Wolff-Parkinson-White syndrome: current concepts regarding its probable mechanism and report of a case with attacks of supraventricular paroxysmal tachycardia

1. The most accepted and, apparently, the most logical explanation for the W-P-W syndrome is the anomalous A-V conduction theory. But, while there is general agreement on the fundamental concept of an accessory pathway, there is much disagreement regarding the details of the mechanism. Among the questions still unsettled are: the nature, number and location of this anomalous bundle; whether the A-V conducting system is functioning or not; and what the course and fate of the short-circuited impulse is after reaching the ventricles2. In view of the conflicting and apparently irreconcilable differences among the various workers, we venture the conclusion that these differences probably need not be reconciled because the pathology present may not be exactly the same in the different patients studied. The anomalous bundle being an anomalous structure, by its very nature, should be variable. Hence, it may be single or multiple, unilateral or bilateral, it may end near or at a distance from the septum and A-V conducting system, and it may, therefore, either supplement the latter or replace it altogether3. A rare case of W-P-W syndrome in a Filipino is presented. This patient came with presenting signs and symptoms of paroxysmal tachycardia of auricular origin4. The anomalous pathway in this patient was localized electrocardiographically at the left posterior position, conducting impulses in an epicardial-to-endocardial direction5. Electrocardiographically, the paroxysmal tachycardia closely simulated paroxysmal ventricular tachycardia. The differentiation between supraventricular and ventricular tachycardia is discussed. The probable mechanism causing the attacks of tachycardia are evaluated6. The predisposition of W-P-W patients to attacks of paroxysmal tachycardia should be borne in mind, for it can serve as an aid both in the prognostication of the arrhythmia, as well as in the diagnosis of W-P-W syndrome. The possibility of W-P-W syndrome should be entertained in patients with histories of repeated attacks of tachycardia. (Summary and Conclusions)

Anti-hemoptic drugs: II. action of emetine on the pulmonary circulation

1. The actions of emetine on the heart and pulmonary circulation were studied in a total of 45 anesthetized dogs2. Emetine was shown to lower both systemic and pulmonic blood pressures when injected intravenously in doses from 0.05 to 7.5 mg./Kg. The mechanism by which this hypotension was brought appeared to be solely by cardiac depression. No significant direct vasodilating action was demonstrated3. The applicability and dangers of emetine as an antihemoptic agent were discussed. (Summary)

Anti-hemoptic drugs: I. Pitressin- a reinvestigation of its actions on the pulmonary circulation

1) In anesthetized artificially respiring dogs, Pituitrin causes a rise of systematic and fall of pulmonary pressure; Pitressin elicits a similar response to Pituitrin but the effects are relatively greater in degree2) A measured by a bubble flowmeter, Pitressin brings about decreased blood flow through the pulmonary circuit3) Lung perfusion experiments sustain the claim that Pitressin actually constricts the pulmonary vessels4) It is inferred from past and present experimental evidences that the pulmonary hypotension and the diminished pulmonary blood flow after Pitressin injection as attributable to depressed cardiac efficiency5) Our investigation give indication that Pitressin may enjoy widespread clinical use in the treatment of pulmonary hemorrhage, especially those cases attended with significant blood loss. (Summary and Conclusion)

Wolff-Parkinson-White Syndrome: current concepts regarding its probable mechanism and report of a case with attacks of supraventricular pyroxymal tachycardia

