Images in cardiology. Multiple ecchymotic lesions on the torso of a patient with unstable angina.
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Angina, Unstable↗
Biomedical subjects
P C Gordon
Publications and source records attributed to P C Gordon.
Myocardial stunning in hyperthyroidism.
The cases of two patients with hyperthyroidism and acute left ventricular (LV) dysfunction with segmental wall motion abnormalities resulting in heart failure are reported. Both had electrocardiographic changes mimicking ischemic coronary artery disease. Treatment with antithyroid medications, beta blockers, and angiotensin-converting enzyme inhibitors rapidly restored LV function. The rapid reversibility suggests a role for myocardial stunning, an important entity to recognize in hyperthyroidism since this form of LV dysfunction can be reversed with appropriate treatment.
Aged↗
Language comprehension and probe-list memory.
Experiments were performed using probe-word recognition methodology in which participants read sentences that were presented 1 word at a time and were then shown a probe word and had to make a speeded response indicating whether the word had occurred in the sentence. One experiment showed that response times to probe words increased with the size of the set of candidate probes. The other experiments showed that the effects caused by name repetition in circumstances in which the repeated name was co-referential also occurred when the repeated name was not co-referential and when the order of words in a sentence was scrambled. The results suggest that responses in the task can be based on probe-list memory, a mental representation created to keep track of those words that the participant believes are likely to be probed, and that the use of the task to make inferences about language comprehension should be accompanied by controls ruling out such strategies.
Adult↗
Acute and nine-month clinical outcomes after "suboptimal" coronary stenting: results from the STent Anti-thrombotic Regimen Study (STARS) registry.
OBJECTIVES: This registry collected the 30-day and 9-month clinical outcomes of patients whose coronary stent implantation was suboptimal, and compared them with the cohort of patients with "optimal" stenting in the randomized portion of the STent Anti-thrombotic Regimen Study (STARS) trial. BACKGROUND: Although "optimal" stenting combined with an aspirin and ticlopidine regimen carries a low (0.5%) incidence of subacute stent thrombosis, only limited data are available for patients in whom stents are deployed suboptimally. METHODS: In the STARS, 312 (15.9%) of 1,965 patients enrolled were excluded from participation in the randomized trial based on a perceived "suboptimal" result of coronary stenting. Of these, 265 patients met prespecified criteria for suboptimal stenting, and were followed in a parallel registry, which was compared with the randomized STARS optimal stenting cohort. The primary end point was a 30-day composite of death, emergent target lesion revascularization, angiographic thrombosis of the target vessel without revascularization and nonfatal myocardial infarction (MI) unrelated to direct procedural complications. RESULTS: Registry patients had a similar frequency of the primary end point compared with the overall randomized cohort (3.0% vs. 2.2%), with this end point correlating to use of multiple stents, smaller final lumen diameter and absence of ticlopidine from the poststent regimen. Overall 30-day mortality (1.1% vs. 0.06%, p = 0.009) and periprocedural non-Q wave MI (8.7% vs. 4.2%, p = 0.003) were more frequent in registry patients, and appeared to be related to acute procedural complications. Clinical restenosis was significantly higher for registry patients (26.8% vs. 16.0%, p = 0.001), relating to greater prevalence of independent predictors such as smaller final lumen diameter and multiple stent use. CONCLUSIONS: In the STARS registry, the inability to perform optimal stenting correlated with smaller final lumen diameter and longer stent length. With ticlopidine-containing regimens, the acute clinical results of "suboptimal" stent deployment are clinically acceptable, although they are not quite as good as those of optimal stenting using similar drug therapy.
Acute Disease↗
The role of the College of Medicine of South Africa Diploma in Anaesthesia in southern Africa.
OBJECTIVE: To determine the role that the College of Medicine Diploma in Anaesthesia (DA) plays in health services in southern Africa. DESIGN: A postal questionnaire. MAIN INFORMATION SOUGHT: Reasons for doing the DA, percentage of diplomates still actively involved in anaesthesia, career pathways of diplomates, perceived value of the DA, geography and type of anaesthetic practice of diplomates, and participation in continuing medical education. SUBJECTS: The 1,096 candidates who passed the DA between 1974 and 1993. METHODS: Questionnaires were sent to all 861 diplomates with known addresses. RESULTS: The response rate was 62.1% (535/861). Over 70% of diplomates are still actively involved in anaesthesia. Approximately one-third of all diplomates specialize in anaesthesia. The majority of GP anaesthetists with the DA have trained in anaesthesia for more than 1 year. Thirty-three per cent of GP anaesthetists work in small towns or rural areas. Nearly 20% of GP anaesthetists spend more than 75% of their time in anaesthetic practice. Twenty-eight diplomates are working in southern African countries outside South Africa. The DA is perceived to have been of value by the majority of specialist and non-specialist diplomates. CONCLUSIONS: Diplomates are playing a valuable role in anaesthesia throughout the southern African region.
