Dimensional Ventricular Electrical Activation Pattern Assessed From A Novel High-Frequency Electrocardiographic Imaging Technique: Principles and Clinical Importance

10.21203/rs.3.rs-133316/v1 ◽

2020 ◽

Author(s):

Pavel Jurak ◽

Laura Bear ◽

Uyên Nguyên ◽

Ivo Viscor ◽

Petr Andrla ◽

...

Keyword(s):

High Frequency ◽

Ex Vivo ◽

Clinical Importance ◽

Electrical Activation ◽

Bundle Branch Block ◽

Electrocardiographic Imaging ◽

3 Dimensional ◽

Intraventricular Conduction ◽

Clinical Measurements ◽

Activation Times

Abstract The study introduces and validates a novel high-frequency (100-400 Hz) electrocardiographic imaging (HFECGI) technique that measures intramural ventricular electrical activation. Ex-vivo experiments and clinical measurements were employed. Ex-vivo, two pig hearts were suspended in a human-torso shaped tank using surface tank electrodes, epicardial electrode sock, and plunge electrodes. We compared conventional epicardial electrocardiographic imaging (ECGI) with intramural activation by HFECGI and verified with sock and plunge electrodes. Clinical importance of HFECGI measurements was performed on 14 patients with variable conduction abnormalities. From 2 kHz ECG records (3x4 needle and 108 sock electrodes, 256 torso or 184 body surface electrodes), transmural activation times, sock epicardial activation times, ECGI-derived activation times, and high-frequency activation times were computed. The ex-vivo transmural measurements showed that HFECGI measures intramural electrical activation, and ECGI-HFECGI activation times differences indicate endo-to-epi or epi-to-endo conduction direction. HFECGI-derived volumetric dyssynchrony was significantly lower than epicardial ECGI dyssynchrony. HFECGI dyssynchrony was able to distinguish between intraventricular conduction disturbance and bundle branch block patients.

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Reduced high-frequency QRS components in electrocardiogram leads facing an area of the heart with intraventricular conduction delay due to bundle branch block

Journal of Electrocardiology ◽

10.1016/j.jelectrocard.2006.07.002 ◽

2007 ◽

Vol 40 (2) ◽

pp. 127-132 ◽

Cited By ~ 6

Author(s):

Elin Trägårdh ◽

Jonas Pettersson ◽

Galen S. Wagner ◽

Olle Pahlm

Keyword(s):

High Frequency ◽

Conduction Delay ◽

Bundle Branch Block ◽

Intraventricular Conduction ◽

Intraventricular Conduction Delay

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High-Frequency Ultrasound: A Novel Diagnostic Tool to Measure Pediatric Tonsils in 3 Dimensions

Otolaryngology ◽

10.1177/0194599819850139 ◽

2019 ◽

Vol 161 (5) ◽

pp. 856-861 ◽

Cited By ~ 2

Author(s):

Emily Kay-Rivest ◽

Christine Saint-Martin ◽

Sam J. Daniel

Keyword(s):

High Frequency ◽

Ex Vivo ◽

Tertiary Care ◽

Correlation Coefficients ◽

High Frequency Ultrasound ◽

Palatine Tonsils ◽

3 Dimensional ◽

Neck Masses ◽

Head And Neck Masses ◽

The Right

Objective A wide variety of pathologies can affect the palatine tonsils. Ultrasound is a commonly used modality for assessing head and neck masses in children; however, its use in tonsillar evaluation has not been widely explored. The objective of this study was to measure 3-dimensional tonsillar size with ultrasound, in centimeters, and correlate these measurements with actual ex vivo dimensions on pathology specimens. Study Design We performed a prospective cohort study. Setting The study was set in a tertiary care children’s hospital. Subjects and Methods Children undergoing tonsillectomy were included in the study. Transcervical high-frequency ultrasonography (HFU) was performed prior to surgery to obtain 3-dimensional measurements of the right and left palatine tonsils. Mean sizes were compared to ex vivo tonsil measurements and correlations were obtained. Results Seventy-five consecutive children underwent a transcervical HFU, with a total of 150 tonsils analyzed. The mean differences between HFU and pathology measurements were −0.08 cm and −0.24 cm for the right and left craniocaudal axes, −0.19 cm and −0.18 cm for the right and left mediolateral axes, and 0.05 cm and 0.03 cm for the right and left anteroposterior axes. Correlation coefficients between ultrasound and pathology measurements were all above 0.5. Conclusion HFU can accurately measure the size of pediatric tonsils in 3 dimensions.

