Search PubMed⌕ Search

Biomedical subjects

J J Rozanski

Publications and source records attributed to J J Rozanski.

At least 37 records · Page 2Linked to original sources
PubMed1982

Electrophysiologic effects of diltiazem hydrochloride on supraventricular tachycardia.

The effects of intravenous diltiazem hydrochloride (0.25 mg/kg body weight) were studied in eight patients with nine episodes of supraventricular tachycardia. Five episodes of tachycardia were due to atrioventricular (A-V) nodal reentry (group A), two were due to retrograde utilization of a concealed A-V accessory pathway (group B) and two were episodes of atrial fibrillation (group C). Intravenous administration of diltiazem slowed the ventricular rate in eight of nine episodes of tachycardias. Supraventricular tachycardia was terminated within 2 minutes after intravenous diltiazem in four of five patients in group A, and one of two in group B. Cycle length alternation was observed before termination of the arrhythmia in two patients from group A. In group C the ventricular response slowed but also became regular during atrial fibrillation. Although diltiazem depressed both anterograde and retrograde conduction as assessed by programmed stimulation, tachycardia termination or slowing or alternation of cycle length all occurred because of the effects of diltiazem predominantly on anterograde A-V nodal properties during supraventricular tachycardia. Although no statistical conclusions can be made from this limited study, it appears that diltiazem has significant depressant electrophysiologic effects on both anterograde and retrograde A-V nodal function as assessed by programmed stimulation during sinus rhythm. Further electrophysiologic studies are needed before determining the clinical efficacy of this agent for treatment or prophylaxis of recurrent supraventricular tachycardias.

Adult↗
PubMed1982

Advanced ventricular arrhythmias during bedside pulmonary artery catheterization.

To determine the incidence of advanced arrhythmias and acute right bundle branch block during beside pulmonary artery catheterization, 119 critically ill patients undergoing 150 pulmonary artery catheterizations were prospectively studied using continuous electrocardiographic monitoring with permanent recordings. Ventricular arrhythmias other than isolated premature ventricular contractions, couplets or bigeminy occurred during 80 of the 150 catheterizations (53 percent). These included ventricular salvos (three to five consecutive premature ventricular contractions) in 30 percent, nonsustained ventricular tachycardia (five to 30 premature ventricular contractions) in 20 percent and sustained ventricular tachycardia (more than 30 consecutive premature ventricular contractions) in 3 percent. In two patients, ventricular fibrillation developed; in another three patients, lidocaine or precordial thump was required to terminate the episodes of ventricular tachycardia. The incidence of advanced ventricular arrhythmias was statistically correlated with either the presence of predisposing risk factors for ventricular ectopy (p less than 0.05) or prolonged catheterization time (p less than 0.01). A new right bundle branch block developed in seven patients (5 percent) and persisted for a mean of 9.5 hours.

Adult↗
PubMed1982

Transverse dissociation of the human His bundle.

"Completed" and "abortive" alternating Wenckebach periods occurred in a symptomatic female with calcification of the mitral annulus. These arrhythmias were attributed to transverse dissociation of the His bundle into two horizontal levels "connected in series," with 2:1 block in the "distal" level and Wenckebach periods in the "proximal" level. Intra-Hisian alternating Wenckebach periods resembled those resulting from transverse dissociation of other infra-AV nodal structures in that they are rare, usually symptomatic and require pacemaker implantation. This contrasts with the variety of rhythms resulting from transverse dissociation of the AV node which occur frequently, are not always malignant, and generally are not treated with implanted pacemakers.

Bundle of His↗
PubMed1982

Alternans of the ST segment of T wave. A sign of electrical instability in Prinzmetal's angina.

