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Biomedical subjects

D H Spodick

Publications and source records attributed to D H Spodick.

At least 37 records · Page 2Linked to original sources

Microphysiology of the pericardium: substrate for intrapericardial therapeutics.

Recent capability to enter the normal effusion-free pericardium has expanded intrapericardial therapy which was formerly restricted to patients with effusive pericardial disease, to intrapericardial treatment of cardiac diseases of all kinds. It is now possible to deposit in the intact pericardium a variety of therapeutic agents targeting the myocardium, valves, conduction system and even the endocardium. In addition to such specific agents, the unique microphysiology of the pericardial mesothelium provides investigators with 2 entirely new applications of intrapericardial therapy: 1. supplementing substances like prostanoids and a variety of immune factors, and 2. stimulating pericardial production of such products of metabolism, e.g., superfusion of the normal pericardium by non-steroidal antiinflammatory agents to stimulate prostanoid production with a variety of effects including possible inhibition of coronary thrombosis. Continuing research and development should determine the precise roles of these new applications in human medicine.

Cardiovascular Agents↗

Intrapericardial treatment of autoreactive myocarditis with triamcinolon. Successful administration in patients with minimal pericardial effusion.

A major clinical drawback in the treatment of autoreactive pericarditis is its inherent feature to relapse. Intrapericardial treatment with triamcinolone was reported to be efficient in patients with large, symptomatic autoreactive pericardial effusions, avoiding side effects of systemic treatment as well as compliance problems. Intrapericardial treatment with 300 mg/m2 triamcinolone was for the first time performed in patients with autoreactive myopericarditis and minimal pericardial effusions (75 to 110 ml). After 12 months of follow-up both patients are asymptomatic and there were no further recurrences of pericardial effusion. Pericardiocentesis in these patients was performed with the application of the PerDUCER device, guided by pericardioscopy. This device has a hemispherical cavity at the top of the instrument connected with a vacuum-producing syringe. In this cavity the pericardium is captured by vacuum and tangentially punctured by the introducer needle. Pericardium that can be captured, must be up to 2 mm thin to fit into the hemispherical cavity. Pericardioscopy performed from the anterior mediastinum significantly contributed to the success of the procedures enabling visualization of the portions of the pericardium free of adipose tissue or adhesions, suitable for puncture with the PerDUCER. In conclusion, intrapericardial treatment of symptomatic autoreactive myopericarditis with minimal pericardial effusion was safely and efficiently performed in 2 patients. Pericardiocentesis was enabled by means of the PerDUCER device, facilitated by pericardioscopy.

Adult↗

Absent septal q wave: the neglected deflection.

Absence of the normal septal q wave in leads I and V6 is often overlooked. It correlates with a range of pathologic changes, including septal scarring and incomplete left bundle branch block.

Adult↗

Electrocardiographic screening for emphysema: the frontal plane P axis.

BACKGROUND: Because the most characteristic and sensitive electrocardiographic (ECG) correlate of pulmonary emphysema in adults is verticalization of the frontal plane P-wave vector (P axis), we investigated its strength as a lone criterion to screen for obstructive pulmonary disease (OPD) in an adult hospital population. METHODS: In all, 954 consecutive unselected ECGs were required to yield 100 with P axis > or = +70 degrees (unequivocally negative P in a VL during sinus rhythm) and pulmonary function tests. and 100 with P axis < or = +50 degrees (unequivocally positive P-aVL). RESULTS: Obstructive pulmonary disease by both pulmonary function test and clinical criteria was present in 89 of 100 patients with vertical P axes and 4 of 100 patients without OPD. CONCLUSION: The high sensitivity (89% for this series) and high specificity (96%) makes vertical P axis a useful screening criterion. Its at-a-glance simplicity makes it "user-friendly."

Adult↗

Global T-wave inversion: limited QT dispersion despite QTc prolongation--a correlate of benignity in patients with strikingly abnormal electrocardiograms.

BACKGROUND: The global T-inversion (GTI) electrocardiogram (ECG) is strikingly abnormal with major QTc prolongation, but with a surprisingly good prognosis by Kaplan-Meier curve. This contrasts with most significant QTc prolongations. HYPOTHESIS: This study was undertaken to ascertain QT interval dispersion (QTd) in global T wave inversion, a clinically benign long QTc ECG. METHODS: Longest and shortest QT intervals in all 12 leads in 35 consecutive patients with GTI were determined by two mutually blinded observers. QTd was determined by subtraction (maximum-minimum) and QTc was calculated using the Bazett formula. RESULTS: There was a 2:1 female preponderance QTc was prolonged and equal for men (0.471) and women (0.469). Observer variability of under 2% permitted averaging of QT measurements. Composite mean QTd was 55 ms. The literature revealed a range of QTd in normal subjects of 39 to 59 ms (mostly 49 to 59 ms). Patient series with abnormal QTd were well above this level. CONCLUSION: Despite a strikingly abnormal ECG with marked QTc prolongation, QT dispersion was limited in global T inversion, consistent with its previously demonstrated benignity.

Arrhythmias, Cardiac↗

Microphysiology of the pericardium in relation to intrapericardial therapeutics and diagnostics.

