BACKGROUND: Patients who have coronary artery surgery normally occupy intensive care beds for less than 24 hours. Longer stays may result in under use of cardiac surgical capacity. One approach to optimise surgical throughput is prospectively to identify fast track patients--that is, those who occupy an intensive care bed for less than 24 hours. A prospective audit of patients was performed to identify fast track patients by simple clinical criteria. Total length of hospital stay was also assessed in an attempt to predict which patients were likely to have a short postoperative stay, defined as < or = 7 days. METHODS: Baseline demographic details, cardiovascular risk factors, angiographic and operative details were recorded for 431 consecutive patients who underwent coronary surgery at a regional centre over a nine month period. Outcome measures were the duration of the stay in the intensive care unit in hours and total duration of the postoperative stay in hospital in days. In addition, two groups of patients who were thought to be fast track were identified prospectively. Fast track 1 patients were identified by criteria selected by cardiovascular physicians. These were age less than 60 years, stable angina, good left ventricular function (ejection fraction > 50%), good renal function (serum creatinine < 120 mumol/l), and no obesity, diabetes, or other serious disease. Fast track 2 patients were identified by criteria defined by cardiovascular surgeons. These were male sex, age less than 65 years, good left ventricular function and no peripheral vascular disease, diabetes, or other serious disease. The efficacy of both sets of criteria in predicting outcome was tested. RESULTS: 344 (79.8%) patients were fast track. Significant factors for the prediction of fast track patients by univariate analysis (with positive predictive accuracy and sensitivity) were left ventricular ejection fraction > 50% (83%, 80%), left ventricular end diastolic pressure < 13 mm Hg (90%, 59%), creatinine less than 120 mumol/l (83%, 87%), and one or two vessel coronary disease (89%, 34%). Of the patients categorised as fast track 1 89% proved to be fast track (sensitivity 24%), however, the fast track 2 characteristics were not significant. Age, sex, obesity, diabetes, hypertension, a history of obstructive pulmonary disease and unstable angina were not predictive of the duration of intensive care stay. Multivariate analysis indicated that only left ventricular end diastolic pressure and the number of diseased coronary arteries predicted fast track patients. These criteria separated patients into three groups. Those who were good risk had one or two vessel disease and left ventricular end diastolic pressure < 13 mm Hg. They comprised 19% of the total and 93% of them were fast track. Those who were intermediate risk had either three vessel disease or left ventricular end diastolic pressure > 13 mm Hg but not both. They comprised 49% of the total and 85% of them were fast track. Those who were poor risk had both three vessel disease and left ventricular end diastolic pressure > 13 mm Hg. They comprised 32% of the total and 62% of them were fast track. The 106 (24%) patients who spent < or = 7 days in hospital after surgery were significantly younger (mean (SD) 55(8) v 58(8) years; P < 0.001) with a lower incidence of previous myocardial infarction (positive predictive accuracy 30%, sensitivity 53%), were less likely to have a history of obstructive pulmonary disease (25%, 98%), and more likely to have one or two vessel coronary disease (33%, 41%). They were more likely to have an internal mammary artery as a bypass conduit (27%, 89%) and more likely to need fewer than three distal anastomoses of the vein graft (29%, 63%). By multivariate analysis only age was significantly predictive of hospital stay. Total hospital stay could not be satisfactorily modelled on the basis of the criteria tested here. Sex, obesity, diabetes, hypertension, unstable angina, renal function, and left ventricular function were not associated with hospital stay. CONCLUSIONS-Most patients who had coronary artery surgery spent less than or equal to 24 hours in intensive care, but most spent > 7 days in hospital. The chance of a patient spending less than or equal to 24 hours in intensive care could be predicted by the number of coronary arteries diseased and the left ventricular end diastolic pressure. Poor risks patients (32%) had only a 62% chance of an intensive care unit stay of less than or equal to 24 hours. A policy of scheduling no more than one such patient for surgery per day would be simple to institute and would maximise the use of surgical capacity.

Coronary Artery Bypass↗

PubMed1995

Antibiotic prophylaxis in permanent pacemaker implantation.

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Antibiotic Prophylaxis↗

PubMed1994

Effects of intravenous adenosine in patients with preexcited junctional tachycardias: therapeutic efficacy and incidence of proarrhythmic events.

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Adenosine↗

PubMed1994

Effects of intravenous adenosine on verapamil-sensitive "idiopathic" ventricular tachycardia.

