Diastolic Filling Time Research Articles

Abstract 14030: Hemodynamic Metrics Can Be Accurately Assessed by a Non-Invasive Sensor Patch: The Portable Technology for Wireless Cardiomyopathy Tracking (Patchwrk) Study

Background: Echocardiographic timing intervals provide valuable prognostic information in patients with pre-clinical cardiac dysfunction. Diastolic filling time (DFT) can identify left bundle branch block (LBBB) patients at higher risk for cardiomyopathy. The need for specialized equipment limits the utility of echo in longitudinal assessment. Hypothesis: A non-invasive multimodal sensor Sansa patch will enable accurate assessment of hemodynamic parameters such as DFT, ejection time (ET), and pre-ejection period (PEP). Methods: Fifty patients scheduled for clinically indicated echocardiography were prospectively enrolled and had simultaneous application of the Sansa patch at the time of echocardiography. Timing intervals were analyzed using continuous wave (CW), pulsed wave (PW), and tissue Doppler imaging (TDI). Data from the Sansa electrocardiogram (ECG), seismocardiogram (SCG), and phonocardiogram (PCG) were independently analyzed to identify valve openings/closures to estimate DFT, ET and PEP. Agreement between echo and Sansa estimates was assessed using the coefficient of determination (R 2 ) and compared with agreement between different echo views. Results: Forty-six of the 50 patients (92%) had data of sufficient quality for analysis. The mean ejection fraction was 53±8% and 11 patients (24%) had LBBB. By echo, the mean DFT, ET, and PEP were 408±137 milliseconds (ms), 297±35ms, and 107±32ms respectively. Sansa estimates for DFT, ET and PEP were 431±135ms, 286±43ms, and 89±34ms respectively. The R 2 for Sansa DFT compared to echo was 0.85. Comparing TDI and PW estimates of DFT within the same patients demonstrated an R 2 of 0.82. Conclusion: Non-invasive Sansa patch monitoring accurately identified key cardiac timing intervals within the error observed between standard echo views. These measures have prognostic value and monitoring them in the ambulatory setting may allow early cardiomyopathy detection and upstream intervention.

Diastolic Filling Time, Chronotropic Response, and Exercise Capacity in Heart Failure and Preserved Ejection Fraction With Sinus Rhythm.

BackgroundExercise‐induced high heart rate may impair exercise tolerance by reducing diastolic filling time and ventricular filling in heart failure with preserved ejection fraction (HFpEF). Given the importance of chronotropic response, we hypothesized that reduction in diastolic filling time because of exercise‐induced increased heart rate would not impair cardiac output reserve and exercise capacity. We sought to determine the association between heart rate, diastolic filling time, hemodynamics, and exercise capacity in HFpEF.Methods and ResultsPatients with HFpEF (n=66) and controls without HF (n=107) underwent bicycle exercise echocardiography with simultaneous expired gas analysis to measure oxygen consumption. Diastolic filling time was assessed by the overlap time between mitral E‐ and A‐waves (longer overlap time indicates shorter diastolic filling duration). Overlap time increased (ie, diastolic filling time shortened) in HFpEF and controls as heart rate increased with exercise, and the relationship was similar between the groups. Greater heart rate response correlated with higher cardiac output (r=0.51, P<0.0001) and oxygen consumption (r=0.50, P<0.0001) during peak exercise. Shorter diastolic filling time, as assessed by longer overlap time, was correlated with higher cardiac output (r=0.47, P<0.0001) and peak oxygen consumption (r=0.38, P=0.007), not with E/e′ or right ventricular‐pulmonary artery uncoupling. Longer overlap time was associated with mitral A velocity (r=0.53, P<0.0001) and left atrial booster pump strain (r=0.42, P<0.0001).ConclusionsShortening of diastolic filling interval in tandem with increased heart rate during exercise does not limit cardiac output reserve or exercise capacity in HFpEF.

Simulation of Acute Pulmonary Hypertension in Beagle Dogs.

