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Biomedical subjects

D Krikler

Publications and source records attributed to D Krikler.

At least 19 recordsLinked to original sources
PubMed1988

The supraventricular tachycardias.

Most supraventricular tachycardias can be diagnosed confidently using the standard 12-lead electrocardiogram, the more so if such a tracing in sinus rhythm is also available. The underlying mechanisms may often be determined and these may have important therapeutic consequences. This chapter reviews the electrocardiographic appearances of the supraventricular arrhythmias. Extrasystoles are common but rarely require specific treatment. Automatic atrial tachycardias are common and usually amenable to simple management. Reentrant circuits related to atrial and atrioventricular tachycardias are also described, and where possible, treatment is related to underlying mechanisms.

Atrial Fibrillation↗
PubMed1985

Criteria for intraventricular conduction disturbances and pre-excitation. World Health Organizational/International Society and Federation for Cardiology Task Force Ad Hoc.

In an effort to standardize terminology and criteria for clinical electrocardiography, and as a follow-up of its work on definitions of terms related to cardiac rhythm, an Ad Hoc Working Group established by the World Health Organization and the International Society and Federation of Cardiology reviewed criteria for the diagnosis of conduction disturbances and pre-excitation. Recommendations resulting from these discussions are summarized for the diagnosis of complete and incomplete right and left bundle branch block, left anterior and left posterior fascicular block, nonspecific intraventricular block, Wolff-Parkinson-White syndrome and related pre-excitation patterns. Criteria for intraatrial conduction disturbances are also briefly reviewed. The criteria are described in clinical terms. A concise description of the criteria using formal Boolean logic is given in the Appendix. For the incorporation into computer electrocardiographic analysis programs, the limits of some interval measurements may need to be adjusted.

Bundle-Branch Block↗
PubMed1979

Effect of nifedipine on atrioventricular conduction as compared with verapamil. Intracardiac electrophysiological study.

Intravenous nifedipine, a powerful calcium antagonist, had no obvious effect on atrioventricular conduction when administered to 11 patients during routine intracardiac electrophysiological studies. Verapamil on the other hand showed potent antiarrhythmic properties, depressing atrioventricular nodal conduction. Nifedipine thus appears safe in patients with angina pectoris who have disorders of atrioventricular nodal conduction, and in those receiving beta-adrenergic blocking drugs. There appear to be differential effects on the slow inward channels of cardiac cells with different 'calcium antagonists'.

Adolescent↗
PubMed1979

Electrophysiological effects soon after intravenous beta-methyldigoxin.

The digitalis derivative beta-methyldigoxin has been shown to be quickly and well absorbed from the gut and, in hemodynamic studies, to start acting rapidly after intravenous administration. However, when tested on 6 patients suffering from paroxysmal reciprocating atrioventricular tachycardia, or having an accessory pathway who might develop this disorder, there was no effect on induced tachycardias or on AV conduction during rapid atrial pacing or the extrastimulus test. One of the 6 patients showed some increase in refractoriness of conduction through the AV node within 25 min after the injection. Beta-methyldigoxin does not appear to be a satisfactory alternative to other effective agents available for the prompt correction of paroxysmal reciprocating atrioventricular tachycardia.

Adolescent↗
PubMed1979

'Bradycardia-tachycardia' syndrome 8 yr after correction of Fallot's tetralogy.

A 13-yr-old boy presented with atrial flutter 8 yr after surgical correction of tetralogy of Fallot; antiarrhythmic therapy caused depression of the sinoatrial node, with syncope. Disordered sinoatrial function and intraventricular conduction were demonstrated by intracardiac electrography, and appear to have resulted from the operation. Sinoatrial disease may be responsible for supraventricular arrhythmias or syncope long after operative correction of Fallot's tetralogy and may be one of the explanations for the tendency of such patients to die suddenly.

Adolescent↗
PubMed1978

Ventricular tachycardia due to cardiac ischaemia: assessment by exercise electrocardiography.