The mechanism of ventricular tachycardia (VT) that occurs in the absence of structural heart disease ("idiopathic" VT) is unknown, but may involve triggered activity or reentry through calcium channel-mediated conduction pathways. It has been suggested that termination of VT by adenosine is specific to ventricular arrhythmias caused by cyclic adenosine monophosphate-mediated triggered activity. The effects of vagotonic maneuvers, and intravenous adenosine (up to 0.25 mg/kg in incremental doses) and verapamil (0.145 mg/kg) administered to 9 patients with "idiopathic" VT were studied during electrophysiologic study. Seven patients had inducible fascicular VT and 2 had incessant right ventricular outflow tract tachycardia. Vagal maneuvers did not have any effect on any VT. Adenosine interrupted both right ventricular outflow tract tachycardias for a period (2 to 15 seconds) that was dependent on the dose of adenosine, but had no effect on VT in any patient with fascicular VT. Verapamil produced stuttering termination of right ventricular outflow tract tachycardia with no preceding change in RR interval in patients with this arrhythmia. Administration of verapamil to patients with fascicular VT was followed by gradual slowing of the arrhythmia (cycle length increased from 397 +/- 45 to 506 +/- 86 ms; p < 0.01) in all 7 patients and by termination of VT in 6. In conclusion, the differential response of fascicular and right ventricular outflow tract tachycardias to both adenosine and verapamil suggests that: (1) These 2 forms of idiopathic VT have different mechanisms. (2) Fascicular VT is unlikely to be due to cyclic adenosine monophosphate-mediated triggered activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗

PubMed1994

Ventricular tachycardia as default diagnosis in broad complex tachycardia.

In the differential diagnosis of broad-complex tachycardia, the most important decision is whether or not the tachycardia is ventricular, since this type carries the worst prognosis. However, the rules for a diagnosis of ventricular tachycardia are so complex that they are not satisfied in many cases, and the default diagnosis, supraventricular tachycardia, is erroneously accepted. We sought to reverse this strategy; unless simple rules for a positive diagnosis of supraventricular tachycardia were satisfied, ventricular tachycardia was diagnosed by default. The criterion for a diagnosis of supraventricular tachycardia was electrocardiographic (ECG) findings typical of bundle branch block (left = rS or QS wave in leads V1 and V2, delay to S wave nadir < 70 ms, and R wave and no Q wave in lead V6; right = rSR' wave in lead V1 and an RS wave in lead V6, with R wave height greater than S wave depth). Twelve-lead ECGs were done for 102 consecutive patients with broad-complex tachycardia (QRS width > 110 ms). Two observers, who were unaware of definitive diagnoses validated by electrophysiology, by our diagnostic rules made correct diagnosis of ventricular tachycardia in 63 and 62 of 69 patients, respectively, and correct diagnoses of supraventricular tachycardia in 28 and 22 of 33 patients (sensitivity for ventricular tachycardia 90% and 91%, specificity 67% and 85%). One observer then sought independent P waves in cases diagnosed as supraventricular tachycardia; sensitivity for the diagnosis of ventricular tachycardia rose to 96%, with a specificity of 64%. These criteria, which require only knowledge of typical bundle branch block patterns, were highly sensitive for the important diagnosis of ventricular tachycardia.

Diagnosis, Differential↗

PubMed1994

Radiofrequency ablation of a Mahaim fiber following localization of Mahaim pathway potentials.

We report radiofrequency ablation of a Mahaim fiber in a patient with wide complex supraventricular tachycardia. Pathway potentials from the lateral aspect of the right AV groove were recorded, which were distinct from the His potential. During atrial pacing, decremental properties of the fiber were demonstrated, which resulted in prolongation of the interval between the atrial electrogram and the Mahaim pathway potential. The pathway potentials, preexcitation, and tachycardia disappeared after a single application of radiofrequency energy, after which the patient has remained free of palpitations. Mapping of a Mahaim fiber by identifying pathway potentials thus allowed accurate localization and successful ablation with minimal energy. We therefore suggest that, where possible, recording of such Mahaim potentials may be the optimal technique for Mahaim fiber localization.

Adult↗

PubMed1994

Mechanical, but not infective, pacemaker erosion may be successfully managed by re-implantation of pacemakers.

