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PubMed1978

Effects of procaine-induced cardioplegia on myocardial ischemia, myocardial edema, and postarrest ventricular function. A comparison with potassium-induced cardioplegia and hypothermia.

The extent of myocardial protection afforded by a procaine cardioplegic solution during cardiac ischemia has been evaluated and compared with the protection seen using a potassium cardioplegic solution. An isolated cat heart model was employed, and ventricular function parameters, intramyocardial gas tensions, and postischemic myocardial edema were measured and compared following 60 minutes of induced ischemia at 37 degrees C. and 27 degrees C. There was no significant improvement in recovery of postarrest ventricular function when procaine cardioplegia was used during normothermic ischemia. When used at 27 degrees C., however, both cardioplegic solutions were associated with significantly better recovery of postarrest ventricular function, although there was less myocardial edema formation in the potassium-treated hearts. Results of this study indicate that procaine-induced cardioplegia provides myocardial protection during anoxic cardiac arrest which is additive to that afforded by hypothermia alone. In addition, procaine cardioplegia results in postarrest functional recovery which is similar to that seen with potassium cardioplegia.

Animals↗
PubMed1998

Evaluation of Right Ventricular Function During CABG: Transesophageal Echocardiographic Assessment of Hepatic Venous Flow Versus Conventional Right Ventricular Performance Indices.

The vulnerability of right ventricle (RV) to ischemic insult during cardiac surgery is being increasingly recognized. This study aims to evaluate right ventricular function by measuring hepatic venous flow (HVF) patterns using intraoperative transesophageal echocardiography (TEE), and to compare HVF with other conventional two-dimensional echocardiographic and hemodynamic indices of RV performance. Patients undergoing coronary artery bypass grafting (CABG) were studied intraoperatively using a multiplane dual frequency 5/3.7-MHz phased array transducer, a pulmonary artery catheter, and an arterial catheter. Peak velocities and time velocity integrals of HVF pattern were studied. Peak systolic-diastolic ratio (S/D) of biphasic HVF and reverse flow ratio (% reverse flow/forward flow = % RF/FF) were also examined. Two-dimensional echocardiographic measurements included: (1) transverse plane long-axis (LA) and short-axis (SA) planimetered areas expressed as ratios; LA maximum major and minor-axis shortening fractions; (2) tricuspid annular plane systolic excursion (TAPSE) ratio. All data were obtained after induction of anesthesia (stage 1), after sternotomy (stage 2), aftercardiopulmonary bypass (CPB) (stage 3), and after sternal closure (stage 4). Pre-CPB all 35 patients had biphasic HVF by Doppler. In 31 patients peak S/D ratio was >1. After CPB, there was significant reduction in systolic forward flow (S wave), along with an increase in late systolic reverse flow (V wave) and an increase in % RF/FF. At this stage TAPSE ratio decreased (pre CPB 0.33 +/- 0.12 vs post CPB 0.30 +/- 0.11). There was simultaneous decrease in 2-D long-axis LA (pre CPB 0.52 +/- 0.11 vs post CPB 0.31 +/- 0.01) and max major axis LA (pre CPB 0.38 +/- 0.06 vs post CPB 0.31 +/- 0.11). Max major axis LA correlated significantly with changes in right atrial pressure (P < 0.05). Tricuspid annular motion diminished significantly at sternal closure. Hepatic systolic forward flow and TAPSE ratio can be an indirect measure of RV systolic functions in correlation with maximum major axis LA changes. Evaluation of HVF provides unique insight into right ventricular dynamics. It is an easy, safe, and sensitive method for assessing RV functions intraoperatively.

Journal Article↗
PubMed1995

Assessment of magnetic resonance velocity mapping of global ventricular function during dobutamine infusion in coronary artery disease.

