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PubMed2005

Optimum control of the Hemopump as a left-ventricular assist device.

A general framework for designing an optimum control strategy for the Hemopump is described. An objective function was defined that includes four membership functions, each constructed based on the desired values of one of the four members: stroke volume, mean left atrial pressure, aortic diastolic pressure and mean pump rotation speed. The Hemopump was allowed to operate either at a constant speed or at two different speeds during a cardiac cycle. The goal was to maximise the objective function by varying the magnitude and timing of the pump speed. Using a canine circulatory model, it was demonstrated that, in general, different cardiac conditions or different clinical objectives require different operation parameters. For example, when a left ventricle with minor ischaemia was simulated, and the main objective was to increase stoke volume, the objective function was maximised, from a value of 0.877 when the pump was off, to 0.946 when the pump was operated at speed 2 (18 500 revolutions min(-1)). On the other hand, for a severely ischaemic heart, the optimum pump speed became speed 3 (20 000 revolutions min(-1)), which maximized the objective function to 0.943 (from 0.707 when the pump was off). The results also suggest that it is more beneficial to operate the Hemopump at two different speeds during a cardiac cycle (a higher speed during systole and early diastole, and a lower speed during late diastole) than to maintain a constant speed throughout the cardiac cycle.

Animals↗
PubMed2000

[Myocarditis].

In the submitted paper the author summarizes findings concerning the controversial disease of contemporary cardiology--myocarditis. The prevalence of myocarditis in post-mortem material is about 1%. It is usually of viral origin (in particular Coxsackie viruses group B). The origin can be however also bacterial, spirochetal, mycoplasmatic, mycotic, protozoan and helminthic. Clinically it is manifested by a wide spectrum of manifestations from subclinical forms to fatal conditions (cardiac failure to cardiogenic shock, arrhythmia). On the ECG it is usually manifested by changes of the repolarization stage ST-T, by impaired conduction, possibly by pathological Q waves. Echocardiography can reveal localized (rarely diffuse) kinetic disorders which frequently do not correspond to classical areas supplied by a certain coronary artery, reversible myocardial hypertrophy is frequent. As to biochemical markers, sometimes a prolonged elevation of cardiospecific enzymes can be recorded. The most accurate evidence is that obtained by endomyocardial biopsy (but low activity). As to treatment, we start in the acute stage with bed rest and antibiotics, administration of angiotensin converting enzyme inhibitors is also recommended. In exceptional cases (in particular progressing acute conditions) administration of corticosteroids and/or immunosuppressives can be tried. Non-steroid anti-rheumatic preparations are not administered with the exception of symptomatic indication, (except in the acute stage of the disease).

Electrocardiography↗
PubMed2000

Severe carotid arterial disease: a diagnostic enigma.

The development of the duplex scanner has made the diagnosis of carotid arterial disease easy to those trained in its interpretation. The difficulty lies in the ability to define the patient population most likely to benefit from early diagnosis and treatment. All patients referred to the vascular laboratories at two major hospitals for evaluation of neurologic symptoms were entered into the study. The indications for the study, comorbid conditions, and medications were tabulated and compared with the results of the carotid duplex scan. The purpose was to see whether there was a relationship between the severity of carotid arterial disease and symptoms. A total of 5,807 carotid duplex scans were performed on 5,001 patients. There were 525 patients (11%) with an internal carotid artery stenosis of >70 per cent and 252 patients (5%) with an occlusion of the internal carotid artery. In addition, there were a group of 139 patients with severe bilateral carotid disease. Bruit and a history of known carotid disease were the only indications that were statistically related to severe carotid arterial disease. Smoking, diabetes, peripheral vascular disease, cardiac conditions, and hyperlipidemia were also statistically related to patients with significant carotid disease. This study indicates that the classic indications for carotid duplex scans such as transient ischemic attack, amaurosis fugax, and dizziness have no correlation with the severity of the disease.

Adolescent↗
PubMed2001

Metabolic cost of walking with and without a shoe lift on the contralateral foot of an immobilised extended knee.