Adult↗
A clinical trial comparing three antithrombotic-drug regimens after coronary-artery stenting. Stent Anticoagulation Restenosis Study Investigators.
BACKGROUND: Antithrombotic drugs are used after coronary-artery stenting to prevent stent thrombosis. We compared the efficacy and safety of three antithrombotic-drug regimens - aspirin alone, aspirin and warfarin, and aspirin and ticlopidine - after coronary stenting. METHODS: Of 1965 patients who underwent coronary stenting at 50 centers, 1653 (84.1 percent) met angiographic criteria for successful placement of the stent and were randomly assigned to one of three regimens: aspirin alone (557 patients), aspirin and warfarin (550 patients), or aspirin and ticlopidine (546 patients). All clinical events reflecting stent thrombosis were included in the prespecified primary end point: death, revascularization of the target lesion, angiographically evident thrombosis, or myocardial infarction within 30 days. RESULTS: The primary end point was observed in 38 patients: 20 (3.6 percent) assigned to receive aspirin alone, 15 (2.7 percent) assigned to receive aspirin and warfarin, and 3 (0.5 percent) assigned to receive aspirin and ticlopidine (P=0.001 for the comparison of all three groups). Hemorrhagic complications occurred in 10 patients (1.8 percent) who received aspirin alone, 34 (6.2 percent) who received aspirin and warfarin, and 30 (5.5 percent) who received aspirin and ticlopidine (P<0.001 for the comparison of all three groups); the incidence of vascular surgical complications was 0.4 percent (2 patients), 2.0 percent (11 patients), and 2.0 percent (11 patients), respectively (P=0.01). There were no significant differences in the incidence of neutropenia or thrombocytopenia (overall incidence, 0.3 percent) among the three treatment groups. CONCLUSIONS: As compared with aspirin alone and a combination of aspirin and warfarin, treatment with aspirin and ticlopidine resulted in a lower rate of stent thrombosis, although there were more hemorrhagic complications than with aspirin alone. After coronary stenting, aspirin and ticlopidine should be considered for the prevention of the serious complication of stent thrombosis.
Aged↗
Intuitive knowledge of linguistic co-reference.
The research reported here is a systematic investigation of what competent, native speakers of English, native to contemporary syntactic theory, judge to be grammatically acceptable patterns of co-reference involving names and pronouns. Its central goal is the specification of syntactic factors that influence co-reference within and between sentences. The results show that naive subjects have consistent intuitions of grammaticality that agree with some principles of contemporary binding theory. The results also show that naive subjects diverge substantially from syntactic theorists in other judgments of grammaticality. In particular, subjects have strong intuitions that reflexives and pronouns are in complementary distribution, a fact that supports contemporary syntactic theory. Beyond that domain, subjects' judgments of co-reference in name-pronoun, name-name, and pronoun-name sequences are systematically influenced by syntactic structure in ways that are not consistent with syntactic theory. Co-reference in name-pronoun sequences is generally quite acceptable but becomes more acceptable as the syntactic prominence of the name increases. Co-reference in name-name sequences is only moderately acceptable and becomes less acceptable as the syntactic prominence of the first name increases. Co-reference in pronoun-name sequences is generally unacceptable and is only weakly influenced by the kinds of syntactic prominence that affect other relations of co-reference. We account for these results through the elaboration of a model of the process by which syntactic representations are mapped onto a representation of discourse capable of expressing generalizations about co-reference both intra-sententially and inter-sententially.
Humans↗
Coherence masking protection in brief noise complexes: effects of temporal patterns.
Three experiments examined listeners' thresholds for classifying the pitch of a target signal in a masking noise when it was presented alone as compared to when it was presented with a "cosignal." The target signal was a narrow band of noise centered on either 375 or 625 Hz and the masker was noise low-pass filtered at 1000 Hz. The cosignal provided no information about the pitch of the target signal but could potentially combine with it to form an auditory object; it was spectrally well separated from the target signal, consisting of a band of noise ranging from 2200 to 2900 Hz. Experiment 1 showed that identification thresholds were lower when the target signal was paired with the cosignal than when it was presented alone if the onsets and offsets of the target signal and cosignal were temporally synchronous. This is an instance of "coherence masking protection," a phenomenon that has previously been established in the perception of vowels [P.C. Gordon, Percept. Psychophys, 59, 232-242 (1997)]. The effect disappears when the cosignal leads and lags the target signal by short durations, a finding that also matches that observed previously with vowels. The finding that temporal relations between the components of a stimulus have similar effects on the perception of nonspeech noise complexes and speech sounds suggests that speech perception makes use of general auditory mechanisms for perceptual integration of this sort. Experiments 2 and 3 examine further the role of temporal relations between the onsets and offsets of the target signal and the cosignal in producing coherence masking protection. The results show that either onset synchrony or offset synchrony is sufficient to produce the effect when the cosignal is of greater duration than the target signal, but that only onset synchrony produces the effect when the target signal has greater duration than the cosignal. This pattern indicates that the target signal and cosignal do not contribute equally to the formation of auditory objects.
