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Left ventricular function and regression of left ventricular hypertrophy in essential hypertension.

Although left ventricular hypertrophy (LVH) is an adaptive response to the increased load imposed on the heart in patients with hypertension, it ultimately is itself a major risk factor for cardiovascular disease. The influence of LVH on left ventricular function and on the coronary circulation, and the occurrence of serious ventricular arrhythmias are the major mechanisms of this increased risk. There is no doubt that regression of LVH occurs, but there are clear differences in this respect among antihypertensive drugs: angiotensin-converting enzyme (ACE) inhibitors and calcium antagonists produce the best response. Whether regression of LVH also causes an improvement in left ventricular function is unclear; various studies using the same drugs have yielded contradictory results. Furthermore, it has yet to be determined whether regression of LVH has a positive influence on the long-term prognosis in such patients; the results of the European Multicenter Study OvA will help in shedding more light on this important question.

Antihypertensive Agents

Potentiation of right ventricular function at a reduced workload: a potential pitfall in assessing right ventricular function by exercise radionuclide ventriculography.

Right ventricular ejection fraction (RVEF) determinations at rest (R) and exercise (E) are a means of demonstrating exercise-induced RV dysfunction. Not all patients are able to maintain peak (P) cardiac workloads during a gated RVEF study or, if a first-pass study is performed, for multiple acquisitions. Reductions from P cardiac workloads have been shown to potentiate LV function; however, the effect on RVEF has not been studied. Supine exercise radionuclide ventriculography was performed on 26 patients: nine normal subjects and 17 patients with coronary artery disease (CAD) (greater than 50% stenosis of one or more coronary artery). Gated RVEF's were obtained from sequential left anterior oblique views obtained at R, P, and at a workload reduced approximately 40% from P work levels postpeak (PP). In normals, RVEFs were at R, P, and PP 27, 38 and 44. In CAD patient RVEFs were 31, 35 and 39, at R, P, and PP, respectively. The conclusions are that RVEF improves from rest to PP exercise levels in normal subjects and in CAD patients and from P to PP levels in normal subjects. This improvement must be considered in interpreting exercise RV studies to aid in the detection of patients with CAD.

Adult

Does septal position affect right ventricular function during left ventricular assist in an experimental porcine model?

Right ventricular (RV) failure has been a major problem with patients supported by left ventricular (LV) assist devices (LVADs). To assess the importance of interventricular septal (IVS) position as a mechanism of RV failure, 7 Yorkshire pigs underwent implantation of a Thoratec LVAD. RV function was assessed before and during LVAD operation under differing conditions: (1) with an LV intraventricular latex balloon inflated or deflated to alter IVS position and (2) with and without pulmonary artery (PA) constriction to assess the effect of changes in afterload. RV stroke work, RV dP/dt, and RV end-diastolic length did not change significantly with LVAD operation or with changing afterload conditions. Septal shift was documented as a change in LV shape index (LVSI) calculated using echocardiography. LVSI decreased by 11% when the LVAD was turned on, indicating leftward shifting of the IVS (P = .01). During LVAD support and increased RV afterload, the LVSI decreased by 14.8% (P = .02). RV cardiac output decreased somewhat during LVAD support. However, RV output was worst when the septal position was normalized using the inflated intraventricular balloon during increased RV afterload (P = .05). Unloading by the LVAD of the left ventricle results in a leftward shift of the interventricular septum, which does not appear to adversely affect RV function. However, during conditions of increased RV afterload, septal shifting may be beneficial to RV function.

Animals

Analysis of effect of two concurrent ischaemic zones on left ventricular function.

Left ventricular (LV) function due to two concurrent ischaemic zones (IZs) is investigated using a cardiovascular system model. The model comprises a three-compartment LV, the venous return and the arterial system. Haemodynamic responses of the LV to changes in the IZ size and myocardial contraction timings are explored. Results show that the greater the degree of asynschonisation is between the normal zone and the IZ, and the larger the ischaemic size, the more severe the LV dysfunction. Pre-load augmentation improves LV function. Model-predicted features are consistent with reported observations associated with myocardial ischaemia. The extent of the usefulness and limitations of this model is also discussed.

Computer Simulation

Pindolol and propranolol in patients with angina pectoris and normal or near-normal ventricular function. Lack of influence of intrinsic sympathomimetic activity on global and segmental left ventricular function assessed by radionuclide ventriculography.