BACKGROUND: Magnetic resonance imaging (MRI) is a versatile technique for examination of the cardiovascular system but only recently has assessment of myocardial ischaemia in coronary artery disease (CAD) become possible, for example by demonstrating abnormalities of regional ventricular contraction during stress. Global ventricular function during stress was assessed by MRI of aortic flow, which has not been previously attempted. DESIGN: Variables measured by MRI reflecting the effect of ischaemia on global ventricular function during dobutamine stress were correlated with thallium-201 myocardial perfusion tomography. PATIENTS: 10 normal controls and 25 patients with CAD. SETTING: Tertiary cardiac referral centre. METHODS: Novel MRI sequences and analysis systems were used to measure the following variables during staged dobutamine infusion to 20 micrograms/kg/min: stroke volume, cardiac output, cardiac power output, peak flow, peak flow acceleration, aortic back flow, and flow wave velocity. Heart rate, blood pressure, double product, and maximum tolerated dobutamine dose were also measured. Multiple regression analysis was used to compare changes during stress with 201TI tomography. RESULTS: All parameters except for stroke volume and diastolic blood pressure increased in the controls. In the patients with CAD a significant relation was shown between the extent of reversible ischaemia and the change in peak flow acceleration (P < 0.00001), peak flow (P = 0.002), cardiac power output (P = 0.036), maximum dobutamine dose (P = 0.039), and systolic blood pressure (P = 0.04). Peak flow acceleration accounted for 58.4% of the variation in reversible ischaemia, and after allowing for this, only cardiac power output remained independently predictive adding a further 4.2% to the model (adjusted r2 = 0.626). A decrease in peak flow acceleration with an increase in dobutamine infusion indicated moderate or severe ischaemia (chi 2 = 10.2, P = 0.017). CONCLUSION: MRI may be used to assess variables of aortic flow during stress, which includes acceleration with high temporal resolution. Peak flow acceleration was the most sensitive indicator of the effect of ischaemia on global ventricular function.

Adult↗
PubMed1998

Effect of Poloxamer 188 on Collateral Blood Flow, Myocardial Infarct Size, and Left Ventricular Function in a Canine Model of Prolonged (3-Hour) Coronary Occlusion and Reperfusion.

Poloxamer 188 is a surfactant with hemorheological, antithrombotic, and neutrophil-inhibitory properties. This agent has been demonstrated to reduce infarct size and to improve left ventricular function in animal models of myocardial infarction and reperfusion, and recently in a randomized trial of patients receiving thrombolytic therapy for acute myocardial infarction. In addition to reducing reperfusion injury, poloxamer 188 might be beneficial by increasing collateral blood flow. The purpose of this study was to determine the effect of poloxamer 188 on collateral blood flow, myocardial infarct size, and left ventricular function in a canine model of prolonged (3 hours) coronary occlusion and reperfusion. Closed-chest dogs (n = 21) underwent a 3-hour coronary occlusion and 3 hours of reperfusion. At 1 hour of occlusion, dogs received poloxamer 188, 75 mg/kg IV bolus, followed by 150 mg/kg/h IV for the final 2 hours of coronary occlusion and throughout reperfusion, or a saline placebo. Regional myocardial blood flow was measured using colored microspheres. Myocardial infarct size and area at risk were determined by postmortem histochemical staining. Compared with controls, poloxamer 188-treated dogs showed no significant increase in collateral blood flow during the final 2 hours of a 3-hour coronary artery occlusion. In addition, poloxamer 188 treatment had no beneficial effect on infarct size or left ventricular function in this model. Increased collateral blood flow is unlikely to be a beneficial mechanism of poloxamer 188 in myocardial infarction. These data also question the benefit of this agent to reduce reperfusion injury in the setting of more prolonged (3-hour) coronary occlusion.

Journal Article↗
PubMed1980

Detecting abnormalities in left ventricular function during exercise before angina and ST-segment depression.

To determine if abnormalities in left ventricular function precede angina pectoris and electrocardiographic evidence of myocardial ischemia, we used radionuclide angiocardiography to measure left ventricular ejection fraction, volumes, cardiac output and wall motion in 10 normal subjects and 25 patients with coronary artery disease at rest and during two levels of upright bicylce exercise. In the patients with coronary artery disease, the first radionuclide study during exercise was performed before and the second after the onset of ST-segment depression. In all normal subjects, the ejection fraction increased more than 5%, the end-diastolic volume increased less than 25% and the end-systolic volume decreased from rest to both levels of exercise. Wall motion was normal at rest and increased with exercise. No patient with coronary artery disease had chest pain or ST-segment depression during the first level of exercise. The ejection fraction either decreased or increased less than 5% in 18 patients, the end-diastolic volume increased more than 25% in nine, the end-systolic volume increased in 19 and a segmental contraction abnormality developed in 14. Hemodynamic and wall motion abnormalities occurred in all patients during the second level of exercise when ST-segment depression was present. During exercise in patients with coronary artery disease, abnormalities in left ventricular function frequently develop before angina pectoris and electrocardiographic evidence of myocardial ischemia.