Auditory Threshold↗
Coherence masking protection in speech sounds: the role of formant synchrony.
Three experiments were performed to examine listeners' thresholds for identifying stimuli whose spectra were modeled after the vowels/I/ and /epsilon/, with the differences between these stimuli restricted to the frequency of the first formant. The stimuli were presented in a low-pass masking noise that spectrally overlapped the first formant but not the higher formants. Identification thresholds were lower when the higher formants were present than when they were not, even though the first formant contained the only distinctive information for stimulus identification. This indicates that listeners were more sensitive in identifying the first formant energy through its contribution to the vowel than as an independent percept; this effect is given the name coherence masking protection. The first experiment showed this effect for synthetic vowels in which the distinctive first formant was supported by a series of harmonics that progressed through the higher formants. In the second two experiments, the harmonics in the first formant region were removed, and the first formant was simulated by a narrow band of noise. This was done so that harmonic relations did not provide a basis for grouping the lower formant with the higher formants; coherence masking protection was still observed. However, when the temporal alignment of the onsets and offsets of the higher and lower formants was disrupted, the effect was eliminated, although the stimuli were still perceived as vowels. These results are interpreted as indicating that general principles of auditory grouping that can exploit regularities in temporal patterns cause acoustic energy belonging to a coherent speech sound to stand out in the auditory scene.
Adult↗
Intravenous tramadol versus epidural morphine for postthoracotomy pain relief: a placebo-controlled double-blind trial.
Tramadol, an analgesic deriving only part of its effect via opioid agonist activity, might provide postoperative pain relief with minimal risk of respiratory depression. We, therefore, evaluated it for the control of postthoracotomy pain. In this randomized, double-blind study, a single intravenous (IV) bolus dose of 150 mg tramadol (Group T) was compared to epidural morphine administered as an initial 2-mg bolus and subsequent continuous infusion at a rate of 0.2 mg/h (Group M). Patients in each group could receive morphine IV from a patient-controlled analgesia (PCA) device. Pain scores, morphine consumption, arterial blood gases, and vital capacity values were recorded at regular intervals postoperatively until 8:00 AM on the first postoperative day. Both groups obtained adequate pain relief, and there were no between-group differences in pain scores or PCA morphine consumption. Pao2 was significantly higher in Group T at 2 h and Paco2 significantly higher in Group M at 4 h postoperatively. There were no other significant respiratory differences. We conclude that a single dose of 150 mg tramadol given at the end of surgery provided postoperative analgesia equivalent to that provided by this dosage regimen of epidural morphine for the initial postoperative period.
Adult↗
Recent advances in cardiology.
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Angioplasty, Balloon, Coronary↗
Lexical and prelexical influences on word segmentation: evidence from priming.
The authors examined the interaction of acoustic and lexical information in lexical access and segmentation. The cross-modal lexical priming technique was used to determine which word meanings listeners access at the offsets of oronyms (e.g., tulips or two lips) presented in connected speech. In Experiment 1, participants showed priming by the meaning of tulips when presented with two lips. In Experiment 2, priming by the meaning of the 2nd word was found in such sequences (e.g., lips in two lips). Finally, Experiment 3 demonstrated that listeners do not show priming by lips when it is pronounced as part of tulips. The results of these experiments show that listeners sometimes access words other than those intended by speakers and may simultaneously access words associated with several parses of ambiguous sequences. Furthermore, the results suggest that acoustic marking of word onsets places constraints on the success of lexical access. To account for these results, the authors propose a new model of lexical access and segmentation.
Humans↗
Failure of the proportioning system to prevent hypoxic mixture on a Modulus II Plus anesthesia machine.
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Anesthesiology↗
Acute and long-term results of coronary stents and atherectomy in women and the elderly.
AIM: To determine the efficacy of new coronary interventions in women and the elderly. PATIENTS AND METHODS: We studied 504 patients who underwent a total of 567 procedures, comprising 275 directional coronary atherectomy and 292 Palmaz-Schatz stents over a 2 1/2 year period; 18% were women and 23% were aged > or = 70 years (elderly). RESULTS: High rates of success were obtained with these procedures in women and the elderly, although the rates were lower in women than in men (89 versus 96%, P = 0.005), and similarly lower in the elderly than in younger patients (91 versus 96%, P = 0.06). In addition to the lower success rates, there was a higher incidence of procedure-related non-Q myocardial infarction and vascular complications in both the women and the elderly, independently. The degree of angiographic restenosis (> or = 50% diameter stenosis), however, was similar in women (36 versus 28% in men, P = 0.22) and in the elderly (28 versus 29% in patients ages < 70 years, P = 0.8). There were no sex-related differences in survival, late myocardial infarction, or repeat revascularization. In the elderly, although the incidence of repeat revascularization was not increased, there was a decrease in late survival (P < 0.001) and an increase in the incidence of late myocardial infarction (P = 0.02), probably reflecting the presence of other co-morbid variables. CONCLUSION: Both directional coronary atherectomy and coronary stenting can be performed safely and effectively in women and the elderly with good long-term clinical results, despite a somewhat lower rate of success and similarly higher rates of acute complications.
