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Biomedical subjects

H Mickley

Publications and source records attributed to H Mickley.

At least 19 recordsLinked to original sources

Changing circadian variation of transient myocardial ischemia during the first year after a first acute myocardial infarction.

In a consecutive series of 123 men (aged 55 +/- 8 years) with a recent first acute myocardial infarction (AMI), 24-hour ambulatory ST-segment monitoring was performed early after discharge (day 11 +/- 5), 6 months (day 185 +/- 6) and 1 year (day 368 +/- 8) after AMI. No difference in the prevalence of transient myocardial ischemia was found between the 3 recordings (17, 17 and 20%), and most ischemic episodes were silent (98, 100 and 97%). In the early postinfarction period, a peak of ischemic activity was demonstrated between 6 P.M. and midnight (40 of 93 episodes [43%]). Over time, the maximal occurrence of ischemia gradually advanced toward the morning hours with a peak activity between 6 A.M. and noon at 1-year follow-up (32 of 73 episodes [44%]). Significantly more patients (16 of 21 [76%]) had ischemia from 6 P.M. to midnight at discharge compared with the findings 1 year later (9 of 23 patients [39%]) (p < 0.03). An opposite trend was found regarding patients who exhibited ischemic episodes in the hours from 6 A.M. to noon: 10 of 21 patients (48%) early after discharge versus 17 of 23 patients (74%) at 1-year follow-up (p = not significant). Results from the 6-month recording displayed characteristics between the findings from discharge and 1-year ambulatory monitoring. The pathophysiologic processes underlying the observations from this study are unknown. The change in circadian periodicity could not be explained from differences in heart rate variation patterns or medical antianginal treatment among the 3 recordings.(ABSTRACT TRUNCATED AT 250 WORDS)

Chi-Square Distribution

Thrombolysis significantly reduces transient myocardial ischaemia following first acute myocardial infarction.

In order to investigate whether thrombolysis affects residual myocardial ischaemia, we prospectively performed a predischarge maximal exercise test and early out-of-hospital ambulatory ST segment monitoring in 123 consecutive men surviving a first acute myocardial infarction (AMI). Seventy-four patients fulfilled our criteria for thrombolysis, but only the last 35 patients included received thrombolytic therapy. As thrombolysis was not available in our Department at the start of the study, the first 39 patients included were conservatively treated (controls). No significant differences in baseline clinical characteristics were found between the two groups. In-hospital atrial fibrillation and digoxin therapy was more prevalent in controls (P less than 0.05). During exercise, thrombolysed patients reached a higher maximal work capacity compared with controls: 160 +/- 41 vs 139 +/- 34 W (P less than 0.02). Thrombolysis resulted in a non-significant reduction in exercise-induced ST segment depression: prevalence 43% vs 62% in controls. However, during ambulatory monitoring the duration of transient myocardial ischaemia was significantly reduced in thrombolysed patients: 322 min vs 1144 min in controls (P less than 0.05). Thrombolysed patients reached a higher heart rate during transient ischaemic episodes: 114 +/- 17 vs 93 +/- 11 b.min-1 in controls (P less than 0.001). In conclusion, thrombolytic therapy administered for a first AMI significantly reduces the burden of transient myocardial ischaemia. This may explain the improvement in myocardial function during physical activities, which was also observed in this study.

Coronary Circulation

Rapid estimation of left ventricular ejection fraction in acute myocardial infarction by echocardiographic wall motion analysis.

Echocardiographic estimates of left ventricular ejection fraction (ECHO-LVEF) in acute myocardial infarction (AMI) were obtained by a new approach, using visual analysis of left ventricular wall motion in a nine-segment model. The method was validated in 41 patients using radionuclide ventriculography (RNV) and contrast ventriculography measurements of LVEF for comparison. ECHO-LVEF from the 41 patients correlated well with the reference methods (y = 1.5x - 14.7, r = 0.93; linear regression analysis; 95% confidence limit for a single determination of ECHO-LVEF was 17.2). Interobserver variability by linear regression was r = 0.89, SEE = 7.1 with a mean difference between paired observations of -1.5 +/- 6.9 (SD). In a random sample of 18 patients (45 observations), ECHO-LVEF allowed separation between RNV-LVEF values greater than or equal to 40 and less than 40, representing low and high risk groups following AMI. Thus, the results showed that simple, readily available wall motion-derived estimates of LVEF were as closely associated with LVEF measured by standard reference methods as were previously published, more cumbersome, planimetric echocardiographic methods. Reporting on global LVEF function in LVEF units rather than in nonstandardized wall motion scores of index values may facilitate intra- and interhospital communication and the use of optimized echocardiographic risk stratification after AMI.

