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PubMedDate not supplied

The influence of pulmonary insufficiency on ventricular function following total correction of Fallot's tetralogy: evaluation using radionuclide ventriculography and clinical findings.

Long-standing pulmonary insufficiency after repair of tetralogy of Fallot may adversely affect ventricular function. We evaluated 20 patients postoperatively by radionuclide ventriculography and clinical findings after total correction of tetralogy of Fallot. Patients were divided into two groups as follows: Group I patients (10) had no pulmonary insufficiency; Group II patients (10) had moderate or severe pulmonary insufficiency. Preoperatively, there was no difference between groups in terms of age, functional capacity according to the New York Heart Association criteria, hemoglobin and hematocrit level, cardiothoracic ratio, McGoon ratio, left and right ventricular ejection fraction, cardiac output or cardiac index. Postoperatively, right ventricular ejection fraction was 40.10 +/- 2.28 in Group I and 29.5 +/- 2.86 in Group II, p < 0.01. Left ventricular ejection fraction was 59.3 +/- 2.90 in Group I and 50.9 +/- 4.19 in Group II, p < 0.01. Radionuclide ventriculography is a useful means of identifying right ventricular dysfunction following repair of tetralogy of Fallot. The dysfunction appears significantly worse in patients with pulmonary insufficiency.

Child↗
PubMed2006

Volumetric analysis of regional left ventricular function with real-time three-dimensional echocardiography: validation by magnetic resonance and clinical utility testing.

BACKGROUND: Quantitative information on regional left ventricular volumes from real-time three-dimensional echocardiographic (RT3DE) images has significant clinical potential but needs validation. AIM: To validate these measurements against cardiac magnetic resonance (CMR) and test the feasibility of automated detection of regional wall motion (RWM) abnormalities from RT3DE data. METHODS: RT3DE (Philips) and CMR (Siemens) images were obtained from 31 patients and analysed by using prototype software to semiautomatically calculate indices of regional left ventricular function, which were compared between RT3DE and CMR (linear regression, Bland-Altman). Additionally, CMR images were reviewed by an expert, whose RWM grades were used as a reference for automated classification of segments as normal or abnormal from RT3DE and from CMR images. For each modality, normal regional ejection fraction (REF) values were obtained from 15 patients with normal wall motion. In the remaining 16 patients, REFs were compared with thresholds that were derived from patients with normal wall motion and optimised using receiver operating characteristic analysis. RESULTS: RT3DE measurements resulted in good agreement with CMR. Regional indices calculated in patients with normal wall motion varied between segments, but overall were similar between modalities. In patients with abnormal wall motion, RWM was graded as abnormal in 74% segments. CMR and RT3DE thresholds were similar (16-segment average 55 (10)% and 56 (7)%, respectively). Automated interpretation resulted in good agreement with expert interpretation, similar for CMR and RT3DE (sensitivity 0.85, 0.84; specificity 0.81, 0.78; accuracy 0.84, 0.84, respectively). CONCLUSION: Analysis of RT3DE data provides accurate quantification of regional left ventricular function and allows semiautomated detection of RWM abnormalities, which is as accurate as the same algorithm applied to CMR images.

Algorithms↗
PubMed1996

Transesophageal echocardiographic assessment of left ventricular function in brain-dead patients: are marginally acceptable hearts suitable for transplantation?

BACKGROUND: The brain-dead donor supply has become one of the criteria limiting the performance of heart transplantation. Conventional screening criteria are too limiting and exclude suitable heart donors. Echocardiography is now widely available and is a reliable tool to assess left ventricular dysfunction in brain-dead donors. Yet few data are available on the degree of left ventricular dysfunction where a transplantation is possible. METHODS: Fifty-five potential brain-dead heart donors (age 38 +/- 11 years) were prospectively evaluated by transesophageal echocardiography (TEE) before harvesting. Fractional area change (FAC) was used to assess left ventricular function in potential brain-dead donors. Transplanted hearts were evaluated on the fifth postoperative day. The transplantation was considered a success if the recipient was alive, not retransplanted, without an assistance device or an epinephrine infusion of more than 1 mg/h and showed an ejection fraction above 40%. RESULTS: Of the 55 potential heart donors, 20 exhibited an FAC of less than 50%. Forty hearts were harvested, 36 of which were successfully transplanted. Nine patients had an FAC below 50% (group H2) and 27 had an FAC over 50% (group H1). Four patients died: 2 from hemorrhage (FAC > 50% in donors); 1 from right and one from left ventricular dysfunction (FAC < 50% in donors). The FAC increased significantly from 51 +/- 15% to 57 +/- 11% in 18 hearts that underwent TEE in donors and afterwards in recipients. Overall actuarial survival was 86.2% versus 64.6% at 1 and 2 years in group H1 and group H2, respectively (p = NS). CONCLUSIONS: TEE is useful to assess left ventricular function in potential brain-dead donors. An FAC less than 50% is present in 36% of potential heart donors. Because left ventricular dysfunction is often reversible shortly after transplantation, an FAC below 50% may not necessarily preclude the use of hearts for transplantation.

