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Biomedical subjects

M Turina

Publications and source records attributed to M Turina.

At least 433 records · Page 24Linked to original sources
PubMed1984

Diastolic function in aortic valve disease: techniques of evaluation and pre-/postoperative changes.

Passive diastolic properties of the left ventricle are determined by several factors intrinsic or extrinsic to the ventricle. In patients with myocardial hypertrophy due to longstanding pressure or volume overload increased muscle mass and structural alterations of the myocardium are responsible for changes in passive elastic properties. Evaluation of diastolic function includes determination of ventricular (= chamber) and myocardial (= muscle) stiffness from simultaneous pressure-volume and stress-strain relations during passive diastolic filling. The slope of the pressure-volume relationship is equal to the constant of chamber stiffness and the slope of the stress-strain relationship equal to the constant of myocardial stiffness. Passive diastolic properties were determined in ten control patients and 21 patients with aortic valve disease before and 17.5 months after successful valve replacement. Ten patients presented with severe aortic stenosis, five patients with combined valve lesions and six patients with severe aortic insufficiency. Simultaneous high-fidelity pressure measurements and M-mode echocardiography were carried out in all patients. Myocardial stiffness was calculated from a viscoelastic stress-strain relationship using a nonlinear curve-fit program. Standard hemodynamic measurements showed a significant decrease in pressure and volume overload after successful valve replacement. Left ventricular muscle mass index decreased in all three groups significantly after surgery, whereas systolic ejection fraction remained unchanged pre-/postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Stenosis, Subvalvular↗
PubMed1984

[Nisoldipine, a new calcium antagonist: its effect on systolic function and relaxation in the dog].

The effect of calcium-blockers on left ventricular (LV) relaxation is still a matter of debate. In 7 open-chest dogs we studied the effect of 0.01 mg/kg Nisoldipine intravenously on LV systolic function and relaxation. LV long and short axes and LV wall thickness were measured by ultrasonic crystals. LV high-fidelity pressure and aortic pressure were recorded at rest, and 2 and 30 min after i.v. Nisoldipine. Partial obstruction of the ascending aorta was performed to keep LV peak systolic pressure close to control values. LV systolic wall stress and LV ejection fraction were calculated in all dogs. The time constant of LV pressure decay (T; ms) was determined from a linear regression of LV pressure and neg. dP/dt. Heart rate and LV end-diastolic pressure remained unchanged following the administration of Nisoldipine. LV peak systolic pressure and wall stress decreased significantly 2 and 30 min after Nisoldipine but were in the normal range with partial obstruction of the ascending aorta. Max. dP/dt decreased slightly although not significantly after Nisoldipine. LV ejection fraction increased, however, significantly from 30% to 39% at 2 min and to 35% at 30 min after Nisoldipine. The time constant T increased from 27 ms to 40 ms (P less than 0.05) at 2 min and amounted to 28 ms at 30 min following Nisoldipine. It is concluded that Nisoldipine is associated with a persistent decrease of LV afterload and a transitory increase in T.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Improved late survival in patients with chronic aortic regurgitation by earlier operation.

Between 1970 and 1979, 156 patients with severe chronic aortic regurgitation underwent aortic valve replacement. Early mortality was 2.5%; 5 and 10 year survival rates were 85.9% and 69.2%, respectively. Early mortality decreased from 3.5% (2/56) in the period from 1970 to 1974 to 2.0% (2/100) in the period from 1975 to 1979; first-year survival rate was similar in the two periods (94.2% and 94.7%); 5 year survival rate increased from 80.1% in the period from 1970 to 1974 to 90.6% in the period from 1975 to 1979. The frequency of late death from heart failure decreased from 5/13 in the period from 1970 to 1974 to 0/9 in the period from 1975 to 1979. Preoperative NYHA class decreased from 2.7 (10 patients in class IV, none in class I) during 1970 to 1974 to 2.1 (one patient in class IV, 15 in class I) during 1975 to 1979 (p less than .001). From 1970 to 1974 preoperative cardiothoracic ratio (0.60 vs 0.57; p less than .001) and left ventricular end-diastolic pressure (33 vs 19 mm Hg; p less than .001) were higher and left ventricular ejection fraction (50% vs 54%; p less than .05) was lower than values during 1975 to 1979. The patients who died of heart failure were in a higher NYHA class before surgery, cardiothoracic ratio and left ventricular end-diastolic pressure were higher, and left ventricular ejection fraction was lower than those in patients who died suddenly. In all patients of both groups left ventricular end-diastolic volume exceeded 200 ml/m2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

[Diagnosis, etiology and clinical course of acute and chronic pericarditis].

