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Biomedical subjects

P Denes

Publications and source records attributed to P Denes.

At least 91 records · Page 5Linked to original sources
PubMed1981

The role of Holter monitoring in detecting digitalis-provoked arrhythmias.

Certain arrhythmias detected on the electrocardiogram are considered to be reliable indicators of digitalis intoxication. We have evaluated the incidence of these arrhythmias on 24-hour electrocardiographic monitoring (Holter monitoring) in 69 consecutive patients who had serum levels of digoxin determined within 24 hours of the onset of continuous electrocardiographic monitoring. According to teh serum level of digoxin, the patients were divided into the following three groups: (1) group 1 had 0 to 1.0 ng/ml (31 patients); (2) group 2 had 1.1 to 2.0 ng/ml (27 patients); and group 3 had greater than or equal to 2.1 ng/ml (11 patients). The following arrhythmias were considered to reflect digitalis-provoked arrhythmias: (1) persistent sinus bradycardia or sinus pauses (or both); (2) atrioventricular block; (3) paroxysmal atrial tachycardia with block; (4) accelerated junction rhythm; (5) complex ventricular arrhythmias (multifocal ventricular premature beats, bigeminy and trigeminy, and pairs); and (6) ventricular tachycardia. There was no significant difference in the incidence of these six categories of arrhythmias among the three groups. In addition, there was no significant difference in the mean serum level of digoxin for patients with and without the arrhythmias within each category. Ten of the 69 patients had combinations of three of the so-called digitalis-provoked arrhythmias, with incidences among the three groups showing no significant differences. In conclusion, rhythms considered to be potentially due to digitalis intoxication are frequently observed in hospitalized patients undergoing 24-hour electrocardiographic monitoring, are frequently unrelated to the serum level of digoxin, and appear unlikely to reflect true digitalis intoxication in many of these patients.

Aged↗
PubMed1980

Infiltrative cardiomyopathy with conduction disease and ventricular arrhythmia: electrophysiologic and pathologic correlations.

Two cases are described, one of cardiac sarcoidosis and another of primary cardiac amyloidosis, in which correlation was made between electrophysiologic and postmortem conduction system studies. In Case 1 the electrocardiogram revealed right bundle branch block with first degree and intermittent third degree atrioventricular (A-V) block and recurrent unifocal paroxysmal ventricular tachycardia. Electrophysiologic studies disclosed normal sinus rhythm with prolonged A-H (175 ms) and H-V (60 MS) intervals and extrastimulus induction of repetitive ventricular firing. Postmortem examination revealed a sarcoid aneurysm of the posterior left ventricle and granulomatous infiltration of the A-V node, His bundle and bundle branches. In case 2 the electrocardiogram revealed sinus bradycardia, a prolonged S-T interval and recurrent ventricular fibrillation. Electrophysiologic studies demonstrated a prolonged sinus nodal recovery time (6,080 ms) and H-V (85 ms) interval. Postmortem examination revealed marked amyloid infiltration of the sinoatrial node, atria, proximal bundle branches and left and right ventricular myocardium. There was thus excellent correlation between electrophysiologic and pathologic findings. These cases indicate the importance of making a clinical diagnosis of the disease that might in some cases allow specific therapeutic intervention in addition to antiarrhythmic therapy.

Adult↗
PubMed1980

Successful surgical excision of focal paroxysmal atrial tachycardia. Observations in vivo and in vitro.

A 41-year-old man had chronic, recurrent, drug-resistant paroxysmal right atrial tachycardia. Electrophysiologic studies revealed features suggesting atrial reentrance, including induction and termination of tachycardia with rapid atrial pacing and atrial extrastimuli. Endocardial catheter mapping localized the origin of tachycardia to the right atrial appendage. Intraoperative epicardial mapping refined the localization to the posterolateral rim of the appendage. The appendage was excised and the tachycardia was permanently cured. Microelectrode studies on the excised tissue revealed an inducible rhythm localized to a small area of the atrial endocardium, characterized by rapid pacing induction, rhythmicity generated from a suprathreshold afterdepolarization, low maximum diastolic potential, low overshoot potential and a smooth transition from phase 4 to phase 0, suggesting triggered automaticity. This is the first observation in man of probable triggerable atrial automaticity, which may be a direct counterpart of the clinical arrhythmia. The successful surgical outcome indicates that a focal atrial tachycardia can be excised in selected patients.

