Carotid atherosclerosis is associated with left ventricular diastolic function

Background

It has been reported that carotid intima-media thickness (IMT) correlates with the risk of stroke or cardiovascular disease. The purpose of this study was to analyze the relationships between echocardiographic findings and carotid atherosclerosis.

Methods

A total of 234 patients (62 ± 15 years) were referred for echocardiography to evaluate the left ventricular (LV) function. The LV ejection fraction, the ratio of the peak velocity of early rapid filling and the peak velocity of atrial filling (E/A), and the peak early diastolic mitral annular velocity (e′) were obtained by echocardiography. The maximum IMT (Max-IMT) and plaque score (PS) were measured by carotid ultrasonography within 1 month of the echocardiographic examination.

Results

The mean values of Max-IMT and carotid PS were 2.41 ± 1.23 mm and 8.5 ± 6.3, respectively. The decreased mean E/A (0.94 ± 0.39) and mitral e′ (5.5 ± 1.9 cm/s) indicated LV diastolic dysfunction. A good correlation was observed between Max-IMT and PS (r = 0.83, p < 0.0001). It was shown that 2.8 mm of Max-IMT was equivalent to 10.1 of carotid PS, which indicated severe carotid atherosclerosis. In multiple logistic stepwise regression analysis, among the echocardiographic parameters, only e′ was independently associated with severe carotid atherosclerosis (Max-IMT ≥ 2.8 mm or PS ≥ 10.1).

Conclusions

The present study demonstrated that decreased early diastolic mitral annular velocity relates to the parameter reflecting carotid atherosclerosis. Therefore, the presence of severe carotid atherosclerosis may affect LV diastolic dysfunction.

     

Associations between left ventricular diastolic function and right ventricular function in patients with and without preserved left ventricular ejection fraction

Background

The purpose of this study was to investigate associations between right ventricular (RV) function and left ventricular (LV) diastolic function in patients with reduced LV ejection fraction (LVEF) and preserved LVEF.

Methods

A total of 139 patients who had undergone echocardiography were recruited. LV diastolic function was determined as the ratio of mitral inflow E to mitral e′ lateral annular velocities (E/e′). RV function was determined as the RV index of myocardial performance (RIMP). Patients were divided into two groups: the preserved LVEF group (n = 100, LVEF ≥ 50%) and the reduced LVEF group (n = 39, LVEF <  50%).

Results

Associations between RV function and LV diastolic function in patients with reduced LVEF and preserved LVEF differed significantly. RIMP correlated significantly with E/e′ in patients with reduced LVEF (r = 0.47, p = 0.003), but not in those with preserved LVEF (r = 0.04, p = 0.68). An important finding of the multivariate regression analysis showed that RIMP was the only independent determinant of E/e′ in patients with reduced LVEF, whereas age and gender (not RIMP) was the independent determinant of E/e′ in patients with preserved LVEF.

Conclusions

Associations between RV function and LV diastolic function in patients with reduced LVEF and preserved LVEF differed significantly, and RV function showed a close correlation with LV diastolic function in patients with reduced LVEF, but not in those with preserved LVEF. Thus, these findings may well have clinical implications for better management of patients with reduced LVEF.

     

Effects of fentanyl on left ventricular diastolic function

Effects of fentanyl on left ventricular diastolic function were investigated in chronically instrumented dogs. An electromagnetic mitral flow probe was placed in the left atrium and a micromanometer was placed in the left atrium as well as in the left ventricle to measure ventricular pressure (LVP), left atrial pressure (LAP), derivative of left ventricular pressure (dp/dt), mitral flow (MIF) and ECG in conscious resting dogs. Following induction of anesthesia with thiopental (15-20 mg.kg-1) and vecuronium (0.1 mg.kg-1), fentanyl (10, 50 and 100 mcg.kg-1) was administered at 30 min intervals. The direct measurement of phasic MIF was used to obtain a set of diastolic indices: peak rapid filling period (PRFR), filling volume (FV), FV due to atrial contraction (FV-A), isovolumic relaxation period (IVRP) and diastolic filling period (DFP). Each diastolic index during conscious resting state was compared with that obtained during fentanyl anesthesia using paired t-test. There were no significant changes in those diastolic indices under fentanyl (10, 50 and 100 mcg.kg-1) anesthesia except PRFR and dp/dt under fentanyl 10 mcg.kg-1 which decreased. Although heart rate decreased about 50% under fentanyl, IVRP and PRFR did not increase significantly, but DFP (P less than 0.05) and FV (P less than 0.01) increased significantly. DFP correlated well with RR interval under conscious resting state under fentanyl anesthesia (r = 0.992 and r = 0.967). This study suggests that in the absence of surgical stress, fentanyl does not impair left ventricular diastolic function.     

