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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: The DTI method can be used for obtaining information of global events in the cardiac cycle from the same heart beat as used for analysis of regional cardiac performance and the expected values for time intervals and index of myocardial performance are confirmed.
Abstract: Objective We sought to evaluate a new method of measuring cardiac time intervals from Doppler tissue imaging (DTI) of the anterior leaflet of the mitral valve. Background For a reliable analysis of the regional cardiac performance by DTI, a reference of time intervals of global cardiac events in the same cardiac cycle and based on the same imaging modality is required to reduce measurement error. Methods We conducted a comparison of the measurements of isovolumic contraction and relaxation time and left ventricular (LV) ejection time by DTI M-mode analysis of the anterior mitral leaflet and the traditional approach based on spectral Doppler recordings. The measurements were done in 20 control subjects and 40 patients with cardiac diseases known to affect cardiac time intervals: heart failure, aortic stenosis, and essential hypertension with LV hypertrophy. Results Mean difference in milliseconds (95% limits of agreement) of measurements were not different overall (−0.20 [−10.58; 10.18], −1.95 [−16.66; 12.76], 1.48 [−8.34; 11.34], and 0 [−0.06; 0.07] for isovolumic contraction time, LV ejection time, isovolumic relaxation time, and calculated index of myocardial performance, respectively). Intraobserver variability was low. Analysis of patients with different categories of cardiac diseases confirmed the expected values for time intervals and index of myocardial performance. Conclusions Measurement of isovolumic periods and LV ejection time was feasible and reliable by DTI M-mode analysis of the anterior mitral valve leaflet. The DTI method can, therefore, be used for obtaining information of global events in the cardiac cycle from the same heart beat as used for analysis of regional cardiac performance.

57 citations

Journal ArticleDOI
TL;DR: Because of the ease with which Doppler echocardiographic measurements of transmitral flow during early diastole (E velocity) and atrial systole (A velocity) can be used to calculate the E/A ratio as a single index of diastolic performance, this method has become most popular for clinical detection of left ventricular diastolics dysfunction.

57 citations

Journal ArticleDOI
TL;DR: Systole is significantly prolonged and diastole correspondingly shortened in heart failure and reversal of the normal systolic/diastolic ratio may compromise cardiac filling and function.
Abstract: Systole and diastole are the fundamental periods of the cardiac cycle, yet little emphasis has been placed on their relative duration when evaluating heart failure. Cardiac intervals are used to assess ventricular function, but the relative duration of systole and diastole for defining function have not been evaluated. We hypothesized that in heart failure, systole is prolonged and diastole shortened. We defined systole and diastole in 16 children with idiopathic dilated cardiomyopathy and in 16 normal controls, matched for age and gender, using the mitral regurgitant (MR) and tricuspid regurgitant (TR) flow duration. The systole and diastole durations (expressed as a fraction of the cardiac cycle) were correlated with heart rate and age and compared between groups. The subjects were compared with gender- and age-matched controls (9.98 +/- 6.1 vs 9.88 +/- 6.08 years, p = NS). The 2 groups had similar heart rates (104 +/- 31 vs 92 +/- 34 beats/min, p = NS). The systole duration was not significantly different when measured by MR versus TR duration (0.60 +/- 0.10 vs 0.57 +/- 0.11 of the cardiac cycle, respectively, p = NS). Systole was prolonged in subjects compared with controls (0.60 +/- 0.1 vs 0.42 +/- 0.08, respectively, using MR duration, p < 0.0001 and 0.57 +/- 0.11 vs 0.41 +/- 0.07, respectively, using TR duration, p = 0.0008). The systolic/diastolic ratio was 0.77 +/- 0.24 in the controls versus 1.57 +/- 0.98 in the patients with idiopathic dilated cardiomyopathy using the TR duration (p < 0.005) and 1.67 +/- 0.68 using the MR duration (p < 0.0001). The systole duration correlated with heart rate in subjects (r = 0.79, p = 0.0003) and controls (r = 0.69, p = 0.003). In conclusion, systole is significantly prolonged and diastole correspondingly shortened in heart failure. Reversal of the normal systolic/diastolic ratio may compromise cardiac filling and function. The systole and diastole duration are easily measured using routine Doppler flow, enhancing assessment of cardiac function in children.

57 citations

Journal ArticleDOI
TL;DR: The results indicate that the timing of recipient atrial contraction and relaxation significantly influences left ventricular filling dynamics.
Abstract: Recipient atrial remnants retain electrical and mechanical activity after orthotopic cardiac transplantation. This study investigated the influence of recipient atrial contraction timing on Doppler ultrasound mitral flow velocity curves, isovolumic relaxation time, peak early mitral flow velocity (M1), mitral valve pressure half-time and peak mitral flow velocity due to atrial systole (M2). Clearly identifiable recipient atrial electrical activity (P waves) was present in 7 of 10 patients studied early postoperatively 2 to 6 months (mean 2.5) (early group) and in 20 of 24 patients seen 1 to 11 years (mean 3) after transplantation (late group). Median age and gender distribution were similar in both groups. For analysis of its influence on isovolumic relaxation time, pressure half-time and M1, recipient atrial contraction was classified by its position in the cardiac cycle as early systole, late systole or diastole. For analysis of M2, it was classified as early diastole, late diastole or systole. Compared with its occurrence in diastole, recipient atrial contraction in late systole was associated with a shorter isovolumic relaxation time, shorter pressure half-time and higher M1. In early systole it was associated with a longer pressure half-time and lower M1 than in diastole; isovolumic relaxation time was unchanged. Recipient atrial contraction in early diastole resulted in a lower M2 than in systole, whereas simultaneous contraction of recipient and donor atria in late diastole resulted in an increase in M2. These results indicate that the timing of recipient atrial contraction and relaxation significantly influences left ventricular filling dynamics.

56 citations

Book ChapterDOI
18 Sep 2011
TL;DR: A method is presented such that a detailed, patient-specific annulus and leaflets are tracked throughout mitral valve closure, resulting in a detailed coaptation region.
Abstract: Segmenting the mitral valve during closure and throughout a cardiac cycle from four dimensional ultrasound (4DUS) is important for creation and validation of mechanical models and for improved visualization and understanding of mitral valve behavior. Current methods of segmenting the valve from 4DUS either require extensive user interaction and initialization, do not maintain the valve geometry across a cardiac cycle, or are incapable of producing a detailed coaptation line and surface. We present a method of segmenting the mitral valve annulus and leaflets from 4DUS such that a detailed, patient-specific annulus and leaflets are tracked throughout mitral valve closure, resulting in a detailed coaptation region. The method requires only the selection of two frames from a sequence indicating the start and end of valve closure and a single point near a closed valve. The annulus and leaflets are first found through direct segmentation in the appropriate frames and then by tracking the known geometry to the remaining frames. We compared the automatically segmented meshes to expert manual tracings for both a normal and diseased mitral valve, and found an average difference of 0.59 ± 0.49mm, which is on the order of the spatial resolution of the ultrasound volumes (0.5-1.0mm/voxel).

56 citations


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