Adult↗
PubMed2004

Comparison in patients having primary coronary angioplasty of abciximab versus tirofiban on recovery of left ventricular function.

In patients treated with primary coronary angioplasty, the use of abciximab improves microvascular perfusion and enhances the recovery of contractile function. This study compared the effects of the new dose regimen of tirofiban (25-microg/kg bolus followed by an 18-hour infusion at 0.15 microg/kg/min) on left ventricular function with those of abciximab in patients who underwent direct angioplasty. One hundred patients who underwent primary coronary angioplasty were randomized to receive a standard dose of abciximab or a large-dose bolus of tirofiban. The primary end point of the study was change in the infarct-zone wall motion score index between the initial and 30-day follow-up echocardiographic studies. The secondary end points were procedural evaluations before and after Thrombolysis In Myocardial Infarction (TIMI) grade flow, TIMI grade myocardial perfusion, and corrected TIMI frame count. Baseline global and regional ventricular functions were similar in the 2 treatment groups. After the procedure, a TIMI grade 3 flow was obtained in 86% of patients treated with abciximab and 88% of those receiving tirofiban (p = 1.0), whereas TIMI grade 3 myocardial perfusion was present in 70% and 76%, respectively (p = 0.65); corrected TIMI frame count was 22.5 +/- 1.9 and 22.1 +/- 2.5 (p = 0.37). After 30 days, we obtained 87 paired echocardiographic studies. The infarct-zone wall motion score index decreased from 2.20 +/- 0.3 to 1.99 +/- 0.2 in the abciximab group and from 2.18 +/- 0.3 to 1.95 +/- 0.3 in the tirofiban group (p = 0.67). Thus, in patients who had primary coronary angioplasty, abciximab, and the large-dose bolus of tirofiban showed similar effects on the initial angiographic results and 30-day recovery of left ventricular function.

Abciximab↗
PubMed1996

[A comparative study of the effects on the left ventricular function of 2 methods of noninvasive ventilation: NIPPV and EFHO-NB].

BACKGROUND: Among the non-invasive ventilatory methods, the Nasal Intermittent Positive Pressure Ventilation (NIPPV) can cause important effects on circulation since a positive intrathoracic pressure is obtained and thus in the transmural cardiac pressure. In contrast, the External High Frequency Oscillation around a Negative Baseline (EHFO-NB) obtains a negative thoracic pressure. Therefore, the opposite circulatory changes should be expected. OBJECTIVE: To study and compare the effects on the left systolic and diastolic ventricular functions derived from the application of both NIPPV and EHFO-NB ventilatory support methods in patients with chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS: Nine patients with COPD were studied. The investigation was carried out from the third to the seventh day of follow-up at the ICU. For each patient three equilibrium radionuclide angiocardiography (ERA) were performed. With the patient breathing room air spontaneously, 45 minutes after ventilatory support with NIPPV and also 45 minutes after ventilatory support with EHFO-NB. Measurements of radionuclide activity (counts) and derived parameter of left systolic and ventricular functions were determined following a previously reported protocol. RESULTS: During ventilatory support with NIPPV a significant increase in the time elapsed since the end of the diastole to the peak systolic ejection was observed. During ventilatory support with EHFO-NB a significant decrease in cardiac radioactivity (counts) in tele-systole was observed together with an increase in the ejection velocity measured in the first third of the systolic phase. These findings occurred both with respect to the basal situation and to the ventilatory phase with NIPPV: CONCLUSIONS: Under the study conditions, none of the non-invasive ventilatory support methods compromised hemodynamic parameters in patients studied. Ventilation with EHFO-NB improved the left ventricular function.

Aged↗
PubMed2000

Contrast echocardiography is superior to tissue harmonics for assessment of left ventricular function in mechanically ventilated patients.

