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R Adamec

Publications and source records attributed to R Adamec.

At least 19 recordsLinked to original sources
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↗
PubMed1992

[Idiopathic sustained ventricular tachycardia in the young adult with right bundle-branch and left axis deviation].

The authors report 4 cases of sustained ventricular tachycardia with right bundle branch block and left axis deviation morphology. These ventricular tachycardias which are usually sensitive to Verapamil are often mistaken for supraventricular tachycardia. However, they are a specific clinical, electrocardiographic and electrophysiological entity. The origin of the tachycardia is probably in the Purkinje fibres of the left posterior hemibranch of the His bundle. The mechanism is controversial: much evidence points to reentrant phenomenon, but, in the present state of our knowledge, triggered activity cannot be formally excluded.

Action Potentials↗
PubMed1991

Ventricular late potentials and induced ventricular arrhythmias after surgical repair of tetralogy of Fallot.

Ventricular tachycardia (VT) and sudden death are rare but recognized complications after surgical repair of tetralogy of Fallot. We prospectively studied 31 patients (19 boys and 12 girls, mean age +/- standard deviation 7 +/- 4 years) with postoperative tetralogy of Fallot, by means of right-sided cardiac catheterization, 24-hour Holter monitoring, body-surface and intracavitary signal-averaging (gain 10(5) to 10(6), filters of 100 and 300 Hz) and programmed ventricular stimulation (1 and 2 extrastimuli, 3 basic cycle lengths, right ventricular apex and outflow tract). All patients were asymptomatic and none had documented or suspected ventricular arrhythmias. Ventricular late potentials were detected in 10 of 31 patients (32%) and spontaneous ventricular arrhythmias in 12 of 31 patients (39%). No sustained VT was induced by programmed ventricular stimulation but nonsustained VT was induced in 3 patients (10%). Patients with inducible VT more often had late potentials (3 of 3 vs 7 of 28, p less than 0.01), and spontaneous ventricular premature complexes (VPCs) during Holter monitoring (3 of 3 vs 9 of 28, p less than 0.05). To predict VT inducibility, late potentials had a sensitivity of 100%, a specificity of 75%, a positive predictive value of 30% and a negative predictive value of 100%. For spontaneous VPCs, the figures were 100, 68, 25 and 100%, respectively. It is concluded that shortly after repair of tetralogy of Fallot, the presence of both spontaneous VPCs and ventricular late potentials are associated with an increased incidence of inducible VT. Conversely, the absence of VPCs and ventricular late potentials may identify patients at low risk of subsequent ventricular arrhythmias.

Adolescent↗
PubMed1991

Reduction in the frequency of ventricular late potentials after acute myocardial infarction by early thrombolytic therapy.

Ventricular late potentials are strong predictors of arrhythmic events after acute myocardial infarction (AMI). To assess the effect of intravenous thrombolysis on the incidence of ventricular late potentials, 223 consecutive patients surviving a first AMI were included in the present study: 59 patients (53 men, 6 women, mean age +/- standard deviation 55 +/- 10 years) received intravenous recombinant tissue-type plasminogen activator (100 mg over 3 hours, group A) and 164 patients (123 men, 41 women, mean age 61 +/- 11 years) received conventional medical treatment (group B). A time-domain signal-averaged electrocardiogram and a high-resolution beat-to-beat recording (gain 10(6), filters 100 to 300 Hz) were performed at 10 +/- 3 days after AMI. There was no difference between group A and B patients in terms of AMI location (anterior in 28 of 59 vs 80 of 164, difference not significant [NS]), mean left ventricular ejection fraction (55 +/- 10 vs 55 +/- 13%, NS), or presence of heart failure (New York Heart Association class III or IV in 12 of 59 vs 40 of 164, NS). The incidence of ventricular late potentials was 10% (6 of 59) in group A and 24% (39 of 164) in group B (p less than 0.05). Among the 146 patients who underwent coronary arteriography, the incidence of ventricular late potentials was 13% (10 of 80) in patients with a patent infarct-related artery and 26% (17 of 66) in patients with an occluded infarct-related artery (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Beat-to-beat detection of ventricular late potentials with high-resolution electrocardiography.

