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R Adamec

Publications and source records attributed to R Adamec.

At least 19 recordsLinked to original sources
PubMed2001

Does long term potentiation in periacqueductal gray (PAG) mediate lasting changes in rodent anxiety-like behavior (ALB) produced by predator stress?--Effects of low frequency stimulation (LFS) of PAG on place preference and changes in ALB produced by predator stress.

The effects on rodent behavior of low frequency bilateral stimulation (LFS, 900 pulses at 1 Hz) of periacqueducatal gray (PAG) was investigated. The first experiment examined aversive qualities of LFS in a place preference paradigm. There was no evidence of a place preference after 1 or 7 applications of LFS. After the first LFS, rats showed longer latencies to leave the conditioned chamber, suggesting a positively reinforcing effect of LFS. Latency differences were not accounted for by freezing or immobility prior to leaving. Rats with electrodes outside the PAG did not show these effects. After repeated LFS, stimulated rats did not differ from controls in place preference or in anxiety-like behavior (ALB). Experiment 2 studied the effects of predator stress in unimplanted rats on an extended battery of measures of ALB in hole board, plus maze and light/dark box tests of rodent anxiety. Effects of electrode damage in the PAG on ALB was also examined. In addition, the effect of 7 applications of bilateral LFS of PAG on ALB following a 5 min unprotected exposure of rats to a cat (predator stress) was examined. Predator stress lastingly changed a wide variety of behaviors in the plus maze, [Rodgers, Behav. Pharmacol. 8 (1997) 477] replicating and extending previous reports. A new finding is an increase in light avoidance in the light/dark box test. Moreover, factor analysis revealed open arm avoidance, risk assessment, light avoidance and cautious exploration loaded on independent factors, replicating and extending previous findings. Bilateral, but not unilateral, damage specific to PAG was also found to be anxiolytic in plus maze measures of ALB. Bilateral implants in the PAG seemed to prevent many of the effects of predator stress on ALB measured 8 days later. Nevertheless, predator stress did decrease head dips in the open arm and LFS reversed this effect. Light avoidance also increased following predator stress and LFS reversed this increase. These findings suggest the PAG occupies an important position in the final common path of substrate changes mediating effects of predator stress on a range of behaviors in the rodent. The fact that LFS in the PAG can reverse stress induced changes in behavior supports the idea that LTP in PAG mediates stress induced increases in anxiety in rodents, as it does in the cat [Adamec, Neurosci. Biobevav. Rev. 21(6) (1997) 755; Adamec, J. Psychopharmacol. 2000 (in press); Adamec, J. Psychopharmacol. 2000 (in press); Adamec, J. Psychopharmacol. 12(2) (1998) 129; Adamec, J. Psychopharmacol. 12(13) (1998) 227].

Animals↗
PubMed2000

Neuroplasticity in specific limbic system circuits may mediate specific kindling induced changes in animal affect-implications for understanding anxiety associated with epilepsy.

In two complementary experiments, we studied the effects of low frequency stimulation (LFS) of the amygdala on behavioral effects of kindling in rats and cats. These studies tested the hypothesis that kindling induced long term potentiation (KLTP) in amygdala circuits underlies interictal behavioral change. Since LFS can depotentiate LTP, it was predicted that LFS should both depotentiate KLTP and reverse behavioral effects of kindling. In cats, the effects of LFS on KLTP of amygdala efferents was studied, and related to behavioral effects. Partial ventral hippocampal kindling in cats and right amygdala kindling in rodents lastingly increased defensive response to rats in cats, and anxiety-like behavior (ALB) in the elevated plus-maze in rats. In addition, partial kindling reduced predatory attack behavior in cats independent of its effects on defensive response. Partial kindling also induced KLTP of amygdala efferent transmission to ventromedial hypothalamus (VMH) and periaqueductal gray (PAG) in left and right hemispheres. Depotentiation of amygdala efferent KLTP by bilateral amygdala LFS selectively reduced KLTP in right amygdala efferents. At the same time, defensive behavior, but not attack behavior, was returned to levels seen prior to partial kindling. Defensiveness returned to post kindling levels between 44 and 76days after LFS. At the same time, LTP was restored in the right Amygdalo-PAG pathway only. These findings suggest that lasting change in affect produced by kindling depends on LTP of right amygdala efferent transmission to PAG, replicating studies of the effects of FG-7142 on brain and behavior in the cat. The findings suggest further that the spectrum of behavioral changes produced by partial kindling are dependent on changes in a variety of neural circuits, and that amygdala efferent transmission changes are responsible for changes in defensive behavior, but not attack behavior. Effects of LFS were not due to damage, as thresholds to evoke amygdala efferent response were unchanged. Other data suggest KLTP and depotentiation in right Amygdalo-PAG may reflect changes in glutamate receptor density/synapse number. Kindling effects on rat ALB persisted for at least 1month. Bilateral but not unilateral amygdala LFS reversed the effects of kindling on risk assessment in the plus maze for at least 3weeks. Bilateral LFS also reversed the effects of kindling on open arm exploration, but effects were shorter lived, appearing at 1day but not 3weeks after kindling and LFS. These findings are consistent with other studies which suggest that amygdala neuroplasticity in separable amygdala circuits mediates lasting changes in open arm avoidance and risk assessment. Taken together, the findings of both studies support the hypothesis that a form of LTP of specific amygdala circuits underlies lasting changes in affect produced by limbic kindling. Clinical implications of these findings are discussed.