To investigate the role of intrinsic sympathomimetic activity on left ventricular (LV) function during antianginal therapy with beta-adrenoreceptor antagonists, 23 patients with chronic, exercise-induced angina pectoris and normal or near normal LV function underwent radionuclide ventriculography at rest and during exercise, during 3 randomly allocated periods: (a) treatment with oral propranolol, a drug without intrinsic sympathomimetic activity, 40 to 80 mg 4 times a day; (2) treatment with pindolol, a drug with marked intrinsic sympathomimetic activity, 5 to 10 mg 2 times a day; and (3) a control period. During the control period, the LV ejection fraction decreased from rest (58.9 +/- 8.2%) to exercise (54.3 +/- 10.7%), and the wall motion score decreased from 0.57 +/- 1.08 at rest to 2.39 +/- 2.10 during exercise, p less than 0.001. After propranolol, the ejection fraction did not change significantly at rest (57.2 +/- 8.1%) but improved during exercise (56.8 +/- 11.8%), compared with control values. After pindolol, the ejection fraction did not change at rest (57.9 +/- 8.6%) but improved during exercise (56.9 +/- 8.1%), compared with control values. Similarly, the wall motion score after administration of both agents did not change significantly at rest, but improved during exercise (p less than 0.001). The number of anginal episodes, nitroglycerin tablets consumed, and magnitude of S-T segment depression decreased significantly with both pindolol and propranolol. With both drugs, a similar improvement in exercise tolerance and a similar decrease in exercise heart rate and blood pressure were obtained. It is concluded that pindolol and propranolol, beta-adrenoreceptor antagonists with and without intrinsic sympathomimetic activity, respectively, have similar effects on global and regional LV function in patients with angina pectoris, at doses producing equal suppression of exercise heart rate and similar antianginal effect.

Adult

Clinical evaluation of left ventricular function in acute myocardial infarction--analysis of factors affecting left ventricular function.

The clinical significance of the possible factors which may affect the cardiac function and prognosis of the patients with acute myocardial infarction were evaluated in 112 patients with this disease. Patients were subdivided into 4 groups according to the levels of pulmonary capillary wedge pressure (PCWP) and left ventricular stroke work index (SWI): Group I (52 patients) PCWP less than 18 mmHg, SWI less than or equal to 30 g.m/m2; Group II (18 patients) PCWP greater than or equal to 18 mmHg, SWI greater than or equal to 30 g.m/m2; Group III (15 patients) PCWP less than 18 mmHg, SWI less than 30 g.m/m2; Group IV (27 patients) PCWP greater than or equal to 18 mmHg, SWI less than 30 g.m/m2. Immediate mortality rate (4 weeks after the onset of myocardial infarction) was 17.0% in all patients and Group IV had the highest mortality rate (48.1%), in contrast to the lowest mortality rate (3.8%) in Group I. The episodes of previous myocardial infarction were noted more frequently in Group IV (74.1%) than in Groups I (7.7%) and II (11.1%) (p less than 0.001). Mean age in Group IV (68.0 +/- 5.2 (SE) years) was also significantly higher than those of the remaining 3 groups (p less than 0.001). In 55 patients without previous myocardial infarction, mean infarct size estimated from total released creatine phosphokinase (CPK) (sigma CPK) in Group IV was largest among the 4 groups, although it was similar to that in Group II: 919.0 +/- 70.0 (SE) IU/ml in Group I, 1470.0 +/- 126.0 in Group II, 958.0 +/- 107.0 in Group III and 1493.0 +/- 145.0 in Group IV. The number of involved coronary arteries differed significantly between Groups I and IV: in Group I involved coronary artery (75% narrowing) was absent or one at most, while in Group IV all 9 patients had at least one coronary lesion and 3 of 9 had triple vessel disease. In this study no significant difference was observed between the incidence of anterior and inferior myocardial infarctions in Groups I, III and IV. Thus, we conclude that age, previous myocardial infarction, infarct size and the number of involved coronary arteries may determine the cardiac function in acute phase of myocardial infarction and hence, immediate mortality of this disease.

Adult

Reliability of bedside evaluation in determining left ventricular function: correlation with left ventricular ejection fraction determined by radionuclide ventriculography.