Between 1976 and 1982 18 patients with acute and 13 with chronic pericarditis (excluding constrictive pericarditis) were seen at the Medical Outpatient Clinic, University Hospital, Zürich. The prominent symptom in acute pericarditis was chest pain (15/18 patients versus 0/13 in chronic pericarditis, p less than 0.001) and in chronic pericarditis dyspnea (7/13 patients versus 1/18 in acute pericarditis, p less than 0.005). Pericardial friction rub and ST elevation were significantly more frequent in acute than in chronic pericarditis. In contrast, elevation of venous pressure occurred more often in the chronic than in the acute form. During the follow-up of 3.2 years the NYHA class decreased from 2.5 to 1.2 (p less than 0.001) in the group with acute pericarditis although 7 recurrences occurred in 3 patients within the first two years. The follow-up in the patients with chronic pericarditis was 4.4 years and the NYHA class decreased from 2.4 to 1.4 (p less than 0.05). There were, however, two deaths in the group with chronic pericarditis and pericardiocentesis and/or pericardiectomy had to be performed in 8/13 patients.

Adult↗
PubMed1983

[Progression of coronary stenosis following aorto-coronary bypass surgery].

In a prospective study (238 men, mean age 53 years) the changes in native vessels were studied 3 months after aorto-coronary bypass operation and 5 months after preoperative angiography. Progression was defined as increase in stenoses of at least 20% or new total occlusion. Progression was significantly more frequent in vessels with bypass than without; it was located proximally to the anastomoses in most cases, less frequently at the anastomoses and very rarely distally to the anastomoses. Proximal progression was significantly more frequent with open bypasses than with occluded ones. Stenoses at the anastomoses were significantly more frequent with occluded bypasses than with open ones. More severe stenoses had a stronger tendency to progression than less severe stenoses. Regression was rare and nearly always caused by surgery.

Aortic Valve Stenosis↗
PubMed1983

[Abdominal aortic aneurysm in the patient over 70--surgery in any case?].

During 1980 and 1981, 36 patients aged 70 years or older were operated on for abdominal aortic aneurysm. The aneurysm was already ruptured in almost half of the patients. Eight patients died early (22%), of whom 7 were operated on because of perforation. Main cause of early death was cardiac failure (5). During an average observation period of 12 months, 4 patients died late and 4 claimed unsatisfactory recovery. All patients over 70 years of age with abdominal aortic aneurysm should be investigated with respect to operability. The risk in elective surgery is low and the postoperative prognosis for these patients is good. Surgery for ruptured aneurysm still carries high operative mortality in this age group and a poor longterm prognosis.

Aged↗
PubMed1983

[Changes in the unmodified vessels after aortocoronary bypass surgery].

In a prospective study (238 men, mean age 53 years) the changes of the native vessels were studied 3 months after a-c-bypass operation and 5 months after preop. angiography. Progression was defined as increase of stenoses of at least 20% or new total occlusion. Progression was significantly more frequent in vessels with than without bypass and was located proximally to the anastomoses in most cases, less frequently at the anastomoses and very rarely distally to the anastomoses. Proximal progression was significantly more frequent with patent than with occluded bypasses. Stenoses at the anastomoses were significantly more frequent with occluded than with patent bypasses. Stenoses of higher degrees had a stronger tendency for progression than slighter stenoses. Regression was rare and nearly always caused by surgery.

Angina Pectoris↗
PubMed1983

Surgical and mechanical support of the failing heart.

The surgical treatment of acute heart failure is limited to cases of pressure or volume overload. Acute valvular regurgitation due to active endocarditis or to prosthetic dysfunction is a classic example of failure which can be cured by restoring valvular competence. Acute pressure load is mostly caused by prosthetic dysfunction or pulmonary embolism; therapy is aimed at removal of the causative agent. Coronary heart disease can cause heart failure by volume overload: acute mitral incompetence or ventricular septal defect lend themselves to surgical correction. In the surgical treatment of acute heart failure maximal attention is devoted to optimal timing of surgery, anesthetic management and postoperative care. Careful attention to the function of the right and left ventricle and combination of catecholamines, afterload reducing agents and volume loading together with respirator support have considerably improved the surgical results. Acute pump failure due to coronary insufficiency and infarction is less amenable to surgical treatment, with rare exceptions of emergencies during coronary angiography and percutaneous dilatation. The intra-aortic balloon pump is the only method of mechanical circulatory assistance which has reached widespread clinical acceptance. The best results are achieved in conjunction with surgery: either as cardiac support in inherently reversible postoperative heart failure or as the means of circulatory stabilization prior to surgery. Ventricular assist devices are still in the experimental stage: their use has been sharply curtailed by the virtual disappearance of the postoperative low output syndrome. In selected cases of end-stage cardiomyopathy cardiac transplantation is nowadays performed with acceptable survival (70% at one year after surgery). Both orthotopic and heterotopic transplantation (transplanted heart in parallel with the natural one) give comparable results, but the procedure is still very restricted due to the lack of donors, multiple contraindications and lack of suitable heart preservation techniques.