Aggression↗
PubMed2000

Intravenous amiodarone or magnesium sulphate is not cost-beneficial prophylaxis for atrial fibrillation after coronary artery bypass surgery.

Our aims were to examine whether the administration of amiodarone or magnesium sulphate after coronary artery bypass graft surgery (CABG) could reduce the occurrence of atrial fibrillation, and to identify the risk factors associated with atrial fibrillation after CABG. Patients scheduled for elective CABG (n = 155) were allocated randomly, in a controlled double-blind study, to receive immediately after surgery a 72-h infusion of amiodarone (900 mg per 24 h), magnesium (4 g per 24 h) or placebo (0.9% NaCl; 50 ml per 24 h) intravenously. A 72-h Holter ECG was recorded concomitantly. The primary end-point was the prevention of atrial fibrillation; its onset was considered as prophylactic failure. An interim safety analysis was performed in 147 patients. The cumulative occurrence of atrial fibrillation was 27% in the placebo group, 14% in the amiodarone group (P = 0.14) and 23% in the magnesium group (P = 0.82). Although amiodarone delayed the onset of the first tachyarrhythmic episode (P = 0.02), it was associated with the need for longer periods of vasoactive drug infusion and invasive monitoring and a longer stay in the intensive care unit. Variables associated with the onset of atrial fibrillation were older age (odds ratio 1.9) and a plasma magnesium concentration at 24 h of less than 0.95 mmol litre-1 (odds ratio 6.7). Postoperative administration of amiodarone reduced the occurrence of atrial fibrillation after elective CABG surgery, but was associated with a longer duration of cardiovascular instability and longer need for intensive care; magnesium prophylaxis had no effect. Advanced age and a low plasma magnesium concentration are risk factors for postoperative atrial fibrillation.

Adult↗
PubMed2000

Atrial overdriving is beneficial in patients with atrial arrhythmias: first results of the PROVE Study.

The AF Prevention by Overdriving (PROVE) trial is an ongoing prospective study of the effectiveness of atrial overdrive pacing combined with an Automatic Rest Rate function in the prevention of atrial arrhythmias. All patients who have received a Talent DR 213 pacemaker are eligible for enrollment into the study. After a 1-month monitoring period, the patients are divided into two groups. Group I includes patients with > or = 2 appropriate mode-switch (MS) episodes, or 1 MS episode of > or = 10 minutes, and/or > 300 atrial runs of > 5 beats/month. Group II includes all other patients. The number and duration of atrial arrhythmias are measured the pacemaker's Automatic Interpretation and Data Analysis software (AIDA). Patients' quality-of-life is measured by a validated functional status questionnaire. After having been grouped, the patients are randomly assigned, in a crossover design, to standard DDDR or overdrive pacing + Rest Rate, each programmed for a 3-month period. Preliminary results in 78 patients show a 34% reduction in the mean number of MS, and a mean 48% shortening of the overall duration of the episodes by overdrive pacing + Rest Rate, achieved by a mean 84% prevalence of atrial pacing. Overdrive pacing + Rest Rate was well tolerated and associated with a slight improvement in quality-of-life.

Aged↗
PubMed1999

Association between nonreentrant supraventricular tachycardia and atrioventricular node reentrant tachycardia: a presentation of dual AV node physiology.