Although ventricular tachycardia is a well-known complication of myocardial ischaemia and may be provoked by exercise, many patients may appreciate only the angina and be unaware of the unduly rapid heart rate that precipitates it. Exercise testing is needed to show this arrhythmia and to enable treatment to be started.Twenty-three patients were found to have chronic ischaemic heart disease complicated by ventricular tachycardia. Six patients with old myocardial infarction had ventricular tachycardia at rest which required conversion to sinus rhythm; 17 patients developed ventricular tachycardia only when they exercised. In 12 of these 17 patients coronary angiography showed disease of the anterior descending branch of the left coronary artery; other vessels were usually also affected. Although beta-adrenergic blocking drugs increased exercise tolerance, ventricular tachycardia still occurred when the heart rate on exercise reached a level similar to that before treatment. In five patients coronary artery bypass surgery was performed because of angina and exercise-induced ventricular tachycardia. Exercise tolerance was increased in all three patients who underwent exercise tests after operation, and in two of these patients, both of whom were known to have patent grafts, ventricular tachycardia was abolished.If part of the beneficial effect of coronary bypass surgery is preventing life-threatening ventricular arrhythmias it is essential to detect these, and ambulatory monitoring and stress testing have a complementary role.

Adult↗
PubMed1978

Concealed pre-excitation causing paroxysmal reciprocating atrioventricular tachycardia in infancy.

We report 3 infants with Wolff-Parkinson-White (WPW) syndrome who presented with life-threatening paroxysmal reciprocating atrioventricular tachycardia in their first month of life. The diagnosis was confirmed by electrophysiological studies at ages 2--4 years, but the characteristic ECG of pre-excitation has not been shown in one patient and was first recorded at 2 and 3 years in the other two. In 2 patients the tachycardia proved refractory to treatment with digoxin alone but responded to the addition of propranalol or verapamil. One of these infants was converted to sinus rhythm by DC countershock, giving time to reconsider his treatment with drugs. Digoxin is a well-tried treatment acting by slowing AV conduction and interrupting the re-entry circuit. However, it may act more slowly than other agents that act on the AV node--such as intravenous verapamil. Our patients illustrate the value of long follow-up as the diagnosis of WPW syndrome could not be made in infancy. Many infants who present with paroxysmal supraventricular tachycardia in infancy may have an inapparent bypass and be examples of the WPW syndrome.

Atrioventricular Node↗
PubMed1978

Palpitations.

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Arrhythmias, Cardiac↗
PubMed1977

Wolff-Parkinson-White syndrome type A obscured by left bundle branch block.

2 patients are presented whom the presence of left bundel branch block obscured the signs of the Wolff--Parkison--White syndrome expected with a bypass on the left side of the heart. While it was possible to infer the presence of both disorders from the surface ECGS, electrophysiological studies proved invaluable in defining the precise situation in both cases. When atypical electrocardiographic appearances are observed in the Wolff-Parkinson-White syndrome, careful investigation may reveal the cause to be bundle branch block on the same side of the hear as the anomalous pathway. In both patients there was in addition evidence of sinoatrial disease, which was associated with the occurrence of arrythmias, and this was also confirmed with intracardiac studies.

Adult↗
PubMed1976

Ventricular arrhythmias and hypokalaemia.

Two cases of life-threatening ventricular arrhythmia (torsade de pointes) due to chronic mild hypokalaemia, caused by hyperaldosteronism and familial periodic paralysis are described. Correction of the hypokalaemia, supplemented by mexiletine, controlled the arrhythmias.

Adult↗
PubMed1976

Dual-demand pacing for reciprocating atrioventricular tachycardia.

By using programmed electrical stimulation of the heart and studying the initiation and termination of reciprocating atrioventricular tachycardia two patients with the Wolff-Parkinson-White syndrome were shown to respond rapidly and consistently to fixed-rate pacing. A demand pacemaker was implanted in each patient, having been modified so as to switch into the fixed-rate mode whenever the tachycardia began, thereby terminating the arrhythmia. This appears to be a promising form of treatment in patients with otherwise intractable paroxysmal tachycardia who have been shown by careful study to respond in this way.

Adult↗
PubMed1976

'Incessant' tachycardias in Wolff-Parkinson-White syndrome. I: Initiation without antecedent extrasystoles or PR lengthening, with reference to reciprocation after shortening of cycle length.

In 6 patients with the Wolff-Parkinson-White (WPW) syndrome, repetitive, almost continuous (incessant) reciprocating atrioventricular (AV) tachycardia has been shown to arise when the sinus cycle length was shortened to a critical point, at which unidirectional block occurred without the classical feature of PR prolongation. Though this phenomenon superficially resembles an aspect of chronic intranodal reciprocating tachycardia of children, basic differences can be identified. It was encountered more frequently in younger subjects; the only patient over 45 developed the arrhythmia as a complication of therapy. This incessant mechanism may explain some cases in which antiarrhythmic treatment does not control reciprocating tachycardia in the WPW syndrome, but such a mechanism can also occur spontaneously.

Adolescent↗