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Biomedical subjects

L F Satler

Publications and source records attributed to L F Satler.

At least 217 records · Page 12Linked to original sources
PubMed1986

Ventricular arrhythmias during reperfusion.

Accelerated idioventricular rhythm has been used as a marker for coronary reperfusion. The incidence of accelerated idioventricular rhythm and ventricular tachycardia was evaluated in 52 consecutive patients undergoing thrombolysis with intracoronary streptokinase during acute myocardial infarction. Complete 12-hour Holter recordings during and after intracoronary streptokinase were obtained in 39 patients. Reperfusion was documented in 17 patients (44%), no reperfusion in 14 (36%), and subtotal occlusion in eight (20%). Accelerated idioventricular rhythm occurred in 83%, 57%, and 63% of patients by group, respectively (p greater than 0.05). Ventricular tachycardia occurred in 100%, 71%, and 100% of patients by group, respectively (p less than 0.05). These data demonstrate that accelerated idioventricular rhythm is not specific for reperfusion and cannot be used as a marker for this event, and that ventricular tachycardia is more common with reperfusion and subtotal occlusion.

Cardiac Catheterization↗
PubMed1986

The assessment of contractile reserve after thrombolytic therapy for acute myocardial infarction.

"Stunned" myocardium prevents the assessment of myocardial salvage after streptokinase. In order to unmask "stunning," we sought to evaluate left ventricular inotropic contractile reserve of patients after streptokinase. Radionuclide ventriculograms were obtained in 75 consecutive patients 2 weeks after myocardial infarction, at rest and during intravenous isoproterenol infusion. Resting and isoproterenol-stressed ejection fractions were compared in the patent and closed-infarct vessel groups. Although there was no difference in the resting ejection fractions between the patent group (0.48 +/- 0.02) and the closed group (0.48 +/- 0.02), isoproterenol increased the ejection fractions in the patent group (increase 0.14 +/- 0.01) significantly more than in the closed group (increase 0.06 +/- 0.01) (p less than 0.0001). Thus, despite identical resting ventricular function, the greater inotropic contractile reserve in the patent infarct vessel group suggests that restoration of blood flow in acute myocardial infarction salvages myocardium.

Adult↗
PubMed1986

Determinants of cardiac failure after coronary bypass surgery within 30 days of acute myocardial infarction.

Timing of coronary artery bypass grafting after acute myocardial infarction (MI) is controversial, especially if myocardial function is depressed. Early coronary artery bypass grafting may result in reperfusion injury causing cardiac failure. Delay, however, may risk a second ischemic event. This study was performed to determine if four preoperative factors--time after MI, ejection fraction, ischemia (need for intravenous administration of nitroglycerin), and failure (need for inotropic support)--independently predict postoperative cardiac failure. Postoperative failure was defined as the need for inotropic support or intraaortic balloon pumping. The study group consisted of 145 patients who underwent isolated coronary artery bypass grafting between January, 1980, and July, 1985, within 4 weeks of an acute MI. Postoperatively 38 patients (26%) had cardiac failure. Five patients, all of whom had postoperative cardiac failure, died. Univariate and stepwise logistic regression analyses showed preoperative failure (p = .0001), ejection fraction less than 45% (p = .002), and preoperative ischemia (p = .02) were predictors of postoperative cardiac failure. Time after MI was not found to be an independent predictor (p = .96). We conclude that if ischemia or threatening coronary anatomy is present early after MI and clinical improvement is not occurring, operative intervention should be strongly considered at that time, as it does not appear that delay itself reduces the risk of cardiac failure and may risk a second ischemic event.

Coronary Artery Bypass↗
PubMed1986

Thrombolysis in acute myocardial infarction.

