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Biomedical subjects

R A Nishimura

Publications and source records attributed to R A Nishimura.

At least 163 records · Page 9Linked to original sources
PubMed1985

Percutaneous transluminal coronary angioplasty, alone or in combination with streptokinase therapy, during acute myocardial infarction.

The treatment strategy in 66 consecutive patients who underwent invasive therapy for acute myocardial infarction was analyzed, and specific attention was focused on the role of percutaneous transluminal coronary angioplasty. The following four treatment regimens were used: angioplasty alone (11 patients), angioplasty followed immediately by administration of streptokinase (15), streptokinase therapy alone (11), and streptokinase therapy followed by angioplasty (29). Reperfusion was achieved in 91%, 80%, 82%, and 72% of these subgroups, respectively. Angioplasty was particularly helpful in patients with severe residual stenoses after intracoronary administration of streptokinase and in patients in whom streptokinase therapy failed to reopen the occluded artery. Angioplasty further reduced the residual stenosis in 11 of 15 patients (73%) with successful thrombolysis, and it restored blood flow in 10 of 14 patients (71%) in whom thrombolysis had failed to do so. The incidence of reinfarction after therapy was similar in all four treatment groups. Patients in whom angioplasty was used either alone or in combination with streptokinase therapy had a significantly decreased incidence of subsequent revascularization (less than 30% compared with 82%). Angioplasty is of considerable value in patients undergoing invasive therapy for acute infarction. In some patients, it may be used as the only treatment; in others, it may be used to treat severe residual stenosis after initial streptokinase therapy. Finally, angioplasty achieves reperfusion in most patients in whom streptokinase therapy has failed.

Adult↗
PubMed1985

Diaphragmatic hernia mimicking an atrial mass: a two-dimensional echocardiographic pitfall.

Two-dimensional echocardiography has become the diagnostic method of choice for identifying intracardiac masses. However, adjacent extracardiac structures may closely mimic intracardiac masses on the two-dimensional echocardiogram. Five cases of a previously unrecognized phenomenon in which a diaphragmatic hernia mimicked an intraatrial mass are reported. Techniques to identify a diaphragmatic hernia properly on two-dimensional echocardiographic examination and distinguish it from intracardiac masses are discussed.

Aged↗
PubMed1985

Continuous wave Doppler determination of right ventricular pressure: a simultaneous Doppler-catheterization study in 127 patients.

Simultaneous continuous wave Doppler echocardiography and right-sided cardiac pressure measurements were performed during cardiac catheterization in 127 patients. Tricuspid regurgitation was detected by the Doppler method in 117 patients and was of adequate quality to analyze in 111 patients. Maximal systolic pressure gradient between the right ventricle and right atrium was 11 to 136 mm Hg (mean 53 +/- 29) and simultaneously measured Doppler gradient was 9 to 127 mm Hg (mean 49 +/- 26); for these two measurements, r = 0.96 and SEE = 7 mm Hg. Right ventricular systolic pressure was estimated by three methods from the Doppler gradient. These were 1) Doppler gradient + mean jugular venous pressure; 2) using a regression equation derived from the first 63 patients (Group 1); and 3) Doppler gradient + 10. These methods were tested on the remaining 48 patients with Doppler-analyzable tricuspid regurgitation (Group 2). The correlation between Doppler-estimated and catheter-measured right ventricular systolic pressure was similar using all three methods; however, the regression equation produced a significantly better estimate (p less than 0.05). Use of continuous wave Doppler blood flow velocity of tricuspid regurgitation permitted determination of the systolic pressure gradient across the tricuspid valve and the right ventricular systolic pressure. This noninvasive technique yielded information comparable with that obtained at catheterization. Approximately 80% of patients with increased and 57% with normal right ventricular pressure had analyzable Doppler tricuspid regurgitant velocities that could be used to accurately predict right ventricular systolic pressure.

Adolescent↗
PubMed1984

Ventricular arrhythmias during coronary angiography in patients with angina pectoris or chest pain syndromes.

Of 7,915 patients undergoing coronary angiography from 1978 to 1983, 39 (25 men and 14 women with a mean age of 57 years [range 37 to 79]) had sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) during the procedure. Nine patients had atypical chest pain and 30 had typical angina. Fifteen had had a previous myocardial infarction. One patient had a history of VT or VF. Electrocardiograms taken at rest revealed a prolonged QT interval in 14. A normal ejection fraction was found in 79%. Coronary angiography revealed that 10 patients had 3-vessel disease, 15 had 1- or 2-vessel disease and 14 had normal coronary arteries. The VT or VF was seen with injection of contrast medium into the right coronary artery in 24, the left coronary artery in 10 and vein bypass grafts in 5 patients. Of the episodes of VT or VF, 67% occurred after injection of contrast medium into a minimally diseased coronary artery. In patients in whom VT or VF occurred after injection into a minimally diseased coronary artery, the arrhythmia was preceded by bradycardia, usually with pronounced widening of the QRS and QT intervals. This response was significantly different from that in patients in whom VT or VF occurred after injection into a coronary artery with significant stenosis; in these patients, VT or VF was initiated by a single premature ventricular contraction on a T wave. VT or VF was successfully cardioverted in all instances, without further arrhythmias.

