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Biomedical subjects

J D Symanski

Publications and source records attributed to J D Symanski.

9 recordsLinked to original sources
PubMed2000

Hemodynamic implications of left bundle branch block.

Left bundle branch block (LBBB), traditionally viewed as an electrophysiologic abnormality, is increasingly recognized for its profound hemodynamic effects. LBBB causes asynchronous myocardial activation, which, in turn, may trigger ventricular remodeling. Exercise nuclear studies frequently show reversible perfusion defects in the absence of obstructive coronary artery disease and some patients with intermittent LBBB develop angina coincident with the onset of LBBB. It is uncertain, however, if these phenomena are because of myocardial ischemia or ventricular asynergy. LBBB is associated with impaired systolic and diastolic function. In patients with dilated cardiomyopathy (DCM), LBBB is accompanied by progressive left ventricular (LV) dilatation and mitral regurgitation. It is not known whether LBBB is the cause or the consequence of LV dilatation. DCM patients with LBBB, as compared to those with normal intraventricular conduction, are more likely to have a nonischemic etiology, profound LV dilatation, lower ejection fraction, increased symptomatology, and shorter survival. Patients with DCM and acceleration-dependent LBBB may benefit from restoration of a narrow QRS complex by suppressing the heart rate with beta-blocker. There is extensive research underway in patients with DCM and LBBB to evaluate the short and long-term effects of normalization of ventricular activation sequence with high septal, LV, or biventricular pacing.

Adrenergic beta-Antagonists↗
PubMed1998

Echocardiography in the invasive laboratory: utility of two-dimensional echocardiography in performing transseptal catheterization.

OBJECTIVE: To evaluate the potential utility of transthoracic two-dimensional echocardiography as an aid in the technique of transseptal catheterization. DESIGN: We performed a prospective study of 58 patients (29 men and 29 women; mean age, 64.2 years) referred for cardiac catheterization, in whom a systematic approach was used with selective application of two-dimensional echocardiography. MATERIAL AND METHODS: The study group of 58 patients had the following diagnoses: mitral stenosis in 17, hypertrophic cardiomyopathy in 13, dilated cardiomyopathy in 13, aortic stenosis in 13, and prosthetic valve dysfunction and pulmonary hypertension in 1 each. With use of only fluoroscopic guidance, initial gentle pressure on the dilator alone was attempted for left atrial access. If the catheter resisted entry into the left atrium, two-dimensional echocardiography was performed to assess the catheter's position relative to the atrial septum, and adjustments were made accordingly. Transseptal puncture with a Brockenbrough needle was performed only after confirmation of the catheter position at the region of the fossa ovalis with two-dimensional echocardiography. RESULTS: The catheterization procedure was performed without complication in all 58 patients; the mean time to catheter placement was 5.6 +/- 3.5 minutes (range, 3 to 20). Two-dimensional echocardiography was used in 33 patients (57%) when left atrial access was not obtained. On the basis of echocardiographic images, the transseptal catheter had to be repositioned in 16 of these 33 patients (48%). CONCLUSION: Two-dimensional echocardiography offers value in demonstrating catheter position during transseptal catheterization and may be used in some patients to ensure transseptal puncture at the region of the fossa ovalis.

Adult↗
PubMed1996

Dual-chamber pacing for cardiomyopathies: a 1996 clinical perspective.

Implantation of a permanent pacemaker is an accepted mode of therapy for symptomatic bradyarrhythmias. Application of pacemaker technology for the treatment of cardiomyopathies has generated considerable interest and enthusiastic support in recent years. In both hypertrophic cardiomyopathy and dilated cardiomyopathy, dual-chamber pacing has been shown to decrease symptoms and improve hemodynamics; however, not all patients will benefit from dual-chamber pacing. Technical considerations must be acknowledged in order to obtain optimal benefit with dual-chamber pacing. In addition, other more accepted therapies are available for patients with symptomatic cardiomyopathies. The purposes of this article are to review critically the current literature on the use of dual-chamber pacemakers in patients with either hypertrophic or dilated cardiomyopathy and to provide a clinical perspective based on current knowledge.

Cardiac Pacing, Artificial↗
PubMed1993

Drug effects on the electrocardiogram. A review of their clinical importance.

It is clear that many patients are now being treated with multiple pharmacological agents which may alter membrane function and ionic fluxes across membranes. Therefore, these agents will frequently influence the electrical behavioural of all excitable tissues including the myocardial cell. The changes in the myocardial cell are often reflected by changes, some subtle, some obvious, on the body surface electrocardiogram. Thus, the electrocardiogram provides the physician with a reasonably simple and inexpensive tool for monitoring drug effects and for detecting changes that may be toxic and/or life-threatening. For this reason, an appreciation of these changes by the noncardiologist has become increasingly important.

Cardiovascular Agents↗
PubMed1986

The intracellular and extracellular changes associated with ischaemia--effects of catecholamines in arrhythmogenesis.

Beta sympathetic stimulation and the beta-adrenergic agonists exert a variety of electrophysiologic effects which contribute to the genesis of ischaemia-related arrhythmias. These are both primary, most likely related to enhancement of the slow calcium current, and secondary, resulting from changes in the metabolism of the ischaemic myocardium as reflected in the accumulation of ions and other end products of metabolism in the extracellular space. In addition, the regional influence of these changes may contribute to the ionic and electrical inhomogeneities. Further studies are needed to define more precisely the factors responsible for the enhanced arrhythmogenicity attributed to beta-adrenergic stimulation.

Adrenergic beta-Agonists↗
PubMed1983

Serum creatine kinase and CK-MB isoenzyme responses to acute and prolonged swimming in trained athletes.

Six highly-trained male swimmers completed a maximum work capacity tethered swim and a 1-h continuous tethered swim at approximately 70% VO2max in order to evaluate total serum creatine kinase and CK-MB isoenzyme changes. Venous blood obtained before, 5 min post-, 6 h post-, and 24 h post-exercise was analyzed for total serum CK (kinetic UV method, normal = less than 100 U/l) and CK-MB isoenzyme (quantitative electrophoretic technique, normal = less than 5 U/l). VO2max averaged 4.59 +/- 0.28 l/min, with a mean total work time of 24.5 min to achieve maximum capacity. Mean resting total CK was 100.5 +/- 15.8 U/l. Compared to rest, neither swim bout produced a significant (p greater than 0.05) elevation in mean total creatine kinase. No CK-MB isoenzyme was observed in any post-exercise blood sample. Swimming, performed by highly-trained swimmers at high levels of intensity or for prolonged durations, may not impose sufficient degrees of trauma producing muscular stress. Therefore, the structural integrity of the cell membrane is maintained and the loss of intracellular creatine kinase to the bloodstream prevented.

Adolescent↗