BACKGROUND: Assessment of left ventricular function by echocardiography is frequently challenging in mechanically ventilated patients. We evaluated the potential value of contrast-enhanced imaging and tissue harmonic imaging over standard fundamental imaging for endocardial border detection (EBD) in these patients. METHODS AND RESULTS: Fifty patients underwent standard transthoracic 2D echocardiography and were imaged in fundamental and tissue harmonic modes and subsequently with intravenous contrast (Optison). Two echocardiographers reviewed all studies for ease of visualization of endocardial border segments and scoring of wall motion. EBD for each wall segment was graded from 1 to 4 (1 = excellent EBD). Wall motion was scored by a standard 16-segment model and 1 to 5 scale. Studies were categorized as nondiagnostic if 4 of 6 segments in the apical 4-chamber view were either poorly seen or not seen (EBD score 3 or 4). Quantification of ejection fraction was independently performed offline. Visualization of 68% of all segments improved with contrast echocardiography versus 17% improvement with tissue harmonics compared with fundamental mode. Significant improvement (poor/not seen to good/excellent) occurred in 60% of segments with contrast echocardiography versus 18% with tissue harmonics. A total of 850 segments were deemed poor/not seen, 78% of which improved to good/excellent with contrast echocardiography versus 23% with tissue harmonics. Interobserver agreement on EBD was 64% to 70%. Conversion of nondiagnostic to diagnostic studies occurred in 85% of patients with contrast echocardiography versus 15% of patients with tissue harmonics. Scoring of wall motion with fundamental mode, tissue harmonics, and contrast echocardiography was possible in 61%, 74%, and 95% of individual segments, respectively (P <.001). Wall motion scoring was altered in 17% of segments with contrast echocardiography and in 8% with tissue harmonics. Interobserver agreement on wall motion scoring was 84% to 88%. Contrast echocardiography permitted measurement of ejection fraction 45% (P =.003) more often over fundamental mode versus a 27% (P =.09) increase with tissue harmonics. CONCLUSIONS: Contrast echocardiography is superior to tissue harmonic imaging for EBD, wall motion scoring, and quantification of ejection fraction in mechanically ventilated patients.

Adult↗
PubMed1990

Development of collateral circulation after acute myocardial infarction: its role in preserving left ventricular function.

The present study evaluated the effects of coronary collateral circulation developing after acute myocardial infarction on global and regional left ventricular function during the chronic stage. The study group consisted of 16 patients with initial myocardial infarction having total occlusion of the proximal left anterior descending coronary artery. To eliminate the effects of collateral circulation existing at the onset of infarction, patients with pre-infarction angina were excluded from this study. The patients were categorized in two groups depending on the extent of their collateral circulation (collateral index: CI 0-3): group A--patients with significant collateral circulation (CI = 2 or 3) to the infarct-related coronary artery; group B--patients without significant collateral circulation (CI = 0 or 1). Their heart rate, left ventricular peak systolic and end-diastolic pressures and cardiac index were similar in the two groups. The left ventricular end-systolic volume index in the group B was significantly greater than that in the group A (60 +/- 21 ml/m2 vs 34 +/- 9 ml/m2, p less than 0.05). Left ventricular ejection fraction in the group A was significantly greater than that of the group B (55 +/- 9% vs 39 +/- 15%, p less than 0.05), and a significant difference was observed in the percentage of segment shortening in the infarct area between the groups A and B (10.8 +/- 9.2% vs -0.2 +/- 5.4%, p less than 0.01). It was concluded that coronary collateral circulation which develops after acute myocardial infarction exerts beneficial effects on global and regional left ventricular function during the chronic stage.

Adult↗
PubMed1992

Left ventricular function and the relationship between left atrial pressure and peak early diastolic filling velocity in dog.