Adult↗
PubMed1984

Prognostic value of predischarge 2-dimensional echocardiogram after acute myocardial infarction.

The prognostic value of a 2-dimensional echocardiogram (2-D echo) was determined in 46 patients (32 men and 14 women) who survived an acute myocardial infarction (MI) from November 1979 to December 1980. The mean age of the patients was 61 years (range 36 to 92). The MI was anterior in 21, inferior in 22 and indeterminate in 3; it was transmural in 31 and nontransmural in 15. A 2-D echo was obtained 10 to 15 days after the MI--that is, 1 to 3 days before hospital discharge. A wall motion score index (WMSI) was derived with the use of a 14-segment model of the left ventricle. Each segment was assigned a number corresponding to its wall motion (0 = hyperkinetic, 1 = normal, 2 = hypokinetic, 3 = akinetic, 4 = dyskinetic and 5 = aneurysm) and the WMSI was calculated by dividing the sum of these numbers by the number of segments visualized (1.0 = normal wall motion). During a mean follow-up of 21 months (range 15 to 28), 17 patients had a complication: death, recurrence of MI, congestive heart failure of New York Heart Association class III or IV, or angina graded New York Heart Association class III or IV. Patients with compared to those without complications had a significantly higher WMSI (2.2 +/- 0.4 and 1.7 +/- 0.5, p less than 0.005). The difference in WMSI between those who died and those who survived was not significant because of the small number of deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Transient atrioventricular block after open-heart surgery for congenital heart disease.

The records of 22 patients with transient atrioventricular (AV) block after open-heart surgery for congenital heart disease from 1972 to 1978 were reviewed to determine the natural history of this entity. Preoperatively, no patient had AV block; 3 had right bundle branch block (BBB), 1 had left BBB and 5 had nonspecific intraventricular conduction delay. Complete AV block developed in 20 patients and Mobitz II AV block in 2. Transient AV block occurred intraoperatively in 14 patients and within 48 hours postoperatively in 8; AV block persisted for greater than or equal to 48 hours postoperatively in all patients, for a mean of 7.3 days (range 2 to 28). During a follow-up of 5.5 years (range 2.5 to 10), late AV block developed in 2 patients. None of the 18 patients whose escape QRS complex morphology during AV block was similar to the final QRS complex during normal sinus rhythm or atrial fibrillation with AV conduction had late AV block, whereas 2 of the 4 in whom it differed did (p less than 0.01). There was no difference in the escape rate between the 2 groups. Thus, late development of high-grade AV block is infrequent among patients with transient postoperative AV block. An escape QRS complex during postoperative AV block that differs from the QRS complex seen on recovery of normal sinus rhythm or atrial fibrillation with anterograde conduction may identify those at high risk of late AV block.

Adolescent↗
PubMed1984

Noninvasive measurement of cardiac output by continuous-wave Doppler echocardiography: initial experience and review of the literature.

Doppler echocardiographic measurement of the velocity of blood flow in the ascending aorta is a noninvasive method for determining cardiac output in the critically ill patient. Fifty-four patients in the medical intensive care unit (35 men and 19 women, age range 41 to 91 years) in whom a Swan-Ganz catheter had been inserted underwent measurement of cardiac output with use of a commercially available continuous-wave Doppler echocardiographic instrument. The aortic root diameter was measured by A-mode echocardiography. An additional 26 patients (17 men and 9 women, age range 20 to 83 years) who had undergone an open-heart surgical procedure and had hemodynamic monitoring in the postoperative period also underwent Doppler measurement of cardiac output. In these patients, the aortic root diameter was measured directly intraoperatively. Cardiac output was also determined by thermodilution in both groups. An adequate A-mode study was possible in 83% of the medical patients but only 27% of the surgical patients. Doppler signals were adequate in 84% of the medical patients and 92% of the surgical patients. The correlation between thermodilution and Doppler-derived cardiac output was good in both the medical (r = 0.94, SEE = 0.78, P less than 0.001) and the surgical (r = 0.85, SEE = 0.78, P less than 0.001) group. Doppler echocardiography is a promising noninvasive method for determining cardiac output in critically ill patients.

