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Biomedical subjects

A Pasternac

Publications and source records attributed to A Pasternac.

At least 37 records · Page 2Linked to original sources
PubMed1982

Pathophysiology of chest pain in patients with cardiomyopathies and normal coronary arteries.

To clarify the pathogenesis of chest pain in patients with cardiomyopathies, we compared coronary blood flow and other indicators of ischemia at rest and during pacing-induced tachycardia in nine patients with cardiomyopathy (four hypertrophic and five congestive) and in five control subjects. Coronary blood flow was reduced at rest and during pacing in cardiomyopathy patients compared with controls. In patients with hypertrophic cardiomyopathy, pacing induced chest pain in all, increased ST-segment depression in three patients and increased coronary venous lactate concentration. With pacing, two of five patients with congestive cardiomyopathy had chest discomfort and three had increased ST-segment depression, but coronary venous lactate concentration did not change significantly. In both groups of cardiomyopathies, the ratio of the systolic and diastolic pressure-time indexes tended to decrease more than in controls during pacing. Thus, myocardial perfusion is decreased in patients with cardiomyopathy, both at rest and during pacing. The changes detected during pacing point to subendocardial ischemia as the likely mechanism for angina in hypertrophic and possibly also in congestive cardiomyopathy.

Angina Pectoris↗
PubMed1982

Increased exercise tolerance and reduced electrocardiographic ischemia with diltiazem in patients with stable angina pectoris.

Diltiazem is a calcium slow-channel blocking drug that may be effective in the treatment of chronic stable angina pectoris. To evaluate the therapeutic efficacy 3 hours after a single oral dose of 120 mg, 12 men with chronic stable angina pectoris performed a maximal exercise test on a bicycle ergometer after ingesting either placebo or diltiazem administered in a double-blind fashion. During submaximal exercise at a fixed work load, diltiazem decreased the average heart rate response from 119 +/- 17 to 107 +/- 14 beats/min (p less than 0.01), systolic blood pressure from 182 +/- 15 to 175 +/- 15 mm Hg (p less than 0.05) and the rate-pressure product from 21.8 +/- 4.2 to 18.8 +/- 3.2 x 10(-3) units (p less than 0.01). The average submaximal work load at which significant ST-segment depression (0.1 mV) first appeared was increased from 355 +/- 142 to 525 +/- 143 seconds (p less than 0.01) after diltiazem. At peak exercise after diltiazem, the average depth of ST-segment depression in any one lead and the extent of myocardial ischemia observed in all 12 ECG leads were decreased (p less than 0.01), even though the average work load was increased by 29% (p less than 0.01). Peak heart rate, systolic blood pressure and rate-pressure product were similar with placebo and diltiazem. The plasma diltiazem concentration was 13.9 +/- 29 ng/ml 3 hours after ingestion and was significantly (p less than 0.05) related to the increased time to the onset of important ST-segment depression (r = 0.65) and to the decrease in the extent of myocardial ischemia observed in all 12 ECG leads (r = -0.61) compared with placebo. Thus, diltiazem is effective in treating chronic stable angina pectoris. It decreases myocardial oxygen requirements during upright exercise and appears to increase myocardial oxygen delivery.

Angina Pectoris↗
PubMed1980

Hypertrophic cardiomyopathy in Friedreich's ataxia: symmetric or asymmetric?

We evaluated 15 patients with Friedreich's ataxia (FA) to define the incidence of myocardial involvement and the type of cardiomyopathy observed. All patients with FA had either ECG, vectocardiographic or echocardiographic abnormalities, suggesting some degree of myocardial involvement. In contrast to reports indicating that asymmetric septal hypertrophy (ASH), often obstructive, is associated with FA, symmetric, concentric hypertrophic cardiomyopathy (SCH) was the predominant abnormality (sixty-seven percent of patients). Echocardiograms should be performed periodically in all FA patients since this technique allows the detection of cardiac hypertrophy.

Adolescent↗
PubMed1979

[Abnormalities of left ventricular contraction in the mitral valve prolapse syndrome].

