Physiological Impact of Afterload Reduction on Cardiac Mechanics and Coronary Hemodynamics Following Isosorbide Dinitrate Administration in Ischemic Heart Disease.

Understanding the cardiac-coronary interaction is fundamental to developing treatment strategies for ischemic heart disease. We sought to examine the impact of afterload reduction following isosorbide dinitrate (ISDN) administration on LV properties and coronary hemodynamics to further our understanding of the cardiac-coronary interaction. Novel methodology enabled real-time simultaneous acquisition and analysis of coronary and LV hemodynamics in vivo using coronary pressure-flow wires (used to derive coronary wave energies) and LV pressure-volume loop assessment.

Internet search volume for chest pain during the COVID-19 pandemic.

During the COVID-19 pandemic there has been a reduction in hospital admissions for acute myocardial infarction. This manuscript presents the analysis of Google Trends meta-data and shows a marked spike in search volume for chest pain that is strongly correlated with COVID-19 case numbers in the United States. This raises a concern that fear of contracting COVID-19 may be leading patients to self-triage using internet searches.

Deleterious Effects of Cold Air Inhalation on Coronary Physiological Indices in Patients With Obstructive Coronary Artery Disease.

Background Cold air inhalation during exercise increases cardiac mortality, but the pathophysiology is unclear. During cold and exercise, dual-sensor intracoronary wires measured coronary microvascular resistance ( MVR ) and blood flow velocity ( CBF ), and cardiac magnetic resonance measured subendocardial perfusion. Methods and Results Forty-two patients (62±9 years) undergoing cardiac catheterization, 32 with obstructive coronary stenoses and 10 without, performed either (1) 5 minutes of cold air inhalation (5°F) or (2) two 5-minute supine-cycling periods: 1 at room temperature and 1 during cold air inhalation (5°F) (randomized order).

Physiology of Angina and Its Alleviation With Nitroglycerin: Insights From Invasive Catheter Laboratory Measurements During Exercise.

Background: The mechanisms governing exercise-induced angina and its alleviation by the most commonly used antianginal drug, nitroglycerin, are incompletely understood. The purpose of this study was to develop a method by which the effects of antianginal drugs could be evaluated invasively during physiological exercise to gain further understanding of the clinical impact of angina and nitroglycerin.

Methods: Forty patients (mean age, 65.

Accurate and Standardized Coronary Wave Intensity Analysis.

Objective: Coronary wave intensity analysis (cWIA) has increasingly been applied in the clinical research setting to distinguish between the proximal and distal mechanical influences on coronary blood flow. Recently, a cWIA-derived clinical index demonstrated prognostic value in predicting functional recovery postmyocardial infarction. Nevertheless, the known operator dependence of the cWIA metrics currently hampers its routine application in clinical practice.

Coronary Physiology During Exercise and Vasodilation in the Healthy Heart and in Severe Aortic Stenosis.

Background: Severe aortic stenosis (AS) can manifest as exertional angina even in the presence of unobstructed coronary arteries.

Objectives: The authors describe coronary physiological changes during exercise and hyperemia in the healthy heart and in patients with severe AS.

Methods: Simultaneous intracoronary pressure and flow velocity recordings were made in unobstructed coronary arteries of 22 patients with severe AS (mean effective orifice area 0.

A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise.

This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input.

Transaortic transcatheter aortic valve implantation using the Lotus valve: first-in-man experience.

Aims: To demonstrate the feasibility of implanting the Lotus second-generation transcatheter heart valve (THV) (designed for a transfemoral procedure) via a transaortic approach.

Methods And Results: We describe a case with severe aortic stenosis in the presence of small calibre and calcified femoral access and severe chronic obstructive pulmonary disease. The transaortic approach was the ideal approach for this patient and we successfully implanted a 25 mm Lotus valve without any complication.

Enhancing coronary Wave Intensity Analysis robustness by high order central finite differences.

Background: Coronary Wave Intensity Analysis (cWIA) is a technique capable of separating the effects of proximal arterial haemodynamics from cardiac mechanics. Studies have identified WIA-derived indices that are closely correlated with several disease processes and predictive of functional recovery following myocardial infarction. The cWIA clinical application has, however, been limited by technical challenges including a lack of standardization across different studies and the derived indices' sensitivity to the processing parameters.