OBJECTIVE: When a pacemaker box causes erosion it is usually removed and a new pacemaker implanted at a contralateral site. In this study when there was no evidence of systemic infection an attempt was made to clean and reimplant the same pacemaker in the same site. RESULTS: Over 10 years 62 patients had pacemaker reimplantation. In 18 patients the procedure was repeated a second time. Reimplantation was successful after at least six months follow up in 38 patients (61%): in nine two attempts had been made. Mean hospital stay for all patients was 21.3 days; for patients in whom the procedure was successful it was 12.5 days and for those in whom it was unsuccessful it was 35.4 days. 31 (82%) of the 38 patients in whom reimplantation was successful had no bacterial growth from wound swabs from 17/24 (71%) patients in whom reimplantation was unsuccessful (p < 0.001). Bacteria were grown from swabs from 7/8 patients with a protruding wire compared with 9/23 patients with a protruding pacemaker (p = 0.05). Thin patients and those who were older were more likely to have successful reimplantation: neither association reached statistical significance. A clinical impression of infection was not helpful. If re-implantation had been attempted only in the patients with negative wound swabs or intact skin the success rate would have been 74% at a cost of 5010 pounds per patient compared with a cost of 6509 pounds per patient for explantation and a reimplantation of a new contralateral pacemaker. CONCLUSION: These data support the hypothesis that pacemaker erosion is caused by primary infection or by a non-infective process (probably mechanical pressure). Pacemaker erosion that is not caused by infection can be successfully managed by ipsilateral reimplantation and this approach saves money.

Adult↗

PubMed1994

Impact of internal audit on pacemaker prescription and the immediate costs of pacing in the northern region: towards implementation of the recommendations of the British Pacing and Electrophysiology Group.

BACKGROUND: In September 1990 a working party of the British Pacing and Electrophysiology Group recommended the routine use of physiological pacing systems in patients with bradycardia. An audit of the impact of these recommendations on pacemaker prescription in the Freeman Hospital between March 1990 and August 1991 has previously been reported. This paper considers the effect of that internal audit on subsequent pacemaker prescription from September 1991 to February 1993. PATIENTS AND METHODS: The records of 1228 patients who underwent first pacemaker implantation at the Freeman Hospital between March 1990 and February 1993 were audited retrospectively. The patient's age, indication for pacing, pacing mode, and cost of the generator and leads were recorded. The indications for pacing were sinus node dysfunction (24.9%) (including patients with coexistent sinus node dysfunction and atrioventricular block), atrioventricular block (57.2%), atrioventricular block and atrial fibrillation (12.2%), and carotid sinus syndrome (5.7%). There was an increase in carotid sinus syndrome (2.7% to 8.1%) between the two study periods but no other differences in the distribution of case mix or characteristics of patients. The cost of the working party's recommended optimal pacing mode was calculated from multiplication of the mean cost of the recommended unit over the second half of the study period by the number of patients who would have received that unit. RESULTS: Between March 1990 and August 1991 atrial pacing for sinus node dysfunction (AAI, AAIR, DDD, or DDDR) increased by 138% (from 25.0% to 59.6%), mainly because of increased use of AAI mode. Physiological pacing for atrioventricular block (DDD or VVIR) increased by 41% (from 17.0% to 24.0%), and VVIR pacing for atrioventricular block with atrial fibrillation increased by 111% (from 10.5% to 22.2%). After the internal audit (that is, between September 1991 and February 1993), physiological pacing for atrioventricular block increased by a further 126% (from 24.0% to 54.2%). Sixty three per cent of this increase was in the first six months after the internal audit. Pacemaker prescriptions in sinus node dysfunction and atrioventricular block with atrial fibrillation were unchanged (59.6% physiological pacing for sinus node dysfunction and 22.2% v 27.3% VVIR pacing for atrioventricular block with atrial fibrillation). These changes in practice were accompanied by an increase in the age of patients receiving physiological units. Costs of pacemaker hardware for the final six months of the audit (excluding carotid sinus syndrome) increased by 38% over the costs that would have accrued had pacing policy remained the same as for the initial six month period before the circulation of the recommendations of the working party. Adoption of the guidelines of the working party in full would lead to a further 66% increase in the costs of hardware. CONCLUSIONS: The principal effect of the recommendations of the working party alone was increased use of AAI pacing for sinus node dysfunction, with little change in the costs of hardware. The internal audit was followed by an increase in physiological pacing for atrioventricular block, and this has had important financial consequences. Internal audit was followed by closer adherence to the recommendations of the working party.

Aged↗

PubMed1994

Antibiotic prophylaxis in permanent pacemaker implantation: a prospective randomised trial.

