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S Pasyk

Publications and source records attributed to S Pasyk.

At least 109 records · Page 6Linked to original sources
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Local dilatory reserve in chronic experimental coronary occlusion without infarction. Quantitation of collateral development.

The local dilatory reserve of the canine coronary vasculature was studied with the particle distribution technique. Normal ventricles and hearts with slowly progressive narrowing of both the left circumflex coronary artery and the right coronary artery were studied. In spite of chronic occlusion of 2 coronary arteries myocardial infarction did not occur in the majority of animals because of collateral development. Coronary reserve was determined by producing graded to maximal coronary vasodilation. In normal hearts flow increased homogeneously over the entire left ventricle. In hearts with chronic coronary occlusion coronary vasodilation produced non-homogeneous increases in flow: collateral dependent myocardium received less blood flow than myocardium supplied by normal coronary arteries. Early after coronary occlusion the total coronary reserve was less than normal and the dilatory reserve of collateral dependent vessels was markedly diminished. Late (6 months) after coronary occlusion the total coronary reserve was still below normal but the dilatory reserve of collateral dependent vessels had improved. A new quantitative index of collateral function is defined as the level of coronary flow (delivered through normal coronary arteries) at which collateral flow deviates from homogeneous perfusion. Collateral function, when so defined, increases by a factor of almost 6 times between 4 weeks (early after coronary occlusion) and 6 months (late after occlusion) after the implantation of occluding devices.

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PubMedDate not supplied

Influence of tachycardia on regional myocardial flow in chronic experimental coronary occlusion.

The influences of tachycardia on regional myocardial flow was studied in normal dogs and in dogs with chronic coronary artery occlusions. Coronary vasodilation was induced by coronary occlusion and subsequent release, i.e. by reactive hyperemia. Local myocardial blood flow was determined with the tracer microspheres technique. In normal hearts atrial pacing produced a slight but significant increase in coronary resistance in the subendocardial layers of the left ventricle. The coronary resistance of the subepicardium remained unaffected. In the right ventricle atrial pacing had no influence on the resistance to flow. In hearts with multiple coronary occlusions tachycardia-induced changes of coronary resistance were more pronounced. In the collateral dependent subendocardium coronary resistance increased from 0.4-2.2 resistance units when the heart rate was raised to 200 beats/min. Perfusion of the right ventricular myocardium became also rate-dependent when the right coronary artery was chronically occluded. We conclude that regional perfusion dependes upon the relationship between the effective perfusion pressure, which is reduced in chronic coronary occlusion, and the integral of effective tissue pressure, which is increased with tachycardia. The results cannot be explained by assuming excessive O2-demand but rather by a rate-induced lowered O2-supply.

Animals↗
PubMedDate not supplied

[Dispersion of the QT interval in unstable angina pectoris].

UNLABELLED: Increased dispersion of the QT interval is a risk factor of sudden cardiac death. In unstable angina pectoris (UA) a few authors described QT dispersion. The aim of the study was to assess QT dispersion in patients with UA in comparison to the healthy subjects and analysis QT dispersion according to the presence during in-hospital stay significant cardiac events like: death due to cardiological causes, myocardial infarction and urgent revascularization. Study group consisted of 54 patients with UA in a class IIIB of Braunwald classification (18 women, 36 men, mean age: 58.2 +/- 9.6 years). In 40 patients after pharmacological treatment stabilization in the first three days of hospitalization was achieved and during in-hospital stay significant cardiac events were not observed--group I. In 14 patients during in-hospital stay significant cardiac events were present, including 5 death due to cardiological causes--group II. During first two days of hospitalization coronary angiography was performed in all patients. The control group comprised 25 healthy subjects (8 women, 17 men, mean age 56.4 +/- 6.1 years). On admission to the hospital in all patients and in control group, using standard 12-leads ECG, following parameters were calculated: QT dispersion (QTd), corrected QT dispersion based on Bazett's formula (QTcd) and QT dispersion ratio (QTdR). In the study group as well as in group I and II values of QTd, QTcd and QTdR were significantly higher than in healthy subjects. In group I all the QT parameters were significantly lower than in group II (QTd: 56.8 +/- 11.2 vs 68.6 +/- 16.6 ms, p = 0.002). The highest value of QT dispersion was found in patients who died during in-hospital stay and it was significantly higher than in survivors (86.0 +/- 13.4 vs 57.1 +/- +/- 10.6 ms, p = 0.004). A cut-off value for QTdR > or = 9% identified patients with high risk of sudden cardiac death. CONCLUSIONS: QT dispersion analysis in unstable angina pectoris allows to distinguish patients according to the risk of sudden cardiac death. Patients with high risk of sudden cardiac death identify the best QTdR.

Aged↗
PubMedDate not supplied

[Use of intravascular ultrasonography (IVUS) for diagnosis and treatment of coronary artery disease--case report].

One of the additional methods of coronary artery assessment is intravascular ultrasound (IVUS). Contrary to coronary angiography this relatively new technic provides new information including precise calculations of stenosis degree, morphology of atheromatous plaque and differentiation of its structure. Coronary angiography was performed in 54 years old male patient with unstable angina, revealing 99% stenosis in distal RCA. Discrepancy between clinical presentation and angiographic findings and exercise test resulted in performing IVUS of LAD. Angiographically clear LM and LAD were found to be narrowed 52% and 58% on IVUS. Subsequent CABG resulted in symptoms withdrawal and increase of physical tolerance. Exercise test after CABG did not reveal ischaemia in area of LCA at 10 METs. IVUS is found to be an important technic in assessment of silent or ambiguous lesions and in many cases allows to choose the optimal method of treatment of coronary artery disease.

Angina, Unstable↗