Background: Safe, effective pulmonary delivery of cardioactive agents in humans is under development.
Objectives: We examined whether intratracheal delivery of metoprolol can reduce ventricular rate during atrial fibrillation (AF) and accelerate conversion to sinus rhythm.
Methods: In 7 closed-chest, anesthetized Yorkshire pigs, AF was induced by intrapericardial infusion of acetylcholine (1 mL of 102.5-mM solution) followed by atrial burst pacing and was allowed to continue for 2 minutes before intratracheal instillation of sterile water or metoprolol (0.2-mg/kg bolus) using a catheter positioned at the bifurcation of the main bronchi. High-resolution electrograms were obtained from catheters fluoroscopically positioned in the right atrium and left ventricle.
Results: Rapid intratracheal instillation of metoprolol caused a 32-beat/min reduction in ventricular rate during AF (from 272 ± 13.7 to 240 ± 12.6 beats/min, P = 0.008) and a 2.3-minute reduction in AF duration (from 10.3 ± 2.0 to 8.0 ± 1.4 minutes, P = 0.018) compared with sterile water control. Conversion of AF to sinus rhythm was associated with rapid restoration (5-6 minutes) of heart rate and arterial blood pressure toward control values. Intratracheal metoprolol reduced AF dominant frequency by 31% (from 8.7 ± 0.9 to 6.0 ± 1.1 Hz, P = 0.04) compared with control and resulted in a trend toward a 5% increase in PR interval (from 174 ± 11.2 to 182 ± 11.4 ms, P = 0.07).
Conclusions: Intratracheal delivery of metoprolol effectively reduces ventricular rate during AF and accelerates conversion to normal sinus rhythm in a pig model of acetylcholine-induced AF.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1097/FJC.0000000000000780 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Clinical Utility of Systolic Left Ventricular Ejection Fraction in Atrial Fibrillation: Role of Prospective ECG-Triggered Cardiac CT.
Heart Rhythm
January 2025
Division of Cardiology, University of Ottawa Heart Institute, Canada. Electronic address:
Background: The assessment of left ventricular (LV) systolic function and quantification of LV ejection fraction (EF) in patients with atrial fibrillation (AF) can be difficult. We previously demonstrated that LV volume changes over the 100 ms of systole (LVEF) can be used as a measure of LV systolic function.
Objective: We sought to evaluate the applicability of LVEF in AF patients.
Ability of dynamic chest radiography to identify left ventricular systolic dysfunction in heart failure.
Int J Cardiovasc Imaging
January 2025
Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
Dynamic chest radiography (DCR) can estimate haemodynamic parameters in heart failure (HF). However, no studies have evaluated its ability to determine cardiac systolic function in HF. This experimental study investigates the correlation between left ventricular (LV) ejection fraction (LVEF) and DCR image parameters in HF.
View Article and Find Full Text PDFHow to correct QT interval after cardiac resynchronisation therapy.
J Electrocardiol
January 2025
Victorian Heart Institute, Monash University, Clayton, VIC, Australia; Victorian Heart Hospital, Clayton, VIC, Australia. Electronic address:
Introduction: This study evaluates various formulae used to correct the QT interval in patients with wide QRS complexes to calculate corrected QT (QTc) following Cardiac Resynchronisation Therapy (CRT).
Methods: We included patients with severe heart failure and left bundle branch block, presenting with a QRS duration of at least 120 milliseconds, who underwent successful CRT implantation. Patients were excluded if they had non-lateral left ventricular lead placement, metabolic disorders, atrial fibrillation, atrial tachycardia, or high-degree atrioventricular block prior to implantation.
Inhibition of p70 Ribosomal S6K1 Protects the Myocardium against Ischemia/Reperfusion-Induced Necrosis through Downregulation of RIP3.
Front Biosci (Landmark Ed)
January 2025
Department of Cardiology, Affiliated Hospital of Jiangnan University, 214122 Wuxi, Jiangsu, China.
Background: Myocardial ischemia-reperfusion (I/R) injury refers to cell damage that occurs as a consequence of the restoration of blood circulation following reperfusion therapy for cardiovascular diseases, and it is a primary cause of myocardial infarction. The search for nove therapeutic targets in the context of I/R injury is currently a highly active area of research. p70 ribosomal S6 kinase (S6K1) plays an important role in I/R induced necrosis, although the specific mechanisms remain unclear.
View Article and Find Full Text PDFCirculating neuropeptide Y dynamics and performance during exercise in heart failure patients with contemporary medical and device therapy.
Exp Physiol
January 2025
Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
High cardiac sympathetic drive and release of the sympathetic cotransmitter neuropeptide Y (NPY) are significant features of congestive heart failure (CHF), in which resting venous NPY levels are known to be associated with mortality. However, whether circulating NPY levels increase during exercise in CHF when they are already elevated is controversial. We sought to establish the dynamics of circulating NPY levels in CHF patients treated with contemporary medical therapy and devices in relationship to indices of performance linked to long-term prognosis.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!