The purpose of the present study was to determine the metabolic cost of walking with and without a shoe-lift on the contralateral foot of an immobilised extended knee. Eight male subjects were randomly allocated and participated in both the treatment (walking with a 2.5 cm shoe-lift) and control (walking without a shoe-lift) conditions. Cardiac output (Q) and related cardiovascular measurements were analysed to determine the effect of a shoe-lift on central (heart rate (HR); stroke volume (SV)) and peripheral (arteriovenous oxygen difference (a-vO2 diff)) components of oxygen consumption (VO2). A metabolic analyser was used to determine VO2 (ml x kg(-1) x min(-1)), which was converted to oxygen cost (ml x kg(-1) x m(-1)). The shoe-lift had no significant (p > 0.05) effect on VO2 or oxygen cost. There were no significant differences in Q, HR, SV, a-vO2 diff, systemic vascular resistance, carbon dioxide production, respiratory exchange ratio, expired ventilation, tidal volume and respiratory rate between the two walking conditions with and without a shoe-lift. These findings demonstrate that a shoe-lift added to the contralateral foot of an immobilised extended knee does not produce clinically important effects on oxygen cost or efficiency during walking.

Adult↗
PubMed2004

Cardiovascular safety of beta(2)-adrenoceptor agonist use in patients with obstructive airway disease: a systematic review.

BACKGROUND: beta(2)-Adrenoceptor agonists have been used as bronchodilators in the management of asthma and chronic obstructive pulmonary disease (COPD); however, there is evidence suggesting that beta(2)-adrenoceptor agonist use may increase morbidity and mortality. METHODS: A systematic review of case-control studies and randomised controlled trials was performed to evaluate the cardiovascular safety of beta(2)-adrenoceptor agonist use in patients with obstructive airway disease, defined as asthma or COPD. RESULTS: Case-control studies have shown that beta(2)-adrenoceptor agonist use is associated with an increased risk of myocardial infarction, congestive heart failure, cardiac arrest and sudden cardiac death. The degree of risk appears to be dose-dependent, and may be highest for new users and those with concomitant cardiac conditions. Pooled data from randomised placebo-controlled trials indicate that beta(2)-adrenoceptor agonist use increases the risk of adverse cardiovascular events by more than 2-fold compared with placebo, thus providing evidence that the association seen in case-control studies is a causal one. Single doses of beta(2)-adrenoceptor agonists significantly increase heart rate and decrease potassium concentrations compared with placebo. CONCLUSIONS: Initiation of beta(2)-adrenoceptor agonist treatment increases heart rate and decreases potassium concentrations, while continued use may increase the risk of adverse cardiovascular events. It could be through these effects of beta-adrenergic stimulation that beta(2)-adrenoceptor agonists may induce ischaemia, congestive heart failure, arrhythmias and sudden cardiac death. In addition to increasing adverse cardiovascular events, beta(2)-adrenoceptor agonist use may induce respiratory tolerance and increase the risk of asthma attacks. It is not clear whether beta(2)-adrenoceptor agonists should be used regularly in the treatment of obstructive airway disease, with or without concomitant cardiovascular disease.

Adrenergic alpha-2 Receptor Agonists↗
PubMed1989

Interocular transfer of preoperatively trained visual discriminations in goldfish (Carassius auratus) following selective commissure transections.

Goldfish were monocularly trained on either a red/green or circle/square discrimination task to show a differential classically conditioned cardiac deceleration. Combined section of the minor and horizontal commissure was then performed in animals trained on the colour problem, and transection of the posterior commissure in fish which had acquired the shape task. Both groups were then examined for retention and transfer. The results indicate that the engram for colour is fully represented bilaterally whilst that for shape is only established weakly in the naive side.

Animals↗
PubMed1995

Procedures associated with infective endocarditis in adults. A case control study.

