Effect of Propranolol on Ventricular Rate During Atrial Fibrillation in the Wolff-Parkinson-White Syndrome

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74695/1/j.1540-8159.1987.tb04511.x.pd

An Analysis of Post-Pacing R-R Intervals During Atrial Fibrillation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74691/1/j.1540-8159.1986.tb04496.x.pd

The interplay between endogenous catecholamines and induced ventricular tachycardia during electrophysiologic testing

Plasma epinephrine and norepinephrine concentrations were measured before, during, and shortly after induced ventricular tachycardia (VT) in 22 selected patients. Sustained, unimorphic VT was induced by programmed ventricular stimulation and terminated after 45 to 384 seconds by overdrive pacing in all patients. In no patient did VT result in loss of consciousness. The baseline plasma catecholamine concentrations did not correlate with the baseline right ventricular effective refractory period, the cycle length of induced VT, or the number of extrastimuli required to induced VT. Induced VT was not associated with a significant increase in the mean plasma epinephrine concentration. In contrast, the plasma norepinephrine concentration increased from a mean baseline level of 317 +/- 136 pg/ml (mean +/- standard deviation) to 418 +/- 220 pg/ml during VT (p = 0.01) and increased further to 569 +/- 387 pg/ml shortly after VT (p p < 0.05 for each). In eight patients the same configuration of VT was induced on two sequential attempts; in five patients the same number of extrastimull were required for the second induction of VT as for the first, whereas in three patients fewer extrastiuli were required. Plasma cateholamine concentrations were not higher in patients requiring fewer extrastimuli to induce the second episode of VT, either shortly after the first episode of VT or shortly after the second episode of VT. In conclusion, plasma catecholamines do not influence baseline ventricular refractoriness, the cycle length of induced VT, or the VT induction technique. Induced VT, which does not require termination by direct-current countershock, is generally associated with little or no increase in plasma epinephrine and a variable increase in plasma norepinephrine concentration, depending on the severity and duration of hypotension during VT. The plasma catecholamine response to VT does not affect a second induction of VT. Therefore, endogenous catecholamines exert little influence on the results of electrophysiologic testing in patients with sustained VT which does not require termination by direct-current countershock.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26830/1/0000389.pd

Effects of chronic aminodarone therapy on ventricular tachycardia induced by programmed ventricular stimulation

Several studies have reported upon the inducibility of ventricular tachycardia (VT) with programmed ventricular stimulation (PVS) during chronic amiodarone therapy; however, few studies have systematically described and compared the morphology, duration, and cycle length of VT induced by PVS before and after amiodarone. In this study, 26 patients with symptomatic VT or ventricular fibrillation were evaluated by PVS by means of one to three extrastimuli (ES) before treatment and after 2 months of amiodarone therapy. Before amiodarone, sustained unimorphic VT was induced in 21 patients (group A) and symptomatic, nonsustained VT was induced in five patients (group B). After 65 +/- 8 days of amiodarone (total dose 64.5 +/- 8.9 gm, mean +/- S.D.), 15 of 21 patients (71%) in group A had sustained VT, five patients (24%) had nonsustained VT, and one patient had no VT induced. Four of five patients (80%) in group B had sustained VT and one patient had no VT induced. VT was induced by the same or by fewer number of ES in 79% of cases. When the morphologies of the VT induced before and after amiodarone were compared, the morphology of VT induced after amiodarone was the same in only 8 of 24 patients (33%), unimorphic but different in 14 patients (58%), and polymorphic in the remaining two patients. No correlation was found between the serum concentrations of amiodarone, desethylamiodarone, tetraiodothyronine, triiodothyronine, or reverse triiodothyroinine, and similarities or differences in VT morphology, VT cycle length, or the relative number of ES required to induce VT after treatment with amiodarone. Although VT is ofter still inducible after 2 months of amiodarone therapy, the VT induced is different from the baseline VT in the vast majority of patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26864/1/0000429.pd

Immediate reproducibility of clinical and nonclinical forms of induced ventricular tachycardia

This prospective study assessed the immediate reproducibility of clinical and nonclinical forms of ventricular tachycardia (VT) induced by programmed ventricular stimulation. Twenty-three clinical VTs were unimorphic and previously documented and 22 nonclinical VTs (17 polymorphic and 5 unimorphic) were induced in patients with either no documented or suspected history of VT, or documented VT that had a configuration different from that of the induced VT. The stimulation protocol included 1 to 3 ventricular extrastimuli, 2 drive cycle lengths, and 2 right ventricular stimulation sites. Each VT was induced on the first attempt, then the stimulation protocol was repeated twice in the drug-free state. After the first VT induction, 21 of 23 clinical VTs (91%) and 17 of 22 nonclinical VTs (77%) were reinduced on the second attempt. After 2 VT inductions, 21 of 21 clinical VTs (100%) and 15 of 17 nonclinical VTs (88%) were reinduced on the third attempt. The reinduction rates of the clinical and nonclinical VTs were not significantly different. Among the clinical VTs, the reproducibility of the induction technique was 81% after 1 induction and 88% after 2 inductions with the same technique. These results imply that (1) acute drug testing can be reliably performed after 2 inductions but not 1 induction of clinical VT; (2) reproducibility is not helpful in determining whether an induced VT is clinical or nonclinical; and (3) changes in induction technique during drug testing should be interpreted with caution because changes may occur in the absence of drugs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26088/1/0000164.pd

