Background: Transcatheter valvular interventions affect cardiac and hemodynamic physiology by changing ventricular (un-)loading and metabolic demand as reflected by cardiac mechanoenergetics. Real-time quantifications of these changes are scarce. Pressure-volume loop (PVL) monitoring appraises both load-dependent and load-independent compounds of cardiac physiology including myocardial work, ventricular unloading, and ventricular-vascular interactions.
View Article and Find Full Text PDFObjectives: To describe hemodynamic effects of iVAC2L mechanical circulatory support (MCS).
Background: MCS is increasingly used in the context of high-risk percutaneous coronary intervention (PCI). The effect of the pulsatile iVAC2L MCS on left ventricular loading conditions and myocardial oxygen consumption (MVO) is unknown.
Invasive pressure-volume loop analysis allows direct monitoring of changing intraventricular cardiac mechanics during structural heart interventions. Our aim was to illustrate changes in right and left ventricular mechanics during transcatheter edge-to-edge tricuspid repair for severe tricuspid regurgitation. ().
View Article and Find Full Text PDFUnderstanding 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.
View Article and Find Full Text PDFVentricular pressure-volume (PV) analysis is the reference method for the study of cardiac mechanics. Advances in calibration algorithms and measuring techniques brought new perspectives for its application in different research and clinical settings. Simultaneous PV measurement in the heart chambers offers unique insights into mechanical cardiac efficiency.
View Article and Find Full Text PDFEvaluation of a new Windkessel model based pulse contour method (WKflow) to calculate stroke volume in patients undergoing intra-aortic balloon pumping (IABP). Preload changes were induced by vena cava occlusions (VCO) in twelve patients undergoing cardiac surgery to vary stroke volume (SV), which was measured by left ventricular conductance volume method (SVlv) and WKflow (SVwf). Twelve VCO series were carried out during IABP assist at a 1:2 ratio and seven VCO series were performed with IABP switched off.
View Article and Find Full Text PDFAims: The aim of the study was to establish the value of new-generation mechanical circulatory support (MCS) devices such as HeartMate PHP, Impella CP and PulseCath iVAC2.
Methods And Results: We retrospectively analysed all consecutive elective high-risk PCI procedures performed in the Erasmus Medical Center (2011-2018) in order to compare MCS protected and unprotected patients. The primary endpoint was a composite of procedure-related adverse events including death (<24 hours), cardiac arrest, need for vasopressors, rescue MCS, endotracheal intubation and limb ischaemia with need for surgery.
Background: Percutaneous mitral valve repair with the MitraClip device has emerged as an alternative to surgery for treating severe mitral regurgitation. However, its effects on left ventricular loading conditions and contractility have not been investigated yet.
Methods And Results: Pressure-volume loops were recorded throughout the MitraClip procedure using conductance catheter in 33 patients (mean age, 78±10 years) with functional (45%), degenerative (48%), or mixed (6%) mitral regurgitation.
Objective: Patients with severely reduced left ventricular function undergoing coronary artery bypass grafting have increased complication rates. We hypothesized that temporary postoperative atrial synchronous biventricular pacing would improve left ventricular function after cardiopulmonary bypass.
Methods: A left ventricular pressure-volume catheter was placed in 21 patients undergoing coronary artery bypass grafting (ejection fraction 29% +/- 5%).
Objective: Coherent averaging is a technique to recover the response to repetitively applied stimuli when that response is embedded in random noise. We derived novel indices for left ventricular dyssynchrony estimation from volume-catheter signals using coherent averaging procedure: mechanical dyssynchrony (DYSCoh) internal flow fraction (IFFCoh) and mechanical dispersion (DISPCoh). The percentage power of non-repetitive components in the volume signals (ResTotAvg) was also estimated.
View Article and Find Full Text PDFDual-chamber pacing with His bundle pacing has theoretical advantages over conventional right ventricular (RV) apical pacing. We compared indexes of left ventricular (LV) function during acute dual-chamber pacing from the His bundle and other RV and LV pacing sites. Twelve patients (6 men; 63 +/- 11 years) with a standard indication for electrophysiologic study were included.
View Article and Find Full Text PDFObjectives: We hypothesize that the implantation of an endoventricular elastic ring at the left ventricle (LV) equatorial site will positively affect the cardiac mechanics in an experimental model of acute LV dysfunction.