Acoustic cardiography (AC) combined with heart sound (HS) recording and electrocardiogram (ECG) provides a noninvasive and inexpensive way to understand the electrical mechanical activity of the heart. Pulmonary artery stenosis can cause hemodynamic abnormalities that might lead to pulmonary hypertension (PH). In this paper, we examined the relationships between the acoustic characteristics of the AC and hemodynamic changes in a beagle dog model of PH.Four healthy beagle dogs were injected with the prostaglandin endoperoxide receptor agonist U-44069 to induce acute PH states. AC was employed to analyze the process of pre-PH, intra-PH, and post-PH. Right ventricular blood pressure (RVBP) was measured via right cardiac catheterization, an invasive method performed in parallel for comparative hemodynamic evaluation. As RVBP increased or decreased, the HS features changed accordingly during acute PH occurrence and development. Right ventricular systolic blood pressure (RVSBP) significantly correlated with the minimum of the first HS (S1) amplitude (correlation coefficient (CC) = -0.82), energy of the S1 (CC = 0.86), energy of the second HS (S2) (CC = 0.67), entropy of the S1 (CC = -0.94), and ratio of electromechanical systolic time (EMST) to the cardiac cycle time (CC = 0.81). The two techniques (AC [HSs and ECG] versus right cardiac catheterization [RVBP]) were significantly correlated. Especially, the diastolic filling time (DFT) had a significant relationship with the right ventricular diastolic time (RVDT) (CC = 0.97), perfusion time (PT) (CC = 0.96), and cardiac cycle time (RR) (CC = 0.96). The CCs between the RVDT and the max dp/dt to min dp/dt, the EMST and the Q to min dp/dt, and the electromechanical activation time and the Q to max dp/dt were 0.95, 0.99, and 0.86, respectively. Furthermore, the logistic regression model with different combinations was used to identify the effective features for monitoring hemodynamic and pathophysiologic conditions.AC provided significant insight into mechanical dysfunction in a rapid and noninvasive way that could be used for early screening of PH.

Noninvasive Assessment Of Cardiovascular Hemodynamics During Exercise Using Systolic Time Intervals

Noninvasive Assessment Of Cardiovascular Hemodynamics During Exercise Using Systolic Time Intervals

Optimal AV delay in ventricularly paced adults with congenital heart disease

BackgroundThe atrioventricular (AV) delay may be altered in ventricularly paced patients with either dual-chamber pacemakers or cardiac resynchronization therapy (CRT), to optimize diastolic filling and cardiac output, but such modifications are virtually unstudied in the setting of complex congenital heart disease (CHD). We sought to assess the optimal AV delay in a pilot study of ventricularly paced adults with CHD. MethodsAV delay optimization was performed by the iterative method utilising pulsed wave Doppler of systemic AV valve inflow, in the patient's presenting rhythm (atrial-sensed or paced). Diastolic filling time (DFT), inflow and outflow velocity time integrals (VTI) were compared at optimal and nominal AV delay settings. ResultsNine patients were studied with the following CHD diagnoses: congenitally corrected transposition of the great arteries (TGA) in 4, D-TGA post Senning in 2, tetralogy of Fallot in 2 and Fontan circulation in 1. The median optimal AV delay was 100 ± 20 ms, shorter than the median nominal AV delay of 150 ± 20 ms. The median difference between optimal and nominal AV delay setting was 50 ± 40 ms, with the optimal AV delay shorter than the nominal in all but one patient. At optimal AV delay, the DFT was longer, and inflow and outflow VTIs were larger, compared to nominal. ConclusionsAV delay optimization in ventricularly paced adult CHD patients resulted in an optimal AV delay that differed to the nominal setting in all patients, and typically was shorter.