Adolescent↗
PubMed1985

Sensitivity of cross-sectional echocardiography in detection of impaired global and regional left ventricular function: prospective study.

In order to establish the sensitivity and specificity of cross-sectional echocardiography for detection of global and regional left ventricular function a prospective study was performed in 80 patients suspected of having coronary artery disease. Twenty four hours before heart catheterization, cross-sectional echocardiograms were recorded in the apical RAO-equivalent view and high quality echocardiograms were obtained in 71/80 patients (89%). M-mode echocardiograms of the left ventricle could be performed in 56/71 patients (79%). Based on normal values sensitivity and specificity of cross-sectional echocardiography were calculated in comparison to cineventriculography. For fractional shortening (normal value greater than 25%) sensitivity measured 46% and specificity 93%, and when the E-point septal separation was measured (normal value less than 7 mm), sensitivity increased to 73% and specificity was 84%. For detection of increased end-diastolic volume (less than 155 ml) sensitivity reached 84% and specificity 98% and for increased end-systolic (less than 70 ml) volume it was 86 and 97%, respectively. A depressed left ventricular ejection fraction (greater than 49%) was found with a sensitivity of 93% and specificity of 100%. Regional left ventricular wall motion, analyzed by an area method, revealed for anterior wall motion a sensitivity of 68% and a specificity of 94%, whereas for posterior wall motion sensitivity reached 80% and specificity 96%. Regression equation between the number of pathological segments and left ventricular ejection fraction for cineventriculography was given by Y = -4.06 X + 73.4, r = 0.93 and for cross-sectional echocardiography by Y = -3.69 X + 62.6, r = 0.85. We conclude that cross-sectional echocardiography can be used as a screening method to detect impaired left ventricular function. It is superior to M-mode echocardiography. Reduced regional function of the posterior wall can be found with high sensitivity, but depressed motion of the anterior wall may be overlooked.

Adult↗
PubMed1993

Turbulence intensity in aortic stenosis: frequency characteristics and effects of alterations in left ventricular function.

Turbulent blood flow can occur downstream from a stenosis. The purpose of this study was to quantitate turbulence intensity and its frequency characteristics in the ascending aorta in adult patients with and without valvular stenosis, and to use extrasystoles to analyze the effects of changes in left ventricular function on turbulence. Turbulence intensity was determined from the digitized, high frequency oscillations seen in high fidelity pressure recordings of 25 patients with valvular aortic stenosis. The intensity of turbulence was quantitated as the root-mean-square (mmHg) of pressure fluctuations and as the total spectral power (mmHg2/beat) of the frequency spectrum between 25 Hz and 400 Hz. Frequency characteristics were summarized by the mean and median frequency of spectral power and partitioning the spectrum into 25 Hz segments. Ten adult patients without aortic valve or outflow tract abnormalities served as controls. Adult patients with aortic stenosis had significantly more turbulence in the ascending aorta than controls (total spectral power 1577 +/- 450 mmHg2 vs. 198 +/- 22 mmHg2, p < 0.01). Furthermore, the frequency distribution in aortic stenosis was biased towards higher frequencies (mean frequency 35 +/- 14 Hz vs 54 +/- 2 Hz, p < 0.001). Turbulence intensity in aortic stenosis demonstrated beat to beat modulation by left ventricular function. The total spectral power of a sinus beat was 1888 +/- 762 mmHg2, and fell to 137 +/- 63 mmHg2 in a weak premature beat, and rose to 3618 +/- 1178 mmHg2 in a potentiated post- extrasystolic beat (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Diltiazem treatment for the management of ischaemia in patients with poor left ventricular function: safety of long term administration.

