Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cardiac Complexes, Premature”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1989

Congestive heart failure after acute myocardial infarction in patients receiving antiarrhythmic agents for ventricular premature complexes (Cardiac Arrhythmia Pilot Study).

The Cardiac Arrhythmia Pilot Study (CAPS) was a randomized, double-blind trial of antiarrhythmic drugs (encainide, flecainide, moricizine, imipramine and placebo) in 502 patients with an ejection fraction greater than 0.20 and at least 10 ventricular premature complexes/hour, 6 to 60 days after acute myocardial infarction. Patients were followed for 1 year and the incidence of new or worsened congestive heart failure (CHF) was evaluated. Heart failure in the 1-year follow-up was gauged by the development (in order of increasing severity) of new symptoms (grade 1), the need for a change in therapy, including addition of digitalis, addition or increase of dose of diuretics or afterload reduction agents or discontinuation of beta-blocking agents (grade 2), or by hospitalization (grade 3). Sixty-one of 502 patients (12%) required hospitalization for CHF in the 1-year follow-up. One hundred five of 403 patients (26%) in the active treatment group and 18 of 99 patients (18%) in the placebo group (difference not significant) developed CHF requiring hospitalization or a change in therapy or both. Although patients with severely impaired ejection fraction were excluded, new or worsened CHF was common in follow-up during CAPS.

Anilides↗
PubMed2005

Diagnostic performance of a computer-based ECG rhythm algorithm.

We examined the accuracy of computer-based rhythm interpretation from one electrocardiograph manufacturer (GE Healthcare Technologies MUSE software 005C) in 4297 consecutive recordings in a university hospital setting. Overreading was performed by either of 2 experienced cardiologists, and all disagreements with the initial computer rhythm statement were reviewed by the second cardiologist to achieve physician consensus used as the "gold standard" for rhythm diagnosis. Overall, 13.2% (565/4297) of computer-based rhythm statements required revision, but excluding tracings with pacemakers, the revision rate was 7.8% (307/3954), including 3.8% involving the primary rhythm diagnosis and 3.9% involving definition of ectopic complexes. The false-negative rate for sinus rhythm was only 1.3%, but a computer diagnosis of sinus rhythm was incorrect in 9.9% of other rhythms. The false-negative rate for atrial fibrillation was 9.2%, whereas a computer diagnosis of atrial fibrillation was incorrect in 1.1% of other rhythms, including sinus. Computer diagnosis of paced rhythms remains problematic, and physician overreading to correct computer-based electrocardiogram rhythm diagnoses remains mandatory.

Algorithms↗
PubMed2003

[Analysis of cases with fetal extrasystole coexisting with cardiac and extracardiac pathology].

OBJECTIVE: The paper presents a review of cases with fetal extrasystole coexisting with different cardiac and extracardiac pathology. DESIGN: The aim of the study is to analyse the results of echocardiographic examinations of fetuses with premature atrial contractions (PAC) quantitatively significant (bigeminy, trigeminy) or coexisting with other abnormal findings in fetal heart or other extracardiac pathologies. MATERIAL AND METHOD: Selected group of 33 (24%) fetuses from 135 with fetal extrasystole was analyzed. The mean gestational time of diagnosis was 29.2 + 4.1 weeks. RESULTS: Quantitatively significant arrhythmia (bigeminy, trigeminy) was diagnosed in 14 fetuses. Blocked PAC (2:1) occurred in two cases causing fetal bradycardia. Premature atrial extrasystole coexisting with different type of arrhythmias were diagnosed in 10 cases (4 x with SVT, 4 x with sinus bradycardia, 2 x with ventricular extrasystole). Heart defects in the analyzed group with PAC were recognized in two fetuses (1 x d-TGA, 1 x heterotaxy syndrome--common a-v canal). Myocarditis was diagnosed in 3 (9%) cases. From the group of 33 fetuses 6 newborns died (1 x d-TGA, 1 x T18, 1 x myocarditis, 1 x circulatory centralization). Mortality in the analyzed group was 18.2%. CONCLUSION: In cases of fetal arrhythmias echocardiography should be widely applied in order to evaluate the kind of arrhythmia, sufficiency of circulation and coexistence of heart defects, extracardiac malformations or functional abnormalities with arrhythmia in fetal circulation.