OBJECTIVE: The aim was to clarify the roles of left atrial pressure and ventricular function in the determination of early diastolic filling. METHODS: Various grades of ventricular dysfunction were made in 12 mongrel dogs by coronary microembolization under pentobarbitone anaesthesia. Left atrial pressure was altered by volume loading. Peak early diastolic filling velocity was measured using pulsed Doppler echocardiography. Ventricular fractional shortening was measured using M mode echocardiography. RESULTS: Peak early filling velocity increased as left atrial pressure increased. There was a direct relationship between mean left atrial pressure and the velocity before and after induction of ventricular dysfunction. The slope of the regression line between mean left atrial pressure and peak early filling velocity decreased as the grade of the dysfunction increased. There was a significant correlation between the slope of the regression line and mean left ventricular fractional shortening (r = 0.65, n = 31, p less than 0.01). CONCLUSIONS: Early diastolic filling was affected by both left atrial pressure and left ventricular function. These facts are useful in interpreting the various transmitral flow patterns observed clinically.

Animals↗
PubMed1994

Cilazapril treatment depresses ventricular function in spontaneously hypertensive rats.

The purpose of this study was to characterize the effect of chronic treatment with an angiotensin-converting enzyme (ACE) inhibitor on left ventricular function in spontaneously hypertensive rats (SHR). Cilazapril (5 mg/kg) was administered in the drinking water continuously for 11 wk, beginning at 4 wk of age. Systolic arterial pressure (SAP) was monitored weekly. At the end of the 11-wk period, left ventricular function was quantified using the perfused working heart preparation. Cilazapril exerted a rapid, complete, and persistent antihypertensive effect in the SHR in vivo but had no effect on SAP in the normotensive Sprague-Dawley (S-D) group. Nevertheless, the drug reduced left ventricular weight to the same extent in both strains. Function of untreated SHR hearts was not different from that of the untreated S-D hearts. Cilazapril treatment depressed heart performance (28-35%) in SHR but had no effect in the S-D group. The decline in pump performance in SHR hearts was associated with diminished tension development and velocity of shortening of papillary muscles. These results demonstrate that an ACE inhibitor, administered to young SHR, produces a reduction in left ventricular contractile function, which may be due to a decline in muscle contractility and which cannot be explained exclusively by the reduction in left ventricular mass.

Aging↗
PubMed1999

Use of an intraaortic balloon pump in patients with impaired left ventricular function.

Prophylactic use of an intraaortic balloon pump (IABP) prior to open-heart surgery in patients with impaired left ventricular function is still under debate. Patients with left ventricular ejection fraction (LVEF) < 40% were therefore compared according to time of IABP placement, viz. preoperative (n = 56), intraoperative (n = 40) or postoperative (n = 17), and also with patients who did not receive mechanical support despite LVEF < 40% (n = 78). The main indication for preoperative IABP insertion was severely impaired left ventricular function (80%), while patients with intraoperative or postoperative IABP placement mainly presented with low cardiac-output syndrome (70%/53%). Preoperative IABP was associated with a low mortality rate (8.9%), whereas patients with intraoperative or postoperative IABP placement had a high mortality risk and an increased catecholamine requirement. Of the patients scheduled for surgery without prophylactic IABP, 19% required intra- or postoperative insertion. Prophylactic placement of IABP thus reduced the mortality rate as well as the postoperative need for mechanical and catecholamine support. Need for intraoperative IABP insertion was associated with high mortality, whereas the outcome after postoperative IABP placement depended on the indication for the measure.

Aged↗
PubMed1999

[Left ventricular function evaluation after mitral valve replacement with preservation the subvalvular apparatus].

The objective of this study was to evaluate the left ventricular function after mitral valve replacement (MVR) with preservation of all chordae. Fourteen patients with a diagnosis of mitral regurgitation were studied. These patients, 4 males and 10 females, age from 24 to 59 years, who underwent mitral valve replacement, in which all chordae tendineae were preserved. The mean follow-up interval was 6 months. Preoperation and postoperation multigated equilibrium radionuclide angiography was performed by Elscint Helix Apex SPECT. Each patient was injected with 740MBq 99mTc-HSA, rest ejection fraction (global EF) of LV (%), regional ejection fraction (EF) of LV (%), PER/S and PFR/S were measured. Regional EF was calculated by the method of dividing the left ventricle into five segments by radial axis. The results showed that the postoperative EF of the whole left ventricle of the chordae-preserved patients was significantly greater than their preoperative EF (40.0% +/- 17.8%, to 51.6% +/- 18.2%, P < 0.02), and also the regional EF at the lateral wall of the chordae-preserved MVR was significantly greater than the preoperative regional EF (an increase from 51.0% +/- 18.1% to 69.7% +/- 21.2%, P < 0.01). MVR with preservation of all chordae, the patient's left ventricular function remarkably improved.