OBJECT: To assess the relative risk of infective endocarditis associated with various procedures and the protective efficacy of antibiotic prophylaxis by a case-control study. BACKGROUND: Recommendations for the prevention of infective endocarditis are based on the hypothesis of a relationship between procedures and infective endocarditis which is supported by anecdotal reports and data from experimental models. METHODS: Cases met the Von Reyn's diagnostic criteria modified with echocardiographic and macroscopic findings Controls were recruited from cardiology or medicinal wards. Cases (n = 171) and controls were matched as regards sex, age and underlying cardiac condition. They were requested to indicate all the medical, surgical or dental procedures within the previous 3 months. Among potential confounding factors, infectious episodes and skin wounds in the previous 3 months were reported. Antibiotic prophylaxis administration was documented for type, dosage, duration and administration schedule. RESULTS: Cases significantly more frequently than controls had undergone at least one procedure (matched odds ratio, 1.6; 95% confidence interval, 1.01 to 2.53). Dental procedures considered as a whole were not associated with an increased risk, although scaling and root canal treatment showed a trend towards a higher risk of infective endocarditis (P = 0.065). Among non-dental procedures, only surgery appeared to be at risk (matched odds ratio, 4.7; 95% confidence interval, 1.02 to 22). Considering all procedures, the risk of infective endocarditis increased significantly with the number of procedures. While general co-morbid conditions did not differ between the two groups, cases significantly more frequently than controls had experienced an infectious episode or a skin wound. In multivariate analysis, only infectious episodes and skin wounds significantly increased the risk of infective endocarditis. Scaling was the only independent risk factor for viridans streptococcal infective endocarditis. The 46% protective efficacy of antibiotic prophylaxis was not significant. CONCLUSIONS: Procedures do increase the risk of infective endocarditis. The interpretation of the apparent low risk associated with dental procedures may be as a result of the current practice of antibiotic prophylaxis. Our data suggest that surgery should be more clearly mentioned in future guidelines, and reemphasize that a rigorous treatment of any focal infection in cardiac patients is mandatory. From the efficacy rate of antibiotic prophylaxis,it can be estimated that the overall incidence of infective endocarditis might be reduced by 5 to 10% in France by appropriate use of antibiotic prophylaxis in cardiac patients.

Adult↗
PubMed1986

Surgery in patients with heart transplants. Anaesthetic and operative considerations.

As cardiac transplantation becomes more common, so an increasing number of patients with functioning heart transplants may require surgery for related or unrelated non-cardiac conditions. Fifteen patients who have undergone a total of 39 operations (excluding retransplantation) since heart transplantation were reviewed; 36% were for infective conditions and 23% each for gastro-intestinal and vascular lesions. There was one postoperative death in a patient undergoing leg amputation for overwhelming Clostridium welchii infection. There were no major non-fatal complications. The conditions for which operation may be necessary, the specific problems of anaesthesia and surgery in such patients, and the prophylactic measures which may be undertaken to ensure an uncomplicated clinical course are discussed. A clear understanding of the physiology and pharmacology of the denervated heart is essential if these patients are successfully to undergo major operations requiring general anaesthesia.

Adolescent↗
PubMed1994

Conformity with guidelines for antimicrobial prophylaxis against bacterial endocarditis.

The extent to which prescribed antimicrobial prophylaxis against bacterial endocarditis conformed with American Heart Association (AHA) guidelines was determined and the frequency of nonconformity with specific elements of the guidelines was evaluated. Patients with conditions defined by AHA as placing them at risk for developing endocarditis were identified through medical records for a four-year period at an 850-bed hospital. Data about the procedures they underwent and prophylaxis prescribed were compared with the AHA guidelines. Conformity with the guidelines was evaluated according to whether prophylaxis was recommended, optional, or unnecessary; nonconformity with specific elements of the guidelines (indication, choice of antimicrobial, dose, dosage interval, timing, and duration) was also evaluated. The following variables were evaluated for possible association with nonconformity to the guidelines: patient's age and sex, penicillin allergy, use of a consultant, and whether the procedure was the first performed in the patient after identification of the cardiac condition. Of the 131 cases analyzed, 29 (22%) involved prophylaxis that conformed with the AHA guidelines. Conformity with the guidelines was significantly lower when prophylaxis was recommended or optional than when it was unnecessary. Nonconformity was most common with the following elements: indication, choice of antimicrobial, and dose. Recommended prophylaxis was given more often in children than in adults and more often before first procedures than before subsequent procedures. More of the regimens prescribed for children exceeded the recommended duration than those prescribed for adults. Unnecessary prophylaxis was given more often when a consultant was involved than when no consultant was involved. In hospitalized patients, conformity with AHA guidelines for antimicrobial prophylaxis against endocarditis was low.