Left bundle-branch block is associated with asimilar dyssynchronous phenotype in heart failure patients with normal and reduced ejection fractions

Few therapies improve outcomes in patients with heart failure with preserved ejection fraction (HFpEF). If left bundle-branch block (LBBB) is associated with left ventricular dyssynchrony and impaired cardiac performance in HFpEF, cardiac resynchronization therapy could be a promising treatment. We performed a cross-sectional analysis of selected patients with HFpEF (ejection fraction ≥50%) with and without LBBB (normal conduction, NC) and patients with HFrEF and LBBB who were suitable cardiac resynchronization therapy candidates to describe and contextualize the mechanical phenotype of LBBB in HFpEF. Systolic and diastolic isovolumic times, ejection time(ET), and diastolic filling time(DFT) were measured on spectral tissue Doppler echocardiographic images and indexed to the heart rate. Dyssynchrony pattern was assessed using speckle-tracked longitudinal strain patterns. Comparisons were performed using analysis of variance and χ2 test with posthoc pairwise comparisons as indicated. Eighty-two HFpEF (50 with NC, 32 with LBBB) and 149 HFrEF (all with LBBB) patients met criteria. Overall, 84.4% with HFpEF/LBBB and 91.3% with HFrEF/LBBB had demonstrable mechanical dyssynchrony compared to 0% with HFpEF/NC. Compared to HFpEF/NC, HFpEF/LBBB had significantly prolonged isovolumetric contraction time (ICT), isovolumetric relaxation time (IRT), and total isovolumetric time and significantly shorter ET (all indexed). LBBB/HFrEF patients, compared to LBBB/HFpEF patients, had increased ICT and IRT with decreased DFT but similar ET. Patients with HFpEF and LBBB frequently have an LBBB dyssynchrony phenotype, prolonged ICT and IRT, and reduced ET compared to HFpEF patients with NC. The electromechanical dyssynchrony and disordered cardiac timing of HFpEF with LBBB are similar to HFrEF with LBBB.

Predicting the Development of Reduced Left Ventricular Ejection Fraction in Patients With Left Bundle Branch Block

Left bundle branch block (LBBB) increases the likelihood of developing reduced left ventricular (LV) ejection fraction (EF) but predicting which patients with LBBB and normal LVEF will develop decreased LVEF remains challenging. Fifty patients with LBBB and normal LVEF were retrospectively identified. Clinical, electrocardiographic, and echocardiographic variables were compared between patients who developed a decreased LVEF and those who did not. A total of 16 of 50 patients developed reduced LVEF after 4.3 (SD = 2.8) years of follow-up. Baseline patient and electrocardiographic variables were similar between patients who did and did not develop decreased LVEF. Baseline LVEF was lower in patients who developed decreased LVEF than in those who did not (51.9% [SD = 2.2%] vs 54.9% [SD = 4.4%], p <0.01). Diastolic filling time (DFT) accounted for a significantly smaller percentage of the cardiac cycle in patients who developed decreased LVEF than in those who did not (35.9%, [SD = 6.9%] vs 44.4% [SD = 4.5%] p <0.01). In univariable logistic regression, DFT had a C-statistic of 0.86 (p <0.0001) for prediction of development of decreased LVEF. In conclusion, patients in whom DFT accounted for <38% of the cardiac cycle had a relative risk of developing decreased LVEF of 7.0 (95% confidence interval 3.0 to 16.0) compared to patients with DFT accounting for ≥38% of the cardiac cycle.

Cardiovascular response of postmenopausal women to 8weeks of sprint interval training.

Menopause is accompanied by decreased aerobic fitness and increased risk of cardiovascular disease. Sprint interval training (SIT) is a time-efficient intervention for improving cardiovascular function and aerobic fitness of young adults. To determine the effect of an 8-week SIT program on the cardiovascular function and aerobic fitness of overweight postmenopausal women. Thirty overweight postmenopausal women were randomized into exercise (n = 15) or control (n = 15) groups. The intervention group completed three SIT sessions a week for 8weeks. Each session consisted of 20min of 8-s sprints and 12s of light pedalling. Participants also completed 8min of light aerobic cycle exercise, before and after the SIT intervention. Cardiovascular function including heart rate, stroke volume (SV), and diastolic filling time (DFT) was assessed before and after the intervention and during 8min of light aerobic exercise. Estimated maximal oxygen uptake ([Formula: see text]) was also assessed. Resting SV was increased (p = 0.001) from pre- (77.5 ± 17.0mL) to post-SIT (81.3 ± 17.0mL), whereas SV during 8min of light aerobic exercise was increased (p = 0.000), from pre- (97.8 ± 1.6mL) to post-test (103.5 ± 17.8mL). Resting DFT was increased, (p = 0.010), at pre- (333.4 ± 94.4mL) to post-SIT (357.4 ± 88.2mL), whereas DFT during 8min of aerobic exercise was increased, (p = 0.000), from pre- (480.1 ± 99.5mL) to posttest (527.2 ± 123.0mL). Predicted [Formula: see text] was increased, (p = 0.016), from pre- (19.5 ± 5.87mLkg-1min-1) to post-SIT (21.4 ± 7.02mLkg-1min-1). SIT improved cardiovascular function and aerobic fitness of overweight postmenopausal women after 8weeks of exercise.