Background: Changes in the elastic properties of LV occur in the dilated and failing heart, contributing to overall cardiac mechanical dysfunction. No interventions are as yet specifically designed to improve LV elasticity in failing hearts.
Objective: The Modelflow method computes cardiac output (CO) from arterial pressure (CO-MFao) by simulating a non-linear three-element Windkessel model of aortic input impedance. We present a novel technique to apply the Modelflow method to the left ventricular pressure (Plv) signal, to obtain an estimation of CO (CO-MFlv).
Methods: We extended the model by simulating the aortic valve as a resistance placed in series to the characteristic impedance.
Objectives: We compared left ventricular (LV) systolic and diastolic function during right ventricular (RV), LV, and biventricular (BiV) pacing in patients with narrow QRS duration with and without LV dysfunction.
Background: The optimal RV pacing lead location for patients with a standard indication for ventricular pacing remains controversial.
Methods: Left ventricular pressure and volume data were determined via conductance catheter during electrophysiology study in 31 patients divided into groups with ejection fraction (EF) > or =40% (n = 17) or EF <40% (n = 14).
Purpose: The efficacy of intraaortic balloon counterpulsation (IABP) during arrhythmic episodes is questionable. A novel algorithm for intrabeat prediction of the dicrotic notch was used for real time IABP inflation timing control.
Description: A windkessel model algorithm was used to calculate real-time aortic flow from aortic pressure.
Background: Intraaortic balloon counterpulsation (IABP) timing errors during arrhythmia may result in afterload increases which may negatively influence left ventricular (LV) ejection and LV mechanical dyssynchrony. The aim of our study was to determine beat-to-beat effects of properly timed IABP, premature IAB inflation, and late IAB deflation on LV performance and LV mechanical dyssynchrony in heart failure patients undergoing cardiac surgery.
Methods: In 15 patients, LV pressure-volume relations and LV dyssynchrony were measured by conductance volume catheter.
Objective: Surgical left ventricular restoration by means of endoventricular patch aneurysmectomy in patients with postinfarction aneurysm should result in acute improved left ventricular performance by decreasing mechanical dyssynchrony and increasing energy efficiency.
Methods: Nine patients with left ventricular postinfarction aneurysm were studied intraoperatively before and after ventricular restoration with a conductance volume catheter to analyze pressure-volume relationships, energy efficiency, and mechanical dyssynchrony. The end-systolic elastance was used as a load-independent index of contractile state.
Am J Physiol Heart Circ Physiol
February 2004
Mechanical dyssynchrony is an important codeterminant of cardiac dysfunction in heart failure. Treatment, either medical, surgical, or by pacing, may improve cardiac function partly by improving mechanical synchrony. Consequently, the quantification of ventricular mechanical (dys)synchrony may have important diagnostic and prognostic value and may help to determine optimal therapy.
View Article and Find Full Text PDFIn this review article, we describe the most common surgical procedures currently used to reverse or arrest remodeling of the left ventricle in patients with congestive heart failure (CHF). The selection of the appropriate operation in a patient is a complex decision-making process, rigorously based on pathophysiologic considerations. In this population, all factors affecting the surgical risk should be carefully evaluated preoperatively, and surgery should be recommended when definite benefits in survival and quality of life can be reasonably predicted.
View Article and Find Full Text PDFA novel algorithm for real-time detection and prediction of the dicrotic notch from aortic pressure waves was evaluated in arrhythmic aortic pressure signals from heart failure patients. A simplified model of the arterial tree was used to calculate real-time aortic flow from aortic pressure. The dicrotic notch was detected at the first negative dip from the calculated flow, prediction of the notch was performed using a percentage of the decreasing flow.
View Article and Find Full Text PDFBackground: The increasing use of off-pump bypass grafting (OPCABG), requires an evaluation of its effects on left ventricular (LV) performance.
Methods: In 8 patients with multivessel coronary disease who were undergoing to off-pump coronary artery bypass grafting, LV performance was analyzed from the pressure-volume (P-V) plane by the conductance catheter technique. Measurements were performed at base line, after the exposure of the vessels, after the application of the stabilization system, and at the end of the procedure.
A comparative study was conducted to evaluate the feasibility of a fiber-optic sensor in invasive blood pressure measurements. Static and wide-bandwidth stimuli were offered to the fiber-optic, Millar, Baxter, and Sentron devices to measure static transfer function and transient response. Animal experiments focused on offset drift, dynamic accuracy, and electromagnetic sensitivity.
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