Left ventricular contraction was studied in 20 patients with mitral valve prolapse presenting with chest pain and/or palpitations. In this group of symptomatic patients systolic abnormalities were observed in 11 patients (55 p. 100): segmental hypokinesis was observed in 5 patients, hyperkinetic motion in 3 patients and an association of hyperkinetic and hypokinetic pareital motion was observed in the other 3 cases. Abnormalities of ventricular relaxation were found in 80 p. 100 patients. In all, 90 p. 100 patients in this selected group demonstrated systolic and/or diastolic abnormalities of the left ventricular myocardium. Symptoms (anginal chest pain, palpitations, neurotic symptoms) appear to be more frequent and more troublesome in patients systolic abnormalities. Hyperkinetic movement may be related to increased levels of circulating catecholamines. Segmental hypokinesis may be the result of focal ischaemia secondary to an abnormality of the coronary microcirculation. Both these abnormalities may be dependant on dysfunction of the autonomic nervous system. Further study is necessary to define the role of the autonomic nervous system in the myocardial abnormalities observed in this valvular syndrome.

Adult↗
PubMed1978

[Myocardial perfusion in myocardiopathies: study at rest and during induced tachycardia].

The authors have compared myocardial perfusion, i.e. the coronary blood flow per unit of myocardial mass, in 9 patients with cardiomyopathy and 5 normal subjects, both at rest and during coronary sinus pacing-induced tachycardia at a rate of 150 beats/mn. In the cardiomyopathies, myocardial perfusion was found to be decreased at rest, and to remain abnormally low during induced tachycardia despite the evidence for a significant coronary reserve. During pacing there were, in addition to induced chest pain, indirect signs of sub-endocardial ischaemia which could explain the angina of effort found in certain cardiomyopathies, especially those of the obstructive hypertrophic type.

Cardiac Pacing, Artificial↗
PubMed1978

[Mitral prolapse syndrome. Simple diagnosis of forms with severe arrhythmia].

The mitral valve prolapse syndrome encompasses a wide clinical spectrum with a majority of patients presenting with a benign course while a few present with severe arrhythmias. Nineteen patients with a systolic click and angiographic mitral valve prolapse were studied to determine which of several simple tests identified the subgroup with severe ventricular arrhythmias. The incidence and type of ventricular arrhythmias, documented by a 24 hour recording (Holter), were correlated with: 1) cardiac size assessed by the cardiothoracic ratio; 2) echocardiographic indices: end-diastolic septal and posterior wall thickness and left ventricular end-diastolic dimension; 3) a ten minute rhythm strip (mini-Holter). Only patients with ventricular hypertrophy (5 patients) or dilatation (7 patients) had frequent and severe arrhythmias. In these two subgroups, the cardiothoracic ratio was larger than in patients with a normal echocardiogram (7 patients). The ten minute rhythm strip was abnormal in all those patients with severe ventricular arrhythmias (ventricular tachycardia). Thus, in patients with mitral valve prolapse, the presence of an abnormal cardiothoracic ratio, echocardiogram and ten minute rhythm strip identifies patients with potentially severe ventricular arrhythmias. The mechanism of these arrhythmias is still poorly understood; however, a certain number of them may be related to a dysfunction of the autonomic nervous system.

Adult↗
PubMed1976

Hemodynamic studies in children four to ten years after the Mustard operation for transposition of the great arteries.

Fourteen patients have been studied hemodynamically 4-10 years (mean 5.5 years) after the Mustard operation for transposition of the great arteries. Investigation was directed principally at 1) the detection of baffle obstruction by catheterization of the pulmonary veins (PV) and venae cavae and recording of simultaneous right ventricular (RV) and pulmonary capillary wedge pressures (PCW); 2) the detection of intra-atrial baffle leaks by dye curves and selective angiography; 3) the assessment of RV and LV function by calculating peak VCE (dp/dt/28p) from high fidelity recordings in 11 patients. Severe baffle obstruction to the PV return was found in only one patient. The others had no or minimal gradients between RV end-diastolic and PCW pressures (mean 1.3 +/- 0.69 mm Hg). Cardiac output was normal at rest (4.1 +/- .22) and increased to 7.1 +/- .62 L/min/m2 (+73%) but the gradient between the RV end-diastolic and PCW pressures remained insignificant (2.2 +/- 1.13 mm Hg). No evidence of caval obstruction was found in any patient. Baffle leaks were found in five patients with mild bidirectional shunting. All arterial oxygen saturations were above 90%. Mild tricuspid regurgitation was demonstrated in two patients by RV angiography and was absent in 12 others. The contractility index peak VCE averaged 1.87 +/- .122 sec-1 for the RV and was significantly lower in the LV (1.53 +/- 1.35 SEC-1, P less than 0.01). Only one patient presented significantly decreased RV contractility with a peak VCE of 1.07 sec-1 and poor contraction on the RV angiogram. These data indicate that the long-term prognosis after the Mustard operation should be good in most patients and that the right ventricle is capable of functioning at the level of contractility of a normal left ventricle.

Angiocardiography↗