Nonsurgical untangling of a multiple-coiled flow-directed catheter.
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Brachiocephalic Veins↗
Biomedical subjects
W Lam
Publications and source records attributed to W Lam.
Procainamide-induced polymorphous ventricular tachycardia.
Seven cases of procainamide-induced polymorphous ventricular tachycardia are presented. In four patients, polymorphous ventricular tachycardia appeared after intravenous administration of 200 to 400 mg of procainamide for the treatment of sustained ventricular tachycardia. In the remaining three patients, procainamide was administered orally for treatment of chronic premature ventricular contractions or atrial flutter. These patients had Q-T prolongation and recurrent syncope due to polymorphous ventricular tachycardia. In four patients, the arrhythmia was rapidly diagnosed and treated with disappearance of further episodes of the arrhythmia. In two patients, the arrhythmia degenerated into irreversible ventricular fibrillation and both patients died. In the seventh patient, a permanent ventricular pacemaker was inserted and, despite continuation of procainamide therapy, polymorphous ventricular tachycardia did not reoccur. These seven cases demonstrate that procainamide can produce an acquired prolonged Q-T syndrome with polymorphous ventricular tachycardia.
Administration, Oral↗
Radionuclide regurgitant index: value and limitations.
The radionuclide regurgitant index, defined as left ventricular/right ventricular stroke counts obtained from gated equilibrium studies, has been reported to predict the presence and severity of left-sided valve regurgitation. This study evaluated the radionuclide regurgitant index in 100 patients in whom left-sided valve regurgitation was angiographically graded (0 to 4+) with regard to most severe mitral or aortic regurgitation. Regurgitation was graded 0 in 44 of the 100 patients, 1+ in 22, 2+ in 8, 3+ in 6 and 4+ in 20. The radionuclide regurgitant index was 0.9 to 1.5 in 51 patients, 1.6 to 2.4 in 23 and 2.5 to 12.0 in 26. The mean radionuclide regurgitant index was 1.34 in the group with no regurgitation and 1.60 in those with 1+, 2.01 in those with 2+, 2.80 in those with 3+ and 3.85 in those with 4+ regurgitation. There was a significant difference (p less than 0.05) in the radionuclide regurgitant index between patients with no regurgitation and each group with regurgitation and between groups with regurgitation separated by two or more grades of angiographic regurgitation. Twelve patients had a discordant radionuclide regurgitant index; their index either predicted clinically significant or severe regurgitation when they had no or trivial regurgitation, or predicted no or trivial regurgitation when they had clinically significant regurgitation. Eight of 10 patients with a left ventricular ejection fraction of less than 0.30 had a discordant index (p less than 0.0005). All three patients with mitral valve prolapse associated with frequent ventricular extrasystoles had a discordant index (p less than 0.0005).
Adolescent↗
Paroxysmal atrial fibrillation in the Wolff-Parkinson-White syndrome.
Eighty-eight patients with preexcitation were studied to determine how 30 patients with documented spontaneous paroxysmal atrial fibrillation differed from 58 patients without this arrhythmia. Inducible reentrant tachycardia was present in 23 (77 percent) of the 30 patients with, versus 28 (48 percent) of the 58 patients without, atrial fibrillation (p less than 0.025). Heart disease was present in 13 (43 percent) of the 30 patients with, versus 15 (26 percent) of the 58 patients without, atrial fibrillation (not significant). Inducible reentrant tachycardia or heart disease, or both, were significant). Inducible reentrant tachycardia or heart disease, or both, were present in 29 (97 percent) of the 30 patients with, versus 34 (59 percent) of the 58 patients without, atrial fibrillation (p less than 0.0005). Of 51 patients with inducible reentrant tachycardia, 23 patients with atrial fibrillation did not differ from 28 patients without this arrhythmia with respect to clinical features and atrial, sinus nodal, or anomalous pathway properties, or cycle length of induced reentrant tachycardia. Spontaneous degeneration of induced reentrant tachycardia to atrial fibrillation was observed in 6 (26 percent) of 23 patients with, versus none of 28 patients without, atrial fibrillation (p less than 0.025). In summary, patients with preexcitation and documented spontaneous paroxysmal atrial fibrillation almost always have inducible reentrant tachycardia or heart disease, or both. It is likely that in many patients with inducible reentrant tachycardia, spontaneously occurring reentrant tachycardia relates to induction of atrial fibrillation. However, it is unclear why some patients with inducible reentrant tachycardia have atrial fibrillation and others do not. In many patients with organic heart disease, atrial fibrillation could relate to hemodynamic changes.
