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Cardiac cycle

About: Cardiac cycle is a research topic. Over the lifetime, 3290 publications have been published within this topic receiving 96159 citations.


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Journal ArticleDOI
TL;DR: Elevated LV end-diastolic pressure is associated with a decrease of peak LA wall strain in the longitudinal direction during LV systole, and this correlation was also significant in patients with preservedLV systolic function.
Abstract: Objective Left atrial (LA) reservoir function is determined by integration of LA relaxation and left ventricular (LV) systolic function, and LV diastolic dysfunction increases LA volume at end systole. This study investigates the effect of LV end-diastolic pressure on LA wall tension during LV systole. Methods A total of 101 stable patients with sinus rhythm undergoing cardiac catheterization were studied. LA wall extension during LV systole was evaluated as LA wall strain in the longitudinal direction obtained using two-dimensional ultrasound speckle tracking imaging. LV end-diastolic pressure and LV end-systolic and end-diastolic volumes were obtained in cardiac catheterization, and LV ejection fraction was determined. Results Peak LA wall strain during LV systole had a significant inverse correlation with LV end-diastolic pressure ( r = − 0.76, P r = − 0.64, P Conclusion Elevated LV end-diastolic pressure is associated with a decrease of peak LA wall strain in the longitudinal direction during LV systole. In patients with peak LA wall strain during LV systole of less than 30%, the majority had elevated LV end-diastolic pressure, while most patients with peak LA wall strain during LV systole 45% or higher had normal LV end-diastolic pressures. In patients whose LV ejection fraction is 50% or more, when peak LA wall strain during LV systole is between 30% and 44%, it is not possible to predict LV end-diastolic pressure from peak LA wall strain measures.

181 citations

Patent
14 Jul 1982
TL;DR: In this article, a heart valve prosthesis incorporating a dynamic stiffener element is disclosed, which allows normal movement of the annulus during the cardiac cycle while providing mechanical support to the valve annulus so as to maintain the valve leaflets in proper physiological alignment.
Abstract: A heart valve prosthesis incorporating a dynamic stiffener element is disclosed. The prosthesis is adapted for securement to the annulus of an atrioventricular valve and has the characteristic of allowing normal movement of the annulus during the cardiac cycle while providing mechanical support to the valve annulus so as to maintain the valve leaflets in proper physiological alignment. The stiffener element has a plurality of reciprocating members allowing it to be modifiable in shape so as to be capable of assuming the optimum shape for a particular heart valve.

180 citations

Patent
28 Nov 2001
TL;DR: An implantable device for measuring mechanical heart function of selected heart chambers using a heart contraction detection system that includes a magnetic field sensor is described in this paper, which is used for monitoring signs of acute or chronic cardiac heart failure, to diagnose the condition of the heart, to prescribe appropriate therapies, and to assess delivered pacing therapies.
Abstract: An implantable device for measuring mechanical heart function of selected heart chambers using a heart contraction detection system that includes a magnetic field sensor. The system may be used for monitoring signs of acute or chronic cardiac heart failure, to enable diagnosis of the condition of the heart, to prescribe appropriate therapies, and to assess delivered pacing therapies. Distance measurements within the heart are made using the magnetic field sensor which is implanted at a sensor site in or on one of the right or left ventricle. A magnet implanted at a site relative to the other of the left or right heart ventricle is sufficiently spaced at a distance that fluctuates with expansion and contraction of the ventricles. The magnetic field sensor provides a sensor output signal having a signal magnitude proportional to the magnetic field strength of the magnet, and which is indicative of changing cardiac dimensions.

179 citations

Journal ArticleDOI
TL;DR: The increased contribution of the atrial contraction to the LV filling in COPD patients in comparison with control subjects was confirmed and a decreased left atrial (LA) filling during the ventricular systole was observed.
Abstract: Abnormal left ventricular (LV) diastolic function has frequently been reported in patients with chronic obstructive pulmonary disease (COPD). In the present work, diastolic function was studied by a combined analysis of pulmonary venous and mitral blood flow velocities in 34 patients with COPD clinically stable and without history of heart disease, and 20 control subjects. We confirmed the increased contribution of the atrial contraction to the LV filling in COPD patients in comparison with control subjects; furthermore, a decreased left atrial (LA) filling during the ventricular systole was observed. Changes in LV filling were not the consequence of a systolic dysfunction, because LV systolic function was normal. Doppler indices indicated that LA pressure was below 15 cm H(2)O in all the patients with COPD and control subjects. Several factors can be put forward to explain these changes; the first one is tachycardia. In addition to hypoxemia and medications, echocardiography suggested that a decreased LV preload participated in increased heart rate. Analysis of Doppler transmitral and pulmonary venous flows demonstrated the role of the ventricular interdependence because a correlation existed between LA and LV filling pattern and right ventricle pressure and diameter.

178 citations

Journal ArticleDOI
TL;DR: Warning arrhythmias are not considered good criteria for institution of antiarrhythmic therapy in order to prevent primary ventricular fibrillation (PVF), and in patients with sinus rhythm there may be an association between heart rate and onset of PVF.
Abstract: In order to evaluate the events preceding primary ventricular fibrillation (PVF), continuous tape recording was performed in 262 patients consecutively admitted to the hospital within six hours of infarction in whom antiarrhythmic therapy was withheld. Warning arrhythmias (defined as ventricular ectopic beats occurring with a frequency of more than five beats per minute, in runs, falling in the vulnerable phase of the cardiac cycle or being multiformed) were registered in an equal percentage in patients who did or did not develop PVF. Immediately prior to PVF seven patients showed sinus tachycardia, 10 a sinus rate ranging from 60 to 100 beats per minute and two bradycardia due to complete atrioventricular block. The ventricular ectopic beat initiating PVF had a late coupling interval (QR'/QT larger than or equal to 0.85) in 11 patients and a left bundle branch block configuration as frequent as a right bundle branch block. Conclusions: 1) Warning arrhythmias are not considered good criteria for instituti...

178 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202377
2022178
202169
202068
201979
201876