In an effort to determine the incidence of ventricular arrhythmias associated with ST segments alternans, the patterns of ST segment and T-wave electrical alternans (STEA) were analyzed in 93 patients during spontaneous Prinzmetal's angina. Twenty-eight of 93 patients, or 30% (Group I), showed STEA during episodes of ST segment elevation. SIxty-five of 93 patients, or 70% (Group II), showed no alternans during episodes of ST segment elevation. In Group I, ventricular arrhythmias, defined as all ventricular ectopic activity greater than 5 beats per minute and complex Lown grades III to V, occurred during 52 of 55 episodes, or 95%; whereas in Group II, ventricular arrhythmias occurred in only 51 of 125 episodes, or 41% (p less than 0.01). The difference in the incidence of ventricular fibrillation (VF) or ventricular tachycardia (VT) in the two groups was more striking. VT or VF occurred in 20 of 55 in Group I (36%) versus 5 of 125 in Group II (4%). Although there were no significant differences in age or sex between Group I and II patients, there was a significant difference in the magnitude of the maximum ST segment elevation (5 mm in Group I versus 3 mm in Group II, p less than 0.01). This study demonstrates that the occurrence of STEA and T wave alternans frequently heralds the onset of ventricular arrhythmias in Prinzmetal's angina. Both the arrhythmias and the alternans occur during the time of maximal ST segment elevation.

Angina Pectoris, Variant↗
PubMed1982

Intrahisian functional bundle branch block.

A patient with functional complete left bundle branch block is presented. The site of block was localized to the area of the His bundle. This case demonstrates that functional complete left bundle branch block may be due to longitudinal dissociation in the His bundle.

Adult↗
PubMed1982

His bundle recordings in double tachycardias not due to digitalis intoxication.

Electrophysiological studies were performed in a patient with chronic chagasic cardiomyopathy, recurrent sustained ventricular tachycardia, and a history (without electrocardiographic documentation) of paroxysmal atrial flutter. Ventriculoauricular conduction occurred during short bursts of ventricular pacing. Moreover, the retrograde P of ectopic ventricular beats which appeared after pacing was stopped precipitated an atrial tachyarrhythmia with an irregular atrial rate. In addition, burst ventricular pacing, performed while this atrial tachyarrhythmia was present, initiated and subsequently terminated a ventricular tachycardia with similar characteristics to the one occurring spontaneously. The double (atrial and ventricular) tachycardias described in this communication were different from those previously reported in that the arrhythmias were not due to digitalis toxicity, but resulted from the modality of ventricular stimulation performed in a patient who had the specific type of cardiomyopathy seen in the chronic stage of Chagas' disease.

Atrial Flutter↗
PubMed1982

Effects of lignocaine on bidirectional tachycardia and on digitalis-induced atrial tachycardia with block.

Most recent studies discussing tachycardias with alternating QRS polarity have referred to those known as torsade de pointes. This report, in contrast, deals with bidirectional tachycardia and the effects of lignocaine on 10 patients with this arrhythmia. Three of the patients also had digitalis-induced atrial tachycardia with block. In one patient, a single bolus of lignocaine was followed (five minutes later) by ventricular fibrillation, but the other nine patients received two boluses of 75 mg followed by a drip infusion of 3 mg/min. The drug terminated the episodes of atrial tachycardia with block and bidirectional tachycardia in all patients thus treated. Whereas the abolition of the bidirectional tachycardia was permanent in the seven patients with digitalis intoxication, it recurred after stopping the drip infusion in the two patients without digitalis toxicity. It is concluded that lignocaine can be useful in the treatment of digitalis-induced bidirectional tachycardia and atrial tachycardia with block. From this study no conclusions can be drawn, however, as to whether lignocaine is superior to other class I or class IV agents.

Adult↗
PubMed1981

Atropine-induced multilevel block in acute inferior myocardial infarction. A possible indication for prophylactic pacing.

The degree of A-V block increased after intravenous administration of atropine in 10 nondigitalized patients with acute inferior myocardial infarction who had narrow QRS complexes during periods of 1:1 A-V conduction. Short episodes of 3:1, 4:1 and 5:1 A-V block were seen to emerge: (a) in 6 patients, directly from Wenckebach periods; (b) in 3 patients, from alternating Wenckebach periods; and (c) in 1 patient, from a 3:2 Wenckebach period which led to a short-lived alternating Wenckebach period. Apparently, the predominance of the chronotropic effects on the sinus node over the dromotropic effects on the A-V node led to a tachycardia-dependent (more ischemic than vagal) process, exposing or producing multi- (two, three or four) level block involving the A-V node (and perhaps the His bundle). Subsequently, therapeutic pacing was instituted in 9/10 patients because they developed spontaneous symptomatic advanced A-V block. Therefore, it is possible that the early effects of atropine identified a narrowly-defined subset of patients in whom prophylactic pacing may be indicated. However, more studies are necessary to corroborate these assumptions.