Adult↗
PubMed1980

Chronic longterm electrophysiologic study of paroxysmal ventricular tachycardia.

Nine patients with recurrent paroxysmal ventricular tachycardia underwent chronic electrophysiologic studies to delineate effective drug therapy for prevention of recurrence of this arrhythmia. The frequency of attacks of ventricular tachycardia necessitating hospitalization ranged from 2 to 12 (mean 5 +/- 4) attacks per year. Pacing induction of ventricular tachycardia was performed prior to and following intravenous or oral administration of procainamide (eight patients), disopyramide phosphate (nine patients), aprindine (five patients) and propranolol (four patients). Successful drug response (prevention of ventricular tachycardia induction or induction of nonsustained episodes of tachycardia) was noted in six of nine patients (66 percent). Lack of drug effect on the ability to sustain ventricular tachycardia was noted in three patients (34 percent). In addition, a deleterious drug response, manifested by potentiation of ventricular flutter or fibrillation, was observed in two of the three patients who failed to respond to drugs. Chronic drug therapy based on successful response in six patients resulted in cure of ventricular tachycardia in five of six patients (83 percent), one patient having one attack necessitating hospitalization. Of the three patients who demonstrated lack of drug effect during chronic electrophysiologic studies, one died suddenly and two had recurrent episodes of ventricular tachycardia while receiving a drug that did not prevent induction of ventricular tachycardia.

Adult↗
PubMed1979

Multiple reentrant tachycardias due to retrograde conduction of dual atrioventricular bundles with atrioventricular nodal-like properties.

A patient is presented who had two paroxysmal supraventricular tachycardias, one slow and incessant and the other fast. Both paroxysmal tachycardias appeared to be atrioventricular (A-V) reentrant, with anterograde conduction by way of a normal A-V pathway. Two pathways conducting in retrograde manner were demonstrated, characterized by different conduction times (fast and slow), identical abnormal atrial activation sequence and A-V nodal-like properties (retrograde Wenckebach periodicity with rapid ventricular pacing, and depression with ouabain and propranolol). Thus, there appeared to be two anomalous A-V bundles with nodal-like properties conducting in retrograde fashion. Whether the paroxysmal tachycardia was fast or slow depended on which of these pathways was utilized. Spontaneous cure of incessant paroxysmal tachycardia was observed and coincided with unexplained total loss of ability for ventriculoatrial conduction.

Atrioventricular Node↗
PubMed1979

Incidence and site of atrioventricular block in patients with chronic bifascicular block.

Four hundred fifty-two patients with chronic bifascicular block and initially intact atrioventricular (AV) conduction were detected, studied, and prospectively followed between January 1970 and March 1978. There were 360 males and 92 females, ages 18--93 years (mean +/- SD, 62 +/- 15 years). Follow-up ranged from 29-2804 days (mean 1066 +/- 97 days). AV block (2 degrees or 3 degrees) developed in 29 patients, nine with apparent cause and spontaneously in 20. Cumulative annual incidence of all heart block for 1--5 years was, respectively, 4%, 5.9%, 8.7%, 10.1% and 11.3%, and for spontaneous block was 2%, 3.1%, 5.2%, 6.7%, and 7.1%. Sites of spontaneous block were probably or definitely AV nodal in ten, His bundle in one, and trifascicular in nine. Cumulative incidence of AV block in surviving bifascicular block patients is 11% at 5 years, with 7% reflecting spontaneous block. The probable or definite site of AV block varies and is trifascicular in less than half of the patients. The small incidence of trifascicular block probably explains the difficulty in predicting this complication with electrophysiological studies.

Adolescent↗
PubMed1979

Congenital abnormalities of the conduction system in two patients with tachyarrhythmias.