Impaired left ventricular diastolic function in children with chronic renal failure

BACKGROUND: Diastolic dysfunction is frequent in adults with renal failure. However, in children with mild-to-moderate chronic renal insufficiency (CRI), it has not been evaluated. We compared diastolic function and assessed risk factors associated with diastolic dysfunction in children with CRI with those on dialysis. METHODS: Thirty-three children with CRI, 17 on chronic dialysis, and 33 control patients, had echocardiography performed. Early diastole was assessed using indices of left ventricular (LV) relaxation derived from transmitral and tissue Doppler, and reported as the peak E/A wave ratio, and septal mitral annular velocities (Em). Late diastole was determined using an index of LV compliance (E/Em ratio). Left atrial (LA) dimension was also determined. RESULTS: Children with CRI had worse diastolic function (lower Em, and higher E/Em ratio than control patients, P < 0.001). Dialysis patients had worse diastolic function (lower E/A ratio and Em, and higher E/Em ratio, P < 0.001) than CRI children. LA dimension was higher in renal patients when compared with control patients (P < 0.001). In children on dialysis, LV relaxation (Em) was significantly related to left ventricular mass (LVM) index (r=-0.58, P= 0.04), and LV compliance (E/Em) was significantly associated with LA index (r= 0.67, P= 0.01), LVM index (r= 0.75, P < 0.01), hemoglobin level (r=-0.65, P= 0.02), serum phosphorus (r= 0.56, P= 0.05), and calcium-phosphorus ion product (r= 0.59, P= 0.04). CONCLUSION: Our results indicate that diastolic dysfunction is already present in children with mild-to-moderate CRI. Worse diastolic function in dialysis patients might be related to LV hypertrophy. The results suggest that children with advanced renal failure and diastolic dysfunction may be at risk for ultimate worsening of cardiac function over time.     

Intra-aortic balloon pumping: effects on left ventricular diastolic function.

OBJECTIVE: The intra-aortic balloon pump is the most widely used form of temporary cardiac assist and often utilised in patients before and after cardiac surgery. Several effects of balloon counter-pulsation have been reported previously, but its effect on left ventricular diastolic function has not been thoroughly investigated. The aim of this study is to examine the effect of the intra-aortic balloon pump on left ventricular wall motion and transmitral flow. METHODS: We studied 20 patients in the intensive care unit, less than 36 h following cardiac surgery. We recorded left anterior descending coronary artery and transmitral E-wave flow velocities using transesophageal echocardiography pulsed Doppler. We also recorded left ventricular long axis free-wall movement using M-mode. The intra-aortic balloon pump was set to full augmentation and recordings were made at pumping cycles 1:1, 1:2, 1:3, and when the pump was on stand-by, leaving a minimum of 5 min between the pumping modes to allow the return to control conditions. In order to eliminate time effects, the sequence of recording was varied between patients using a 4 by 4 Latin-square. RESULTS: The peak diastolic left anterior descending coronary artery and transmitral E-wave flow velocities, and left ventricular free-wall early diastolic lengthening velocity increased significantly with intra-aortic balloon pumping cycles 1:1, 1:2 and 1:3 compared to their value with the pump on stand-by, all P < 0.001. The increase in peak transmitral E-wave flow velocity correlated with the increase in peak left anterior descending coronary artery diastolic flow velocity (r = 0.74, P = 0.02), and with the increase in left ventricular free-wall early diastolic lengthening velocity (r = 0.80, P < 0.001). CONCLUSION: Using the intra-aortic balloon pump post-cardiac surgery significantly increases peak diastolic left anterior descending coronary artery flow velocities and left ventricular free-wall early diastolic lengthening velocity, whose increase explains the increase in peak transmitral E-wave velocity. Although coronary flow is epicardial and mitral flow is intracardial, their close relationship suggests an improvement in left ventricular diastolic function with intra-aortic balloon pump.     

