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Dive into the research topics where John A. Callahan is active.

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Featured researches published by John A. Callahan.


Circulation | 1993

Carcinoid heart disease. Clinical and echocardiographic spectrum in 74 patients.

Patricia A. Pellikka; Abdul J. Tajik; Buoy K. Khandheria; J B Seward; John A. Callahan; H C Pitot; L K Kvols

BACKGROUND The carcinoid syndrome is a rare cause of acquired valvular heart disease. Although the typical echocardiographic features of carcinoid heart disease are well recognized, this large series provides new information about unusual manifestations of the disease as well as the role of Doppler echocardiography. METHODS AND RESULTS Between 1980 and 1989, 132 patients with carcinoid syndrome underwent echocardiographic study. The echocardiographic, Doppler, and clinical features of the 74 patients (56%) with echocardiographic evidence of carcinoid heart disease are described. Among these patients, 97% had shortened, thickened tricuspid leaflets. Tricuspid regurgitation was present in all 69 patients with carcinoid heart disease who underwent Doppler examination, and it was of moderate or severe degree in 62 patients (90%). Severe tricuspid regurgitation was characterized by a dagger-shaped Doppler spectral profile with an early peak pressure and rapid decline. The pressure half-time was prolonged (mean, 116 msec), which is consistent with associated tricuspid stenosis. The pulmonary valve appeared thickened, retracted, and immobile in 36 patients (49%) and was diminutive to the extent of not being visualized in an additional 29 patients (39%). Among the 47 patients who underwent Doppler evaluation of the pulmonary valve, regurgitation was present in 81%, and stenosis was present in 53%. Left-sided valvular involvement was present in five patients (7%), four of whom had patent foramen ovale or carcinoid tumor involving the lung. Previously undescribed myocardial metastases were present in three patients (4%) and were confirmed by biopsy in each case. Small pericardial effusions were present in 10 patients (14%). Patients with and without echocardiographic evidence of carcinoid heart disease did not differ with regard to sex, age, location of the primary tumor, duration of diagnosis, or duration of symptoms of carcinoid syndrome. However, the mean pretreatment level of urinary 5-hydroxyindoleacetic acid was higher in patients with carcinoid heart disease than in patients without carcinoid heart disease (270 versus 131 mg/24 hrs, p < 0.001). The symptom of dyspnea was more prevalent among patients with carcinoid heart disease than in patients without the disease (54% versus 27%, p = 0.003); as expected, heart murmurs were also noted more frequently in patients with disease (92% versus 43%, p < 0.0001). Treatment regimens and response to therapy were similar in the two groups. Survival of patients with echocardiographic evidence of carcinoid heart disease was reduced compared with those without cardiac involvement (p = 0.0003). ECG and chest roentgenographic findings in patients with carcinoid heart disease were nonspecific. CONCLUSIONS The broad spectrum of carcinoid heart disease is detailed in this large series. This includes not only right-sided valvular lesions but also left-sided involvement, pericardial effusion, and myocardial metastases.


Journal of the American College of Cardiology | 1983

Sensitivity of two-dimensional echocardiography in the direct visualization of atrial septal defect utilizing the subcostal approach: Experience with 154 patients

Clarence Shub; I.N. Dimopoulos; James B. Seward; John A. Callahan; Robert G. Tancredi; Thomas T. Schattenberg; Guy S. Reeder; Donald J. Hagler; Abdul J. Tajik

In the standard precordial echocardiographic imaging planes, there is frequent dropout of atrial septal echoes in the region of the fossa ovalis that can be minimized by use of the subcostal imaging approach. The diagnostic sensitivity of this approach was reviewed in 154 patients (mean age 31 years, range 2 months to 74 years) with documented atrial septal defect in whom a satisfactory image of the atrial septum could be obtained. Subcostal two-dimensional echocardiography successfully visualized 93 (89%) of the 105 ostium secundum atrial septal defects, all 32 (100%) ostium primum defects and 7 (44%) of the 16 sinus venosus defects. A defect was not visualized (false negative response) in 12 patients (11%) with an ostium secundum defect and in 9 patients (56%) with a sinus venosus defect. In three of the former and five of the latter, a two-dimensional echocardiographic contrast examination established the presence of the interatrial shunt. Twenty-four patients (16%) with clinical findings of uncomplicated atrial septal defect confirmed by two-dimensional echocardiography underwent surgical repair of the defect without preoperative cardiac catheterization. There were no perioperative complications. Two-dimensional echocardiographic examination of the atrial septum utilizing the subcostal approach is the preferred method for the confident, noninvasive diagnosis and categorization of atrial septal defects. Two-dimensional echocardiographic contrast and Doppler examinations complement the technique and enhance diagnostic accuracy.