Echocardiography

Circadian variation of transient myocardial ischemia in the early out-of-hospital period after first acute myocardial infarction.

Circadian rhythms have been demonstrated in acute myocardial infarction (AMI) and in other clinical cardiac dysfunctions. The purpose of this study was to elucidate whether a circadian pattern of transient myocardial ischemia exists after first AMI. Prospectively, 24-hour ambulatory ST-segment monitoring was initiated at discharge on day 11 +/- 5 in 123 consecutive survivors of first AMI. A total of 93 ischemic episodes (91 asymptomatic) occurred in 21 of the 123 patients (17%) (mean duration of 30 minutes, range 4 to 292). A significant circadian rhythm of transient myocardial ischemia was found with a peak activity occurring in the evening hours (p less than 0.01). Thus, 43% of ischemic episodes and 42% of ischemic time occurred between 6 P.M. and 12 midnight. The characteristics of morning and evening episodes were similar, except for the heart rate at maximal ST-segment depression, which was significantly higher during morning episodes (p less than 0.02). Patients with transient myocardial ischemia had a diurnal distribution similar to the circadian variation displayed during ischemic activity. Thus, 16 of the 21 patients had ischemic episodes from 6 P.M. to 12 midnight versus 10 patients from 6 A.M. to 12 noon (p less than 0.01). The 24-hour mean minimal heart rate was significantly higher in patients with than without ischemic episodes (p less than 0.02). In conclusion, this study has established a significant circadian peak of transient myocardial ischemia in the evening hours in survivors of first AMI. Whether the pattern displayed is due to endogenous biologic functions or cyclic variations, or both, in the external environment needs to be clarified.

Circadian Rhythm

[Temporary pacemaker treatment in Denmark].

The employment of temporary pacing (TP) in Denmark in 1986 is illustrated by means of a questionnaire investigation. Seventy-four out of 77 Danish hospitals with a medical-cardiological specialist returned usable replies. Facilities for temporary pacing were available in 39 (53%) of the hospitals. The method of pacing most extensively employed was the transvenous method which was used in 33 hospitals while external transcutaneous pacing by Zoll's method was available in 13 hospitals. In transvenous pacing, the subclavian vein was employed routinely in 24 hospitals while a cubital vein was used primarily in eight hospitals. More than 85% of the pacing catheters employed were of disposable type. Only one hospital always employed a permanent pacing lead which could be utilised if permanent pacing should be required. A total of 486 patients with or without acute myocardial infarction (AMI) were submitted to temporary pacing. Employment of temporary pacing in patients with AMI was 0-8.3% (average 3.7%). In general, it was found that hospitals with cardiac laboratory facilities showed the greatest temporary pacing activity. The indications for temporary pacing are assessed on the basis of two case reports. The greatest employment of temporary pacing was found in patients with AMI with third degree atrioventricular block and ventricular escape rhythm (anterior wall 74%, posterior wall 56%). Employment of temporary pacing was least in symptomfree patients with anterior wall AMI and bifascicular block (9%).

Cardiac Pacing, Artificial

Predischarge maximal exercise test identifies risk for cardiac death in patients with acute myocardial infarction.