Ninety-nine patients with chronic coronary artery disease were prospectively evaluated to determine the reliability of historical, physical, electrocardiographic and radiologic data in predicting left ventricular ejection fraction. The left ventricular ejection fraction measured by radionuclide angiography was normal (greater than or equal to 50%) in 44 patients (group 1) and abnormal (less than 50%) in 55 patients; 36 of those 55 patients had an ejection fraction between 30 and 49% (group 2) and the remaining 19 patients had an ejection fraction of less than 30% (group 3). The ejection fraction was correctly predicted in 33 of the 44 patients (75%) in group 1 and in 47 of the 55 patients (85%) with abnormal ejection fraction (groups 2 and 3), but the degree of ventricular dysfunction was correctly predicted in only 19 patients (53%) in group 2 and in only 9 patients (47%) in group 3. Stepwise linear regression analysis was performed. The single most predictive variable was cardiomegaly as seen on chest roentgenography (R2 = 0.52). Four optimal predictive variables--cardiomegaly, myocardial infarction as seen on electrocardiography, dyspnea and rales--could explain only 61% of the observed variables in left ventricular ejection fraction. Thus, radionuclide ventriculography adds significantly to the discriminant power of the clinical, radiographic and electrocardiographic characterization of ventricular function in patients with chronic coronary heart disease.

Adult

Recovery of right ventricular function following repair of acute ventricular septal defect.

Ventricular septal defect is a serious complication of acute myocardial infarction with a high mortality rate. Right ventricular dysfunction, which frequently accompanies septal defect, can be due to several etiologies. We describe two cases of septal defect following infarction, with sequential studies of right and left ventricular function. Right ventricular infarction was found in both patients. Postoperatively, the right ventricular ejection fraction improved significantly. The pathophysiology and expectation for recovery are discussed.

Aged

[Histological and ultrastructural study of the left ventricular myocardium in mitral stenosis. Correlations with angiocardiographic indices of left ventricular function. Eleven cases].

Left ventricular myocardial biopsy was carried out at operation in 11 patients with pure, isolated mitral stenosis after preoperative angiocardiographical assessment of left ventricular function. The biopsy specimens were examined by light and electron microscopy. The diameter of the myocytes was normal (20 +/- 1.6 mu). The changes observed were probably of a degenerative type with anarchy and irregularities in the sarcomeres, modification of the Z bands, as seen in Nemaline myopathies, and changes in the intercalatory discs. Moderate interstitial fibrosis with scanty histiocytes was also observed. A quantitative assessment by two dimensional planimetry showed a significant increase in the interstitial space (37 +/- 5.5%) compared to a control group without fibrosis (22 +/- 1.1%). The angiocardiographical indices of left ventricular function were all decreased. The amplitude of circumferential fibre shortening was reduced: 25 +/- 6% the ejection fraction by 52 +/- 9% and the average speed of circumferential fibre shortening by 1.0 +/- 0.3 circ/s. Only four patients had normal left ventricular function (ejection fraction > 55%). However, it was not possible to establish a significant correlation between the degree of fibrosis and the reduction in left ventricular function. Left ventricular fibrosis may be one of the factors responsible for the reduction of myocardial function, but it does not in itself explain all the changes in left ventricular function observed in mitral stenosis.

Adolescent

Effects of coronary artery bypass grafting on left ventricular function assessed by multiple gated ventricular scintigraphy.

The effect of coronary artery bypass grafting on global left ventricular ejection fraction and regional contraction was studied in 56 consecutive patients with chronic stable angina pectoris by means of multiple gated ventricular scintigraphy at rest and during dynamic supine exercise before and six weeks after myocardial revascularisation. Before operation, exercise induced a significant fall in ejection fraction and regional wall motion score. Six weeks after operation 52 patients were symptomless. Resting ejection fraction and regional wall motion score were unchanged but during exercise ejection fraction increased significantly, and the previous exercise induced regional wall motion abnormalities were abolished. All four patients with persisting angina showed the same pattern as before operation, with a fall in left ventricular ejection fraction and regional wall motion score during exercise. Multiple gated ventricular scintigraphy affords a safe, objective, reproducible, and non-invasive means of assessing serial ventricular function at rest and during exercise in patients with ischaemic heart disease. The technique confirms that coronary bypass surgery abolishes exercise induced abnormalities of left ventricular function, but has no influence on resting function.

Angina Pectoris

Transfer function analysis of the ventricular function: a new method for calculating right ventricular ejection fraction.