Adolescent↗
PubMed2003

Comparison of P-wave duration and dispersion in patients aged > or =65 years with those aged < or =45 years.

P-wave dispersion (PWD) is a new electrocardiographic marker that reflects discontinuous and inhomogeneous propagation of sinus impulses, which has been studied in some cardiac conditions as a useful predictor of paroxysmal atrial fibrillation (AF). The aim of the peresent study was to compare P-wave duration and PWD in patients < or =45 versus > or =65 years of age. The study consisted of 2 groups. Group I included 118 patients aged > or =65 years (86 men, 32 women, mean age= 69 +/- 4 years). Group II included 72 patients aged < or =45 years (53 men, 19 women, mean age= 41 +/- 4 years). All patients were selected from those who were undertaken coronary angiography in our hospital with a suspicion of coronary artery disease and detected as having angiographically normal coronary arteries. All patients were undertaken transthoracic echocardiography to evaluate the presence of any structural and functional cardiac abnormality. Maximum and minimum P-wave durations and PWD were calculated from 12-lead surface electrocardiogram. Maximum P-wave duration and PWD were significantly higher in group I patients than in group II patients (P <.001). However, there was no statistically significant difference between group I patients and group II patients regarding minimum P-wave duration (p=0.9). Left atrial diameter, left ventricular wall thicknesses, mitral A velocity, deceleration time and isovolumic relaxation time were significantly higher in group I patients than in group II patients. However, mitral E velocity were significantly lower in group I patients than in group II patients. A significant positive correlation was detected between PWD and age, left atrial diameter, mitral A velocity, deceleration time and isovolumic relaxation time. In addition, we found a significant negative correlation between PWD and mitral E velocity. PWD, indicating increased risk for paroxysmal AF, was found to be significantly higher in patients > or =65 years of age than in those < or =45 years of age. Further prospective studies that include larger series and long term follow-up are needed to clarify the clinical utility of PWD as a predictor of increased risk for paroxysmal AF in old patients.

Adult↗
PubMed1997

Microemboli in patients with vertebrobasilar ischemia: association with vertebrobasilar and cardiac lesions.

BACKGROUND AND PURPOSE: Microembolic high-intensity transient signals (HITS) on transcranial Doppler ultrasound (TCD) are associated with carotid stenosis, artificial heart valves, and other cardiac conditions. Only one case report describes stroke-related HITS in the posterior cerebral circulation. This study was designed to assess prospectively the prevalence of asymptomatic microemboli in vertebrobasilar ischemia and to determine whether potential cardioembolic sources, vertebral or basilar occlusive disease, and infarct subtypes predict the detection of HITS. METHODS: We investigated 52 consecutive patients with acute or recent vertebrobasilar ischemia within 48 hours after admission. TCD monitoring was performed according to established criteria for 20 minutes on each posterior cerebral artery. Fetal origin of the posterior cerebral artery was an exclusion criterion and ruled out by carotid compression. RESULTS: Microembolic signals were detected in 10 patients (19.2%). In a multivariate logistic regression analysis that included all independent variables, potential cardiac sources were significantly associated with HITS (odds ratio [OR], 14.3; 95% confidence interval [CI], 1.6 to 128.4), in particular when more than one cardiac abnormality (OR, 32.7; CI, 4.1 to 259.3) or a high-risk source (OR, 14.0; 95% CI, 2.3 to 84.9) was found. Vertebrobasilar vessel lesions and infarct subtype were not related to the detection of microemboli. CONCLUSIONS: Cardiac sources of embolism are a determinant of HITS in posterior cerebral circulation ischemia, suggesting that cardioembolic infarcts in that territory might be more common than suspected. Vertebrobasilar vessel abnormalities are less likely to lodge microemboli, which may indicate histopathological changes different from carotid artery disease.