To detect dynamic changes of VLPs we developed a low-noise, HR-ECG with a gain of 10(5)-10(6)X. This system allows the beat-to-beat detection of low-amplitude signals at the bedside in a nonshielded room without any averaging process. Analysis was performed in 39 normal subjects (group A: 27 men, 12 women, mean age, 28 +/- 8 years), in 98 patients with coronary artery disease without documented sustained ventricular tachycardia (group B: 86 men, 12 women, mean age, 59 +/- 10 years) and in 41 patients coronary artery disease with sustained monomorphic ventricular tachycardia (group C: 36 men, 5 women; mean age 63 +/- 9 years). Comparison was made with time-domain signal-averaging (SA-ECG) in all cases at the same electrode position and with identical band-pass filtering. In group A no VLPs were detected; the total filtered QRS duration was 84 +/- 8 msec (mean +/- SD), and the time interval during which the terminal QRS did not exceed 40 microV (I-40) was less than 30 msec in all cases (mean, 17 +/- 6 msec). In group B, VLPs were detected by HR-ECG in 34 of 98 patients (35%); the total QRS duration was 102 +/- 16 msec (mean +/- SD, p less than 0.01 vs group A), and the I-40 was 29 +/- 13 msec (mean +/- SD, p less than 0.01 vs (group A). In group C, VLPs were detected by HR-ECG in 38 of 41 patients (93%); the total QRS duration was 123 +/- 22 msec (mean +/- SD, p less than 0.01 vs group A and group B), and the I-40 was 40 +/- 14 msec (mean +/- SD, p less than 0.01 vs group A and group B). Concordant results between HR-ECG and SA-ECG were observed in 91% of the cases (59 positive and 103 negative results). Late potentials that exhibited dynamic variations were detected by HR-ECG alone in 13 cases, and very low amplitude VLPs were detected by SA-ECG alone in three cases. In conclusion, the present study demonstrates the feasibility of body-surface recording of VLPs on a beat-to-beat basis, without any averaging process, at the bedside in a nonshielded room. This new approach may allow the study of dynamic changes of VLPs during spontaneous ventricular arrhythmias or ischemia.

Coronary Disease↗
PubMed1991

Intra-hisian 2:1 atrioventricular block secondary to Lyme disease.

We describe a case of Lyme carditis with intra-hisian 2:1 atrioventricular (AV) block documented by electrophysiological study. To our knowledge, only two cases of AV block at the level of the His bundle has been described in the literature. Sinus rhythm was restored after 4 days of i.v. ceftriaxone.

Atrioventricular Node↗
PubMed1989

The relationship between the amygdala and bed nucleus of the stria terminalis in the cat: an evoked potential and single cell study.

The effects of amygdala stimulation on excitability of cells in the bed nucleus of the stria terminalis (BNST) were investigated in the cat. The predominant effect of stimulation was to excite cells localized in the lateral BNST. Cells responded either with single spikes to a stimulus pulse or in short bursts. Spontaneous firing of cells after a pulse to the amygdala was observed to both increase and decrease over a 4-s interval. Increases in firing rate, however, were the predominant response. Cells in more anterior locations in the BNST responded with latencies shorter than those of cells in more posterior locations, reflecting either differences in conduction time of excitation from the amygdala or differences in transmitters mediating the excitatory effects. Associated with increases in cell firing was a compound field potential with an initial negative component and a later positive component. These components may be generated by different cell types within the BNST. The negative component likely represents a field EPSP. Effective sites of amygdala stimulation were restricted to the posterior basal amygdala, and effects observed in the BNST were restricted to the lateral BNST. These data correspond well with anatomical studies showing a monosynaptic projection of basal amygdala to lateral BNST in the cat. This study suggests that this projection is predominantly excitatory.

Amygdala↗
PubMed1988

Vasovagal syncope during rectosigmoidoscopy: report of a case.

Cardioinhibitory vasovagal syncope with sinus arrest and asystole of 28 seconds' duration occurred during rectosigmoidoscopy in a patient with frequent previous symptoms and a syncopal episode. A ventricular inhibited pacemaker was implanted and the patient has remained asymptomatic for 18 months.

Adult↗
PubMed1987

[Nyctohemeral arterial pressure profile and heart rate in autonomic diabetic neuropathy].

Autonomic failure reduces the physiological nocturnal decline of blood pressure (BP) and heart rate (HR). To assess the effect on circadian hemodynamic rhythms of sympathetic (s) and parasympathetic (ps) impairment in diabetic autonomic neuropathy (DAN), we measured BP automatically every 15 min and HR continuously for 24 hour in 11 diabetic patients. They were divided into 3 groups according to the results of cardiovascular reflex tests: a) DAN s + ps, b) DAN ps, c) no DAN. Nine of the patients were hypertensive. Eleven non-diabetic hypertensives served as controls. The disturbance of the circadian BP profile was related to the severity of the DAN, nocturnal BP tending to rise in group a, to fall in group b, and falling markedly in group c and in the control group. FC fell to a similar extent in all the groups. We conclude that the circadian BP profile is more affected by DAN than the FC profile, and that study of the circadian BP profile could reveal the presence of predominantly nocturnal hypertension.

Adult↗
PubMed1987

Frequency of ventricular late potentials and fractionated right ventricular electrograms after operative repair of tetralogy of Fallot.