Serial sections of the conduction system (CS) were performed in two patients with recurrent tachyarrhythmias. Case 1, a 34-year-old female who had dual atrioventricular (AV) nodal pathways with recurrent paroxysmal supraventricular tachycardia, committed suicide. Autopsy revealed an abnormally formed atrial septum with insertion of eustachian valve on the AV part of the pars membranacea. The intercuspid portion of the pars membranacea was muscular. The AV node was located adjacent to the membranous part of the ventricular septum rather than the central fibrous body. In addition, there was an accessory anterior AV node on the parietal wall of the right atrium. Case 2, a 13-year-old boy with history of recurrent ventricular tachycardia, died suddenly. CS revealed a right-sided, markedly septated bundle. The first part of right bundle branch was divided into three parts, which later joined together. Both cases showed fatty infiltration of the atrial septum, more than normal for the age of the patients. The relationship of the recurrent tachyarrhythmias to the congenital abnormalities in the CS in the two cases and the fatty infiltration is reviewed.

Adolescent↗
PubMed1979

Effects of atropine on induction and maintenance of atrioventricular nodal reentrant tachycardia.

The electrophysiologic effects of atropine were studied in 14 patients with dual atrioventricular (AV) nodal pathways and recurrent paroxysmal supraventricular tachycardia (PSVT). During PSVT, all patients used a slow pathway (SP) for antegrade and fast pathway (FP) for retrograde conduction. Atropine enhanced both SP antegrade and FP retrograde conduction, shown by a decrease in paced cycle lengths (atrial and ventricular) producing AV and ventriculoatrial block. Five patients had induction of sustained PSVT before and after atropine. Seven patients failed to induce or sustain PSVT before atropine, because of retrograde FP refractoriness. All seven had induction of sustained PSVT after atropine due to facilitation of FP retrograde conduction. Two patients had only single atrial echoes before atropine, reflecting SP antegrade refractoriness. After atropine, sustained PSVT was inducible in one, and nonsustained in the other, PSVT cycle length could be compared in seven patients before and after atropine and decreased from 383 +/- 25 to 336 +/- 17 (p less than 0.05). Thus, in patients with dual AV nodal pathways, atropine facilitated SP antegrade and FP retrograde conduction, shortened cycle length of PSVT and potentiated ability to sustain PSVT.

Adult↗
PubMed1979

Significance of chronic bifascicular block without apparent organic heart disease.

Eighty-six of 452 patients (19%) with chronic bifascicular block were found to have no clinically apparent associated organic heart disease (OHD) and were defined as having primary conduction disease (PCD). Comparison of patients with PCD and OHD revealed a significantly lower incidence of the following clinical variables in the PCD patients (p less than 0.001): exertional angina, dyspnea, congestive heart failure, cardiomegaly, functional class I (all by study design), left bundle branch block and premature ventricular contractions. Both mean AH and HV intervals were significantly shorter in patients with PCD (p less than 0.01). The incidence of HV prolongation was 21% in PCD and 41% in OHD patients (p less than 0.001). All patients were prospectively followed for 21-2998 days with a mean +/- SEM of 1209 +/- 66 days for PCD and 1172 +/- 36 days for OHD. Atrioventricular (AV) block developed in three patients from the PCD group and 26 from the OHD group (NS), with spontaneous block occurring in one (1%) PCD patient and 19 (5%) OHD patients (p less than 0.05). Annual mortality due to sudden death as well as total cardiovascular mortality (including sudden death) for the 5-year follow-up was significantly lower in patients with PCD. Patients with PCD have significantly lower incidence of electrophysiologic abnormalities and subsequent spontaneous AV block as well as cardiovascular and sudden death mortality. The diagnosis of PCD based on clinical criteria probably underestimates the presence of underlying OHD, as suggested by a small but definite risk of cardiovascular mortality.

Adult↗
PubMed1979

Significance of block distal to the His bundle induced by atrial pacing in patients with chronic bifascicular block.

Twenty-one of 496 (4%) patients with chronic bifascicular block, studied and followed prospectively, had block distal to the His bundle (BDH) induced by atrial pacing during initial electrophysiologic studies. In six, BDH was noted during pacing-induced atrioventricular (AV) nodal Wenckebach periods (at paced rates of 150--190 beats/min), with BDH in the short HH cycles after the AV nodal blocked P (lond cycle). The AH interval was normal in all six patients and HV was normal in four. None of the six patients has developed AV block during a mean follow-up of 5.33 +/- 0.48 years. In 15 patients, pacing-induced BDH was noted during intact AV nodal conduction (paced rate of 80--200 beats/min). The AH interval was prolonged in one, and HV was prolonged in 10 of the 15 patients. During a mean follow-up of 3.4 +/- 0.59 years, seven of these patients developed AV block, one had treadmill-provoked AV block, and two died suddenly (major morbid event in 10 of 15 patients). In conclusion, BDH induced by atrial pacing is an infrequent finding in patients with bifascicular block, and can be a functional as well as a pathologic response. The latter is associated with a high risk of major morbid events (AV block and sudden death).