Aged↗
PubMed1990

Myocardial effects of adrenaline, isoprenaline and dobutamine at hypothermic conditions.

The pharmacodynamic myocardial effects of adrenaline, isoprenaline and dobutamine were studied in isolated, perfused and spontaneously beating rabbit hearts at hypothermic conditions. Cardiac contraction amplitude increased from the control value at 37 degrees set equal to 100% to about 165% at 22 degrees, whereas contraction velocity decreased to 52%, frequency to 30% and oxygen consumption to about 19%. At 22 degrees all drugs produced pronounced positive inotropic and chronotropic effects. Em-values related to contraction velocity, frequency and oxygen consumption were for isoprenaline 152, 98 and 136%, respectively, for adrenaline 127, 100 and 198% and for dobutamine 120, 86 and 165%, respectively. The corresponding EC50-values decreased and a marked left-shift of the log-concentration response curves was observed as an expression of increased myocardial sensitivity to the drugs. Em for contraction velocity for dobutamine was distinctly reduced at 32 and 27 degrees and for adrenaline at 27 degrees in comparison to the increase seen at 22 and 37 degrees. Em for oxygen consumption showed for all drugs an increase at decreasing temperatures. The frequency-corrected QTc-interval decreased slightly to moderately during exposure to the drugs at hypothermic conditions. None of the drugs caused arrhythmias during the experiments. Coronary flow rate decreased only moderately at the higher drug concentrations at decreased temperatures. Dobutamine and adrenaline at 37 degrees and isoprenaline at 37 and 22 degrees caused an increase of Em for oxygen consumption that was slightly less than proportional to the increase of Em for contraction velocity.

Animals↗
PubMed1996

Mixed total pulmonary venous drainage: still a surgical challenge.

OBJECTIVE: The aim of this report is to review the surgical experience of a single institution with a relatively large series of patients with mixed total pulmonary venous drainage. PATIENT POPULATION: Between January 1, 1971, and December 31, 1994, 232 patients with total pulmonary venous drainage underwent surgical correction. Twenty of these patients (8.6%) had mixed type total pulmonary venous drainage. Ages at operation ranged from 1 day to 46 months, with a median of 2.3 months. RESULTS: Both cardiac catheterization and echocardiography were performed before operation in 12 patients. Four patients underwent only cardiac catheterization, and another four patients underwent only echocardiography. The sensitivity and specificity for catheterization were 94% and 99%, respectively; they were 31% and 100%, respectively, for echocardiography. Severe pulmonary venous obstruction was present in three patients, all of whom underwent emergency operation. Three patients (15%), all of whom had preoperative pulmonary venous obstruction, died after operation. There were two late deaths, one of pulmonary vein stenosis and the other of probable pulmonary hypertension. The actuarial survival at 10 years was 73% for all patients; patients who survived the initial operation had a 10-year survival of 87%. CONCLUSION: The diagnosis of mixed total pulmonary venous drainage can be difficult to establish by echocardiography or at the time of operation. For patients in stable condition, cardiac catheterization may be considered if fewer than three pulmonary veins are identified by echocardiography. Pulmonary venous obstruction is relatively infrequent in this group of patients but when present impacts patient survival significantly. The long-term results with this lesion are excellent.

Actuarial Analysis↗
PubMed1999

[Serum markers for ischemic myocardial damage].