BACKGROUND: Pacemaker pocket infection is a potentially serious problem after permanent pacemaker implantation. Antibiotic prophylaxis is commonly prescribed to reduce the incidence of this complication, but current trial evidence of its efficacy is conflicting. A large prospective randomised trial was therefore performed of antibiotic prophylaxis in permanent pacemaker implantation. The intention was firstly to determine whether antibiotic prophylaxis is efficacious in these patients and secondly to identify which patients are at the highest risk of infection. METHODS: A prospective randomised open trial of flucloxacillin (clindamycin if the patient was allergic to penicillin) v no antibiotic was performed in a cohort of patients undergoing first implantation of a permanent pacing system over a 17 month period. Intravenous antibiotics were started at the time of implantation and continued for 48 hours. The trial endpoint was a repeat operation for an infective complication. RESULTS: 473 patients were entered into a randomised trial. 224 received antibiotic prophylaxis and 249 received no antibiotics. A further 183 patients were not randomised but were treated according to the operator's preference (64 antibiotics, 119 no antibiotics); these patients are included only in the analysis of predictors of infection. Patients were followed up for a mean (SD) of 19(5) months. Among the patients in the randomised group there were nine infections requiring a repeat operation, all in the group not receiving antibiotic (P = 0.003). In the total patient cohort there were 13 infections, all but one in the non-antibiotic group (P = 0.006). Nine of the infections presented as erosion of the pulse generator or electrode, three as septicaemia secondary to Staphylococcus aureus, and one as a pocket abscess secondary to Staphylococcus epidermidis. Infections were significantly more common when the operator was inexperienced (< or = 100 previous patients), the operation was prolonged, or after a repeat operation for non-infective complications (principally lead displacement). Infection was not significantly more common in patients identified preoperatively as being at high risk (for example patients with diabetes mellitus, patients receiving long term steroid treatment), although there was a trend in this direction. CONCLUSIONS: Antibiotic prophylaxis significantly reduced the incidence of infective complications requiring a repeat operation after permanent pacemaker implantation. It is suggested that antibiotics should be used routinely.

Aged↗

PubMed1994

Value of physical signs in the diagnosis of ventricular tachycardia.

BACKGROUND: Although the use of physical signs for the diagnosis of ventricular tachycardia (VT) was described in the early 1900s, their value in this role has never been systematically assessed. METHODS AND RESULTS: Using a blinded, randomized protocol, we examined the ability of 26 clinicians to detect ventriculoatrial (VA) dissociation during cardiac pacing in 21 patients with both atrial and ventricular pacing wires in situ after successful ablation of accessory pathways. In protocol 1 (10 patients), pacing was randomized to either ventricular pacing alone (simulating VT) or to atrioventricular sequential pacing (simulating supraventricular tachycardia or VT with intact VA conduction) at rates of 150 or 180 beats per minute. Each patients was examined by four clinicians blinded to the pacing mode. Clinicians were asked to make a diagnosis of "VA association" or "VA dissociation" after examining the patient for variability of the arterial pulse, jugular venous pulse (JVP), and first heart sound. In protocol 2 (11 patients), randomization of pacing mode was performed between examination of each of the three physical signs so that the value of each sign was assessed individually. In protocol 1, a diagnosis of VA dissociation (VT) was made in 21 of 40 observations, with a specificity of 75%, sensitivity of 70%, and a positive predictive value (PPV) of 71%. In protocol 2, from a total of 132 observations (44 for each sign), the sensitivity, specificity, and PPV for a diagnosis of VT were as follows: arterial pulse, 61%, 71%, 70%; JVP, 96%, 75%, 82%; and first heart sound, 58%, 100%, 100%. CONCLUSIONS: It is concluded that, in patients with a regular tachycardia of uncertain origin, clinically detectable variations in the first heart sound and JVP are highly specific and sensitive indicators, respectively, of a diagnosis of VT. Assessment of the arterial pulse is of little value in this role.

Adult↗

PubMed1993

Intravenous adenosine can reveal accessory pathways not revealed by routine electrophysiological testing.

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Adenosine↗

PubMed1993

Intravenous adenosine reveals intermittent preexcitation by direct and indirect effects on accessory pathway conduction.