This study was conducted to assess the incidence of abnormalities of ventricular depolarization in sinus rhythm after repair of tetralogy of Fallot and their relation to spontaneous ventricular arrhythmias. Forty-four patients were studied, 10 before surgery (mean age 6.9 years) and 34 after repair (mean age 8.1 years, mean age at surgery 6.5 years, mean interval between surgery and evaluation 11 months). Evaluation was performed by means of body surface and intracavitary signal-averaging techniques, by recording local right ventricular (RV) electrograms at several sites and by 24-hour Holter monitoring (n = 28). No electrophysiologic abnormality was observed in children before surgery. Ventricular late potentials were detected in 18 patients (53%) after repair. Body surface detection of ventricular late potentials was frequently masked by the postoperative right bundle branch block pattern. Local RV electrograms were fractionated in 11 cases (32%) (mean duration 103 +/- 33 ms), most often in the RV outflow tract (n = 9), but no relation was found between fragmentation of RV electrograms and the presence of ventricular late potentials. Spontaneous ventricular arrhythmias occurred in 12 children after repair (43%), but were complex in only 4 patients (14%). There was no correlation between spontaneous ventricular arrhythmias and the presence of ventricular late potentials, presence of fractionated RV electrograms, presence of a proximal right bundle branch block or postoperative hemodynamic status.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1986

[Long-term improvement of exercise performance in patients with activity-dependent pacemakers].

Exercise performance after implantation of the pacemaker with physical activity dependent pacing rate (Activitrax, Medtronic) was assessed by treadmill tests one month afterwards in 10 patients and a further 6 months later in 6 of them, who had long been VVI pacing dependent (reimplantation subgroup). In the 1 month test exercise performance had improved in 7 of 10 in activity pacing mode compared to VVI mode. After 6 months of physical activity dependent pacing the patients in the reimplantation subgroup showed an improved exercise test in VVI mode compared to the 1 month test in VVI mode. In activity pacing mode there was an additional improvement (increase of exercise duration from 12.1 +/- 2.5 to 14.5 +/- 2.7 min, p less than 0.005, and of accumulated work from 31.1 +/- 15.1%, p less than 0.002) compared to the VVI mode. Since Activitrax PM allows better exercise performance at longterm follow-up, it becomes a pacing mode of choice when double chamber pacing is impossible.

Adolescent↗
PubMed1986

[Nyctohemeral blood pressure profiling by automatic measurement in ambulatory hypertensive patients. Treatment with acebutolol].

Variations in night and day blood pressure were evaluated in 11 patients with essential hypertension. The instrument used (Pressurometer II) automatically records blood pressure every 15 minutes for a mean period of 22 hours and ECG tracings continuously. The mean values of arterial pressure and heart rate were significantly higher during day time than at night, revealing a relative "hypotension" and "bradycardia" during sleep. The cardioselective beta-blocker acebutolol induced a significant fall in diurnal and nocturnal blood pressure, thus uniformly lowering the 24-hour profile.

Acebutolol↗
PubMed1986

Effect of bopindolol on the circadian blood pressure profile in essential hypertension.

The effect of bopindolol on circadian blood pressure and heart rate profile was evaluated by means of an automatic recording technique (Pressurometer II). Blood pressure and heart rate was measured every 15 min for 24 h in 11 ambulant hypertensive patients. Recordings were made after 2 weeks on placebo then after treatment for 4 and 8 weeks with single daily doses of 0.5 or 1 mg bopindolol, according to a double-blind crossover plan. The results show a significant fall in the mean 24-h values for systolic and diastolic blood pressure and heart rate on both dosages of bopindolol. The low-dose level had a more marked effect on the day phase of the blood pressure profile, whereas the high-dose level affected day and night phases equally. Over all, the circadian rhythms of blood pressure and heart rate were not influenced. In conclusion, bopindolol has a well-defined antihypertensive effect on the various phases of the 24-h blood pressure and heart rate profiles.

Adrenergic beta-Antagonists↗
PubMed1986

[Late potentials and ventricular arrhythmia].

When electrodes are placed at the surface of the thorax, high-amplification electrocardiography (HA-ECG) combined with signal summation as a function of time provides a non-invasive method for detecting electric potentials occurring after the QRS complex of the clinical electrocardiogram. These potentials are called late, and can probably be likened to the "divided" or "fragmented" potentials recorded directly on the heart or in its ventricles near zones of ischemia, infarction or aneurysm. The prevalence of late potentials of ventricular activation (LPVA) and their association with the occurrence of ventricular arrhythmias seems well established, notably in the presence of ventricular aneurysm and anamnesis of severe ventricular arrhythmia. Some studies have shown that detection of LPVAs is of value in identifying heart patients at risk of ventricular arrhythmia or sudden death. Heart disease aside, the presence of LPVAs has been demonstrated in arrhythmogenic right ventricular dysplasia and reported in Fallot's tetralogy after complete correction. A standardization of recordings and a more precise definition of LPVAs are necessary before HA-ECG can become a routine clinical method. Further, the possibility of "beat by beat" recordings with "spatial" summation will allow detection of LPVAs which vary with time and in nature and hence provide a better understanding of the genesis of ventricular arrhythmias.

Arrhythmias, Cardiac↗