Assays of serum enzymes, such as aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and isoenzyme MB, are widely performed in the early phase of suspected ischemic myocardial injury. However, these enzymes are not restricted to cardiac muscle tissue and increases in their serum concentrations have been observed in non-cardiac conditions. The levels of CK, and especially those of the myocardial specific isoform (CK-MB), have served as essential components for clinical decision in emergency rooms for over 25 years. This standard diagnostic test is far from perfect in specificity and the time delay necessary for the detection of a rise in levels. The clinician needs specific and sensitive biological parameters that can be rapidly measured in serum immediately after ischemic damage. In the last years, several new serum markers of myocardial damage have been developed. Currently, an important place is reserved for some non-enzyme muscle constituents, such as myoglobin and troponin sub-units, which have better specificity and allow an earlier detection of myocardial damage. The immunoassay of human cardiac troponin is a specific and sensitive diagnostic method for acute and sub-acute myocardial damage. It is ideal for the detection of myocardial necrosis in complex clinical situations when the usual enzymatic markers may be ineffective. An important prognostic value of troponin levels, especially troponin T, is currently under investigation. Myoglobin is a protein with low molecular weight that is abnormally high in serum two hours after myocardial infarction. Despite their high sensitivity, the use of serum measurements in the emergency room is controversial because of their low specificity, requiring the exclusion of skeletal muscle damage. Sensitivity could be lost in patients with renal function damage. The measurement of CK-MB protein weight (CK-MBmass) is another marker that has been confirmed as more accurate than CK-MB activity assays, especially in patients presented within four hours after the onset of chest pain, but could be inaccurate in several circumstances. In this research article, the authors describe the most important parameters of enzymatic and non-enzymatic markers, the kinetics of serum release, the clinical applications and the problems.

Aspartate Aminotransferases↗
PubMed1992

Recruitment strategies in the studies of left ventricular dysfunction (SOLVD): strategies for screening and enrollment in two concurrent but separate trials. The SOLVD Investigators.

SOLVD was a double-masked, placebo-controlled trial whose initial sample size goal was to randomize 6100 participants into two concurrent trials: treatment and prevention. The objective was to determine if participants with severe left ventricular dysfunction (left ventricular ejection fraction < or = 35%, with congestive heart failure (2569) and participants without overt heart failure (4228) had improved survival with angiotensin-converting enzyme inhibitors. Participants were identified from cardiac catheterization, echocardiography and radionuclide laboratories, and inpatient units. The treatment trial recruitment goal was attained 13 months ahead of schedule while recruitment for the prevention trial was extended 11 months beyond the scheduled time. Recruitment of relatively asymptomatic participants with a low ejection fraction in a hospital-based trial necessitated novel strategies. Coronary care units and clinics for follow-up of acute cardiac conditions, not typically employed in studies of chronic diseases, were useful recruitment sources. Different approaches to encourage participation also needed to be employed. Expanding selected entry criteria was evaluated and the success of varying strategies was reviewed. The authors recommend tailoring of strategies to the target population, staffing flexibility, principal investigator involvement, and broad entry criteria in recruitment activities.

Cardiac Output↗
PubMedDate not supplied

Lonidamine plus cyclophosphamide in the treatment of adanced non-small cell lung cancer in the elderly: a phase II study.

AIM AND BACKGROUND: The aim of this Phase II trial was to verify the therapeutic activity and tolerability of chemotherapy with lonidamine (LND) plus cyclophosphamide (CTX) in advanced non-small cell lung cancer (NSCLC) in the elderly. The rationale of the combination is reported. CTX showed mild toxicity, with a 12% objective response (OR) in monochemotherapy; LND potentiated the in vitro antiproliferative activity of alkylating agents, mainly CTX, without increasing myelotoxicity, particularly important in the elderly. METHODS: The schedule consisted of CTX, 600 mg/m2/i.v. on day 1 every 21 days for 6 cycles; LND, 450 mg/die/p.o. from day 1 to progression. RESULTS: Between November 1990 and April 1991, 41 patients with stage III-IV NSCLC were enrolled; 35 were assessable for response. Median age was 73 years (range, 71-79 years); 13 patients (32%) presented stage III A, 20 (49%) stage III b, and 8 (19%) stage IV disease. Cardiovascular conditions and/or chronic respiratory failure contraindicated surgical treatment in stage III A patients. Of enrolled patients, 14.6% experienced PR, 48.8% SD and 14.6% dropped out of the study. Median time to progression was 4 months (range, 2-9 months) and median survival 9 months (range 3-45 months). No patient showed WHO grade IV LND-related toxicity. In 1 patient (2.5%), LND was discontinued after 5 therapy cycles due to WHO grade III myalgia; in 80% of patients, LND oral dosage was reduced to 300 mg/day due to WHO grade II myalgia, and 20% of patients completed treatment with the full dose. CONCLUSIONS: CTX plus LND can be considered a well tolerated therapeutic approach in the elderly with NSCLC with good PS and good liver, renal and cardiac conditions, but 14.6% PR is a slightly better result as compared with 12% PR obtainable with CTX alone as reported in the literature, even though most patients presented with advanced disease and no specific toxic effect was observed. Therefore, a confirmatory randomized trial (CTX vs CTS plus LND) would hardly be useful.