Influence of PEEP on left ventricular diastolic function]

We investigated the influence of PEEP on left ventricular diastolic function using the pressure-volume loops by employing a micromanometer catheter and a conductance catheter placed in the left ventricle of the eight mongrel dogs. Time constant of diastolic interval was shortened under the condition of 15 cmH2O of PEEP compared with the control value (PEEP 0 cmH2O) and the diastolic stiffness constant was prolonged under 15 cmH2O of PEEP. It was considered that the shortened time constant of diastolic interval was due to the decrease of preload. The prolongation of diastolic stiffness constant was possibly due to compression of the heart by increased intrapleural pressure. We conclude that decreased compliance of left ventricle caused by PEEP might impair the left ventricular function.     

Dynamic cardiomyoplasty acutely impairs left ventricular diastolic function.

In patients with congestive heart failure, medical treatment has a high rate of mortality and morbidity, and transplantation is limited by the availability of donor hearts. Dynamic cardiomyoplasty is being investigated as surgical therapy to improve left ventricular function in these patients. To evaluate the early postoperative effects of this procedure on left ventricular diastolic function, we studied seven dogs through the use of sonomicrometry and micromanometry in a canine model of dynamic cardiomyoplasty. Left ventricular diastolic parameters were determined before wrapping the latissimus dorsi muscle (baseline), after latissimus dorsi muscle wrap but without stimulation, and with synchronous left ventricular contraction-latissimus dorsi muscle stimulation. End-diastolic pressure was increased in both conditions after latissimus dorsi muscle wrap (without stimulation, 5 +/- 1; with stimulation, 6 +/- 2 mm Hg; p < 0.05) compared with baseline (3 +/- 2 mm Hg). The peak rate of diastolic pressure decay was greater at baseline (1560 +/- 370 mm Hg/sec) than after latissimus dorsi muscle wrap, both without (1260 +/- 330 mm Hg/sec, p < 0.01) and with (1120 +/- 420 mm Hg/sec, p < 0.01) stimulation. The constant of pressure decay was prolonged both without (53 +/- 10 seconds, p < 0.05) and with (62 +/- 11 seconds, p < 0.01) latissimus dorsi muscle stimulation compared with the baseline (38 +/- 5 seconds). Compared with baseline (0.2 +/- 0.2 cm-2), the constant of passive chamber stiffness increased after the latissimus dorsi muscle was wrapped around the heart (1.6 +/- 0.7 cm-2, p < 0.05) and with stimulation (2.1 +/- 1.0 cm-2, p < 0.01). The maximal diastolic filling rate (baseline, 18.1 +/- 6.7; without stimulation, 16.6 +/- 8.9; with stimulation, 16.6 +/- 4.1 cm2/sec, not significant) and end-diastolic short-axis area (baseline, 7.3 +/- 2.3; without stimulation, 7.4 +/- 2.1; with stimulation, 7.5 +/- 2.3 cm2, not significant) were similar among the three conditions. The latissimus dorsi muscle wrap prolonged relaxation and increased left ventricular passive stiffness. Synchronous latissimus dorsi muscle stimulation with left ventricular contraction did not improve diastolic function in this model. The results suggest that in the early postoperative period, dynamic cardiomyoplasty impairs diastolic function.     

The effects of aorto-coronary bypass grafting on left ventricular diastolic function in patients with left ventricular dysfunction

To determine the effects of aorto-coronary bypass grafting on left ventricular diastolic function in patients with low ejection fraction (EF less than or equal to 0.40), 17 patients were studied. They were divided into two groups, Group I: 8 patients without previous myocardial infarction, Group II: 9 patients with previous myocardial infarction. Left ventricular diastolic function was assessed by maximum negative dp/dt, constant T, diastolic compliance and 1/3 functional filling. In conclusions, when ejection fraction is depressed (EF less than or equal to 0.40), myocardial revascularization improves left ventricular diastolic function in patients without previous myocardial infarction, but not with previous myocardial infarction.     