Adult↗
PubMed1984

Role of two-dimensional echocardiography in the prediction of in-hospital complications after acute myocardial infarction.

To evaluate prospectively the prognostic value of two-dimensional echocardiography after acute myocardial infarction, two-dimensional echocardiography was performed on 61 consecutive patients who were admitted to the hospital with this condition. A left ventricular wall motion score index was derived from analysis of regional wall motion; an index of 2.0 or more within 12 hours of admission identified patients at high risk for pump failure, malignant ventricular arrhythmia or death. These complications occurred in 24 of 27 patients with an initial wall motion score index of 2.0 or more, but in only 6 of 34 with an initial index of less than 2.0 (p less than 0.0005). Of the 47 patients who were in Killip class I on admission, complications developed in 11 (79%) of the 14 with an initial index of 2.0 or more, but in only 6 (18%) of the 33 with an initial index of less than 2.0. After acute myocardial infarction, early determination of the wall motion score index by two-dimensional echocardiography is useful for identifying patients at high risk for complications and is especially valuable in the subset of patients who initially seem to be in stable condition as judged from clinical variables.

Aged↗
PubMed1983

Papillary muscle rupture complicating acute myocardial infarction: analysis of 17 patients.

The records of 17 patients (10 men and 7 women) with the diagnosis of acute papillary muscle rupture secondary to acute myocardial infarction (AMI) were reviewed to determine the clinical course and pathologic features of this entity. Eight patients underwent operation after papillary muscle rupture had been diagnosed, and 9 had the diagnosis confirmed at autopsy without a prior surgical procedure. The ages were 44 to 80 years (mean 64). The site of AMI was inferolateral in 15 and anterior in 2. The recorded onset of mitral regurgitation ranged from less than 24 hours to 28 days after AMI (mean 6 days). Of the 11 patients presenting with pulmonary congestion alone, 6 remained stable and had subsequent mitral valve replacement and coronary artery bypass graft operation; however, 5 patients' condition initially stabilized with medical therapy and then suddenly deteriorated after a variable period (1 to 60 days), followed by death. Of the 6 patients who presented with systemic hypotension and pulmonary congestion, 4 were treated medically and died; 1 of the 2 who had surgical treatment survived. The extent of the AMI at autopsy was small and was limited to the subendocardium in half of the patients. Significant coronary artery disease was limited to a single vessel in 7 of 14 patients. The unpredictable and rapid clinical deterioration and the limited extent of coronary atherosclerotic disease and infarct size suggest that early surgical repair should be undertaken in patients with papillary muscle rupture after AMI.

Adult↗
PubMed1983

Outcome of dual-chamber pacing for the pacemaker syndrome.

Symptomatic hypotension induced by VVI pacing (ventricular paced, ventricular inhibited) is characteristic of the pacemaker syndrome. Recent observations indicate that it is due to atrioventricular dyssynchrony. Since 1980, we have used the approach of converting the ventricular pacing to a dual-chamber pacing system in patients with this syndrome. The clinical course, hemodynamics, and response to dual-chamber pacing were evaluated in nine patients with the pacemaker syndrome whose ages ranged from 41 to 78 years. The indication for initial implantation of a pacemaker was symptomatic sinus node dysfunction in eight patients and intermittent Mobitz II block in one patient. One patient had a history of heart failure. The mean cardiothoracic ratio was 0.44. After initial implantation of a VVI pacemaker, all patients had syncope or near-syncope (mean duration, 10 months; mean frequency, one episode per month) despite normal pacemaker function. Eight of the nine patients had a symptomatic decrease in systolic blood pressure of greater than 20 mm Hg and ventriculoatrial conduction during VVI pacing. Dual-chamber pacing was instituted in all nine patients. This mode abolished pacing hypotension and its related symptoms. During a mean follow-up of 10 months, no patient has had recurrent syncopal or near-syncopal attacks related to pacemaker function. Dual-chamber pacing is an effective approach for treatment of the pacemaker syndrome.

Adult↗
PubMed1983

Reentrant tachycardia associated with atrial synchronous pacing. Report of a case with intact ventriculoatrial conduction.

Reentrant tachycardia occurred after implantation of an atrial synchronous ventricular-inhibited pacemaker in a patient with bradycardia caused by second-degree (Mobitz II) atrioventricular block. Despite the presence of antegrade atrioventricular block, intact ventriculoatrial conduction was present at a cycle length that exceeded the atrial refractory period of the pacemaker. Consequently, a reentrant or "endless-loop" tachycardia occurred. Application of a magnet terminated the tachycardia. Because the episodes were frequent and could not be prevented by medication, the pacemaker was reprogrammed to a ventricular-inhibited mode. All candidates for atrial synchronous pacing should undergo an appropriate electrophysiologic study preoperatively.