Match and mismatch between opening area and resistance in mild and moderate rheumatic mitral stenosis.

Mitral valve resistance (MVR) is a hemodynamic consequence of mitral stenosis (MS), but it has no clear threshold with a shortage of data to be reliable. We aimed to investigate match and mismatch between opening area and resistance especially in patients with moderate and mild MS. This study comprised 88 patients with moderate and mild rheumatic MS. Transthoracic echocardiographic study estimated the following: mitral valve area (MVA) by both planimetry (2D) and pressure half-time (PHT), mitral valve score (MVS), mean transmitral pressure gradient (MPG), diastolic filling time (DFT), left ventricular out flow tract diameter (LVOTd) and velocity-time integral (LVOTvti), and MVR = MPG/aortic flow ratio [(LVOTd) (LVOTvti)/DFT] in dynes·s/cm5 . Patients were classified into two groups: group 1 (51 patients) with matched MVR and group 2 (37 patients) with mismatched higher MVR. In the matched group, moderate MS showed MVR <105 dynes·s/cm5 and <76dynes·s/cm5 with mild MS. Group 2 compared to group 1 had higher NYHA class (1.4±0.6 vs 1.2±0.4, P<.05) and higher MVS (8.1±1.8 vs 7±0.9, P<.05). MVR showed positive correlation with MVS (r=.5, P<.05), and logistic regression analysis showed that MVS is the only independent predictor of the MVR severity in the mismatched group (i.e., with higher MVR compared to the ROC analysis results) (B±SE=6.997±2.826, t=2.476, 95% CI 1.241±12.752 with an odds ratio=0.412, P<.05). On investigating match and mismatch between opening area and resistance, the only independent predictor of mismatch is the mitral valve score.

Role of the Mitral Valve Resistance in Evaluation of Mitral Stenosis Severity

Background: Mitral valve resistance (MVR) is an important hemodynamic consequence of mitral stenosis (MS). We aimed to determine whether the mitral valve resistance could be used as a clinically reliable method for estimation of MS severity. Materials and Methods: Transthorathic echocardiographic study of 128 patients with rheumatic MS to estimate; mitral valve area (MVA); planimerty (2D) and pressure half time (PHT), mitral valve score (MVS), right ventricular systolic pressure (RVSP), mean transmitral pressure gradient (MPG), diastolic filling time (DFT), left ventricular out flow tract diameter (LVOTd) and velocity time integral (LVOT vti), MVR calculated as: MPG/aortic flow ratio [(LVOTd) (LVOTvti)/DFT] in dynes.sec.cm-5. Results: MVR at cut off values of: ≥105.26 dynes.sec.cm-5, had a sensitivity of 86.7% and a specificity of 74.5% for severe MS, between 76.02 and 105.26 dynes.sec/cm5 it had a sensitivity of 85.2% and a specificity of 72% for moderate MS, at ≤76.02 dynes.sec/cm5 it had a sensitivity of 81% and a specificity of 91% for mild MS. MVR in moderate MS; can detect symptomatic patients at a cut off value ≥85.65 dynes.sec/cm5 with a sensitivity of 87% and a specificity of 100%. MVR had positive correlations with MVS and RVSP (r=0.618 and 0.401), -ve correlations with MVA-2D and PHT (r=-0.559 and -0.284), P<0.01. MVR was an independent predictor of the NYHA functional class (B ± SE0.003 ± 0.001, odds ratio 0.3, P<0.01). NYHA functional class showed the best correlation with MVR (r=0.630, P<0.01). Conclusion: MVR can be used as a parameter for expression of stenosis severity, and could be used for evaluation of symptomatic moderate MS.