Effects of sevoflurane and propofol on left ventricular diastolic function in patients with pre-existing diastolic dysfunction

Background. The effects of anaesthetics on left ventricular(LV) diastolic function in patients with pre-existing diastolicdysfunction are not well known. We hypothesized that propofolbut not sevoflurane will worsen the pre-existing LV diastolicdysfunction. Methods. Of 24 randomized patients, 23 fulfilled the predefinedechocardiographic criterion for diastolic dysfunction. Theyreceived general anaesthesia with sevoflurane 1 MAC (n=12) orpropofol 4 µg ml^–1 (n=11). Echocardiographic examinationswere performed at baseline and in anaesthetized patients underspontaneous breathing and under positive pressure ventilation.Analysis focused on peak early diastolic velocity of the mitralannulus (E_a). Results. During spontaneous breathing, E_a was higher in thesevoflurane than in the propofol group [mean (95% CI) 7.0 (5.9–8.1)vs 5.5 (4.7–6.3) cm s^–1; P<0.05], reflectingan increase of E_a from baseline only in the sevoflurane group(P<0.01). Haemodynamic findings were similar in both groups,but the end-tidal carbon dioxide content was more elevated inthe propofol group (P<0.01). During positive pressure ventilation,E_a was similarly low in the sevoflurane and propofol groups[5.3 (4.2–6.3) and 4.4 (3.6–5.2) cm s^–1, respectively]. Conclusions. During spontaneous breathing, early diastolic functionimproved in the sevoflurane but not in the propofol group. However,during positive pressure ventilation and balanced anaesthesia,there was no evidence of different effects caused by the twoanaesthetics.     

Quantitative analysis of myocardial revascularization on left ventricular diastolic function

To evaluate the effects of myocardial revascularization on left ventricular diastolic function, we studied three groups of subjects. Group I consisted of 10 patients without any previous myocardial infarction. Group II consisted of 10 patients with previous myocardial infarction. The control group consisted of 8 normal subjects, all with no evidence of cardiac disease as determined by cardiac catheterization. Left ventricular diastolic function was assessed by maximum negative dp/dt, constant T, diastolic compliance and 1/3 fractional filling before and after surgical revascularization. (1) Constant T, maximum negative dp/dt and diastolic compliance: There was no significant difference among groups I, II and the control group preoperatively, and the variables were not improved postoperatively. (2) 1/3 fractional filling: 1/3 fractional fillings in groups I and II were significantly lower (p less than 0.05, p less than 0.01) than the control group preoperatively, and it was significantly improved in group I, but unchanged in group II postoperatively. In conclusion, myocardial revascularization improves left ventricular diastolic function in the patients without previous myocardial infarction. The effects of myocardial revascularization, however, in the patients with prior myocardial infarction do not bring about an enhancement of left ventricular diastolic function.     

Influence of chronic renal insufficiency on left ventricular diastolic function in hypertensives without left ventricular hypertrophy

BACKGROUND: Patients with chronic renal insufficiency (CRI) have a much greater cardiovascular risk than the general population. Moreover, hypertension is common in these patients, as is left ventricular hypertrophy (LVH) and diastolic dysfunction, which contribute to a worse prognosis. While these findings are well established for end-stage renal disease, fewer data are available in mild to moderate CRI. Furthermore, little is known about diastolic function in CRI patients without LVH. METHODS: We performed a cross-sectional study to evaluate LV structure and function in hypertensives with CRI, compared with hypertensives with normal renal function (EH), by means of mitral inflow and tissue Doppler echocardiography. Patients with LVH were excluded from both groups. RESULTS: CRI patients had higher left ventricular end-diastolic diameter, end-systolic diameter (p<0.0001 and p=0.0001, respectively) and left ventricular mass index (LVMI) (p<0.0001) than EH patients. The CRI group also showed greater alterations of the diastolic function indexes than hypertensives: lower E-wave peak velocity (p=0.02), E-wave peak velocity to A-wave peak velocity ratio (p=0.03) and early diastolic myocardial velocity (p=0.04), higher A-wave peak velocity (p=0.07), E-deceleration time (p=0.02) and isovolumic relaxation time (p=0.0001). Multiple regression analysis demonstrated that renal function was a predictor of LVMI and diastolic function independently of age, sex, pulse pressure, body mass index and duration of hypertension. CONCLUSIONS: Our data showed a greater alteration of diastolic function in the CRI group, in part independent of LVMI. In CRI, factors other than LVMI and blood pressure seem to play an important role in causing early diastolic dysfunction.     