Emergency cardiac catheterization and angiography in patients have resulted in an appreciation of the pathogenesis of AMI and the efficacy of thrombolytic therapy. Simple reperfusion of the infarcted myocardium, however, does not necessarily guarantee myocardial salvage, and preliminary studies have been somewhat confusing as to its beneficial effects. Metabolic support of the ventricle during early reperfusion may enhance left ventricular performance. Although the potential effects of thrombolytic therapy are still unclear, the routine administration of these agents has resulted in more frequent performance of early coronary angiography, with the result that appropriate therapeutic decisions can be made immediately regarding medical treatment, coronary angioplasty, or complete myocardial revascularization. In fact, in prolonged chest pain syndromes, emergency angiography may play a very important role in establishing appropriate initial therapy early in the course of hospitalization, potentially lowering mortality, morbidity, and cost. These issues will be answered ultimately only by carefully designed long-term randomized trials.

Fibrinolytic Agents↗
PubMed1986

Use of hemodynamic measurements for management of acute myocardial infarction.

The modern coronary care unit now can provide hemodynamic measurements that characterize the determinants of myocardial oxygen consumption and mechanical performance. These determinants of preload, afterload, contractile state, and heart rate can be obtained from measurements with the Swan-Ganz catheter, systemic blood pressure, assessment of ventricular function, and heart rate. With the hemodynamic characterization of the determinants of left ventricular function, drugs can be selected that either decrease or increase the specific determinants in order to optimize left ventricular performance. Thus, a physiologic approach can be taken to the pharmacologic management of patients with acute myocardial infarction based on hemodynamic measurements and appropriate therapeutic strategies.

Blood Pressure↗
PubMed1985

Ischemia during angioplasty after streptokinase: a marker of myocardial salvage.

Although thrombolytic therapy can result in lysis of a coronary artery thrombus, salvage of myocardium as measured by enzymatic, electrocardiographic and regional wall motion evaluation has not been clearly documented. Many patients after successful reperfusion continue to experience recurrent chest pain. The presence of recurrent chest pain suggests salvaged myocardium. Controlled reocclusion of the infarct vessel with the use of coronary angioplasty may support evidence for myocardial salvage. Experience in 50 patients who underwent angioplasty was reviewed retrospectively. Sixteen of the 50 patients had electrocardiographic or clinical evidence of ischemia at the time of balloon inflation. Prospectively, all patients who underwent angioplasty after they had received streptokinase were evaluated, and 5 of 5 patients had chest pain and ST-segment elevation during balloon inflation. The development of ischemic changes during balloon catheter inflation suggests the presence of persistently viable, salvaged myocardium after successful thrombolysis.

Angioplasty, Balloon↗
PubMed1985

Inhibition of a physiologic pacing system due to its anti-pacemaker-mediated tachycardia mode.

Newer programmable DDD pacemakers prevent pacemaker-mediated tachycardia by automatic extension of the atrial refractory period after a detected premature ventricular contraction. We present an example in which the automatic extension of the atrial refractory period resulted in pacemaker inhibition, which should not automatically be assumed to represent pacemaker malfunction. A careful understanding of pacemaker timing intervals may allow for identification and correction of this problem.

Cardiac Pacing, Artificial↗
PubMed1984

Radiographic evaluation of the patient with chest pain of suspected myocardial origin.

The evaluation of the patient with suspected angina pectoris is discussed and an approach presented which makes use of radiologic tests in conjunction with exercise testing to quickly and efficiently determine the likelihood and severity of coronary artery disease. The relative merits and limitations of chest radiography, cardiac fluoroscopy, nuclear medicine, and coronary arteriography are discussed.

Cardiac Catheterization↗
PubMed1976

Effects of isoproterenol and norepinephrine on regional ocular blood flows.

The effects of norepinephrine and isoproterenol on regional ocular blood flows were studied by the labeled microspheres using the reference sample method in pigs. Total and regional ocular flows increased in response to norepinephrine and isoproterenol infusions. Increase in flows during norepinephrine infusion may be due to increased ocular perfusion pressure induced by the drug, thereby masking its reported direct vasoconstrictor effect in isolated perfused ocular vessels. Increase in flows during isoproterenol infusion occurred despite a decrease in arterial pressure suggesting the existence of vasodilatory beta-adrenergic receptors in the ocular circulation of the pig.