The tendency of oral diltiazem (a calcium entry blocking agent and a negative inotrope) to induce or exacerbate congestive heart failure when used for the long term management of myocardial ischaemia in patients with poor left ventricular function has not been investigated before. Twenty two patients (aged 42-73 years) with pretreatment left ventricular ejection fraction ranging from 0.11 to 0.39 were given open label oral diltiazem (120-360 mg/24 h (mean 254 mg)) for two weeks to 16 months (mean 7.5 months, median 6.2 months). There was a weight change of greater than 3 lb (1.35 kg) in nine patients--five gained weight and four lost it. Diltiazem treatment did not alter the mean (SD) cardiothoracic ratio on chest x ray (0.47 (0.06) before vs 0.48 (0.05) after) or the left ventricular ejection fraction at rest (0.28 (0.09) before vs 0.26 (0.08) after). Diltiazem was discontinued in one patient because of symptoms indicative of worsening congestive heart failure. No patient required admission to hospital for treatment of symptoms resulting from further left ventricular decompensation. Diltiazem was discontinued in six other patients for other reasons. Long term administration of oral diltiazem was not regularly associated with a deterioration in clinical, radiographic, or radionuclide ventriculographic estimates of left ventricular function, even in patients with poor baseline left ventricular systolic performance.

Adult↗
PubMed1992

Right ventricular function at rest and during exercise in chronic obstructive pulmonary disease.

Right ventricular ejection fraction (RVEF), a measure of systolic pump performance of the right ventricle, is frequently depressed at rest or during exercise in patients with chronic obstructive pulmonary disease (COPD). The most common cause of reduced RVEF in COPD is augmentation of right ventricular afterload, namely an increase in pulmonary artery pressure and pulmonary vascular resistance. Therapy with agents that decrease the afterload on the right ventricle have the potential to improve the systolic performance of this chamber. Oxygen, vasodilators such as hydralazine and nifedipine, theophylline, and sympathomimetics all may augment RVEF in part by reducing pulmonary vascular resistance and, in some cases, pulmonary artery pressures in patients with COPD and cor pulmonale. However, only oxygen therapy has been shown to improve survival.

Digitalis↗
PubMed1978

Effect of potassium cardioplegia on myocardial ischemia and post arrest ventricular function.

To assess the effects of moderate potassium cardioplegia (37 mEq/l KCl) on the severity of myocardial ischemia during arrest and on post arrest ventricular function, 32 isolated, isovolumic feline hearts were studied before, during and 1 hour after ischemic arrest. Normothermia (37 degrees C) was maintained in the remaining 16 hearts, eight without KCl and eight with KCl. Hypothermia (27 degrees C) was maintained in the remaining 16 hearts, eight with KCl and eight without KCl. Myocardial oxygen (PmO2) and carbon dioxide tensions (PmCO2) were measured by mass spectrometry. Maximum developed intraventricular pressure (max DP) and max dP/dt were used as indices of performance. Compared with normothermic or hypothermic arrest alone, the addition of potassium cardioplegia resulted in a significant reduction in the peak PmCO2 measured during the arrest period. Hypothermia alone resulted in morphologic evidence of improved myocardial preservation and a significant reduction in peak PmCO2 compared with normothermia. Post arrest ventricular function was best with the combination of hypothermic arrest and potassium cardioplegia (max DP = 96 +/- 6% of control and max dP/dt = 99 +/- 5% of control). These data suggest that the beneficial effects of postassium cardioplegia and 27 degrees hypothermia are additive, and that reduction in myocardial ischemia as evidenced by a reduction in peak PmCO2 correlated with improvement in ventricular performance in the post arrest period and with preservation of myocardial structure.

Animals↗
PubMed1980

Left ventricular function in Friedreich's ataxia. An echocardiographic study.