In some patients with accessory pathways preexcitation occurs intermittently during sinus rhythm. In these patients the antegrade refractory period of the accessory pathway may either exceed the sinus cycle length under some circumstances, or conduction block in the accessory pathway may be variable. The ability of intravenous adenosine to unmask intermittent preexcitation was determined in patients with intermittent preexcitation but absent preexcitation at the time of study. Six patients undergoing assessment of the Wolff-Parkinson-White syndrome received incremental doses of intravenous adenosine (3, 6, and 12 mg). Adenosine administration was repeated in three patients after intravenous beta blockade (propranolol 0.2 mg/kg). Adenosine unmasked preexcitation in all patients. P delta intervals with preexcited beats were substantially shorter than resting PR intervals in all cases (range 40-80 msec shorter). In 4/6 patients preexcitation was seen early, coincident with the onset of atrioventricular nodal block. In 4/6 patients preexcitation was seen late during the secondary sinus tachycardia that follows the direct cardiac effects of adenosine. Two patients exhibited early preexcitation and late preexcitation. Beta blockade failed to prevent early preexcitation (2/2 patients) but abolished preexcitation related to sinus tachycardia (3/3 patients). Early preexcitation, coincident with the onset of AV nodal block, suggests a direct effect of adenosine on accessory pathway conduction. Late preexcitation, occurring during secondary sinus tachycardia, and abolished by beta blockade, suggests enhanced accessory pathway conduction due to sympathetic activation.

Adenosine↗

PubMed1993

Financial audit of antitachycardia pacing for the control of recurrent supraventricular tachycardia.

OBJECTIVE: To assess the financial implications of antitachycardia pacing in patients with frequent supraventricular tachycardia. PATIENTS: Intertach pacemakers were implanted in 25 patients (mean age 47 years, five men): 22 had atrioventricular nodal reentry tachycardia. The patients had failed a mean of 4.9 (range zero to eight) drugs and had been admitted to hospital 3.7 (zero to 31) times over a symptomatic period of 13.9 years (two months to 54 years). RESULTS: The mean admission time for implantation was 2.8 (two to seven) days. One patient with Wolff-Parkinson-White syndrome subsequently underwent surgery. Infection occurred in two patients, and pain over the pacemaker required its resiting in two. Two patients have had one admission each for tachycardia. Six patients remain on anti-arrhythmic drugs. Costs were calculated including value added tax, capital charges, and allocated overheads. The cost a year before pacing was 1174 pounds including drug costs, clinic visits, and hospital admissions. The mean cost of pacemaker implantation was 3364.22 pounds, including the pacemaker and lead, admission and procedure, readmissions and first pacing check. Subsequent annual follow up cost was 73.72 pounds including annual clinic visits and drug costs. The cost of pacing is 4241 pounds whereas medical management costs 7044 pounds assuming pacemaker life of six years: with a 10 year life the cost is 4537 pounds compared with 11,740 pounds: with a 12 year life the cost is 4685 pounds compared with 14,088 pounds. CONCLUSION: The excess cost of implantation of an antitachycardia pacemaker is minimal in patients with frequent supraventricular tachycardia despite drug treatment and is justified by excellent control of symptoms and reduction of drug use and hospital admissions.

Adult↗

PubMed1992

Treatment of hemophilia A with a highly purified factor VIII concentrate prepared by anti-FVIIIc immunoaffinity chromatography.

To reduce the risk of pathogenic virus transmission associated with the therapeutic administration of plasma-derived anti-hemophilic factor (FVIIIc), a process utilizing anti-FVIIIc immunoaffinity chromatography to isolate FVIIIc has been developed. In addition, the starting cryoprecipitate solution has been treated with an organic solvent/detergent mixture to inactivate lipid-enveloped viruses. A final ion exchange chromatography step is used to further remove contaminants, e.g., anti-FVIIIc antibody, potentially leached with FVIIIc during the immunoaffinity step. The purified FVIII is stabilized for lyophilization and storage by the addition of human albumin. The monoclonal anti-FVIIIc antibody used in the immunoaffinity step of the process is not detectable in the final preparation. Viral reduction studies performed at specific steps of the process demonstrate that 11 logs of human immunodeficiency virus (HIV) and greater than 4-5 logs of other lipid-enveloped viruses are inactivated within the first 30 s of exposure to the solvent/detergent mixture and 4-5 logs of various model viruses, e.g. Endomyocarditis virus (EMC), are physically removed during washing of the immunoaffinity column. The lyophilized product is reconstituted using sterile water in a matter of seconds. The pharmacokinetics of Hemofil M were compared to those obtained using a standard heat-treated concentrate (Hemofil CT) in five severe factor VIII deficient hemophiliacs in a randomized, cross-over study. No statistically significant differences were observed in mean half life (p greater than 0.6) or median recovery (p = 0.4) between the two preparations. No clinically significant adverse effects were observed in patients receiving either FVIII preparation.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