Adolescent↗
Tricuspid insufficiency detected by equilibrium gated radionuclide study.
The results of a gated radionuclide cardiac study are reported in a patient with biventricular failure and tricuspid insufficiency demonstrated by clinical evaluation, M-mode and 2-D sector echocardiography, and cardia catheterization. The processed gated radionuclide cardiac study showed a left ventricular/right ventricular stroke volume ratio of 0.5; expansion of the hepatic blood pool demonstrated by hepatic time activity curve and calculation of an "'expansion fraction"; and synchronous changes of count rate of the atrial and hepatic regions detected by phase analysis (similar phase shifts).
Echocardiography↗
Transitional-cell carcinoma of the maxillary sinus.
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Carcinoma, Transitional Cell↗
Echocardiographic findings at onset of paroxysmal supraventricular tachycardia.
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Echocardiography↗
Left-to-right shunt via left superior vena cava communication with left atrium.
The findings in a 22-year-old man with Ebstein's anomaly of the tricuspid valve, Wolff-Parkinson-White syndrome, and a persistent left superior vena cava are reported. This is the first reported case of this combination of anomalies in which the atrial septum was intact and the left superior vena cava communicated with the left atrium. Uniquely, blood was shunted left to right via the left superior vena cava from the left atrium. Only one previous case of left-to-right shunting via a left superior vena cava (in the absence of mitral valvular disease or cor triatriatum) has been reported (associated with aortic coarctation). Angiograms demonstrated the left atrial connection of the left superior vena cava to be at the entrance of the right superior pulmonary vein into the left atrium. In the absence of demonstrable left-sided heart disease, this anatomic juxtaposition is suggested as a possible explanation for the direction of shunting.
Adult↗
Coronary hemodynamic and myocardial metabolic alterations accompanying coronary spasm.
Arterial pressure, coronary sinus blood flow with the thermodilution technique and calculated coronary vascular resistance were measured and coronary arteriography performed at rest and after the administration of ergonovine in 14 patients with atypical chest pain (group 1) and 6 patients with variant angina (group II). Mild diffuse narrowing of the left coronary bed in group I was not accompanied by S-T segment shifts, and coronary vascular resistance did not change significantly. In contrast, severe focal spasm (greater than 90 percent narrowing) of the left anterior descending coronary artery in group II patients was accompanied by S-T elevation and a marked overall increase in coronary vascular resistance (from 0.65 +/- 0.07 to 1.14 +/- 0.10 mm Hg/ml per min) (P less than 0.005). In addition, the myocardial arteriovenous oxygen difference increased and net lactate extraction changed to lactate production in the two patients in group II in whom these measurements were made. Thus, thermodilution coronary sinus blood flow measurement may be a sensitive method for detecting primary increases in coronary vascular resistance due to a high grade focal spasm in the left anterior descending coronary artery.
Adult↗
Oroantral fistula: broad-contact closure.
1. A modified Rehrmann's buccal advancement flap technique is described for the treatment of medium-sized oroantral fistulae. 2. Its advantages are listed. 3. Disadvantages are: a slightly longer operating time, and because of the longer movement of the buccal flap the buccal sulcus temporarily is shallower than the traditional buccal flap technique. 4. The buccal sulcus however, is reconstituted after a period of two months.
Humans↗
Apex sector echocardiography in evaluation of the right atrium in patients with mitral stenosis and atrial septal defect.
Cross-sectional echocardiography utilizing the four chamber apical view was used to evaluate right atrial dimensions as a means of detecting abnormal right heart hemodynamics in 20 patients with mitral stenosis, 5 patients with an atrial septal defect and 10 patients without heart disease. Right and left atrial dimensions on apex echocardiography were 40 mm or less in control subjects. There was a good correlation (r = 0.81) between left atrial size assessed with apex sector and M mode echocardiography. In patients with an atrial septal defect, the left atrium was of normal size on apex sector echocardiography; in patients with mitral stenosis, it was larger on apex echocardiography (59 +/- 9 mm) than on M mode echocardiography (51 +/- 8 mm). The right atrium was enlarged (54 +/- 5 mm) on apex echocardiography in all five patients with an atrial septal defect, but the right ventricle was enlarged in only four. Seventeen of 20 patients with mitral stenosis had an enlarged right atrium (53 +/- 7 mm) on apex echocardiography, whereas 15 had normal right ventricular dimensions (21 +/- 9 mm) on M mode echocardiography. Right atrial size on apex echocardiography was enlarged (54 +/- 6 mm) in 10 of 11 patients with mitral stenosis and pulmonary arterial hypertension. Thus, evaluation of the right atrial dimension with apex echocardiography may be more sensitive than M mode echocardiography in detecting early right heart involvement in specific cardiac conditions.