Left ventricular function was assessed in seven patients with Friedreich's ataxia using computer-assisted analysis of the left ventricular echocardiograms and compared with those of 45 normal children matched for age and sex. The left ventricle in Friedreich's ataxia was symmetrically hypertrophied, cavity dimension was normal or small, and septal motion and peak velocity of circumferential shortening were normal in all patients. In diastole the duration of rapid filling was normal, peak rate of increase in left ventricular dimension was reduced in two patients, mitral valve opening was delayed with respect to minimum cavity dimension in seven, and there were significantly greater than normal increases in left ventricular dimension during the isovolumic period to mitral valve opening in seven, indicating abnormal and incoordinate relaxation. Peak rates of posterior wall systolic thickening and diastolic thinning were reduced in four and six patients, respectively, whereas peak rates of septal systolic thickening and diastolic thinning were reduced in one and four, respectively, suggesting a disproportionately greater impairment of the posterior wall than of septal function. The absence of asymmetric septal hypertrophy and mid-systolic closure of the aortic valve, the presence of normal septal motion, and the greater reduction in posterior wall than in septal dynamics are inconsistent with previous ideas that the heart disease of Friedreich's ataxia is identical to hypertrophic cardiomyopathy. Computer-assisted analysis of echocardiograms permits recognition of heart disease in Friedreich's ataxia before the onset of cardiac symptoms or development of clinical signs of heart disease.

Adolescent↗
PubMed2002

Precardiopulmonary bypass right ventricular function is associated with poor outcome after coronary artery bypass grafting in patients with severe left ventricular systolic dysfunction.

UNLABELLED: Patients with severe left ventricular systolic dysfunction (LVSD) undergoing coronary artery bypass grafting (CABG) have an increased risk for morbidity and mortality. The purpose of this study was to assess the association of pre-CABG right ventricular (RV) function with outcome for patients with severe LVSD. We performed a retrospective evaluation of 41 patients with severe LVSD (left ventricular ejection fraction [LVEF] < or =25%) scheduled for nonemergent CABG. Data were obtained from review of medical records, transesophageal echocardiography tapes, and phone interview. The pre- and post-cardiopulmonary bypass (CPB) LVEF and the RV fractional area of contraction (RVFAC) were calculated by using intraoperative transesophageal echocardiography. Group 1 patients had an RVFAC < or =35% (n = 7), whereas Group 2 patients had RVFAC >35% (n = 34). The durations of mechanical ventilation and of intensive care unit and hospital stays are presented as the median. Pre-CABG LVEF was similar between Groups 1 and 2 (15.8% +/- 3.3% versus 17.8% +/- 3.9%). Compared with Group 2, Group 1 patients required greater duration of mechanical ventilation (12 days versus 1 day; P < 0.01), longer intensive care unit (14 versus 2 days; P < 0.01) and hospital (14 versus 7 days; P = 0.02) stays, had a more frequent incidence and severity of LV diastolic dysfunction, and had a smaller change in LVEF immediately after CPB (4.1% +/- 8.3% versus 12.5% +/- 9.2%; P = 0.03). All Group 1 patients died of cardiac causes within 2 yr of surgery; five died during the same hospital admission. Three Group 2 patients died: one of colon cancer at 18 mo after CABG and two of cardiac causes 24 and 48 mo after surgery. A fourth patient was awaiting cardiac transplantation 4 yr after surgery. The remaining Group 2 patients were New York Heart Association Classification I or II. For patients with severe LVSD undergoing CABG, pre-CPB RV dysfunction was associated with poor outcome. Patients with RVFAC >35% had a relatively uneventful perioperative course and good long-term survival, whereas patients with RVFAC < or =35% had a poor early and late outcome. Assessment of RV function is useful to further assess the risk of CABG. IMPLICATIONS: Right ventricular function before cardiopulmonary bypass is associated with poor outcome after coronary artery surgery in patients with poor left ventricular function.

Aged↗
PubMed1998

Left ventricular function and exercise tolerance in patients with type II diabetes mellitus.