Revisiting diastolic filling time as mechanistic insight for response to cardiac resynchronization therapy

Intraventricular dyssynchrony and commonly associated prolonged atrioventricular conduction both reduce diastolic filling time (DFT), which can be improved by cardiac resynchronization therapy (CRT). Our aim was to investigate whether change in DFT corrected for RR interval (DFTC) after CRT might serve to assess the mechanistic response to CRT. Echocardiography data of consecutive patients in sinus rhythm (n = 91) were studied before and 6 months after implantation. Mortality and heart failure hospitalization data were collected. Patients with vs. without DFTC increase after 6 months were compared. The programmed atrioventricular delay, percentage of biventricular pacing, and change in PR interval were similar in both groups. DFTC increase after 6 months reflected favourable reverse left ventricular remodelling and was significantly associated with freedom from death or heart failure admission (P = 0.008). In multivariate analysis including guideline criteria for CRT (i.e. QRS width, presence of left bundle branch block, and ejection fraction), interventricular mechanical delay, and Tei index, baseline DFTC was the strongest predictor of adverse outcome. Notably, while patients with impaired relaxation had a large and highly significant reduction in all-cause mortality and heart failure admissions when DFTC increased [hazard ratio (HR), 95% confidence interval (CI) = 0.24, 0.08-0.73; P = 0.012], this benefit was less pronounced and did not reach statistical significance in patients with pseudonormal or restrictive filling (HR, 95% CI = 0.64, 0.23-1.77; P = 0.388). DFTC increase after CRT reflects favourable reverse remodelling and is associated with better clinical outcome.

Evaluation of Diastolic and Systolic Cardiac Function in Beta Blocked Pediatric Patients using Exercise Echocardiography

PURPOSE: To evaluate the effect of beta blockade on diastolic and systolic cardiac function during exercise in pediatric patients. METHODS: We evaluated 20 normal controls (N, 14 females, mean age 14.8 yrs) and 11 patients with congenital prolonged QT treated with beta blockers (BB, 7 females, mean age 13.4 yrs) using the James cycle ergometer protocol with echocardiography and tissue Doppler. RESULTS: There were no significant differences in N and BB height (1.61 vs 1.55 meters) or weight (59.8 vs 55.6 kilograms). The working capacity was significantly decreased in BB compared to N (789 vs 1153 watts, P<0.05). Aerobic capacity (VO2), resting and maximal heart rate (HR), cardiac output index (CI), and systolic tissue velocity (SaLAT) were significantly decreased in BB compared to N. Diastolic filling time (DFT) and systolic ejection time (SyET) were significantly prolonged in BB compared to N. The DFT and SyET proportions to the entire cardiac cycle, myocardial relaxation (Em) and index of ventricular filling pressure (E/Em) were not significantly different in BB compared to N.Table: Caption not availableCONCLUSION: This group of pediatric patients treated with beta blockade showed decreased aerobic and working capacity associated with impaired cardiac output and systolic tissue velocity. Indices of myocardial relaxation (Em) and ventricular filling (E/Em) were unchanged compare to normals. This suggests that beta blockade impacts cardiac output by impairing the augmentation of systolic function which occurs normally with exercise-induced sympathetic stimulation.