American Journal of Cardiology | 1986

Percutaneous pericardial catheter drainage: Report of 42 consecutive cases

Stephen L. Kopecky; John A. Callahan; A. Jamil Tajik; James B. Seward

Test results of 42 consecutive patients with pericardial effusion treated with percutaneous pericardial drainage were analyzed. Intermittent (79%) or continuous (21%) drainage through a 60-cm pigtail catheter (No. 6Fr to 8Fr) was used. Clinical indications were urgent or semiurgent treatment of large (38%), life-threatening (24%), recurrent (21%) or acute (traumatic) (17%) pericardial effusion. Sixteen patients had a malignant cause for the effusion. Mean duration of use of the indwelling pericardial catheter was 3.5 days (range less than 1 day to 19 days). Two of the 9 catheters in patients on continuous drainage but only 1 of 33 catheters in patients on intermittent drainage became occluded. There was only 1 possible infective complication. Six patients had subsequent elective surgical intervention for persistent or recurrent effusion. Placement of an indwelling pericardial catheter guided by 2-dimensional echocardiography is safe and effective for initial treatment of selected pericardial effusions.


Circulation | 1961

Ruptured mitral chordae tendineae.

Philip J. Osmundson; John A. Callahan; Jesse E. Edwards

The present study presents pertinent clinical and pathologic findings in 20 cases of ruptured mitral chordae tendineae encountered at the Mayo Clinic between 1934 and 1958 inclusive. Mitral insufficiency results from the rupture of chordae tendineae, the severity being related to the number of chordae ruptured. The resulting heart disease may be severe and may progress to cardiac decompensation and death. Bacterial endocarditis was the major etiologic factor in rupture of the chordae tendineae in this study.


Mayo Clinic Proceedings | 1984

Serial Echocardiographic Observations in Patients With Primary Systemic Amyloidosis: An Introduction to the Concept of Early (Asymptomatic) Amyloid Infiltration of the Heart

Luis Cueto-Garcia; A. Jamil Tajik; Robert A. Kyle; William D. Edwards; Philip R. Greipp; John A. Callahan; Clarence Shub; James B. Seward

Echocardiography was used for the serial assessment of 27 patients with primary systemic amyloidosis. Thirteen patients had no clinical cardiac deterioration between the two echocardiographic studies (group 1), whereas in 14 patients (group 2), congestive heart failure or arrhythmias (or both) appeared or worsened during a mean observation period of 19 months. The only echocardiographic changes in group 1 were a mild increase in left ventricular mass and a mild decrease in left ventricular wall systolic thickening. Patients in group 2 had significant changes in left ventricular wall thickness (mean increase, 34%), in left ventricular mass (mean increase, 42%), in right ventricular wall thickness (mean increase, 78%), in left atrial size (mean increase, 19%), in left ventricular mass/voltage ratio (mean increase, 68%), in left ventricular radius/thickness ratio (mean decrease, 29%), and in left ventricular fractional shortening (mean decrease, 13%). Significant correlations were found in group 2 between changes in systolic and diastolic blood pressure and changes in ventricular wall thickness and mass. Changes in left ventricular systolic function did not correlate significantly with changes in other clinical, electrocardiographic, or echocardiographic measurements. In six cases (two in group 1), in which amyloid infiltration of the heart was proved by myocardial biopsy or autopsy, the only echocardiographic abnormality when the patients were asymptomatic was a moderate increase in left or right ventricular wall thickness. We found that M-mode and two-dimensional echocardiographic examinations can substantiate progressive amyloid infiltration of the heart and are useful tools for the noninvasive serial assessment of patients with primary systemic amyloidosis.


Mayo Clinic Proceedings | 1985

Cardiac Tamponade: Pericardiocentesis Directed by Two-Dimensional Echocardiography

John A. Callahan; James B. Seward; A. Jamil Tajik

Symptomatic pericardial effusion has been recognized as a diagnostic and therapeutic problem for many centuries. Although surgical incision and blind needle puncture of the pericardium for removal of the fluid have been available for somewhat more than 150 years, both procedures are associated with serious complications. Echocardiography provides a unique means of diagnosing and managing pericardial effusion. The two-dimensional echocardiographic beam demonstrates the presence of the pericardial effusion and locates an ideal entry point and track for the needle used in pericardiocentesis. At our institution, echocardiography-directed pericardiocentesis has been the procedure of choice for cardiac tamponade for the past 4 years, during which time 132 consecutive pericardial taps have been performed. Our experience has shown that this is a safe, effective technique that can be used by a physician who is familiar with two-dimensional echocardiography. We recommend its wide acceptance and use.