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Intraventricular conduction defects in patients with st-segment elevation myocardial infarction – the paradox of right bundle branch block

European Heart Journal ◽

10.1093/ehjci/ehaa946.1615 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

S Fernandes ◽

F Montenegro ◽

M Cabral ◽

R Carvalho ◽

L Santos ◽

...

Keyword(s):

Hospital Mortality ◽

Right Bundle Branch Block ◽

Independent Predictor ◽

Left Ventricular Ejection ◽

Bundle Branch Block ◽

Hospital Outcomes ◽

St Segment Elevation ◽

Intraventricular Conduction ◽

St Segment ◽

Worse Prognosis

Abstract Intraventricular conduction defects (IVCD) in patients with acute myocardial infarct (AMI) are predictors of a worse prognosis. When acquired they can be the result of an extensive myocardial damage. Purpose To assess the impact of IVCD, regardless of being previously known or presumed new, on in-hospital outcomes of patients with AMI with ST segment elevation (STEMI) or undetermined location. Methods From a series of patients included in the National Registry of Acute Coronary Syndrome between 10/1/2010 and 9/1/2019, were selected patients with STEMI or undetermined AMI, undergoing coronary angiography. Results 7805 patients were included: 461 (5.9%) presenting left bundle branch block (LBBB), 374 (4.8%) with right bundle branch block (RBBB) and 6970 (89.3%) with no IVCD. Clinical characteristics as well as in-hospital outcomes are described in the table 1. An unexpected worse prognosis in patients with RBBB has motivated a multivariate analysis. RBBB remained an independent predictor of in-hospital mortality (OR 1.91, 95% CI 1.04–3.50, p=0.038), along with female gender (OR 1.73, 95% CI 1.11–2.68, p=0.015), Killip Class>1 (OR 2.26, 95% CI 1.45–3.53, p<0.001), left ventricular ejection fraction <50% (OR 3.93, 95% CI 2.19–7.05, p<0.001) and left anterior descending artery as the culprit lesion (OR 1.85, 95% CI 1.16–2.91, p=0.009). Conclusion In spite of an apparent better clinical profile, in the current large series of unselected STEMI patients, the presence of RBBB is associated with the worst in-hospital outcome. RBBB doubles the risk of death, being an independent predictor of in-hospital mortality. Funding Acknowledgement Type of funding source: None

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Synthetic Aperture Imaging Using High-Frequency Convex Array for Ophthalmic Ultrasound Applications

Sensors ◽

10.3390/s21072275 ◽

2021 ◽

Vol 21 (7) ◽

pp. 2275

Author(s):

Hae Gyun Lim ◽

Hyung Ham Kim ◽

Changhan Yoon

Keyword(s):

Image Quality ◽

Penetration Depth ◽

Spatial Resolution ◽

High Frequency ◽

Imaging System ◽

Ex Vivo ◽

Synthetic Aperture ◽

Single Element ◽

High Frequency Ultrasound ◽

Synthetic Aperture Imaging

High-frequency ultrasound (HFUS) imaging has emerged as an essential tool for pre-clinical studies and clinical applications such as ophthalmic and dermatologic imaging. HFUS imaging systems based on array transducers capable of dynamic receive focusing have considerably improved the image quality in terms of spatial resolution and signal-to-noise ratio (SNR) compared to those by the single-element transducer-based one. However, the array system still suffers from low spatial resolution and SNR in out-of-focus regions, resulting in a blurred image and a limited penetration depth. In this paper, we present synthetic aperture imaging with a virtual source (SA-VS) for an ophthalmic application using a high-frequency convex array transducer. The performances of the SA-VS were evaluated with phantom and ex vivo experiments in comparison with the conventional dynamic receive focusing method. Pre-beamformed radio-frequency (RF) data from phantoms and excised bovine eye were acquired using a custom-built 64-channel imaging system. In the phantom experiments, the SA-VS method showed improved lateral resolution (>10%) and sidelobe level (>4.4 dB) compared to those by the conventional method. The SNR was also improved, resulting in an increased penetration depth: 16 mm and 23 mm for the conventional and SA-VS methods, respectively. Ex vivo images with the SA-VS showed improved image quality at the entire depth and visualized structures that were obscured by noise in conventional imaging.

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Abstract 13286: Non-Specific Intraventricular Conduction Delay and Risk of Sudden Death

Circulation ◽

10.1161/circ.130.suppl_2.13286 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Audrey Uy-Evanado ◽

Carmen Teodorescu ◽

Kyndaron Reinier ◽

Kumar Narayanan ◽

Harpriya Chugh ◽

...