Abstract 2209: Impaired Diastolic Filling During Exercise Negatively Impacts Exercise Capacity in Children Who Have Undergone the Fontan Operation

Background: Increased cardiac output during exercise relies on synergy between forward pumping of the heart and a peripheral pump, comprised of skeletal muscle function and arteriolar dilation, which augments venous return. The critical component of this two-pump system is the maintenance of normal filling pressures, by enhancing diastolic filling. We hypothesized that children with normal systemic ventricular function, who have undergone the Fontan operation, have impaired diastolic filling during exercise which may negatively impact exercise capacity. Methods: Stress echocardiography was performed during upright cycle ergometry in a group of Fontan patients with normal systolic function (n=14) and a group of normal controls (n=17). Echo parameters obtained at each stage of exercise included early myocardial velocity at the systemic atrioventricular valve lateral annulus (Em), continuous wave Doppler velocity of ventricular inflow (E), calculation of the E/Em ratio (index of ventricular filling pressures), diastolic filling time (DFT), stroke volume (SV) and cardiac output (Q). Heart rate (HR) and maximal aerobic capacity (MVO2) were recorded. All data were normalized to percentage of MVO2. Results: The mean age was 14 years in both groups (p=0.8). The gender distribution was similar (p=0.1). The mean body mass index was slightly lower in the Fontan group (23 vs 19, p=0.05). All studies were judged to be maximal. Exercise and echo data are provided below:

Effect of Radiofrequency Catheter Ablation on Doppler Echocardiographic Parameters in Patients With Wolff-Parkinson-White Syndrome

The aim of this study was to compare the conventional Doppler echocardiographic parameters before and after accessory pathway ablation in patients with Wolff-Parkinson-White (WPW) syndrome. Thirty patients (19 males, 11 females) aged 35.5 +/- 14.4 years were enrolled in the study. All patients underwent successful radiofrequency catheter ablation (RFCA). Echocardiograhic examination was performed before and after RFCA. Aortic and pulmonary flows, diastolic early (E) and late (A) transmitral filling velocities, their velocity time integrals (VTI), mitral diastolic filling time (DFT), deceleration time (DT), isovolumic relaxation time (IVRT), aortic ejection time, and aortic VTI were assessed before and after RFCA. We found that the pulmonary valve opened earlier than the aortic valve when the accessory pathway was located on the right ventricular side (P = 0.02). Otherwise, if the accessory pathway was located on the left ventricular side, the aortic valve opened earlier (P < 0.01). Intervals between the onsets of aortic and pulmonary flows were shortened after RFCA (P = 0.01). We also observed prolongation of DFT (P < 0.001), increases in A velocity (P < 0.05) and its VTI (P < 0.01), as well as a decrease in the E/A ratio (P < 0.01) and shortening of aortic ejection time (P = 0.01) with restoration of AV conduction. We conclude that Doppler echocardiographic examination can provide clues about accessory pathway location and RFCA causes some significant changes in Doppler echocardiographic time intervals. These changes confirm that cardiac synchrony is restored after RFCA.

Cardiac resynchronization therapy acutely improves diastolic function

Invasive studies have shown that cardiac resynchronization therapy (CRT) acutely improves left ventricular (LV) systolic performance and lowers filling pressures in a majority of patients with medically-refractory severe heart failure. Measurements included LV volume, ejection fraction, PWD early (E-wave) and atrial (A-wave) velocities, diastolic filling time (DFT), and DTI early diastolic mitral annular velocity (Em) at the lateral and septal annulus; PWD mitral E-wave/Em and E/FP were calculated to estimate LV filling pressures. Immediately after CRT, LV volumes decreased and LVEF increased significantly. PWD mitral E-wave velocity decreased and E-wave duration and DFT increased significantly; mitral E/FP ratio also decreased significantly, consistent with a decrease in LV filling pressure. Patients with a pre-CRT mitral E/A ratio >1 (n = 20), demonstrated improvements in LV diastolic filling and lower filling pressures whereas those with an E/A ratio < or =1 (n = 21) did not show significant changes in diastolic indices. The acute effects of CRT include echocardiographic evidence of reduced LV volumes and increased LVEF with improved diastolic filling and lower filling pressures; LV relaxation is not significantly altered. The benefits in diastolic function are dependent on the PWD-determined LV filling characteristics prior to CRT.

Arrhythmias: appraisal of symptoms by haemodynamic concepts

Arryhthmias can afflict any heart, even in the absence of disease. Given that Cardiac Output (CO) is a product of heart rate and stroke volume, the end-result of brady- and tachy-arrhythmias is the same: low CO with symptoms of low-output state. In bradyarrhythmias, myocardial inotropy operates maximally but the product of stroke volume and slow heart rate yields a low CO. In tacharryhthmias, myocardial inotropy is redundant because the product of low stroke volume arising from low Diastolic Filling Time (DFT) and heart rate also yields a low CO. The hallmark of extrasystole is the duplex of symptoms: dizziness followed by palpitation.