Persistent simultaneous conduction of P waves over a fast and a slow nodal pathway defines the nonreentrant type of supraventricular tachycardia, usually not associated with reciprocating movements. We report a unique association between this uncommon tachycardia and a usual AV nodal reentrant tachycardia, made possible by the existence of three different nodal pathways.

Atrioventricular Node↗
PubMed1998

Neural plasticity, neuropeptides and anxiety in animals--implications for understanding and treating affective disorder following traumatic stress in humans.

Exposure of rats to cats (predator stress) lastingly increases rodent anxiety-like behavior (ALB) in the elevated plus-maze. Previous work shows that lasting changes in ALB following predator stress depend on NMDA and CCKB receptors. In this paper we describe the effects of differing degrees of predator exposure on behavior. Effects depend on the behavioral measure. In general, exposure to predator odor is less provocative of lasting change in ALB than is unprotected exposure to a cat. In addition, we examine the development of effects of unprotected predator exposure over time. Lasting effects on ALB begin at 30 min to 1 h after predator stress and persist for at least 3 weeks. We also report a complex pattern of effects of predator stress on neuroendocrine and stress peptide (bombesin, CRF and AVP) levels in a variety of brain areas. Not surprisingly, predator exposure increases plasma levels of corticosterone and ACTH. Central changes in peptide content in the hypothalamo-pituitary axis, related hypothalamic nuclei, limbic and brain stem areas are also noted. Finally, path analysis demonstrates a replicable relationship between cat behavior, rat defensive behavior and degree of increase in ALB one week later. It is proposed that behavioral changes following predator stress may model anxiety associated with PTSD.

Animals↗
PubMed1998

Atrial vulnerability in patients with paroxysmal "lone" atrial fibrillation.

Little is known about the electrophysiological properties of the atrium predisposing to paroxysmal atrial fibrillation (AF), especially in patients without structural heart disease. This study was conducted to analyze intraatrial conduction, atrial refractoriness, and arrhythmia inducibility in patients with lone paroxysmal AF. An electrophysiological study was performed in 24 patients with a documented history of lone paroxysmal AF but in sinus rhythm at the time of the electrophysiological study. Twelve patients without any history of atrial arrhythmias served as controls. The patients with lone paroxysmal AF showed a significant prolonged local conduction time S1A1 (70 +/- 21 ms vs 36 +/- 12 ms, P < 0.0001), a lack of rate adaptation of the functional refractory period (FRP changes/cycle length changes < 10% in 15 of 24 patients with lone paroxysmal AF vs 1/12 controls, P = 0.002) and a higher incidence of inducible AF with only one extrastimulus (13/24 vs 0/12, P = 0.0014). The total P wave duration in the surface ECG (89 +/- 14 ms vs 83 +/- 8 ms, P = 0.15), the intraatrial conduction time (36 +/- 14 ms vs 28 +/- 8 ms, P = 0.07), the presence of a fragmented atrial electrogram (16/24 vs 7/12, P = 0.62), the absolute value of the effective refractory period (204 +/- 28 ms vs 212 +/- 23 ms, P = 0.42), and the vulnerability index (3.0 +/- 1.5 vs 3.6 +/- 1.5, P = 0.26) were not statistically different between the two groups. The presence of a prolonged (> 50 ms) S1A1 and/or the presence of a lack of rate adaptation of the FRP and/or the presence of inducible AF identified patients with spontaneous lone paroxysmal AF with a sensitivity of 96%, a specificity of 67%, a positive predictive value of 85%, and a negative predictive value of 89%. In patients with lone paroxysmal AF, the electrophysiological study using conventional techniques allows not only to detect AF inducibility using a nonaggressive protocol, but also to reveal several electrophysiological abnormalities related to the atrial substrate itself. This atrial vulnerability may explain the high incidence of recurrences in patients with lone paroxysmal AF.

Atrial Fibrillation↗
PubMed1997

Long-term prognostic significance of ventricular late potentials after a first acute myocardial infarction.

