Cerebral thromboembolization after cardioversion of atrial fibrillation in patients without transesophageal echocardiographic findings of left atrial thrombus.
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Adult↗
Biomedical subjects
K Saeian
Publications and source records attributed to K Saeian.
Atrial fibrillation complicating transesophageal echocardiography.
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Aged↗
Usefulness of transesophageal echocardiography in diagnosing lipomatous hypertrophy of the atrial septum with comparison to transthoracic echocardiography.
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Adipose Tissue↗
Regional redistribution of myocardial perfusion by UL-FS 49, a selective bradycardic agent.
The effects of UL-FS 49, a specific bradycardic agent, on systemic hemodynamics, regional myocardial function (sonomicrometry, percentage of segment shortening), and regional coronary blood flow (radioactive microspheres) were studied in open-chest, anesthetized dogs with severe left circumflex coronary artery (LCX) stenosis. UL-FS 49 was administered as two sequential bolus injections of 0.25 mg/kg. Heart rate decreased from 149 +/- 13 beats/min to 102 +/- 6 and 77 +/- 4 beats/min after 0.25 and 0.5 mg/kg cumulative doses of UL-FS 49, respectively. The reduction in heart rate was not associated with any significant change in left ventricular pressure or mean arterial pressure, left ventricular dp/dt, or coronary vascular resistance. Similarly no hemodynamic changes occurred with atrial pacing to the initial heart rate. Application of an LCX stenosis of sufficient severity to produce a 50% reduction in mean LCX blood flow (44 +/- 4 to 22 +/- 2 ml/min) resulted in a significant reduction in the percentage of segment shortening in the ischemic zone (9.8 +/- 1.6% to 6.5 +/- 1.1%). The percentage of segment shortening in the ischemic zone progressively improved to 8.4 +/- 1.2% and 9.4 +/- 0.5% after 0.25 and 0.5 mg/kg UL-FS 49, respectively. Subepicardial perfusion in the ischemic zone was decreased and subendocardial perfusion was increased after administration of UL-FS 49. Consequently the ischemic zone endocardial/epicardial ratio increased from 0.43 +/- 0.08 to 1.12 +/- 0.22 and 1.48 +/- 0.32 with low and high doses of UL-FS 49.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Coronary artery fistula formation secondary to permanent pacemaker placement.
We present the findings in two patients who apparently developed a coronary artery fistula as a complication of an endocardial pacing electrode. This complication may actually be occurring more frequently than recognized because the patient may be asymptomatic or minimally symptomatic and therefore not undergo a coronary angiogram. Awareness of this potentially serious complication is important and stresses the need for proper electrode placement without excess pressure on the tip.
Cardiac Pacing, Artificial↗
Ultrasonic tissue characterization of normal and ischemic myocardium.
Cardiac ultrasonic tissue characterization is designed to use the alterations in acoustic signals from the myocardium to differentiate normal from ischemic or infarcted tissue due to their characteristic backscatter attenuation. Various approaches such as use of a gray scale, color display, or quantitative image analysis have been used for tissue characterization, but all depend on subjective assessments and are not necessarily reproducible. The most promising method has been the use of "raw" radiofrequency signals and measure changes in the ultrasonic attenuation with an index of backscatter to distinguish normal from abnormal myocardium called "integrated backscatter" (IB). Various studies have demonstrated the changes in the ultrasonic backscatter with ischemia or infarction. In this review we summarize our experience with a research prototype instrument in tissue characterization and differentiation of normal, ischemic, infarcted, and post ischemic reperfused myocardium in anesthetized open chest dogs. Currently we are investigating the role of ultrasonic tissue characterization to estimate infarct size and plan to apply these observations to patients in order to detect viable myocardium and quantitate infarct size.
Animals↗
Doppler echocardiographic evaluation of left ventricular function.
Invasive measurements of maximum acceleration of aortic blood flow are sensitive indicators of left ventricular function. Doppler echocardiography provides noninvasive measurements of aortic blood flow acceleration. Our studies establish the accuracy of Doppler-derived indices of aortic blood flow velocity for evaluation of left ventricular function. Doppler-derived peak velocity and mean acceleration showed excellent correlation with invasively measured peak left ventricular dP/dt and maximum aortic blood flow (dQ/dt) under varying heart rate, preload, afterload, and inotropic states. Similar correlations were observed between Doppler-derived peak velocity and mean acceleration and invasively measured left ventricular dP/dt and dQ/dt under conditions of varying degrees of myocardial ischemia. Thus, Doppler echocardiography provides an accurate noninvasive method to evaluate left ventricular performance.
Animals↗
Thyrotoxic periodic paralysis in a hispanic man.
Thyrotoxic periodic paralysis occurs much more frequently in Orientals than in whites, and has rarely been reported in patients of Hispanic descent. A 28-year-old Mexican man presented with acute onset of bilateral lower extremity weakness after ingestion of a large carbohydrate meal. Laboratory investigation revealed severe hypokalemia, with a serum potassium level of 2.1 mmol/L (2.1 mEq/L), and hyperthyroidism. Administration of potassium chloride resulted in normalization of the serum potassium level and resolution of muscle weakness. Treatment with propranolol, and subsequent restoration of a euthyroid state with iodine 131, was effective in preventing further episodes of paralysis. Thyrotoxic periodic paralysis, although rare, may occur in Hispanic patients, and should be considered in the differential diagnosis of muscle weakness in this population.
Adult↗