The effect of coronary artery disease defined by quantitative coronary angiography and SYNTAX score upon outcome after transcatheter aortic valve implantation (TAVI) using the Edwards bioprosthesis.

Aims: We sought to evaluate the effects of significant coronary artery disease (CAD) upon outcome after transcatheter aortic valve implantation (TAVI).

Methods And Results: We performed a retrospective study of 271 consecutive patients undergoing TAVI using either the Edwards SAPIEN or Edwards SAPIEN XT valve. Pre-procedural coronary angiograms were analysed by quantitative coronary angiography (defining significant CAD as a stenosis of ≥70% or ≥50% if in the left main stem or a vein graft).

Coronary and microvascular physiology during intra-aortic balloon counterpulsation.

Objectives: This study sought to identify the effect of coronary autoregulation on myocardial perfusion during intra-aortic balloon pump (IABP) therapy.

Background: IABP is the most commonly used circulatory support device, although its efficacy in certain scenarios has been questioned. The impact of alterations in microvascular function on IABP efficacy has not previously been evaluated in humans.

Multicenter core laboratory comparison of the instantaneous wave-free ratio and resting Pd/Pa with fractional flow reserve: the RESOLVE study.

Objectives: This study sought to examine the diagnostic accuracy of the instantaneous wave-free ratio (iFR) and resting distal coronary artery pressure/aortic pressure (Pd/Pa) with respect to hyperemic fractional flow reserve (FFR) in a core laboratory-based multicenter collaborative study.

Background: FFR is an index of the severity of coronary stenosis that has been clinically validated in 3 prospective randomized trials. iFR and Pd/Pa are nonhyperemic pressure-derived indices of the severity of stenosis with discordant reports regarding their accuracy with respect to FFR.

Diagnostic classification of the instantaneous wave-free ratio is equivalent to fractional flow reserve and is not improved with adenosine administration. Results of CLARIFY (Classification Accuracy of Pressure-Only Ratios Against Indices Using Flow Study).

Objectives: This study sought to determine if adenosine administration is required for the pressure-only assessment of coronary stenoses.

Background: The instantaneous wave-free ratio (iFR) is a vasodilator-free pressure-only measure of the hemodynamic severity of a coronary stenosis comparable to fractional flow reserve (FFR) in diagnostic categorization. In this study, we used hyperemic stenosis resistance (HSR), a combined pressure-and-flow index, as an arbiter to determine when iFR and FFR disagree which index is most representative of the hemodynamic significance of the stenosis.

Does the instantaneous wave-free ratio approximate the fractional flow reserve?

Objectives: This study sought to examine the clinical performance of and theoretical basis for the instantaneous wave-free ratio (iFR) approximation to the fractional flow reserve (FFR).

Background: Recent work has proposed iFR as a vasodilation-free alternative to FFR for making mechanical revascularization decisions. Its fundamental basis is the assumption that diastolic resting myocardial resistance equals mean hyperemic resistance.

Hybrid iFR-FFR decision-making strategy: implications for enhancing universal adoption of physiology-guided coronary revascularisation.

Aims: Adoption of fractional flow reserve (FFR) remains low (6-8%), partly because of the time, cost and potential inconvenience associated with vasodilator administration. The instantaneous wave-Free Ratio (iFR) is a pressure-only index of stenosis severity calculated without vasodilator drugs. Before outcome trials test iFR as a sole guide to revascularisation, we evaluate the merits of a hybrid iFR-FFR decision-making strategy for universal physiological assessment.

The intra-observer reproducibility of cardiovascular magnetic resonance myocardial feature tracking strain assessment is independent of field strength.

Background: Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a promising novel method for quantification of myocardial wall mechanics from standard steady-state free precession (SSFP) images. We sought to determine whether magnetic field strength affects the intra-observer reproducibility of CMR-FT strain analysis.

Methods: We studied 2 groups, each consisting of 10 healthy subjects, at 1.