Arrhythmias, Cardiac↗
PubMed1992

The effect of enalapril on cardiac arrhythmias in patients with congestive heart failure.

The purpose of the study was to evaluate the effect of enalapril on the frequency of ventricular premature beats in patients with congestive heart failure. The study group consisted of 30 patients with a mean age of 47 +/- 0.6 years with chronic congestive heart failure (NYHA classes III and IV) due to primary dilated cardiomyopathy and cardiomyopathy in the course of ischaemic heart disease. Initial therapy with digitalis and diuretics was supplemented with enalapril at a dose of 5-20 mg daily. Initially and at three months after enalapril, the following parameters were evaluated: NYHA functional class, the presence of premature ventricular beats in 24-hour ECG recording and left ventricular function by echocardiography. The scheduled therapy was completed by 23 patients; in 5 patients, the intake was discontinued because of hypotension, one patient died after 14 days due to worsening heart failure, and one patient was submitted for pacemaker implantation. Clinical improvement manifesting itself by a shift to lower NYHA classes was found in 20 patients. A reduced number of premature ventricular beats was observed in 52% of the patients. Termination of cardiac arrhythmias, especially of complex beats, was parallel to the circulatory improvement.

Adult↗
PubMed1988

Correlation between directly measured and indirectly estimated sinoatrial conduction time in children.

The indirectly estimated sinoatrial conduction time has been widely used in children to assess sinus node (SN) function, but has never been validated in pediatric patients. Using a standard quadripolar catheter with high amplification and low-pass filters, SN electrograms were recorded in 11 of 26 (42%) pediatric cardiac patients (age range 10 months to 18 years) with normal SN function. The sinoatrial conduction time was measured directly from the SN electrogram and estimated indirectly by the premature stimulation and continuous pacing methods. The direct sinoatrial conduction time (15 to 91 ms) in these 11 patients (ages 1 to 18 years) correlated well with that estimated by the premature stimulation method (r = 0.81, n = 9, p less than 0.01). There was a poor correlation between the direct and continuous pacing methods (r = 0.53, n = 8, p = 0.17). It was concluded that SN electrograms can be recorded in children and that there is a good correlation between the directly measured sinoatrial conduction time and the indirectly estimated sinoatrial conduction time by the premature stimulation method.

Adolescent↗
PubMed1986

Functional characteristics of human macro-reentry: a study of "pre-excited" circuits by extrastimulus method.

The effect of improved conduction in areas of delay was tested during macro-reentry within the His-Purkinje system, in an attempt to separate the role of conduction delay from that of prematurity of the extrastimulus as the key determinant of reentry. Using the right ventricular extrastimulus technique (S1S2 method), both the critical His-Purkinje system delays and the zone of S1S2 intervals causing His-Purkinje system reentry were determined. Then, using a previously described technique of atrioventricular (AV) sequential pacing during the basic drive, the potential site of His-Purkinje system conduction delay was (anterogradely) excited earlier (pre-excitation), as compared with the control S1S2 method. This produced a decrease in retrograde His-Purkinje system delay (S2H2), as compared with the same S1S2 interval during the control method. Changing the degree of pre-excitation at each S1S2 interval allowed for determination of the critical (or shortest) S2H2 delay necessary for His-Purkinje system reentry at each coupling interval. Of importance was the observation that the critical delay was not specific for each case but varied with the prematurity of S2. For example, the critical S2H2 delay required for reentry was actually less at shorter S1S2 intervals as compared with longer S1S2 intervals (from 206 +/- 25 to 187 +/- 20 ms, p less than 0.01). These data suggest that manifestation of reentry is a complex interplay between degree of prematurity and conduction delay. The so-called critical conduction delay can be readily modified by altering the site of block, which in turn may be dependent on prematurity of the extrastimulus.

Bundle of His↗
PubMed2002

Is there an optimal pacing site to prevent atrial fibrillation?: an experimental study in the chronically instrumented goat.