BACKGROUND: Left ventricular (LV) preload changes may alter exercise tolerance (ET), probably lessening activation of the Maestrini-Starling mechanism. Reduced LV filling (pre-load) during the diastolic phase, usually impaired in diabetic patients, could affect ventricular function. HYPOTHESIS: To evaluate the relationship between some echocardiographic LV function indices and ET, 24 patients (age 43-75 years, mean 54 +/- 13 years, Group A) with type II diabetes mellitus (DM), not suffering from other pathologies, and for whom the ergometric stress test (EST) resulted in an early interruption because of muscular fatigue and/or dyspnea, and 14 patients (age 38-70 years, mean 53 +/- 12 years, Group B) with type II DM and maximal ergometric stress test, used as control group, were studied. METHODS: The EST was performed by increasing the load by 25 W every 2 min; its duration was used as an ET index and correlated with clinical parameters of LV function obtained with M-mode, two-dimensional, and Doppler echocardiography. RESULTS: No patients in either Group A or Group B showed a high systolic blood pressure value at rest and/or an LV hypertrophy and/or an alteration of systolic functional indices. In neither group was there significant correlation between ET and duration of DM, basal heart rate, basal and max systolic blood pressure, and EF values. Linear regression analysis showed a significant correlation between Doppler parameters of the diastolic function and ET index in Group A, while there was no significant correlation in Group B. CONCLUSION: From these data we can deduce that in absence of left systolic ventricular dysfunction the impairment of LV relaxation in DM can influence exercise tolerance, probably by limiting activation of the contractile reserve.

Case-Control Studies↗
PubMedDate not supplied

Functional recovery of subepicardial myocardial tissue in transmural myocardial infarction after successful reperfusion: an important contribution to the improvement of regional and global left ventricular function.

BACKGROUND: The transmural extent of myocardial necrosis after an acute coronary artery occlusion can vary considerably. The contribution of residual subepicardial viable myocardium to global left ventricular function is largely unknown. METHODS AND RESULTS: We studied 12 patients with single-vessel disease 1 week after successful reperfusion of a first transmural anterior myocardial infarction (MI). With PET, myocardial blood flow (MBF) and glucose metabolism were measured regionally, and the viability was graded as normal, mismatch, or match with severely (<50% of normal) or intermediately (50% to 80% of normal) impaired MBF. Magnetic resonance tagging was used to regionally quantify fiber strains, wall thickening, and ejection fraction in patients 1 week and 3 months after the MI and in age-matched healthy volunteers. From 1 week to 3 months, subepicardial fiber shortening improved significantly in the match region (MBF <50%, -5.1+/-7.0% to -9.9+/-8. 7%; MBF of 50% to 80%, -7.1+/-7.6% to -14.9+/-7.9%). This was associated with an improvement in regional ejection fraction in the infarcted myocardium (29.6+/-21.8% to 43.5+/-15.5%, P<0.0001) and in normal regions (54.3+/-15.1% to 56.5+/-13.1%, P=0.013), contributing to an increase in global ejection fraction from 44.2+/-22.2% to 49. 3+/-17.9% (P<0.0001). CONCLUSIONS: Functional recovery of viable subepicardial regions is a mechanism of late improvement in regional and global ejection fraction after a so-called transmural MI.

Aged↗
PubMed1999

Expression of ACE mRNA in the human atrial myocardium is not dependent on left ventricular function, ACE inhibitor therapy, or the ACE I/D genotype.

The activity of the cardiac renin-angiotensin system is altered in human heart failure, but the regulatory mechanisms are unknown. We analyzed whether angiotensin-converting enzyme (ACE) mRNA expression in heart failure is altered in the atrial myocardium, and whether a correlation exists between atrial ACE mRNA expression and the parameters of left ventricular function. We also investigated whether the use of ACE inhibitors or the ACE I/D genotype modulates the atrial ACE mRNA content. For this purpose patients who were to undergo routine cardiac surgery were selected in a prospective manner according to left ventricular function and ACE inhibitor therapy. Samples of atrial myocardium were taken, and ACE mRNA expression was determined by internally standardized reverse transcription polymerase chain reaction. Atrial ACE mRNA expression did not differ in patients with left ventricular ejection fraction higher than 55% (2423+/-199 copies/ng RNA) and those with a value less than 45% (2661+/-143 copies/ng RNA, n.s.). ACE mRNA expression also did not differ in patients using ACE inhibitors (2585+/-175 copies/ng RNA) and those not using ACE inhibitors (2476+/-185 copies/ng RNA). Furthermore, atrial ACE mRNA expression was not affected by the ACE genotype (DD 2573+/-203, ID 2472+/-215, II 2563+/-249 copies/ng RNA). We conclude that the regulation of atrial ACE mRNA expression occurs predominantly by local mechanical or para- or autocrine factors.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

Evaluation of left ventricular function and mitral regurgitation during left ventricular-based pacing in patients with heart failure.