Animals↗
PubMedDate not supplied

Three-dimensional intravascular ultrasonography: reconstruction of endovascular stents in vitro and in vivo.

BACKGROUND: Intravascular ultrasonography displays an artery in loosely related cross-sectional images with limited axial information. However, intravascular ultrasound images are suited to three-dimensional reconstruction. METHODS: A comprehensive intravascular ultrasound imaging system was used to reconstruct planar images in three-dimensions. This system consisted of a 25MHz transducer-tipped rigid probe (for in vitro studies) or a 25MHz transducer-tipped catheter within a 3.9F monorail imaging sheath (for in vivo studies), a motorized catheter pullback device that withdraws the transducer at 0.5mm/s, and an image processing computer that stacks 15 cross-sectional images/mm of stent axial length and then performs thresholding-based three-dimensional image rendering. We imaged 10 stents (4 Palmaz-Schatz, 3 Wiktor, 2 Strecker, and 1 Medinvent) in vitro after implantation in freshly harvested saphenous veins and 37 Palmaz-Schatz stents in vivo, 10 in native coronary arteries and 27 in vein grafts, 21 acutely and 18 on follow-up. RESULTS: Three-dimensional reconstruction of images obtained with this system reproduced the geometry of each stent design. In vitro, images of the Palmaz-Schatz stents showed the expanded diamonds, the central articulation, and flaring of both ends of both halves of the stents. Images of the Wiktor stents showed the sinusoidal wave-shaped coils in their helical configuration. Images of the Strecker stents showed the interlocking-loop design with gaps between the terminal loops at either end of the stent. Images of the Medivent stent reproduced the woven texture formed by braiding the stent wires. Three-dimensional reconstruction of images obtained in vivo also reproduced the spatial geometry of the Palmaz-Schatz stent. However, reconstruction of in vivo images was limited by cardiac-cycle-linked vessel motion and torsion and the presence of echo-dense tissue that could not be separated completely from the stent itself. CONCLUSIONS: Properly acquired intravascular ultrasound images can be used to reconstruct the spatial geometry of endovascular stents. Because stent spatial geometry is known and unambiguous, reconstruction of endovascular stents should be one of the tests of imaging systems designed to perform three-dimensional reconstruction of ultrasound images.

Adult↗
PubMedDate not supplied

Intracoronary radiation for patients with refractory in-stent restenosis: an analysis from the WRIST-Crossover Trial. Washington Radiation for In-stent Restenosis Trial.

BACKGROUND: In-stent restenosis (ISR) is a limitation of intracoronary stent implantation. In animal models and clinical trials, ionizing radiation has been shown to decrease in-stent neointimal formation. METHODS AND MATERIALS: In the Washington Radiation for In-stent Restenosis Trial (WRIST), patients with in-stent restenosis were first treated with conventional catheter-based techniques and then randomized to gamma irradiation (l92Ir, 15 Gy at 2 mm from the source) or placebo. Patients randomized to placebo that developed recurrent ISR and presented with anginal symptoms were crossed-over to active therapy. We compared the clinical and angiographic outcomes of 39 patients in the crossover group with 65 patients treated primarily with radiation. The primary clinical endpoints were mortality, morbidity, and repeat target lesion revascularization (TLR) at 6 months. RESULTS: Procedural success was 100%. In-hospital and 30-day complications were minimal. At 6 months, the rate for any multiple adverse cardiac events (MACE: death, MI, or TLR) was 25.6% in the crossover group vs. 29.2% in the primary treatment group (p = 0.86). Three patients in the crossover group and four in the primary treatment group died (p = NS). There were no Q-wave myocardial infarction. Ten (9.6%) of the patients presented with late thrombosis and total occlusion: 6.2% (4/65) in the primary treatment group vs. 15.4% (6/39) in the crossover group (p = 0.13). CONCLUSIONS: Patients who fail conventional catheter-based intervention without radiation can be treated with 192Ir with results similar to those who initially receive brachytherapy. This is of specific importance with respect to patients initially assigned to the placebo arm of randomized clinical trials.

Brachytherapy↗