Ventricular late potentials (VLP) have been shown to be independent predictors of arrhythmic events after myocardial infarction. However, many studies have had one or more limitations: limited follow-up period, small study group, possible selection bias, inadequate statistical analysis, or inclusion of patients with previous infarction. The purpose of this study was to assess the long-term prognostic value of VLP in a large group of unselected patients after a first acute myocardial infarction. Time-domain signal averaging was performed in 458 patients (380 male, 78 female, mean age 59 +/- 11 years) a mean of 10 days (range 7 to 13 days) after a first acute myocardial infarction. The overall prevalence of VLP was 20% (90 of 458 patients). By univariate analysis a left ventricular ejection fraction <40% (p = 0.002) and the presence of an occluded infarct-related artery (p = 0.006) were the only statistically significant predictors for the development of VLP. During a median follow-up of 70 months, 21 (5%) patients died suddenly, and 11 (2%) patients had documented sustained ventricular tachycardia. The presence of VLP (p < 0.0001), older age (p = 0.02), and an occluded infarct-related artery (p = 0.045) were the only variables significantly associated with the occurrence of serious arrhythmic events during follow-up. The probability of having no arrhythmic events was 99% at 1 year and 96% at 5 years in the absence of VLP and 87% at 1 year and 80% at 5 years in the presence of VLP (4.6-fold increase in arrhythmic risk; 95% confidence interval: 2.3 to 9.1). VLPs are powerful predictors of serious arrhythmic events in patients after a first acute myocardial infarction, and their prognostic value, although waning with time, persists for at least 7 years. This study also provides further evidence that an open infarct-related artery may reduce the arrhythmic risk after myocardial infarction.

Action Potentials↗
PubMed1997

Transmitter systems involved in neural plasticity underlying increased anxiety and defense--implications for understanding anxiety following traumatic stress.

Lasting changes in anxiety-like behavior (ALB) may be produced in several ways. These include partial limbic kindling, injection of the beta-carboline FG-7142, and brief, non-injurious, exposure of rodents to cats (predator stress). Both seizures and FG-7142 induce long-term potentiation (LTP) in efferent pathways of the amygdala known to participate in feline defensive behavior. By comparing the behavioral and physiological effects of partial kindling and injection of FG-7142, NMDA-dependent LTP in the right amygdalo-periacqueductal gray (PAG) pathway emerges as being critical to maintained increases in feline ALB. A similar dependence on NMDA-mediated processes is described for lasting increases in rodent ALB following predator stress. The lasting aftereffects of predator stress on a variety of measures parallel many of the symptoms of post-traumatic stress disorder (PTSD). Support is provided for the idea that behavioral changes following FG-7142 and predator stress may model anxiety associated with PTSD. Moreover, it is suggested that both models share mechanisms in common involving the PAG. These mechanisms likely involve initiation of LTP by NMDA receptors, and prolongation of LTP by CCKB receptors. To the extent that response to the stressors reviewed here mimics the symptoms of PTSD, the data implicate NMDA-mediated processes in the creation of what van der Kolk has called permanent emotional memories in PTSD. Their representation may be in the form of NMDA-dependent LTP of transmission within the amygdala and between the amygdala and its efferents. CCK may play a pivotal role in prolonging limbic LTP and anxiety following traumatic stress. Since block of CCKB receptors before and after the stressor prevents lasting increases in ALB, pharmacological intervention to block CCK receptors shortly after a traumatic stressor might be efficacious in mitigating the permanence of these emotional memories.

Aggression↗
PubMed1996

Immediate and day-to-day reproducibility of the signal-averaged electrocardiogram in patients with coronary artery disease.

The purpose of this study was to prospectively evaluate the immediate (5 minutes) and short-term (1 day) reproducibility of the signal-averaged electrocardiogram (SAECG) in patients with coronary artery disease. A total of 59 consecutive patients with coronary artery disease (50 male, 9 female, mean age 59 +/- 13 years) were included. Analysis was performed using a commercially available system with high-pass filters of 25, 40, and 80 Hz without any change in electrode position. The following time-domain parameters were measured: (1) total filtered QRS duration; (2) duration of high-frequency low-amplitude signals (HFLA); and (3) root-mean-square voltage of the terminal 40 ms of the QRS complex (RMS40). Correlation between pairs of measurements was excellent, ranging from 0.91-0.99 for QRS and HFLA duration, and from 0.83-0.98 for RMS40 value. However, the range of differences was wide for all parameters, especially at 25 and 80 Hz, revealing marked individual variations in selected cases. The immediate reproducibility of an initially normal SAECG was 95% at 25 Hz, 100% at 40 Hz, and 81% at 80 Hz; figures for an initially abnormal SAECG were 89%, 91%, and 93%, respectively, and the coefficient of agreement kappa was highest at 40 Hz than at 25 or 80 Hz. Discordant results were most frequently observed in patients with borderline values, or in cases with nonsimilar residual noise levels. In conclusion, the immediate and day-to-day reproducibility of the SAECG is excellent in patients with chronic stable coronary artery disease. However, individual variations are observed in selected cases, leading to modification in interpretation of the result. For this reason, individual reproducibility should be considered before evaluating the effect of any therapeutic intervention on the SAECG, especially in patients with borderline values of the quantitative parameters of the SAECG.