Adult↗
PubMed1994

Recombinant human superoxide dismutase (h-SOD) fails to improve recovery of ventricular function in patients undergoing coronary angioplasty for acute myocardial infarction.

BACKGROUND: Animal studies have demonstrated a burst of oxygen free radical generation after reperfusion of ischemic myocardium that could be blocked by administration of the free radical scavenger recombinant human superoxide dismutase (h-SOD). A multicenter, randomized, placebo-controlled clinical trial was designed to test the hypothesis that free radical-mediated reperfusion injury could be reduced by intravenous administration of h-SOD begun before percutaneous transluminal coronary angioplasty (PTCA) in patients with acute transmural myocardial infarction. METHODS AND RESULTS: One hundred twenty patients were randomized to receive placebo (n = 59) or h-SOD (n = 61) given as a 10-mg/kg intravenous bolus followed by a 60-minute infusion of 0.2 mg.kg-1.min-1. Left ventricular function was analyzed via paired contrast left ventriculograms performed before PTCA and after 6 to 10 days and paired radionuclide ventriculograms performed within 24 hours of PTCA and after 4 to 6 weeks. Both h-SOD- and placebo-treated patients showed improvement in global and regional left ventricular function after successful reperfusion. Compared with the placebo group, no additional improvement was observed in the patients treated with h-SOD. CONCLUSIONS: The results of this clinical trial failed to demonstrate a beneficial effect of h-SOD on global or regional left ventricular function in patients who underwent successful PTCA for treatment of acute myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed1986

Relation between the phosphocreatine to ATP ratio determined by 31P nuclear magnetic resonance spectroscopy and left ventricular function in underperfused guinea-pig heart.

The relation between the PC/ATP ratio and left ventricular function was examined in the Langendorff-perfused guinea-pig heart over a range of perfusion flow rates. PC/ATP ratios were determined from the 31P-nuclear magnetic resonance spectra of hearts obtained at 80.98 MHz and ventricular function estimated by measuring pressure in the left ventricle. When flow rates were increased over the range 0.6 to 6.0 ml/min, the PC/ATP ratio increased from 0.64 +/- 0.05 at 0.6 ml/min to 1.82 +/- 0.12 at 3.8 ml/min with no further increase up to a flow rate of 6.0 ml/min. Developed pressure (DP) increased with the flow rate up to 6.0 ml/min but the end diastolic pressure (EDP) also increased. The DP/EDP ratio was found to correlate closely with the PC/ATP ratio over the range of flow rates examined. The PC/ATP ratio may be a practical index of myocardial function available to the clinician when the topical magnetic resonance technique is fully developed.

Adenosine Triphosphate↗
PubMed1988

Spontaneous recovery of left ventricular function following acute anterior myocardial infarction.

Four patients with acute anterior wall myocardial infarction showing spontaneous and marked improvement in systolic left ventricular function are described. All 4 patients showed abnormal Q waves and severe wall motion abnormalities soon after acute infarction. In all 4 patients, at least some regeneration of R-wave forces occurred and the regional wall motion in the involved area of the left ventricle improved dramatically without coronary angioplasty or surgical revascularization during the intervening period. The improvement in left ventricular function was attributed to spontaneous increase in nutrient flow to the involved area. It is concluded that Q waves and severe wall motion abnormalities do not necessarily indicate irreversible scar formation.

Electrocardiography↗
PubMed2005

[Left ventricular function in congenital hypothyroidism neonates before and after thyroxine substitution therapy].