Atropine↗
PubMed1981

The mechanism of flutter electrical alternans.

We have had the opportunity to observe the occurrence of flutter electrical alternans in which two distinct populations of flutter waves are present and which alternate in 1:1 and 2:1 patterns. The flutter alternans whether 2: or 3:1, was concordant with the pattern of preceding ventricular conduction (ventriculophasic variation). This concordance occurred reproducibly and remained consistent. Our example of flutter alternans probably represents mechanical artefact caused by catheter movement during ventricular mechanical systole. We reproduced this pattern consistently at a slower rate during coronary sinus pacing. These findings appear to suggest an explanation for certain types of so-called atrial flutter electrical alternans.

Atrial Flutter↗
PubMed1981

Body surface detection of delayed depolarizations in patients with recurrent ventricular tachycardia and left ventricular aneurysm.

In eight patients with chronic ventricular tachycardia and left ventricular aneurysms, we detected delayed ECG wave forms after the QRS complex from the body surface using a high-resolution ECG recorder, amplification and signal averaging. Delayed wave-form activity (D wave) extended a mean of 70 msec beyond the termination of th QRS complex. This delayed activity frequently extended to the limit of the recording window, and may thus continue throughout much of diastole. Antiarrhythmic agents never abolished the delayed activity; however, it was abolished by aneurysmectomy in four patients. Ventricular tachycardia did not recur after surgery in the four patients during a mean follow-up of 1 year. The D wave was not found in eight control patients who had chronic recurrent ventricular tachycardia nor in 11 of 12 who had aneurysms alone. The surface D wave can be readily and reproducibly detected by high-resolution electrocardiography and appears to be specific for patients with left ventricular aneurysms who also have chronic recurrent ventricular tachycardia. This delayed wave-form activity has been noted during catheter and surgical endocardial and epicardial mapping. It may represent persistence of the cardiac impulse in islands of myocardium and may be a manifestation of the delayed and fractionated activity, noted by previous investigators.

Adolescent↗
PubMed1981

Left fascicular blocks during right-heart catheterization using the Swan-Ganz catheter.

During insertion of Swan-Ganz catheters, mechanical right bundle branch block occurred in association with left posterior fascicular block in two patients and with left anterior fascicular block in two. None of the four patients had acute myocardial infarction or acute (spontaneous or iatrogenic) pulmonary disease. In two cases, electrophysiologic studies demonstrated the coexistence of intra- and infra-Hisian conduction delays and blocks. Although the right bundle branch block may have resulted from injury to the central or peripheral right branch, the left fascicular blocks could not be explained by direct trauma to these left-sided structures. Our findings support the recent clinical and experimental reports that show that left fascicular block (as well as right bundle branch block) may be due to lesions involving the His bundle; presumably because of longitudinal dissociation of this structure affecting the transverse interconnections. In one patient, 2:1 intra-Hisian block may have coexisted with bradycardia-dependent (phase 4) right bundle branch block. More studies are required to determine the implications of catheter-induced conduction disturbances in other clinical settings, such as acute myocardial infarction.

Bundle of His↗
PubMed1980

Clinical evaluation of an improved high resolution ECG cart for recording the His bundle electrogram non-invasively.

The Marquette high resolution MCA-1 ECG cart can record the His bundle electrogram non-invasively at the bedside. The second generation MAC-1 has several unique features and technical advances which may now make the technique clinically applicable. In addition to amplification and signal averaging, an adjustable input filtration system excludes beats which are unacceptably "noisy" compared to a 4 beat template. Thus, extremely "clean" signals are presented for processing by the average allowing resolution of very low amplitude signals. Clear unequivocal His bundle recordings were obtainable in 25 of 55 patients (45%). A correlation coefficient of +.97 was obtained between invasive and non-invasive HV intervals. The 55% failure rate was attributed to prolonged atrial activity in 31%, short PR in 9%, and technically unsatisfactory recordings with excessive or overwhelming noise which did not allow appreciable signal resolution in 15%.