Adult↗
Surgical access: the access-line concept.
Adequacy of surgical access is determined by the position of the access line and not by the size of the flap as commonly believed. The case for small flaps in surgery is strongly argued for.
Humans↗
Evaluation of a microscopy method for rapid detection and identification of Mycoplasma pneumoniae.
A microscopy test that used the typical shape of Mycoplasma pneumoniae cells growing on glass was investigated for its value for diagnostic purposes. Suspensions from 108 throat swabs were infected artificially with 102, 103, and 104 colony-forming units of three M. pneumoniae strains per ml. Agar medium, a diphasic medium, and the microscopy method with liquid medium in cover slip chambers were compared for isolation of the mycoplasmas. The mycoplasms were detected first by the microscopy method in nearly all concentrations tested. Typical M. pneumoniae cells could often be detected after 48 h. No differences were found between a laboratory strain and two low-passage strains. The experimental results suggest that under special circumstances the microscopy method could be a useful tool for isolation and identification of M. pneumoniae.
Agar↗
[Detection of Mycoplasma pneumoniae].
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Microscopy, Phase-Contrast↗
Discovering knowledge from medical databases using evolutionary algorithms.
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Algorithms↗
Supramedullary modulation of sympathetic vasomotor function.
1. Supramedullary structures including the ventral medial prefrontal cortex (MPFC) and the midbrain cuneiform nucleus (CnF) project directly and indirectly to premotor sympatho-excitatory neurons of the rostral ventrolateral medulla (RVLM) that are critically involved in the generation of sympathetic vasomotor tone. 2. Electrophysiological studies have demonstrated that activation of depressor sites within the MPFC is associated with splanchnic sympathetic vasomotor inhibition and inhibition of the activity of RVLM sympathoexcitatory neurons. 3. Antidromic mapping and anatomical studies support the notion that a relay in the nucleus tractus solitarius is involved in the cardiovascular response to MPFC stimulation. 4. The midbrain CnF, which lies adjacent to the midbrain periaqueductal grey, is a sympathoexcitatory region of the midbrain reticular formation. Sympathoexcitatory responses evoked from the CnF are associated with short-latency excitation of RVLM neurons. 5. Cuneiform nucleus stimulation induces the expression of mRNA for the immediate early genes c-fos and NGFI-A in mid-brain, pontine and hypothalamic structures. 6. The MPFC and CnF are supramedullary structures with opposing modulatory influences on sympathetic vasomotor drive, whose roles in cardiovascular control mechanisms warrant further investigation.
Animals↗
Partial synergism between dextran-conjugated doxorubicin and cancer drugs on the killing of multidrug resistant KB-V1 cells.
One of the major problems in cancer chemotherapy is the development of tumor resistance to drug treatment. In in vitro experiments, the stepwise selection of cancer cells resistant to a single antineoplastic agent may lead to resistance to multiple agents (multidrug resistance). One of the well known mechanisms leading to multidrug resistance is the over-expression of the mdr1 gene product, the 170 kDa membrane P-glycoprotein which is an ATP-driven efflux pump of xenobiotics. We studied the effects of dextran-conjugated doxorubicin in combination with colchicine, vinblastine and free doxorubicin respectively on the killing of human KB 3-1 carcinoma cells and its multidrug resistant subclone KB-V-1 cells. Cell survival was quantified by the tetrazolium salt MTT assay Cytotoxicity studies were designed so that data could be analyzed by the medium-effect principle and the calculated Combination Indices at different cell survival levels. When added alone conjugated doxorubicin was not as effective as doxorubicin in cell killing. When conjugated doxorubicin was combined with free doxorubicin or colchicine at high (over 75%) killing rates, a significant degree of synergism was observed in the killing of multidrug resistant KB-V1 cells. This synergism was not observed in non-resistant KB-3-1 cells nor when conjugated doxorubicin was combined with vinblastine.
Antibiotics, Antineoplastic↗