Atrioventricular Node↗
PubMed1982

Hemodynamic and symptomatic consequences of ventricular pacing.

After implantation of a ventricular demand pacemaker (VVI), occasional patients continue to have dizziness, syncope, or near syncope ("pacemaker syndrome"). To identify patients in whom VVI pacing may have deleterious effects, we compared cuff blood pressure responses to VVI pacing with blood pressure responses to atrioventricular sequential pacing (DVI) or sinus rhythm in 50 consecutive patients. Patients with intact ventriculoatrial conduction had a much greater decrease in systolic blood pressure with VVI pacing (24 +/- 11 mm Hg) than those with ventriculoatrial dissociation (-4 +/- 15 mm Hg) (P less than 0.005). Patients who were in heart failure had a lesser decrease in blood pressure with VVI pacing than did those without failure (P less than 0.05); 13 of the 14 heart failure patients lacked ventriculoatrial conduction. Ten patients had symptomatic dizziness after VVI pacing; the incidence of symptoms was higher in patients with ventriculoatrial conduction (9 of 23) than in those without ventriculoatrial conduction (1 of 27) (P less than 0.003). We conclude that the presence of intact ventriculoatrial conduction appears to be a crucial determinant of the hemodynamic response to VVI pacing, and its presence may identify patients who are at risk for "pacemaker syndrome."

Adult↗
PubMed1982

Early follow-up of lead performance in atrioventricular sequential systems.

Recent developments in pacemaker technology led us to report our initial and follow-up assessment of atrioventricular (A-V) sequential systems in 50 consecutive patients. Primary indications for pacing were sinus node dysfunction or A-V block. Leads were introduced through the subclavian vein. Atrial J-tined leads (27 silicone, 19 urethane) were positioned in the atrial appendage or stump in 46 patients, and coronary sinus or Bisping leads were placed in 4 patients; all 50 patients had tined ventricular leads. A Medtronic 5992 generator was placed in 35 patients and an Intermedics 259-01 generator in 15. Median implantation time was 105 minutes. Complications requiring reoperation in 409 patient-months of follow-up included lead retraction (one patient), phrenic nerve stimulation (one), pseudofracture (one), and atrial lead-induced "cross talk" (one). Monthly telephone transmission confirmed atrial capture in 35 patients and loss of capture in 1; the remainder had no identifiable P wave. Ventricular capture was confirmed in all. Postimplant and follow-up checks showed good stability of lead positions. We conclude that these systems have a low incidence of problems in short-term follow-up.

Adult↗
PubMed1976

Regulation of the oxidative NADP-enzyme tissue levels in Drosophila melanogaster. I. Modulation by dietary carbohydrate and lipid.

Wild-type third instar larvae of Drosophilia melanogaster fed a casein-sucrose synthetic diet supplemented with phosphatidylcholine (4 mg/ml) possessed 33% more tissue lipid and a modified fatty acid profile compared to larvae fed a fat free-sucrose diet. The rates of lipid synthesis and pentose shunt activity were 2.1 and 2.2 times greater respectively in larvae fed the fat free-sucrose diet than in fat-sucrose fed animals. The tissue concentrations of acetyl-CoA and acyl-CoA were 80 and 61% higher respectively, CoA 49% lower, and the NADPH/NADP+ ratio greater in fat-sucrose fed larvae than in larvae fed a fat free-sucrose diet. Thus, larvae effectively utilized dietary lipid for lipid synthesis and as a supplementary energy source to carbohydrate.

Acetyl Coenzyme A↗
PubMedDate not supplied

Clinical features and long-term natural history of the postpericardiotomy syndrome.

We followed 34 consecutive patients with the postpericardiotomy syndrome for a median of 7 years. In each patient, the syndrome was documented by the occurrence of: (1) a pericardial type of pain or pericardial rub (or both); and (2) fever or an elevated erythrocyte sedimentation rate. The postpericardiotomy syndrome occurred at a median postoperative time of 4 weeks (range, 2 to 52 weeks). The duration of the syndrome was highly variable (range, 2 to 100 days; median, 22 days) and depended primarily on treatment; the median duration of symptoms in 21 patients treated with salicylates alone was only 4 days. Of the 9 patients receiving anticoagulants alone and in whom this treatment was continued, none had clinical evidence of hemopericardium. On follow-up, 7 patients (21%) had an initial recurrence at an interval of 1 to 3 months; 5 of these patients had further recurrences at an interval of 3 to 30 months. This long-term study indicates that the postperiocardiotomy syndrome is a benign but often recurrent clinical entity, presumably related to viral and/or immunologic factors.

Adolescent↗