Acute Disease↗
PubMed1983

Physiologic or pathologic hypertrophy.

Physiologic hypertrophy occurs as the result of exercise conditioning and is characterized by normal or supranormal left ventricular (LV) contractile function and reversibility of structural alterations. Whether hypertrophy produced by chronic abnormal loading can be termed 'physiologic' is a matter of debate because in experimental pressure overload hypertrophy normal in vivo ventricular function may be associated with abnormal in vitro function of the papillary muscles. In patients with moderate LV hypertrophy from aortic valve disease (angiographic mass less than 180 g/m2) ejection fraction (EF) is preserved, but at similar levels of afterload, when mass exceeds 180 g/m2, EF is depressed. Comparison of LV function with myocardial structure (endomyocardial biopsies) has shown that in patients with compensated LV function and those with left heart failure (EF less than 57%, LVEDP greater than 20 mm Hg and/or cardiac index less than 2.5 l/min/m2) interstitial fibrosis (IF) was increased to a similar extent (16 and 18%; normal less than 5%), whereas muscle fiber diameter (MFD; normal less than or equal to 20 mu) was larger (P less than 0.05) in the patients with failure (30 mu) than in those with preserved function (27 mu). Moreover patients with depressed postoperative function had a larger (P less than 0.01) preoperative MFD (35 mu) than those with normal postoperative function (30 mu). Seventeen months after successful aortic valve replacement IF increased (P less than 0.02) and MFD decreased (P less than 0.001) but did not become normal regardless whether postoperative function was normal or depressed. Thus in secondary hypertrophy myocardial structure is pathologic even in the presence of normal LV function and depressed function appears likely to be related to excessive fiber hypertrophy rather than to IF. Massive fiber hypertrophy heralds an unfavorable postoperative LV function and fibrosis is irreversible after surgical correction of the abnormal load.

Animals↗
PubMed1983

Surgical treatment versus medical treatment in hypertrophic obstructive cardiomyopathy.

Sixty-three patients operated upon for HOCM and 49 patients selected for non-surgical treatment have been followed-up for 15 years. Pre-operatively, surgical patients had a higher left ventricular outflow tract gradient at rest and, on the average, more severe symptoms than non-surgical patients. Septal myectomy relieved the pressure gradient and symptoms more consistently than long-term treatment with beta-blockers or verapamil. Within an average observation time of 7 1/2 years, there was late deterioration or death in almost half of the non-surgical patients but in less than one-quarter in the operated patients. The 10 year mortality rate was 80% in the surgical series and 71% in the non-surgical series. In operated patients, pre-operative symptomatic status was significantly related to early and late mortality. In medically treated patients, mortality was unrelated to symptoms; however, it was significantly lower in patients receiving long term treatment with beta-blockers or verapamil. In conclusion, a high basal pressure gradient associated to limiting symptoms is a clear-cut indication for surgery. Other indications are more debatable. In medically treated patients, long-term administration of beta-blockers or verapamil is beneficial even without symptoms as it appears to improve prognosis.

Adolescent↗
PubMed1983

Left ventricular relaxation at rest and during handgrip in aortic valve disease before and after valve replacement.

In 14 patients (pts) with aortic valve disease (AVD) left ventricular (LV) relaxation was assessed by the time constant (T) of LV pressure (tipmanometer) fall before and 19 months after successful aortic valve replacement (AVR). 12 control pts (CO) were studied by the same technique. Preoperative LV ejection fraction in AVD (64%) and in CO (69%) did not differ. In AVD T was increased (60 ms) as compared to the CO (38 ms, P less than 0.05). During handgrip (HG) there was a similar increase of LV peak systolic pressure (LVSP), heart rate and peak measured contractile element velocity of shortening in AVD and in the CO. LV end-diastolic pressure varied minimally in both groups. T decreased during handgrip in CO (38 to 33 ms, P less than 0.01) and remained unchanged in AVD. Following AVR T at rest decreased insignificantly to 52 ms, but remained increased (P less than 0.025) as compared with CO. During postoperative HG however, a decrease to 47 ms (P less than 0.05) was noted. Postoperative angiographic LV muscle mass (105 g/m2) and LVSP at rest (137 mmHg) remained elevated (P less than 0.02) as compared to CO (72 g/m2; 119 mmHg). It is concluded that (1) in AVD with normal ejection performance LV relaxation at rest is prolonged and the reaction of relaxation to HG is abnormal despite preserved contractile response, (2) following AVR the response of LV relaxation to HG becomes normal and (3) elevated postoperative T at rest appears to be related to residual hypertrophy and probably also to the still increased LVSP rather than to intrinsic disturbances of myocardial relaxation.

Adult↗