INTRODUCTION: Atrial pacing can reduce the number of recurrences of atrial fibrillation (AF). It is unclear the extent to which this effect is determined by the site(s) of pacing. METHODS AND RESULTS: In six electrically remodeled goats (24-hour AF), the window of inducibility of AF was determined by applying premature stimuli (S1-S2) at the right (RA) or left (LA) atrium (baseline values). Determination of the window of inducibility of AF at RA and LA was repeated during preventive pacing at four sites: RA, LA, Bachmann's bundle (BB), and RA+LA (biatrial). Mapping was used to elucidate the mechanisms of prevention of AF. At baseline, the window of inducibility of AF was 49 +/- 9 msec at RA and 45 +/- 17 msec at LA. Initiation of AF was associated with conduction block of the premature beat at BB. Preventive pacing at BB markedly shortened the window of inducibility of AF at RA (25 +/- 11 msec) and LA (17 +/- 8 msec, P < 0.01). Pacing at RA only shortened the window of inducibility of AF at LA (23 +/- 9 msec, P < 0.01), whereas pacing at LA only shortened the window of inducibility of AF at RA (23 +/- 11 msec, P < 0.01). Biatrial pacing failed to shorten the window of inducibility of AF both at RA and LA. Prevention of AF by pacing was due to prolongation of the premature interval at BB. CONCLUSION: In the caprine model of AF, BB is a critical area of conduction of premature beats and initiation of AF. Pacing at BB can prevent but not completely abolish the initiation of AF by single premature beats (shortening of the window of inducibility). Prevention of AF by pacing is based on prolongation of the premature interval at BB, thus preventing conduction block and reentry. In general, the optimal site for preventive pacing is close to the area of block and remote from the origin of premature beats.

Animals↗
PubMed1983

Electrophysiologic consequences of chronic experimentally induced left ventricular pressure overload.

Cardiac electrophysiologic alterations were evaluated 1 to 8 months after partial supracoronary aortic constriction in cats. This procedure induced left ventricular systolic hypertension and hypertrophy with marked connective tissue infiltration. In situ, premature ventricular complexes were observed during or after vagal slowing of sinus rate in 8 (26%) of the 31 experimental animals, while an additional 3 of the 31 developed ventricular fibrillation. No arrhythmias were recorded in 31 normal or 7 sham-operated cats. In vitro, 29% of the left ventricular preparations from cats with pressure overload and 5% from control cats showed spontaneous ectopic activity. During stimulation at cycle lengths of 800 to 1,000 ms, multiple site impalements of subendocardial muscle cells within fibrotic regions revealed heterogeneous electrical abnormalities. These included short action potential duration, low amplitude action potentials generated from low resting potentials, split upstrokes and electrically silent areas. Impalements in nonfibrotic areas of the left ventricle showed prolongation of muscle action potential duration. Long-term disturbances in cellular electrophysiologic properties may favor the development of arrhythmias and thereby contribute to sudden cardiac death in left ventricular hypertension and hypertrophy.

Animals↗
PubMed1987

Orthodromic tachycardia initiation dependent on 1:2 atrioventricular conduction in the presence of a left lateral bypass tract.

This report describes a patient who presented with atrial fibrillation associated with a rapid ventricular response (270 bpm) and wide QRS complexes. At the time of electrophysiology study, a left lateral bypass tract with both anterograde and retrograde conduction was demonstrated. Orthodromic tachycardia with atrial premature impulses was initiated and was dependent on two ventricular responses to one atrial impulse. Intravenous procainamide administration had little effect on anterograde or retrograde conduction in the accessory pathway; however, it prevented orthodromic tachycardia initiation with atrial premature impulses by prolonging atrial muscle refractoriness.

Adult↗
PubMed1978

Effect of ventricular extrasystoles on idioventricular rhythm in patients with complete heart block.

Idioventricular rate, QRS width, site of block and responses to premature ventricular stimulation were studied in 23 patients with chronic complete heart block in an attempt to distinguish patients liable to syncopal attacks. Seven patients were asymptomatic, five gave a history of presyncope and 11 of syncope. Although the mean idioventricular rate of the nine patients in the narrow QRS group (39.7 per min) was significantly faster than that of the 14 patients in the wide QRS group (35.3 per min; P less than 0.05), the rate did not distinguish symptomatic patients within either the narrow or the wide QRS groups. His bundle studies of the site of block and the effect of single and paired right ventricular stimulation upon idioventricular rhythm were also unhelpful. The response of the return cycle to increasingly premature ventricular extrasystoles, however, proved more complex than was anticipated.

Adams-Stokes Syndrome↗