OBJECTIVE: To evaluate left the systolic and diastolic functions in neonates with congenital hypothyroidism (CH) as well as the effect of thyroxine substitution therapy on left ventricular function and its correlation with thyroid hormones serum levels. METHODS: M-mode echocardiography was used to examine the left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS), pulse wave Doppler was used to examine the peak early diastolic mitral inflow velocity (E(m)) and peak late diastolic mitral inflow velocity (A(m)), quantitative tissue velocity imaging (QTVI) was used to examine the systolic peak mitral annular velocity (s(m)), early diastolic peak mitral annular velocity (E(m)), and the late diastolic peak mitral annular velocity (a(m)), and tissue tracking imaging (TTI) was used to detect the systolic mitral annular displacement (MAD) in 40 neonates with congenital hypothyroidism aged 15-28 days before and after 1-month levothyroxine substitution treatment. Thirty normal neonates were used as controls. Chemiluminescent immunoassay was used to measure the TT(3), TT(4) and TSH levels. Correlation analysis was also made between the ventricular function parameters and the serum TT(3), TT(4), and TSH levels. RESULTS: The left systolic function parameters (LVEF, s(m), MAD, E(m) and e(m)) was 0.61 +/- 0.08, 2.60 cm/s +/- 0.60 cm/s, 0.29 cm +/- 0.06 cm, 0.59 m/s +/- 0.12 m/s and 2.72 cm/s +/- 1.43 cm/s respectively, in CH group, and 0.67 +/- 0.06, 3.25 cm/s +/- 0.51 cm/s, 0.41 cm +/- 0.08 cm, 0.72 m/s +/- 0.11 m/s and 4.51 cm/s +/- 1.23 cm/s in control group (P < 0.01). Left function in CH neonates before treatment were all lower than those of the controls (P < 0.01), which significantly increase after 1-months L-T(4) substitution therapy, 0.69 +/- 0.05, 3.46 cm/s +/- 0.64 cm/s, 0.45 cm +/- 0.08 cm, 0.82 m/s +/- 0.17 m/s and 5.09 cm/s +/- 1.37 cm/s, (P < 0.01). Those parameters were positively correlated with TT(4) serum levels (P < 0.01), and were negatively correlated with TSH (all P < 0.01). In particular, MAD, sm, E(m), and em were highly correlated with serum TT(4) and TSH (r = 0.667, 0.538, 0.478, and 0.599 respectively, all P < 0.001;and r = -0.670, -0.521, -0.490, and -0.583 respectively, all P < 0.001). CONCLUSION: Neonates with CH have lower left systolic and diastolic functions. Early L-T(4) substitution therapy can reverse these changes.

Congenital Hypothyroidism↗
PubMedDate not supplied

Effect of changes in load carriage while walking on the left ventricular function in highly trained elderly subjects.

BACKGROUND: In previous studies, the effect of isometric stress on the dynamic performance of a graded exercise test in normal subjects augmented afterload and brought about changes in left ventricular function more often than did results from physical exercise. OBJECTIVE: This study used the metabolic charts and echocardiography to examine the influence of two different types of load carriage during 30 min of treadmill walking on left ventricular function, hemodynamics, and cardiovascular responses. METHODS: Fifteen elderly (age 66.1 +/- 3.5 years) aerobically well-trained male subjects (VO(2 peak) 44.2 +/- 5.0 ml x kg(-1) x min(-1)) volunteered in this study. The subjects walked on a treadmill (at a speed of 4.5 km x h(-1)), carrying a load of 20 kg during one session and a load of 30 kg during a second session. RESULTS: Following the 30-min exercise in each session, significant (p < 0.05) differences were noted between the 20-kg and the 30-kg work loads with regard to cardiac output (6.8 +/- 0.5 and 7.8 +/- 0.4 l.min(-1)), heart rate (114.0 +/- 11.0 and 126.0 +/- 10.0 beats.min(-1)), diastolic blood pressure (79.4 +/- 5.0 and 84.3 +/- 5.0 mm Hg, mean arterial blood pressure (104.0 +/- 4.0 and 109.2 +/- 3.0 mm Hg), and left ventricular contractility ratio (3.3 +/- 0.4 and 3.6 +/- 0.3). No significant differences were noted between the work loads with regard to systolic blood pressure, cardiac output, left ventricular volumes, and ejection fraction. CONCLUSIONS: This study suggests that in the highly trained elderly, the influence of the autoregulation mechanism dominates during combined dynamic and isometric exercises, thus the opposing force to the left ventricular ejection is reduced which in turn does not change left ventricular global function.

Aged↗