A maximal exercise test was performed in 54 patients with acute myocardial infarction (AMI) before discharge and in 49 age-matched control subjects. The long-term prognosis was assessed after an average follow-up of 7.6 years in AMI patients and 5.8 years in control subjects. The maximal work capacity and systolic blood pressure increase in AMI patients was 59% that of control subjects (p less than 0.001). Seventeen AMI patients had significant ST-segment shifts, 13 with ST depression and 4 with ST elevation. In AMI patients experiencing a cardiac death during follow-up the maximal work capacity and systolic blood pressure increase were significantly lower than in survivors and those who died from noncardiac reasons (p less than 0.01; p less than 0.05), with no difference between these groups in the number of patients with ST-segment shifts. The average maximal work capacity of control subjects was 143 watts. A maximal work capacity half this (less than or equal to 72 watts) predicted long-term mortality in AMI patients (p less than 0.001). In addition a low increase in systolic blood pressure (less than 30 mm Hg) also predicted long-term mortality (p less than 0.005), whereas ST shifts were of no significant value. In this study maximal work capacity turned out to be the best single exercise variable for identifying groups of AMI patients with very low and relative high risk of cardiac death. When all 3 exercise variables were combined, the predischarge maximal exercise test was of great value in identifying AMI patients at low risk for cardiac death (predictive value of a negative test: 95%).

Aged

[Complications of long-term treatment with vitamin K antagonists].

Long-term treatment with vitamin K antagonists (vKA) frequently involves complications. The commonest complication is haemorrhage and cases of serious haemorrhage are stated in the literature to occur with a frequency per 1,000 treatment years of 12-108, of which 2-17 are fatal. The majority of deaths associated with haemorrhage are due to intracranial haemorrhage. Notifications of complications of vKA treatment in Denmark are considerably fewer than might be anticipated from the literature. The stability of anticoagulation treatment decreases with the number of drugs administered simultaneously and numerous drugs and other factors interact with the effect of vKA. A series of examples are reviewed and some known drugs which do not interact are mentioned. Non-haemorrhagic side effects of coumarin derivatives are rare. Anticoagulation treatment during pregnancy is associated with very special problems and must be regarded as a specialist task.

Anticoagulants

Antiarrhythmic treatment with flecainide (Tambocor). Clinical experience from 107 patients.

The long-term clinical effect of oral flecainide treatment was evaluated in 107 pts (10-82 yrs). Indications for treatment were: atrial fibrillation 38%, atrial flutter 16%, ventricular tachycardia 24%, ventricular ectopic beats 10% and supraventricular tachycardia 12%. Daily flecainide dosage was 200 (100-400) mg. Follow-up period 3 mths (15 days-15 mths). Based on the history and ECG flecainide had been effective in 51 pts. The improvement was most pronounced in pts suffering from supraventricular tachycardia involving an accessory bypass tract (84-92%). Flecainide had been discontinued in 50 pts due to: insufficient effect in 28, side effects in 17 and for other reasons in 5. The side effects indicating flecainide withdrawal (pts) were: cerebral symptoms (4), gastrointestinal complaints (2), bradyarrhythmias (2), heart failure (3) and suspected pro-arrhythmia (4). (Ventricular tachycardia in 3, 1:1 AV-conducting during atrial flutter in 1).

Administration, Oral

[Exercise-induced ST segment depression following acute myocardial infarction. Occurrence and prognostic significance].

On the basis of a review of 20 investigations (3,587 patients), the prevalence of significant ST-segment-depression (ST-depr) in patients performing an exercise test 9-30 days after acute myocardial infarction (AMI) was found to be 33% (3-70%). The reason for the considerable variation is due to a combination of several factors: 1) different and frequently incomplete definition of significant ST-depr; 2) heterogenically composed patient groups (first vs subsequent AMI, different prevalence of infarct types and localization, consecutive vs selected patients, +/- cardioactive drugs during the exercise test); 3) different procedures for the exercise tests (submaximal vs maximal; few vs several ECG leads). The great variation in the prevalence of ST-depr, is also reflected in the prognostic significance. In about half of the investigations ST-depr has been prognostic for future death and/or cardiac events while ECG changes as an isolated variable did not prove to be of prognostic significance in the remainder. In general, it may be stated that a maximal exercise test with several ECG leads is more sensitive while ST-depr at a submaximal work capacity appears to be more specific for subsequent cardiac events.

Aged

[Leisure activities and sports in younger pacemaker patients].