Coronary Disease↗
PubMed1995

Successful term pregnancy after Mustard operation for transposition of the great arteries.

Transposition of the great arteries is a complex cardiac malformation with poor prognosis without surgical correction. Since the introduction of surgical procedures such as the intra-auricular reorientation of the venous return (Mustard procedure), an increasing number of patients may reach adulthood and experience pregnancy. Because long-term complications after the Mustard operation include systemic heart failure, arrhythmias, venous return stenosis and pulmonary edema, hemodynamic changes during pregnancy and delivery may potentially engender life-threatening complications in these patients. We report the case of a 24-year-old primigravida who underwent a Mustard procedure at the age of 2 years for transposition of the great vessels, and who carried out a full-term pregnancy. The pregnancy was uneventful until the 34th week, when the woman developed signs of moderate right ventricular failure and frequent episodes of accelerated junctional rhythm. Digitalisation improved symptoms and elicited return to normal sinus rhythm. The patient delivered at term by elective cesarean section, under close hemodynamic monitoring.

Adult↗
PubMed1995

Effects of exposure to hypoxia on the signal-averaged electrocardiogram in healthy subjects.

The effects of hypoxia on the signal-averaged ECG (SAECG) were investigated in 26 healthy active subjects with no suggestion of cardiac disease. The SAECG was recorded in each resting subject in normoxic and hypoxic normobaric conditions (inspired O2 fraction 20.7 vs 10.0%) which lowered resting arterial O2 saturation from 98.6 +/- 0.6% to 77.7 +/- 8%. Recordings from four subjects (three men) met the definition of abnormal late potentials at baseline; in all these subjects but one, who exhibited an improved but still abnormal QRS duration, these parameters returned to normal in hypoxic conditions. The duration of the filtered QRS was significantly reduced (from 107.6 +/- 13.2 to 101.6 +/- 11.3 ms, P < 0.01), the duration of the low amplitude signals in the terminal portion of the QRS < 40 microV (LAS) significantly decreased (from 26.5 +/- 9.5 to 22.7 +/- 7.9 ms, P < 0.05) and the root mean square voltage in the last 40 ms (Term-RMS) increased non-significantly (from 55.8 +/- 40.2 to 69.1 +/- 38.3 microV, P = 0.058). Hypoxia determined a higher (P < 0.05) heart rate increase in subjects with abnormal records than in normal subjects. These data could be related to a sympathic discharge. They suggest that: (1) variation in heart rate could affect the SAECG; (2) exposure to hypoxia improves SAECG parameters in healthy subjects, possibly related to sympathetic discharge; (3) abnormal records collected during sinus bradycardia could represent a type of false-positive expression of late potentials in young active adults.

Adult↗
PubMed1995

Acute coronary occlusion secondary to radiofrequency catheter ablation of a left lateral accessory pathway.

A case of asymptomatic acute coronary occlusion secondary to radiofrequency catheter ablation of a left lateral accessory pathway is reported. Due to post-procedural ST modifications of the surface ECG, a coronary angiography was performed which disclosed total occlusion of the first marginal branch of the left circumflex coronary artery. Acute myocardial infarction was confirmed by moderate cardiac enzyme release, abnormal myocardial perfusion scan and mild lateral hypokinesia at echocardiography. This rare but potentially harmful complication of interventional electrophysiology should be kept in mind and coronary angiography performed immediately when coronary occlusion related to radiofrequency application is suspected.

Catheter Ablation↗
PubMed1994

Efficacy of rapid atrial pacing for conversion of atrial flutter in medically treated patients.