Adolescent↗
PubMed1979

Evaluation of criteria for diagnosis of myocardial infarction: study of 256 patients with intermittent left bundle branch block.

In an attempt to elucidate the specificity and sensitivity of atypical findings during left bundle branch block (LBBB) with respect to myocardial infarction (MI), we analyzed ECGs from patients with intermittent LBBB obtained by mail solicitation of cardiologists. The group consisted of 256 patient files fulfilling the following criteria: 1) complete LBBB present on one or more 12-lead ECGs, and 2) at leat one 12-lead ECG taken subsequent to a LBBB tracing exhibiting absence of LBBB (non-LBBB). The sensitivity of atypical LBBB for predicting presence of MI was 0.41, the specificity 0.64, and the accuracy 0.59. No specific atypical finding was significantly better than any other in predicting MI. We conclude that atypical findings present during LBBB are of little value in predicting the presence of MI (as diagnosed by significant Q waves present during non-LBBB conduction).

Bundle-Branch Block↗
PubMed1979

Paroxysmal supraventricular tachycardia induction in patients with Wolff-Parkinson-White syndrome.

In 54 patients with pre-excitation, 30 (56%) had inducible A-V re-entrant paroxysmal tachycardia. Of these 30, 20 had spontaneous paroxysmal tachycardia (four also had atrial fibrillation), four had spontaneous paroxysmal atrial fibrillation, five had a history of palpitation without arrhythmia, and one was asymptomatic. In 24 patients (44%), paroxysmal tachycardia was not inducible. Of these 24, none had documented paroxysmal tachycardia, four had atrial fibrillation, none had palpitation without arrhythmia, and 11 were asymptomatic. The incidence of documented paroxysmal tachycardia was higher in the patients with inducible tachycardia (P less than 0.001). Tachycardia induction was noted in 20 of 20 patients with spontaneous paroxysmal tachycardia, eight of 12 patients with paroxysmal atrial fibrillation, five of 14 patients with palpitation and no arrhythmia, and one of 12 asymptomatic patients. The frequency of ability to induce paroxysmal tachycardia was significantly higher in both the patients with documented spontaneous paroxysmal tachycardia and the patients with paroxysmal atrial fibrillation than in the asymptomatic group (P less than 0.01).

Adolescent↗
PubMed1978

Clinical, electrocardiographic and electrophysiologic observations in patients with paroxysmal supraventricular tachycardia.

Seventy-nine patients without ventricular preexcitation but with documented paroxysmal supraventricular tachycardia were analyzed. Electrophysiologic studies suggested atrioventricular (A-V) nodal reentrance in 50 patients, reentrance utilizing a concealed extranodal pathway in 9, sinus or atrial reentrance in 7 and ectopic automatic tachycardia in 3. A definite mechanism of tachycardia could not be defined in 10 patients (including 7 whose tachycardia was not inducible). The three largest groups with inducible tachycardias were compared in regard to age, presence of organic heart disease, rate of tachycardia, functional bundle branch block during tachycardia and relation of the P wave and QRS complex during tachycardia. A-V nodal reentrance was characterized by a narrow QRS complex and a P wave occurring simultaneously with the QRS complex during tachycardia. Reentrance utilizing a concealed extranodal pathway was characterized by young age, absence of organic heart disease, fast heart rate, presence of bundle branch block during tachycardia and a P wave following the QRS complex during tachycardia. Sinoatrial reentrance was characterized by frequent organic heart disease, a narrow QRS complex and a P wave in front of the QRS complex during tachycardia. In conclusion, a mechanism of paroxysmal supraventricular tachycardia could be defined in most patients. Observations of clinical and electrocardiographic features in these patients should allow prediction of the mechanism of the tachycardia.

Adolescent↗