BACKGROUND: Beneficial effects of left ventricular (LV)-based pacing on acute hemodynamic parameters were reported in several series, but only a few studies examined the long-term effects of this new pacing procedure. AIMS: To assess long-term effects of permanent LV-based pacing on LV function and mitral regurgitation (MR) in patients with refractory congestive heart failure (CHF). METHODS: A prospective evaluation of LV function and MR was performed in 23 patients with severe but stable CHF and left bundle branch block (mean QRS: 186+/-31 ms) by radionuclide and echocardiographic techniques at baseline and 6 months after implantation of a permanent LV-based (LV alone: 13 patients; biventricular: 10 patients) pacemaker programmed either in a DDD mode (sinus rhythm; n=14) or in a VVIR mode (atrial fibrillation; n=9). RESULTS: Compared to baseline, the 6 months follow-up visit demonstrated a significant increase in radionuclide derived LV ejection fraction from 23.3+/-7 to 26.2+/-7% (P<0.01) and in echocardiographic LV fractional shortening from 13+/-4 to 16+/-6% (P<0.05), without any change in cardiac index, a significant decrease in LV end-diastolic diameter (from 73.2+/-6 to 71.2+/-7 mm; P<0.05), end-systolic diameter (from 63.6+/-6 to 60.2+/-8 mm; P<0.05) and color Doppler MR jet area (from 11.5+/-6 to 6.6+/-4 cm(1); P<0.001). A comparison of patients with LV pacing alone and patients with biventricular pacing showed similar beneficial effects of pacing on MR severity in the two subgroups and a non-significant trend for a better improvement of LV function during biventricular pacing. CONCLUSION: Thus, in patients with severe CHF and left bundle branch block, permanent LV-based pacing may significantly improve LV systolic function and decrease MR.

Adult↗
PubMed2006

Right and left ventricular function after chronic pulmonary artery banding in rats assessed with biventricular pressure-volume loops.

In many patients with congenital heart disease, the right ventricle (RV) is subjected to abnormal loading conditions. To better understand the state of compensated RV hypertrophy, which could eventually progress to decompensation, we studied the effects of RV pressure overload in rats. In the present study, we report the biventricular adaptation to 6 wk of pulmonary artery banding (PAB). PAB resulted in an RV pressure overload to approximately 60% of systemic level and a twofold increase in RV mass (P < 0.01). Systemic hemodynamic parameters were not altered, and overt signs of heart failure were absent. Load-independent measures of ventricular function (end-systolic pressure-volume relation, preload recruitable stroke work relation, maximum first time derivative of pressure divided by end-diastolic volume), assessed by means of pressure-volume (PV) loops, demonstrated a two- to threefold increase in RV contractility under baseline conditions in PAB rats. RV contractility increased in response to dobutamine stimulation (2.5 microg.kg(-1).min(-1)) both in PAB and sham-operated rats in a similar fashion, indicating preserved RV contractile reserve in PAB rats. Left ventricular (LV) contractility at baseline was unaffected in PAB rats, although LV volume in PAB rats was slightly decreased. LV contractility increased in response to dobutamine (2.5 microg.kg(-1).min(-1)), both in PAB and sham rats, whereas the response to a higher dose of dobutamine (5 microg.kg(-1).min(-1)) was blunted in PAB rats. RV pressure overload (6 wk) in rats resulted in a state of compensated RV hypertrophy with preserved RV contractile reserve, whereas LV contractile state at baseline was not affected. Furthermore, this study demonstrates the feasibility of performing biventricular PV-loop measurements in rats.

Animals↗
PubMed1992

[Diagnostic accuracy of coronary artery lesion by 99mTc-MIBI exercise myocardial scintigraphy--containing the utility of simultaneous assessment of left ventricular function].