To determine factors affecting the success rate of rapid atrial pacing in converting atrial flutter to sinus rhythm in medically treated patients, we prospectively used this technique for 120 consecutive episodes in a total of 110 patients (94 male, 16 female, mean age 63 +/- 14 years). Structural heart disease was present in 77%, and all patients were receiving antiarrhythmic drugs at the time of the procedure. Atrial flutter type I was present in 92 of 110 patients (84%), and atrial flutter type II in 18 of 110 (16%). Primary success rate (return to sinus rhythm either immediately or after < 10 min of atrial fibrillation) was 70% (71/102) for flutter type I, and 6% (1/18) for flutter type II (p < 0.001). Delayed success (conversion to sinus rhythm in > 10 min but < 24 h) was observed in 15 additional episodes of flutter type I (15%) and in 1 additional episode of flutter type II (6%). The only clinical factors predicting primary success were (a) characteristics of flutter waves on the 12-lead surface electrocardiogram, (b) duration of flutter (primary success rate of 81% if flutter < 1 month vs. 57% if > 1 month, p < 0.05), and (c) flutter rate (primary success rate of 78% if < 260/min vs. 56% if > 260/min, p < 0.05). In 6/71 episodes of flutter type I (8%), prolonged sinus pauses or severe bradyarrhythmias occurred after conversion to sinus rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Ventricular late potentials and spontaneous ventricular arrhythmias after surgical repair of tetralogy of Fallot: do they have prognostic value?

OBJECTIVE: To determine the prognostic significance of ventricular late potentials and spontaneous ventricular arrhythmias detected early after surgical repair of tetralogy of Fallot. DESIGN: Prospective observational. SETTING: Cardiology department of a teaching hospital. METHODS: Between June 1984 and June 1991, 104 children (63 boys, 41 girls) were studied by signal averaging and 24 hour ambulatory monitoring after surgical repair of tetralogy of Fallot. Mean (SD) age at operation was 6 (3) years, mean interval between operation and evaluation was 8 (25) months, and the follow up after evaluation was one to 88 (mean 30) months. RESULTS: Ventricular late potentials were detected in 24/104 patients (23%) and spontaneous ventricular arrhythmias in 39/96 patients (38%); usually (in 81%) these were unifocal and rare. Patients with ventricular late potentials were older at operation than patients without late potentials (9 (3) v 6 (3) years, P = 0.002). No correlation was found between the presence of ventricular late potentials and the presence or complexity of spontaneous ventricular arrhythmias early after operation. During the mean follow up of 2.5 years no case of sudden death or sustained ventricular tachycardia was found. CONCLUSION: Short-term prognosis after surgical repair of tetralogy of Fallot is good; ventricular late potentials and spontaneous ventricular arrhythmias are often detected shortly after operation, but in the medium term follow up they do not predict sudden death or serious ventricular arrhythmias.

Adolescent↗
PubMed1992

Significance of ventricular late potentials in non-ischaemic dilated cardiomyopathy.

To assess the incidence and clinical significance of ventricular late potentials in non-ischaemic dilated cardiomyopathy, 51 consecutive (44 male, seven female, mean age 53 +/- 11 years) patients with dilated cardiomyopathy were studied. Twenty-eight patients (55%) were in New York Heart Association functional class III or IV, 34 out of 51 (76%) had a left ventricular ejection fraction of less than 40%, 10 out of 51 (20%) had a history of sustained ventricular tachycardia (VT), 24 out of 37 (65%) had runs of non-sustained ventricular tachycardia during Holter monitoring and 15 out of 51 (29%) had a left bundle branch block. A signal-averaged electrocardiogram (gain 10(6) x, bipolar chest leads, filters 100-300 Hz) was performed in all the patients; late potentials were considered present if the total filtered QRS duration was longer than 118 ms and the interval between the end of QRS and the voltage 40 microV was more than 40 ms in the absence of left bundle branch block (total filtered QRS duration greater than 140 ms and interval between the end of QRS and the voltage 40 microV greater than 50 ms in the presence of left bundle branch block). Ventricular late potentials were detected in 22 out of 51 patients (43%). Late potentials were present in 80% (eight out of 10) of patients with sustained ventricular tachycardia but in only 34% (14 of 41) without sustained ventricular tachycardia (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Late ventricular potentials and myocardial infarction. A critical analysis].

The identification of patients at high risk of developing severe ventricular arrhythmias or sudden death after acute myocardial infarction is one of the major preoccupations of cardiologists. In this field, electrocardiographic signal averaging represents a promising technique and the prognostic value of late potentials in the post-infarction period has been well demonstrated during the last 10 years. However, in order to use optimally the information obtained by this technique the limitations should be understood: what do late ventricular potentials represent from the electrophysiological point of view? Do they play an active role in the genesis of ventricular arrhythmias or are they only a marker? What is the best method of recording late potentials? What are the criteria of normality of signal averaged recordings? What is the predictive value of late potentials in the post-infarction period? At what moment should they be searched for? Are they affected by medical therapy? These are some of the questions which have not yet been answered and which are addressed in this article.

Action Potentials↗