Keyword(s):

Sudden Cardiac Death ◽

General Population ◽

Left Bundle Branch Block ◽

Cardiac Death ◽

Conduction Delay ◽

Bundle Branch Block ◽

Intraventricular Conduction ◽

Qrs Morphology ◽

Qrs Duration ◽

Intraventricular Conduction Delay

Introduction: We and others have reported an independent association between prolonged QRS duration and risk of sudden cardiac death (SCD) in the general population. Left and right bundle branch block have been studied previously, but there is little information regarding non-specific intraventricular conduction delay and risk of SCD. Hypothesis: Completed conduction defects, including non-specific IVCD, are associated with increased SCD risk. Methods: Sudden cardiac death cases and controls from an ongoing large population based study in the Northwestern US (2002 to 2010) were included if age ≥ 35 years with a non-paced 12-lead ECG (recorded prior and unrelated to SCD in cases). QRS morphology was subcategorized as normal, intermediate [left anterior fascicular block (LAFB), left posterior fascicular block (LPFB), and incomplete right or left bundle branch block (IRBBB/ILBBB)] or completed conduction defects [left bundle branch block (LBBB), right bundle branch block (RBBB), or nonspecific intraventricular conduction delay (IVCD)]. Comparisons were conducted using chi-square tests for categorical variables and independent samples t-tests for continuous variables. Logistic regression was used to evaluate the association of QRS morphology with SCD. Results: We evaluated 761 SCD cases (64% male) and 539 controls (65% male). Cases were significantly older (69.7 vs 66.3 years, p<0.0001) with greater QRS duration (102 vs. 98 ms, p=0.001). For conduction categories, intermediate or completed conduction defects were significantly more common in cases whereas normal QRS morphology was more common among controls (p=0.01). And for specific morphology overall, QRS morphology patterns differed between cases and controls (p=0.03); abnormal QRS morphologies were more frequent in cases than controls except for LAFB. After adjustment for age and gender, however, only a finding of LBBB or non-specific IVCD remained a significant predictor of SCD [OR 1.34 (95% CI 1.03-1.75)]. Conclusions: LBBB and non-specific IVCD, but not RBBB, are significant predictors of SCD in the general population. These findings contribute to the utility of the 12-lead EKG for SCD risk stratification.

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Distribution of Electrical Activation to Parasternal Intercostal Muscles during High Frequency Spinal Cord Stimulation (HF‐SCS)

The FASEB Journal ◽

10.1096/fasebj.27.1_supplement.lb871 ◽

2013 ◽

Vol 27 (S1) ◽

Author(s):

Anthony F. DiMarco ◽

Krzysztof E. Kowalski

Keyword(s):

Spinal Cord ◽

Spinal Cord Stimulation ◽

High Frequency ◽

Electrical Activation ◽

Intercostal Muscles

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The Use of Electrocardiographic Imaging in Localising the Origin of Arrhythmias During Catheter Ablation of Ventricular Tachycardia

Arrhythmia & Electrophysiology Review ◽

10.15420/aer.2021.27 ◽

2021 ◽

Vol 10 (3) ◽

pp. 211-217

Author(s):

Adam J Graham ◽

Richard J Schilling

Keyword(s):

Inverse Problem ◽

Ventricular Arrhythmia ◽

Clinical Tool ◽

Electrocardiographic Imaging ◽

Surface Electrodes ◽

Non Invasive ◽

Large Target ◽

The Us ◽

Activation Times ◽

Unipolar Electrograms

Non-invasive electrocardiographic imaging (ECGI) is a novel clinical tool for mapping ventricular arrhythmia. Using multiple body surface electrodes to collect unipolar electrograms and conventional medical imaging of the heart, an epicardial shell can be created to display calculated electrograms. This calculation is achieved by solving the inverse problem and allows activation times to be calculated from a single beat. The technology was initially pioneered in the US using an experimental torso-shaped tank. Accuracy from studies in humans has varied. Early data was promising, with more recent work suggesting only moderate accuracy when reproducing cardiac activation. Despite these limitations, the system has been successfully used in pioneering work with non-invasive cardiac radioablation to treat ventricular arrhythmia. This suggests that the resolution may be sufficient for treatment of large target areas. Although untested in a well conducted clinical study it is likely that it would not be accurate enough to guide more discreet radiofrequency ablation.

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