Based on a semistructured questionnaire the consequences of pacemaker treatment on leisure activities in 81 patients aged 20 to 60 years were investigated. At follow up after an average of 33.8 months, 36 of the 72 survivors participated in the following out-of-the-home physical activities: Badminton (3), bicycle-riding (6), firefighting (1), fishing (3), golf (2), gymnastics (3), handball (1), hunting (4), riding (1), running/jogging (4), sailing (5), shooting (2), skiing (3), soccer (5), swimming (1), theatre (1), chorus (1), and tennis (2). No significant changes in the levels of activity before and after pacemaker implantation were observed. Twenty of the patients did not feel the pacemaker had affected their levels of physical activity while ten patients experienced improvement in their physical capacities. Six patients felt that the pleasure in performing their favourite sport was restricted mainly due to fear of damaging the battery. Fifteen patients (21%) were members of sport clubs. These results imply that several leisure activities are available for pacemaker patients. In case a particular sport is of interest, this should be taken into account when the sitting of the pacemaker battery is decided.

Adult

Runaway pacemaker: a still existing complication and therapeutic guidelines.

Runaway pacemaker is a rare, but still existing potential lethal complication in permanent pacemakers. Within 4 1/2 years, we saw two cases of runaway pacemaker in patients with multiprogrammable, VVI pacemakers (Siemens-Elema, Model 668). In both cases a pacemaker-induced ventricular tachycardia (rate 240-260 beats/min) was documented. One patient died. Runaway pacemakers must be exchanged as soon as possible. Until this can be accomplished, different emergency maneuvers should be tried. As documented in the cases presented, placing a magnet over the pacemaker may result in a lower, more physiological pacing rate. Reprogramming the pulse generator to a lower output or the use of external chest wall overdrive stimulation may also be successful, but these procedures require the presence of an adequate escape rhythm. If this is not the case or the former maneuvers have failed, an external pacemaker may be connected to the permanent pacing lead. Thereafter, the lead can be safely cut. As an alternative, a temporary transvenous pacing lead may be established prior to disconnecting the permanent pacing lead.

Aged

The effect of carotid sinus massage is independent of posture in patients with heart disease.

The influence of posture on the effect of carotid sinus massage (CSM) in patients with heart disease has not been systematically evaluated. In the present study CSM was performed in 80 patients (mean age 55 +/- 10 (SD) years) suffering from various cardiovascular diseases. Each subject had unilateral right- and left-sided CSM performed in the supine and in the sitting position, while heart rate and systolic blood pressure were monitored. No statistically significant differences in the CSM-induced response in systolic blood pressure or heart rate were found between the two postures. In the supine position the drop in heart rate was significantly greater after right-sided than after left-sided CSM (P less than 0.05). In only one patient (1%) was a significant carotid sinus reflex evoked. The response was cardioinhibitory with asystole for 3700 ms during right-sided, supine CSM. These results imply that posture does not influence the effect of CSM in patients suffering from heart disease.

Aged

Subjective consequences of permanent pacemaker therapy in patients under the age of retirement.

During a 5-year period, 81 patients ages 20 to 60 years old had implantation of a permanent cardiac pacemaker at the University Hospital, Odense. At follow-up, during 1985, the 73 survivors received a semi-structured questionnaire regarding subjective consequences of pacemaker therapy, and 72 people (98.6%) agreed to participate. The mean pacing period (range) was 33.8 (11-72) months. Surgical intervention was required in 14 patients (19.4%) during follow-up. Regarding all symptoms 67 patients (93.1%) perceived benefit from the pacemaker. The effectiveness of cardiac pacing was most pronounced in subjects suffering from syncope and/or dizziness. Eight patients (11.1%) perceived anxiety most frequently due to fear of pacing failure. Physical complaints were present in 17 patients (23.6%), and the discomfort was mainly due to the size of generator, pain/tenderness from the scar or a sensation of "impulses"/palpitations. To the majority (49 patients or 68.1%) pacemaker treatment did not influence quality of sexual activity. Six patients (8.3%) perceived an improvement, whereas a corresponding number felt deterioration in sexual activity following pacemaker implantation. Pacemaker therapy had not affected life quality in 30 (41.7%) of the patients. However 31 patients (43%) felt an improvement, and only a minority of ten patients (13.9%) perceived deterioration in quality of life owed to pacemaker therapy.

Adult