Age Factors↗
Pronominalization and discourse coherence, discourse structure and pronoun interpretation.
Two self-paced reading-time experiments are reported that examine the time course of pronoun interpretation processes based on local discourse structure and on world knowledge. The characterization of local discourse structure is based on recent work on centering, which provides a specific formulation of how the ways in which sentences make reference to common entities determines the coherence of discourse segments and how discourse structure influences interpretation of ambiguous pronouns. The results of the first experiment show that readers generate a default interpretation of a pronoun based on features of local discourse structure, and that that default interpretation is later confirmed or overridden by knowledge-based processes. The results of the second experiment show that local discourse structure continues to influence pronoun interpretation even when the semantic information that ultimately compels interpretation occurs before the pronoun. These results support the view that processes acting on local discourse structure play a powerful role in guiding language comprehension.
Adult↗
Is 40% to 70% diameter narrowing at the site of previous stenting or directional coronary atherectomy clinically significant?
Traditional binary definitions of coronary restenosis based on 6-month continuous angiographic measurements (e.g., > 50% diameter stenosis) may give confusing results for lesions whose late percent stenosis falls near the arbitrary threshold. To determine the long-term clinical consequences of such lesions, the overall correlation between follow-up percent stenosis and the performance of subsequent ischemia-driven target vessel revascularization (triggered by significant angina or a positive exercise study result, or both) was examined in 443 consecutive lesions treated with directional coronary atherectomy or Palmaz-Schatz coronary stenting. Follow-up angiograms (available in 355 lesions, 82%) were stratified into 3 groups: severe late stenosis (> 70% stenosis, n = 59), moderate late stenosis (40% to 70% stenosis, n = 72), and minimal late stenosis (< 40% stenosis, n = 224). With an average clinical follow-up of 933 +/- 394 days, 92% of lesions in the "severe late stenosis" group were treated with ischemia-driven target vessel revascularization, compared with 0% of the lesions in the "minimal late stenosis" group. Ischemia-driven target vessel revascularization was performed in 38% of patients in the "moderate late stenosis" group. However, patients in this group who did not undergo revascularization (despite the fact that 43% of them had a late stenosis of > 50%) showed a similarly favorable long-term clinical outcome to patients with a minimal late stenosis. These results support a strategy of conservative management for the 20% of patients who have a moderate (40% to 70%) late stenosis after stenting or atherectomy, but do not have evidence of ischemia.
Atherectomy, Coronary↗
Total intravenous anesthesia using propofol and alfentanil for coronary artery bypass surgery.
Total intravenous anesthesia (TIVA) using alfentanil and propofol was used in 10 patients undergoing coronary artery bypass grafting. In an attempt to diminish unwanted side effects, lower doses were chosen than if either drug had been used alone. Anesthesia was induced with alfentanil, 75 micrograms/kg, followed by a sleep dose of propofol (mean dose 0.5 mg/kg). Maintenance in the precardiopulmonary bypass (CPB) period was achieved by infusions of propofol (6 mg/kg/h) and alfentanil (100 micrograms/kg/h). These were decreased by two thirds on commencement of CPB, and increased to half the initial rate on rewarming to 32 degrees C. Additional boluses of alfentanil were used to control breakthrough hypertension. The mean arterial pressure (MAP) and left ventricular stroke work index (LVSWI) fell significantly on induction. MAP but not LVSWI returned to baseline levels at skin incision. The cardiac index (CI) was maintained. A degree of myocardial depression was suggested by a fall in LVSWI despite maintaining preload, and by the failure of CI to increase in the presence of a reduced SVR. Anesthesia was satisfactory in all but one patient who developed breakthrough hypertension on sternotomy with transient ST segment depression, and awareness after CPB despite a plasma alfentanil concentration of 450 ng/mL. Mean time to wakening was 55 minutes. The study indicated that TIVA using propofol and alfentanil in the dosages described provides satisfactory basal anesthesia for coronary artery bypass surgery in patients with good left ventricular function, but requires additional pharmacologic manipulation, particularly with boluses of alfentanil, to control breakthrough hypertension.
Adult↗
Difficult intubation prior to coronary artery surgery.
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Anesthesia, Inhalation↗