The hemodynamic effects of ventricular pacing with and without atrioventricular synchrony in patients with normal and diminished left ventricular function

The relative hemodynamic effects of heart rate, inotropic state, and atrioventricular (AV) synchrony during ventricular pacing were evaluated in 10 patients with normal left ventricular ejection fraction (LVEF) (0.66 +/- 0.07, mean S.D.) and in eight patients with a diminished LVEF (0.34 +/- 0.18). Hemodynamics were measured at AV intervals of 130, 0, and -130 msec during ventricular pacing at a baseline rate that was 10 pulses/min greater than the resting heart rate, at 130 pulses/min alone, and at 130 pulses/min during continuous intravenous infusion of dobutamine. During baseline ventricular pacing and during ventricular pacing at 130 pulses/min with and without dobutamine, both groups of patients had a significant decrease in cardiac index, stroke volume index, and stroke work index when the AV pacing interval was decreased from 130 to 0 msec. The observed decrease in these three hemodynamic variables was similar when patients with diminished LVEF were compared to patients with normal LVEF. No further significant decrease in cardiac index, stroke volume index, and stroke work index occurred in either group when the AV interval was changed from 0 to -130 msec during baseline ventricular pacing or during ventricular pacing at 130 with and without dobutamine. Beneficial hemodynamic effects occur during ventricular pacing when AV synchrony is maintained at resting heart rates and during increases in heart rate and inotropic state in patients with normal and diminished LVEF.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26988/1/0000555.pd

Pharmacodynamics of intravenous procainamide as used during acute electropharmacologic testing

No previous studies have determined the pharmacodynamics of intravenous procainamide when administered in a dose of 15 mg/kg and at a rate of 50 mg/min, as is common practice during etectropharmacologic testing. In this study, 30 patients received procainamide in this fashion; the right ventricular effective refractory period and the QRS duration at a ventricular pacing rate of 120/minute were then determined every minute for 20 minutes. Ten patients received no maintenance infusion of procainamide (group A), 10 received a 4 [mu]g/min maintenance infusion (group B) and 10 received an 8 mg/min maintenance infusion (group C). Ten additional patients received no procainamide and served as control subjects (group D). The plasma procainamide concentration was measured at 1, 5, 10,15 and 20 minutes after the loading dose was administered. A stable plasma procainamide concentration was not present in group A, B, or C until 15 minutes after infusion of the loading dose. The effective refractory period and QRS duration increased compared with baseline at 1 minute, decreased between 1 and 10 minutes and then remained essentially unchanged between 10 and 20 minutes in all 3 treatment groups. Concentration-effect relation was linear in each treatment group. The plasma procainamide concentrations in group C were significantly greater than in group A; however, the effects on refractoriness and QRS duration were similar in both groups. These findings indicate that with a procainamide dosing method commonly used during electropharmacologic testing, the plasma procainamide concentration decreases significantly during the first 15 minutes after the loading dose is administered; the effects of procainamide on ventricular refractoriness and conduction parallel the changes in the plasma procainamide concentration; and an 8 mg/min maintenance infusion of procainamide results in higher plasma procainamide concentrations without an associated increase in ventricular refractoriness or slowing of conduction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27475/1/0000517.pd

Need for recovery amongst emergency physicians in the UK and Ireland: A cross-sectional survey

OBJECTIVES: To determine the need for recovery (NFR) among emergency physicians and to identify demographic and occupational characteristics associated with higher NFR scores. DESIGN: Cross-sectional electronic survey. SETTING: Emergency departments (EDs) (n=112) in the UK and Ireland. PARTICIPANTS: Emergency physicians, defined as any registered physician working principally within the ED, responding between June and July 2019. MAIN OUTCOME MEASURE: NFR Scale, an 11-item self-administered questionnaire that assesses how work demands affect intershift recovery. RESULTS: The median NFR Score for all 4247 eligible, consented participants with a valid NFR Score was 70.0 (95% CI: 65.5 to 74.5), with an IQR of 45.5-90.0. A linear regression model indicated statistically significant associations between gender, health conditions, type of ED, clinical grade, access to annual and study leave, and time spent working out-of-hours. Groups including male physicians, consultants, general practitioners (GPs) within the ED, those working in paediatric EDs and those with no long-term health condition or disability had a lower NFR Score. After adjusting for these characteristics, the NFR Score increased by 3.7 (95% CI: 0.3 to 7.1) and 6.43 (95% CI: 2.0 to 10.8) for those with difficulty accessing annual and study leave, respectively. Increased percentage of out-of-hours work increased NFR Score almost linearly: 26%-50% out-of-hours work=5.7 (95% CI: 3.1 to 8.4); 51%-75% out-of-hours work=10.3 (95% CI: 7.6 to 13.0); 76%-100% out-of-hours work=14.5 (95% CI: 11.0 to 17.9). CONCLUSION: Higher NFR scores were observed among emergency physicians than reported in any other profession or population to date. While out-of-hours working is unavoidable, the linear relationship observed suggests that any reduction may result in NFR improvement. Evidence-based strategies to improve well-being such as proportional out-of-hours working and improved access to annual and study leave should be carefully considered and implemented where feasible

Local government finance in Ireland

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