The relationship between the ventricular transfer function and ejection fraction has been investigated by the routine procedure of first-pass radionuclide angiocardiography. Ejection fraction has been shown to equal 1-e(-b), where b is the ratio of the R-R interval over the mean transit time difference between ventricular and atrial time-activity curves. To evaluate the effect of region of interest (ROI) on the right ventricular ejection fraction (RVEF), the results of the transfer function analysis (TFA) technique using precise ROI, TFA using rectangular ROI, and the routine method were compared. Regression analyses among RVEFs obtained from the above ROI methods yielded good correlations. Reliable RVEFs have been obtained even in the case of an improper bolus injection. Thus, the TFA technique is a new, simple, and reliable method for calculating RVEF without needing to outline the right ventricle precisely.

Heart

[Right ventricular function in patients with chronic right ventricular infarction].

To assess right ventricular function in patients with chronic right ventricular infarction, Tc-99m angiocardiography was performed in 64 patients one to three months after the onset of myocardial infarction. These patients were categorized into four groups according to their hemodynamic data in the acute stage using the Forrester classification: 39 patients in group I, 15 in group II, eight in group III and two in group IV. Mean right atrial pressure was nearly equal to or greater than diastolic pulmonary arterial pressure in all patients in group III. We calculated right ventricular ejection fraction (RVEF) and the right ventricular end-diastolic volume index (RVEDVI) as the parameter of right ventricular function, and assessed right ventricular wall motion using the right ventricular regional ejection fraction images (RVREFI). 1. RVEF in group III (25 +/- 3%) was significantly lower than those in groups I, II and IV (44 +/- 6%, 45 +/- 7% and 37 +/- 4%, respectively), and RVEF of all patients in group III was less than 30%. 2. RVEDVI in group III (150 +/- 25 ml/m2) was significantly greater than those in groups I, II and IV (74 +/- 20 ml/m2, 59 +/- 14 ml/m2 and 91 +/- 36 ml/m2, respectively). 3. RVREFI in group III decreased at the inferior and/or septal regions of the right ventricle, indicating wall motion abnormalities at the corresponding sites. 4. Six patients in group III were examined by coronary angiography and all had definite lesions in the proximal portion of the right coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Determinants of subsequent late postoperative left ventricular function and reversal of ventricular dilatation after mitral valve replacement for chronic mitral regurgitation.

We studied 16 patients with chronic mitral regurgitation by echocardiography before, and at 3 weeks, at 6-8 months and at 1-9 years after mitral valve replacement (MVR) to investigate serial changes in left ventricular (LV) function and reversal of ventricular dilatation. All patients at an average of 2.6 years after, and 8 patients before MVR were also studied by echocardiography and, except for 3 patients by measuring plasma catecholamines from the right atrium during bicycle exercise. Before operation, all patients were divided into group A (n = 12) with end-systolic dimension (ESD) < 4 cm and systolic blood pressure (SBP)/ESD > 3, and group B (n = 4) with ESD > 4 cm and SBP/ESD < 3. Maximum reduction in end-diastolic dimension (EDD) occurred at 3 weeks in all patients after MVR (from 60.5 +/- 3.7 to 49.0 +/- 4.5 mm, p < 0.05). ESD was reduced significantly (p < 0.5) only in group A. LV function was normal in group A, but it was depressed in group B at early and late periods after MVR. The slopes of the relationship between the mean velocity of circumferential fiber shortening (Vcf) and plasma norepinephrine (NE) during exercise in all patients in group B decreased along with the depression in LV function. After operation, all patients in group A reached New York Heart Association (NYHA) functional class I, while patients in group B were in NYHA class II. It is concluded that the surgical outcome after MVR for chronic MR will be better if preoperative ESD < 4 cm and SBP/ESD > 3. The relationship between mean Vcf and plasma NE during exercise seemed to be a useful index to evaluate the inotropic reserve of the LV.

Echocardiography

[Evaluation of echocardiography for determining left ventricular function].

Left ventricular ejection fraction (LVEF) was calculated by echocardiography and gate blood pool (GBP) in 33 patients including those with coronary heart disease, acute and old myocardiac infarction, cardiomyopathy or mitral prolapse. Fourteen of the 33 had segmental wall motion abnormalities and 19 had non-segmental wall motion abnormalities. The results of comparing echocardiography and GBP showed that the former could substitute for other invasive and expensive examinations to determine LVEF (r = 0.804-0.964 in the 5 echocardiography methods used). Mod-Simpsons method of cross-sectioned echocardiography was the most accurate echocardiographic method (r = 0.964, sensitivity 90.9%) in all patients. The Teich method of M-mode echocardiography was useful in patients who had non-segmental wall motion abnormalities only (r = 0.957, sensitivity 94.7%) but not in patients who had segmental wall motion abnormalities (r = 0.703, sensitivity 42.9%).

Adult