Journal of Molecular and Cellular Cardiology | 2013

Interaction of δ and κ opioid receptors with adenosine A1 receptors mediates cardioprotection by remote ischemic preconditioning

Harinee Surendra; Roberto J. Diaz; Kordan Harvey; Michael B. Tropak; John A. Callahan; Alina Hinek; Taneya Hossain; Andrew N. Redington; Gregory J. Wilson

Multiple initiatives are underway to harness the clinical benefits of remote ischemic preconditioning (rIPC) based on applying non-invasive, brief, intermittent limb ischemia/reperfusion using an external occluder. However, little is known about how rIPC induces protection in cardiomyocytes, particularly through G-protein coupled receptors. In these studies, we determined the role of opioid and adenosine receptors and their functional interactions in rIPC cardioprotection. In freshly isolated cardiomyocytes subjected to 45-min simulated ischemia followed by 60-min simulated reperfusion, we examined the ability of plasma dialysate (derived from blood obtained from rabbits remotely preconditioned by application of brief cycles of hind limb ischemia/reperfusion, rIPC dialysate) to protect cells against necrosis. rIPC dialysate and selective activation of either δ-opioid receptors or κ-opioid receptors significantly reduced the % of dead cells after simulated ischemia and simulated reperfusion. Inhibition of adenosine A1 receptors, but not adenosine A3 receptors, blocked the protection by rIPC dialysate, δ-opioid receptor and κ-opioid receptor activation. In HEK293 cells expressing either hemagglutinin A-tagged δ-opioid receptors or hemagglutinin A-tagged κ-opioid receptors, selective immunoprecipitation of adenosine A1 receptors pulled down both δ-opioid and κ-opioid receptors. This molecular association of adenosine A1 receptors with δ-opioid and κ-opioid receptors was confirmed by reverse pull-down assays. These findings strongly suggest that rIPC cardioprotection requires the activation of δ-opioid and κ-opioid receptors and relies on these receptors functionally interacting with adenosine A1 receptors.


American Journal of Cardiology | 1982

Echocardiographic features of carcinoid heart disease

John A. Callahan; Edmund M. Wroblewski; Guy S. Reeder; William D. Edwards; James B. Seward; Abdul J. Tajik

We reviewed the records of the Mayo Clinic patients with known carcinoid syndrome in whom echocardiographic studies had been done. Nineteen patients had M-mode and 2-dimensional echocardiographic examinations, and 1 patient had an M-mode examination only. Of the 20 patients, 8 had no evidence by echocardiogram of carcinoid heart disease; 2 had changes in the tricuspid valve echogram suggestive of early carcinoid heart disease, and the other 10 patients had the following distinctive echocardiographic findings: (1) the pattern of right ventricular volume overload (enlarged right ventricle with abnormal septal motion); (2) abnormal right-sided valves, including (a) a striking appearance of the tricuspid valve, the leaflets appearing thickened, retracted, and fixed in a semiopen position throughout the cardiac cycle, and (b) thickened, retracted pulmonic valve cusps, when visualized; and (3) the left-sided valves and chambers rarely involved. These echocardiographic features are distinctive of advanced carcinoid heart disease and correlate closely with pathologic findings.


Mayo Clinic Proceedings | 1984

Mitral Stenosis Associated With Valvular Tophi

Ja Nahn Scalapino; William D. Edwards; James M. Steckelberg; Robert S. Wooten; John A. Callahan; William W. Ginsburg

Chronic tophaceous gout has become less common since the introduction of allopurinol and probenecid. Cardiac tophi have rarely been reported. In this article, we report a case of severe mitral stenosis in which valvular tophi played a major role in the pathogenesis. The case was well substantiated by echocardiography, surgical pathology, and chemical analysis.


Circulation | 1955

Pulmonary Stenosis and Ventricular Septal Defect with Arteriovenous Shunts A Clinical and Hemodynamic Study of Eleven Patients

John A. Callahan; Robert O. Brandenburg; H. J. C. Swan

Patients who have pulmonary stenosis and ventricular septal defect usually have a right-to-left intracardiac shunt. This paper presents hemodynamic and clinical data on 11 patients who have pulmonary stenosis, ventricular septal defect and left-to-right shunts. Four of these patients also have defects in the atrial septum, and three have demonstrable bidirectional shunts. The level and direction of shunts were determined by blood oxygen-saturation data and indicator-dilution studies. Choice of the form of treatment to be used in patients such as these should be based largely on hemodynamic considerations. Many resemble patients with tetralogy of Fallot who have had a successful pulmonary valvotomy.

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A. Jamil Tajik

University of Wisconsin-Madison

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