Aged↗
PubMed2005

Thyrotoxicosis and the cardiovascular system.

Thyrotoxicosis is associated with increased cardiovascular morbidity and mortality, primarily due to heart failure and thromboembolism. Palpitations, caused by sinus tachycardia and occasionally by atrial fibrillation, are the most frequent cardiovascular symptom. As atrial fibrillation may be the only manifestation of thyrotoxicosis, thyroid hormone excess should routinely be excluded in patients with this rhythm disturbance. Heart failure occurs mostly in the presence of underlying heart disease or tachycardia-induced cardiomyopathy in patients with long-standing atrial fibrillation. On occasion, long-standing hyperthyroidism may lead to heart failure even in the absence of concomitant cardiac conditions. Beta-blockers offer symptomatic relief and at the same time slow the ventricular response in patients with atrial fibrillation. Amiodarone, and occasionally iodinated contrast agents, may cause iodine-induced thyrotoxicosis. Clinical suspicion is essential in the diagnosis of amiodarone-induced thyrotoxicosis (AIT), because the antiadrenergic effect of the drug may conceal symptoms. AIT should be considered in any patient on amiodarone in the presence of new-onset or recurrent atrial arrhythmias or unexplained weight loss. Beyond discontinuation of amiodarone, treatment options include propylthiouracil or methimazole, potassium perchlorate, steroids, lithium and, if pharmacological treatment fails, surgery. Amiodarone may potentially be used less frequently in the future since recent studies have shown that this drug is inferior to implantable cardioverter defibrillators in prevention of sudden cardiac death in patients with severe heart failure. In addition, non-iodinated amiodarone analogues are currently in advanced phase of clinical testing.

Adrenergic beta-Antagonists↗
PubMed1998

Complications after placement of an intracoronary stent: nursing implications.

BACKGROUND: Care of patients after stent placement has evolved with the goal of reducing thrombosis and bleeding. Initially, all patients received full antithrombotic therapy; now most receive antiplatelet therapy only. Despite this evolution, no description of the differences in complications and nursing care with these two treatments has been published. OBJECTIVES: To determine the differences in complications and nursing care for patients receiving different pharmacological therapies after placement of an intracoronary stent. METHODS: A nonrandomized, noncontrolled, retrospective, comparative design was used with 176 sequential patients assigned to treatment groups on the basis of the adjunctive pharmacological therapy the patient received after placement of a stent. The equivalency of baseline characteristics and risk of complications, as well as the differences in length of stay, intensity of nursing care, and frequencies of bleeding and ischemic or thrombotic events were determined for the two groups: 65 patients who received anticoagulant therapy and 111 patients who received antiplatelet therapy. RESULTS: The two groups were equivalent with respect to baseline characteristics of sex, concomitant illness, and cardiac condition before stent placement. The two groups differed with respect to predisposing risks for bleeding and ischemic or thrombotic events. Patients receiving antiplatelet therapy alone had significantly shorter lengths of stay, less use of intensive care, fewer requirements for nursing care, and fewer bleeding complications, with no increase in ischemic or thrombotic events. CONCLUSIONS: Patients receiving anticoagulant therapy had more complications and required a higher intensity of nursing care than did patients who received antiplatelet therapy alone.

Adult↗