Henry J.L. Marriott

Intermittent Ventricular Parasystole with Observations on Its Relationship to Extrasystolic Bigeminy

Abstract 1. 1. Two cases of intermittent parasystole are described in which there is alternate extrasystolic and parasystolic impulse formation from the same focus; transitions between the two rhythms are repeatedly observed. 2. 2. It seems that intermittence results when the parasystolic focus is subjected to the enhancing effect of the sinus discharge whereby the automatic beat is prematurely precipitated, thus becoming a forced beat. 3. 3. This phenomenon can be explained on the basis of a property of automatic centers; namely, that their resting potentials exhibit a gradual upward “slope” of depolarization. With critical timing, the terminal part of the “slope” (i.e. its near threshold level) may encounter the enhancing effect of the preceding sinus beat and thus be precipitated prematurely. 4. 4. It is suggested that the form of extrasystolic bigeminal rhythm described may constitute a link between parasystolic and extrasystolic rhythm.

ACUTE PANCREATITIS SIMULATING MYOCARDIAL INFARCTION IN THE ELECTROCARDIOGRAM.

Excerpt It is well known that acute abdominal disease can alter the electrocardiogram in ways that mimic myocardial ischemia. It is not so widely known that the acute abdomen can simulate myocardia...

Atrioventricular Synchronization and Accrochage

Complete heart block implies an absolute independence between atria and ventricles that does not in fact always exist. Segers showed that, after complete block was artificially produced in the frogs heart, atria and ventricles would sometimes begin to beat exactly in phase, most commonly in a 2 to 1 ratio. He subsequently reported one clinical example of 2 to 1 A-V synchronization in a patient with complete heart block. Two further cases that may illustrate different varieties of synchronization are here presented.

Isorhythmic dissociation: Atrioventricular dissociation with synchronization

Abstract 1.1. During A-V dissociation there is a tendency for atria and ventricles to contract synchronously or almost synchronously. 2.2. Five examples of A-V dissociation manifesting this tendency to synchronize are presented. 3.3. Graded criteria for suspecting the presence of synchronization are suggested. 4.4. Possible mechanisms of A-V synchronization are briefly discussed.

A-V dissociation: A reappraisal∗

Abstract 1. (1) Attention is drawn to regrettable inconsistencies in usage of the terms dissociation, escape, and interference. The senses in which interference has been mainly used are detailed and discussed. 2. (2) The early history of A-V dissociation (interference-dissociation) is traced, especially as it exemplifies usage of the terms dissociation and interference. In the interest of clarity it is urged that A-V dissociation be reserved for this arrhythmia and be not applied to complete A-V block. By so reserving it, and by eschewing the maltreated term interference, much of the existing terminologic confusion could be avoided. 3. (3) Reasons are given for regarding interference-dissociation, dissociation with interference, complete dissociation, and incomplete dissociation as now unsatisfactory terms. It is recommended that A-V dissociation be simply divided into dissociation with and dissociation without ventricular capture. 4. (4) None of the six criteria often regarded as characteristic of A-V dissociation (sinus control of atria, nodal control of ventricles, independence between atria and ventricles, ventricles beating faster than atria, presence of retrograde block, normal forward conduction) is essential to the definition of this arrhythmia; indeed, exceptions to these terms are numerous. Such exceptions are illustrated and discussed and an attempt is made to redefine A-V dissociation. 5. (5) Interference (in one sense) is sometimes regarded as the cause of dissociation. It can be argued, however, that the principium of dissociation is not interference (in any sense); rather the original sin is the dysrhythmic whim of a truant (defaulting) or insubordinate (usurping) pacemaker. 6. (6) The incidence and significance of A-V dissociation is briefly commented upon. In a series of 10,000 consecutive tracings in a general hospital, this arrhythmia was diagnosed 48 times (0.48 per cent or one in every 208 records). It occurred mainly in elderly patients with severe degenerative cardiovascular disease.

Digitalis Delirium A Report on Three Cases

The use and suitability of the term digitalis delirium are briefly discussed. Attention is drawn to the paucity of detailed reports on this important manifestation of digitalis poisoning. Three cases of digitalis delirium resulting from toxicity with 3 different preparations—gitalin, digoxin, and digitoxin—are presented. The first case demonstrates how the signs of early intoxication in a single patient may vary with different preparations and indeed with the same glycoside on separate occasions. The second case provides an alarming example of delirium which, although provoked by a short-acting glycoside, nevertheless lasted longer than 2 weeks. The third illustrates how easily the diagnosis of digitalis intoxication can go unrecognized when superimposed on a complex clinical picture. The clinical features of these cases are discussed in the light of previous reports.

Ventricular Fusion Beats

Relatively precise criteria are proposed for the recognition of ventricular fusion beats. Apart from the obvious and widely accepted criteria involving contour, duration, and time of appearance, other less obvious characteristics have been adduced: (1) the P-S time of the fusion beat must always be considerably longer than the P-R interval of the component sinoatrial beat; (2) the P-R interval of the fusion beat is generally not more than 0.06 second shorter than the sinoatrial P-R; (3) the terminal vector of the fusion beat is always different from that of the sinoatrial beat, while the initial vector may or may not differ. Exceptions to these criteria are seen in the presence of bundle-branch block, during periods of inconstant atrioveutricular conduction times, and presumably in the presence of diffuse intraventricular conduction delays. The shortcomings of conventional diagrams for depicting the mechanisms of arrhythmias are noted, and a plea is made for the use of more accurate symbols in their construction. Fusion beats are not an indispensable criterion for the diagnosis of ventricular parasystole.

Left bundle branch block with right axis deviation: a marker of congestive cardiomyopathy.

Three patients with primary congestive cardiomyopathy (COCM), complete left bundle branch block (LBBB) and right axis deviation in the standard leads are described. Review of 50 additional patients from the literature since 1950 indicates that the uncommon combination of LBBB and RAD is a marker of severe myocardial disease, especially COCM. The mechanism of production of this electrocardiographic pattern appears to be diffuse conduction system involvement in advanced myocardial disease.

Main-Stem Extrasystoles

Extrasystoles arising in the main stem of the bundle of His are generally regarded as very rare; only 7 examples have been published since their original description by Lewis in 1911 and 2 of these fail to satisfy rigid criteria for diagnosis. Four further examples, encountered in a relatively small series of tracings, are here presented and it is concluded that such extrasystoles are not so much rare as they are overlooked.

The T-V1 taller than T-V6 pattern: Its potential value in the early recognition of myocardial disease

Abstract Attention is drawn to the possible usefulness of the T - V 1 > T - V 6 pattern as an early diagnostic sign of myocardial disease, particularly hypertensive or ischemic. Representative tracings illustrating this electrocardiographic syndrome are included. It is estimated that this pattern is present as the only abnormality in approximately one per cent of consecutive hospital tracings.