Intrapericardial delivery of therapeutic agents for pericardial diseases has long been available in the presence of excess pericardial fluid. Most patients with myocardial and coronary disease have no such excess so that their direct treatment requires pericardial access, for which a new instrument has succeeded in animals with induced infarctions, coronary lesions and arrhythmias. Nitric oxide (NO) donors, calcium-avid drugs, antibodies, angiogenic agents (pharmacologic coronary bypass), and hypothermic solutions have been instilled intrapericardially, and even iontophoresis has been used; gene therapy is also promising. Intrinsic pericardiogenic substances may potentially be stimulated for comparable purposes.

Angiogenesis Inducing Agents↗

Initial clinical experience with PerDUCER device: promising new tool in the diagnosis and treatment of pericardial disease.

BACKGROUND: The idea to enter the normal pericardial sac safely was unrealistic until recently. The development of a novel instrument (PerDUCER pericardial access device) for percutaneous access to the pericardium could potentially have a significant impact, not only on patients with pericardial diseases but even more, or primarily, on diagnosis and treatment of myocardial and coronary disease and arrhythmias. HYPOTHESIS: The overall objective of the present study was to evaluate the feasibility and safety of the percutaneous pericardial access with PerDUCER in patients with pericardial disease, and to analyze our initial experience with this new technique, with particular emphasis on sequential procedural steps. METHODS: The device was studied in five patients with pericardial disease (two men, mean age 50.4 years, range 30-68, four with normal body mass index). The procedure consists of two distinct techniques: (1) access to the mediastinal space, and (2) pericardial capture, puncture, and insertion of the guidewire. Access to the mediastinal space includes the introduction of a blunt cannula, a 0.038 guidewire, a dilator-introducer sheath set, and insertion of the PerDUCER device. Key points of the PerDUCER procedure are as follows: introduction of the blunt cannula without resistance, placement of the dilator-introducer sheath at the upper third of the heart, systolic movements of the PerDUCER device, successful vacuum and capture of pericardium, puncture and introduction of the intrapericardial guidewire. RESULTS: Access to the mediastinal space was accomplished in four of five patients, as were pericardial capture and probably puncture. However, despite numerous successful captures and probably punctures of pericardium, we were not able to confirm introduction of the intrapericardial guidewire into the pericardial cavity in any of our patients (0/5). The procedure was very well tolerated in all patients (5/5). No major complications developed during the procedure, bearing in mind that the intrapericardial placement of the guidewire was not achieved. Minor complications included pain at the dilator-introducer sheath entry site (5/5) and mild transient fever (2/5). CONCLUSIONS: According to the present experience, we believe that, with minor modifications, the PerDUCER device could be successfully implemented for pericardial entry in patients with pericardial disease. Further studies are needed to evaluate the feasibility and safety of this new instrument in patients with a normal pericardium. This could open a most exciting spectrum of possible implementations of the device in the future.

Adult↗

Constrictive pericarditis: clinical and pathophysiologic characteristics.

Constrictive pericarditis is an uncommon disorder with various causes. Although most often idiopathic, it may also occur after cardiovascular surgery, radiation therapy, and tuberculosis, especially in developing countries. The encasement of the heart by a rigid, nonpliable pericardium results in characteristic pathophysiologic effects, including impaired diastolic filling of the ventricles, exaggerated ventricular interdependence, and dissociation of intracardiac and intrathoracic pressures during respiration. Constrictive pericarditis typically presents with chronic insidious signs and symptoms of predominantly systemic venous congestion. Notoriously difficult to diagnose and distinguish from restrictive cardiomyopathy (RCM), the use of cardiac catheterization, echocardiography (transthoracic and transesophageal), central venous (hepatic and pulmonary) and transvalvular Doppler measurements, and magnetic resonance imaging should secure the diagnosis in most cases, eliminating the need for diagnostic thoracotomy. Although medical treatment may temporarily alleviate symptoms of heart failure, patients do poorly without pericardiectomy.

Animals↗

Q-wave versus non-Q wave myocardial infarction: a meaningless distinction.

The whole subject can thus be summed up in two statements. 1. Every appropriately designed study comparing first Q and NQMI's has found no difference in post-MI course of the two categories and no foundation for the common notion that the NQMI is a uniquely "unstable" entity, to be classed with unstable angina in terms of prognosis and management. Nine such studies have been published. On the other hand, all studies alleging the "unstable" character of the NQMI have been invalidated by major flaws, chief among them the comparison of undifferentiated mixtures of first and subsequent infarcts with widely differing mortality and morbidity. This confusion is further compounded by the fact that subsequent infarcts generate Qwaves less than half as often as first infarcts. 2. All current studies indicate that there is no benefit to an invasive as compared with a conservative protocol for management of NQMI. Since the characterization of an infarct as "non-Q' conveys no therapeutic implications, the classification becomes irrelevant and should be discarded. Two quotations sum the whole matter succinctly. Moss (63) commented that "The Q-wave versus non-Q-wave categorization does not provide sufficient sensitivity, specificity, or predictive accuracy about the subsequent clinical course of patients with a first myocardial infarction to use it as reliable data in the clinical decision-making process." Surawicz (64) put the matter even more concisely: ". . . a non-Qwave MI is not a unique entity: rather it is a smaller and less extensive MI." In a word, the magnitude of a myocardial infarction should be judged on anatomical and functional considerations rather than on the designation of Qwave versus non-Qwave infarction.

Aged↗