Calcium infusion and left ventricular diastolic function in patients with chronic renal failure

Background. Left ventricular (LV) function is sensitive to disorders in calcium metabolism. Most previous reports have focused on the effects of calcium on systolic performance. We studied the acute effect of calcium infusion on LF diastolic function in patients with moderate to severe chronic renal failure (CRF) and secondary hyperparathyroidism (SHP). Methods. We infused calcium gluconate at a constant rate of 45 &mgr;mol/kg/h to 14 patients with severe to moderate CRF and SHP. Our aim was to reach slightly supranormal levels of serum ionized calcium (1.35-1.45 mmol/l). LV diastolic function was assessed by pulsed Doppler echocardiography before and after the calcium infusion. The echocardiographic indices were compared to those of 14 age- and sex-matched healthy controls. Results. Before calcium infusion the patients had significantly greater LV dimensions than the controls, but there was no differences in the diastolic indices. During calcium infusion, serum ionized calcium increased from 1.18±0.03 to 1.40±0.03 mmol/l (P<0.0001) and plasma intact PTH decreased from 38.6±5.6 to 9.0±2.2 pmol/l (P<0.0001). Calcium infusion did not affect the LV dimensions or fractional shortening. The peak early diastolic velocity (Emax) decreased and peak late diastolic velocity (Amax) increased, and their relationship decreased significantly (1.552±0.586 vs 1.414±0.535 m/s, P=0.03). These changes reflect impairment of LV diastolic function. Conclusions. Induction of acute hypercalcaemia by calcium infusion impairs LV diastolic function in patients with CRF and SHP.     

Impairment of left ventricular diastolic function during coronary artery bypass grafting

Twelve patients were studied by transoesophageal Doppler echocardiography to determine diastolic function during coronary artery bypass grafting. Haemodynamic and Doppler-derived variables were measured after induction of anaesthesia and after closure of the sternum. Early diastolic filling of the left ventricle decreased from 55% to 35% during surgery. The contribution of atrial contraction to left ventricular filling increased from 41% to 62% (p less than 0.001). We conclude that coronary artery bypass grafting results in impairment of diastolic function during the operation.     

Evaluation of left ventricular diastolic function in IgE-mediated anaphylaxis in dogs

Depressed left ventricular (LV) systolic function remains controversial in patients with anaphylaxis and anaphylactic animal models. However, LV diastolic function has not yet been investigated in either patients or animal models. Therefore, we assessed LV diastolic and systolic function in IgE-mediated anaphylaxis in dogs. Seven dogs sensitized to Ascaris suum antigen were studied. An aqueous extract of Ascans suum antigen was administered over 30 s into the systemic circulation to induce anaphylaxis. To assess LV function, the time constant of the fall of isovolumic LV pressure (T), as an index of LV diastolic function, and the maximum rate of rise of LV pressure (dP/dtmax), as an index of LV systolic function, were measured for a period of 120 min after antigen challenge. T was prolonged during the period of 5 to 15 min; however, changes in T were not significantly different from prechallenge values. LV dP/dtmax significantly decreased to 0.49±0.12 times the prechallenge value 5 min after antigen challenge, and significantly increased during the period from 30 to 120 min. However, these changes in dP/dtmax almost paralleled the changes in LV end-diastolic pressure, indicating that left ventricular systolic function was relatively well preserved. In conclusion, LV diastolic function, i.e., isovolumic relaxation, is little impaired in anaphylaxis, and IV systolic function is relatively well preserved during the early stage following the onset of anaphylaxis.     

Mild hypothermia impairs left ventricular diastolic but not systolic function.

Hypothermia is a component of myocardial protection during cardiopulmonary bypass (CPB) and cardioplegic arrest (CA). Patients in the early post CPB period often show mild hypothermia and cardiac dysfunction. We sought to investigate the impact of hypothermia on left ventricular (LV) function. Anesthetized dogs (n = 12) were instrumented with myocardial ultrasonic crystals and LV micromanometer. Systolic function was measured by preload recruitable stroke work (PRSW). Diastolic function was measured by -dP/dt(max) and tau. In six dogs (Norm group), body temperature was maintained at baseline levels. In another six dogs (Hypo group), body temperature dropped gradually over the time course of the experiment. The body temperature in the Hypo group decreased from 37.0 +/- 0.3 degrees C to 35.2 +/- 1.0 degrees C. -dP/dt(max) decreased and tau increased significantly with hypothermia but were stable in the Norm group. Both tau and -dP/dt(max) showed a linear relationship to the body temperature (r =.91 and r = .93, respectively). PRSW did not change and cardiac output decreased with hypothermia. Thus, even mild hypothermia impairs LV diastolic but not systolic function. Cardiac output is temperature sensitive and therefore rewarming of patients post-CPB has priority.