Endurance athletes?? stroke volume does not plateau

Left ventricular function was examined during incremental work rates to maximum using simultaneous determinations of stroke volume, left ventricular ejection time (LVET), and diastolic filling time (DT). Seven endurance trained and seven untrained young adult males were studied on a cycle ergometer at matched heart rates of 90, 120, 140, 160, 180, and 190 bpm (+/- 1 bpm). Stroke volume of the untrained subjects reached a plateau at 120 bpm, but stroke volume of the trained subjects continued to increase to their maximum heart rate with no plateau. Throughout incremental work rates, LVET was significantly longer and DT was significantly shorter in the trained subjects. At a heart rate of 190 bpm, the corresponding rates of ventricular emptying and ventricular filling of the trained versus the untrained subjects were 20% and 71% greater, respectively (P < 0.01). We conclude that during incremental work rates the stroke volume of endurance trained athletes increases progressively to maximum with no plateau. In addition, although trained athletes rely on enhancements in both ventricular filling and ventricular emptying to augment stroke volume, by far their major advantage over untrained subjects is in ventricular filling.

Left ventricular diastolic filling alterations in subjects with mitral valve prolapse: a Doppler echocardiographic study

To assess left ventricular diastolic filling in mitral valve prolapse (MVP), we studied 22 patients with idiopathic MVP and 22 healthy controls matched for sex, age, body surface area and heart rate. A two-dimensional, M-mode and Doppler echocardiographic examination was performed to exclude any cardiac abnormalities. The two groups had similar diastolic and systolic left ventricular volumes, left ventricle mass and ejection fraction. Doppler measurements of mitral inflow were: E and A areas (the components of the total flow velocity-time integral in the early passive period of ventricular filling, E; and the late active period of atrial emptying, A), the peak E and A velocities (cm.s-1), acceleration and deceleration half-times (ms) of early diastolic rapid inflow, acceleration time of early diastolic flow (AT), total diastolic filling time (DFT) (ms), and the deceleration of early diastolic flow (cm.s-2). From these measurements were calculate: peak A/E ratio (A/E), E area/A area, the early filling fraction, the atrial filling fraction, AT/DFT ratio. All the Doppler measurements reported are the average of three cardiac cycles selected at end expiration. The mean peak A velocity, A/E velocity ratio, deceleration half time and atrial filling fraction were each significantly higher for subjects presenting a MVP (60 +/- 12 cm.s-1 vs 49 +/- 14, P < 0.008; 98 +/- 13% vs 64 +/- 12%, P < 0.0001; 120 +/- 36 ms vs 92 +/- 11, P < 0.002; 0.45 +/- 0.14 vs 0.36 +/- 0.08, P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of left ventricular filling during increased preload and inotropy.

To examine the factors contributing to left ventricular filling, experiments were performed in anesthetized, open-chest dogs with intact or mechanically constricted mitral ostium. Stroke volume was raised either by increasing left ventricular end-diastolic volume (preload) by blood volume expansion or by infusing isoproterenol, a beta-adrenergic agonist. In all experimental settings, stroke volume rose in proportion (r greater than 0.9) to the pressure time product (PTP = integral of the diastolic atrio-ventricular (A-V) pressure difference). During saline infusion atrial distention and contraction increased atrial pressure more than ventricular pressure whereas diastolic filling time (DFT) was not lengthened. Peak mitral and peak aortic flow rose almost equally. During isoproterenol infusion at constant heart rate (atrial pacing), the increase in PTP was mainly caused by a longer DFT. When heart rate was allowed to rise, DFT was reduced and the A-V pressure difference increased because of a greater reduction in ventricular than in atrial pressure in early diastole. Thus, the A-V pressure difference is generated in different ways by raising preload and inotropy with and without changes in heart rate.