Bundle of His↗
PubMed1980

TQ segment (baseline) alternans during Prinzmetal's variant angina.

In a study of 93 patients who met criteria for Prinzmetal's angina, alternans of the ST segment was observed in 28 of 93 patients (30%). In 8 of these 28 patients, a hitherto undescribed variant of alternans, namely alternation (larger than or equal to 1 mm shift in 2:1 pattern) in the amplitude of the baseline or TQ segment (TQ Alt) was observed. In all eight patients serious ventricular arrhythmias were noted, namely, ventricular fibrillation in two, ventricular tachycardia in four, and multiform or advanced ventricular ectopic activity in eight. The TQ Alt developed only after ST segment alternans occurred. It is postulated that the alternations of the ST and TQ segments are due to differences in current flows due to inhomogeneity of depolarization and repolarization of the action potential caused by ischemia. Furthermore, the associated arrhythmias observed are related to the inhomogeneous state initiated by the ischemia.

Action Potentials↗
PubMed1980

Ventricular ectopy and sudden death.

The occurrence of certain complex forms of chronic ventricular arrhythmias or high frequency of less complex forms constitutes an independent risk factor for subsequent sudden death proportional to the degree of host organic heart disease. Currently, grade is probably best defined by referring to either simple or complex ventricular arrhythmias--complex forms being a combination of Lown's modified grades 3, 4, and 5, plus bigeminy. Frequency may provide an equally good expression of the information contained in gradation analysis, but one must recognize the potentially important transient advanced grades which may occur when overall frequency is low. The importance of such transient events has not yet been determined. The recently emphasized problem of spontaneous variation of frequency has yet to be resolved, both in terms of the patient who is not on drug therapy and those who are on long-term, steady-state therapy. For purposes of risk assessment for sudden death, until some of the controversies mentioned are resolved, the best compromise between accuracy, limitations, and economics remains the use of a single 24-hour Holter monitor analyzed for both frequency and the occurrence of complex or advanced grades. The goal of treatment should be a marked reduction or abolition of chronic VPDs, but if this is not successful, simply maintaining therapeutic blood levels of antiarrhythmic drugs may afford some protection against symptomatic or potentially lethal arrhythmias. The roles of provocative testing employing exercise, psychologic stressing, or electrophysiologic testing to identify high risk individuals are all being intensively investigated at the present time.

Angina Pectoris, Variant↗
PubMed1979

Right ventricular apical activation times in patients with conduction disturbances occurring during acute transmural myocardial infarction.

His bundle and right ventricular apical electrograms were recorded in 18 patients with acute transmural myocardial infarction in whom catheter insertion was considered necessary for clinical reasons. The V-RVA and H-V intervals were of normal duration (5 to 30 and 35 to 55 msec, respectively) in five patients (Group 1) with persistently narrow (less than 100 msec) QRS complexes. In contrast, 13 patients (Group 2) who manifested a "complete" right bundle branch block pattern within 96 hours after admission had prolonged V-RVA intervals (range 50 to 80 msec, mean 59.2 msec) and H-V intervals that were at the upper limits of normal or prolonged (range 55 to 90 msec, mean 63 msec). In 6 of these 13 patients, the duration of the V-RVA interval became normal when the "complete" right bundle branch block pattern disappeared and was replaced by a "complete" left bundle branch block pattern in three patients and by narrow QRS complexes in the three other patients. This study showed that transmural myocardial infarction in itself did not increase the duration of the V-RVA interval even when "complete" left bundle branch block was present. Moreover, a prolonged V-RVA interval coexsting with a "complete" right bundle branch block pattern was not due to distal right bundle branch block but resulted from a conduction disturbance located in the proximal portions of the right bundle, or perhaps, even within the His bundle itself.

Adult↗