To determine whether technetium-99m hexakis-2-methoxy isobutyl isonitrile (99mTc-MIBI) myocardial scintigraphy is a superior method in the detection of coronary artery disease, exercise and rest 99mTc-MIBI planar and SPECT scintigraphy were performed on 27 patients with coronary artery disease. When 99mTc-MIBI (555 MBq (15 mCi)) was injected, first-pass radionuclide angiography (FPRNA) was simultaneously performed by a new mobile multicrystal gamma camera (SIM-400), and LV function (LVEF) was evaluated quantitatively. Visual semiquantitative detection of coronary lesions using 99mTc-MIBI images showed superior accuracy to that obtained using 201TlCl images. 99mTc-MIBI SPECT images were particularly useful in diagnosing LCX and RCA lesions. Moreover, the simultaneous assessment of perfusion and left ventricular function by 99mTc-MIBI FPRNA proved to be useful in the diagnosis of multi-vessel disease. In summary, 99mTc-MIBI SPECT scintigraphy with simultaneous assessment of left ventricular function showed better diagnostic accuracy than 201TlCl myocardial scintigraphy.

Aged↗
PubMed2004

Hemodynamic characterization of left ventricular function in experimental coxsackieviral myocarditis: effects of carvedilol and metoprolol.

BACKGROUND: Carvedilol, a vasodilating nonselective beta-adrenoceptor antagonist, but not metoprolol, a selective beta1-adrenoceptor antagonist, has been shown to increase the production of cardiac antiinflammatory cytokines in experimental myocarditis. However, the hemodynamic consequences of these differences had not been investigated until today. Therefore, we determined the effects of carvedilol and metoprolol on left ventricular function in a murine model of coxsackievirus B3 (CVB3)-induced myocarditis. METHODS: BALB/c mice were inoculated with the coxsackie-B3 virus. Four and 10 days after infection, left ventricular function was investigated using a conductance micromanometer system. Additional groups were treated starting 24 h after infection using equipotent doses of carvedilol and metoprolol and studied on day 10. RESULTS: On day 4, infected mice manifested increased afterload-enhanced contractility and abnormal diastolic function. On day 10, contractile function of untreated mice was impaired. Carvedilol significantly improved cardiac index and most systolic indices, whereas metoprolol was substantially less effective. Diastolic dysfunction was not influenced by either of the beta-adrenoceptor antagonists. CONCLUSIONS: These hemodynamic data indicate that not only beta1-adrenoceptor blockade but also pleiotropic effects are involved in the cardioprotective effects of carvedilol on the pathophysiology of acute viral myocarditis.

Animals↗
PubMed1999

Myocardial perfusion and right ventricular function.

OBJECTIVE: Maximal right ventricular (RV) performance is influenced by left heart hemodynamics and hence coronary perfusion. We examined the role of myocardial perfusion of the right ventricle as potential determinant of maximal RV function. MATERIALS AND METHODS: In 6 canine isovolumic right heart preparations, incremental volumes were introduced into a high compliance RV balloon until RV failure occurred. Maximal RV developed pressure (RVDP) and maximal positive RV dP/dt were determined at a constant controlled left ventricular (LV) output of 2 l/min and at controlled mean arterial pressures of 50, 80 and 120 mmHg. Right coronary artery (RCA) flow was measured. RESULTS: Maximal RVDP increased significantly with increasing mean arterial pressures (44.8+/-11.2 vs 57.2+/-15.5 vs 75.4+/-2.5 mmHg for systemic pressures of 50, 80 and 120 mmHg respectively, p < 0. 05). With increasing mean arterial pressures RCA flow increased significantly (33.1+/-11.0 vs 46.1+/-20.4 vs 79.6+/-35.3 ml/min). At the onset of RV failure, RCA blood flow significantly decreased in all preparations compared to the maximal flow in the RCA (1.9+/-1.0 vs 33.1+/-11.0 ml/min at 50 mmHg; 13.6+/-10.2 vs 46.1+/-20.4 ml at 80 mmHg and 18.7+/-8.0 vs 79.6+/-35.3 ml/min at 120 mmHg; p < 0.05). CONCLUSIONS: These results suggest that coronary perfusion is a major determinant of maximal RV function. The coronary artery driving pressure must be sufficient to avoid the onset of RV failure. Maintaining systemic pressure and hence RV myocardial blood flow may thus extend RV function.

Animals↗