The most accepted and, apparently, the most logical explanation for the W-P-W syndrome is the anomalous A-V conduction theory. But, while there is general agreement on the fundamental concept of an accessory pathway, there is much diasagreement regarding the details of the mechanism. Among the questions still unsettled are: the nature, number and loation of this anomalous bundle; whether the A-V conducting system is functioning or not; and what the course and fate of the shortcircuited impulse is after reaching the ventricles2) In view of the conflicting and apparently irreconcilable differences among the various workers, we venture the conclusion that these differences probably need not be reconciled because the pathology present may not be exactly the same in the different patients studied. The anomalous bundle being an anomalous structure, by its very nature, should be variable. Hence, it may be single or multiple, unilateral or bilateral, it may end near or at a distance from the septum and A-V conducting system, and it may, therefore, either supplement the later or replace it altogether3) A rare case of W-P-W syndrome in a Filipino is presented. This patient came with presenting signs and symptoms of paroxysmal tachycardia of auricular origin4) The anomalous pathway in this patient was localized electrocardiographically at the left posterior position, conducting impulses in an epicardial-to-endocardial direction5) Electrocardiographyically, the paroxysmal tachycardia closely simulated paroxysmal ventricular tachycardia. The differentiation between supraventricular and ventricular tachycardia is discussed. The probable mechanism causing the attacks of tachycardia are evaluated6) The predisposition of W-P-W patients to attacks of paroxysmal tachycardia should be borne in mind, for it can serve as an aid both in the prognostification of the arrhythmia, as well as in the diagnosis of W-P-W syndrome. The possibility of W-P-W syndrome should be entertained in patients with histories of repeated attacks of tachycardia. (Summary and Conclusion)

The diagnosis of coronary insufficiency by the combined dynamic-postexercise electrocardiographic test

Analysis of the results of the Dynamic Exercise and Post-Exercise ECG tests given to 206 young normal subjects and to 302 patients with probable, presumptive, or definite evidence of coronary heart diseases revealed the following1. Using ischemic ST depression of at least 1.0 mm as the sole criterion for a positive test, the Dynamic Exercise ECG did not give more "false positive" results than the Post-Erxercise ECG in the known normal subjects while in the "coronary" patients, the Dynamic Exercise ECG detected almost five times as many coronary insufficiencies as the Post-Exercise ECG2. Junctional ST depressions of 1.5 mm or more in the Post-Exercise ECG were found to be residuals of previous ischemic ST depressions in about 60 per cent of cases, and should therefore be regarded as suspicious indications of coronary insufficiency whenever the Dynamic Exercise ECG is unavailable3. The significance of and the possibility of the inclusion of "prolonged" QTc interval as a criterion to increase the sensiitivity of the Exercise Test was discussed4. Despite the demonstrated superiority of the Dynamic Eercise ECG it had a few limitations which the post exercise ECG could compensate. In view of this, it was recommended that the two exercise ECG tests be combined for which the name "Combined Dynamic-Post-exercise ECG Test" was proposed."(Summary and Conclusions)

Anti-henoptic drugs: its effects of nitroglycerin (NG) on the pulmonary circulation

1. Nitroglycerin, 10 to 5000 mcg./kg. intravenously, caused pulmonary hypotension in 10 dogs. In these 10 dogs, left and right atrial pressure measurements do not support the possibility that the pulmonary hypotension is secondary to decreased right ventricular output or increased left ventricular output2. Nitroglycerin, intra-arterially administered in 12 dogs prepared for constant inflow perfusion, caused a decrease in perfusion pressure in 11 and no change in one. Decrease in pulmonary perfusion pressure can be shown to occur with doses which cause no change in systemic blood pressure. Furthermore, when the intra-arterial doses of NG are large enough to bring about the known systemic hypotensive property of NG, the fall in pulmonary perfusion pressure always precedes the systemic hypotension. These phenomena speak speak strongly of a pulmonary vasodilatation caused by NG. No experiments were done to determine what role decreased transpleural pressure plays in the pulmonary vasodilatation3. Nitroglycerin, 10 mcg. to 12 mg. total doses, caused no change in the cardiac output of 8 dog heart-lung preparations4. The efficacy of NG, interavenously, as an anti-hemoptic was discussed.(Summary)

The sodium and potassium content of normal human hearts

Forty-four hearts, showing no signs of hypertrophy or disease, were selected from persons dying suddenly from accidental, suicidal or homicidal causesSamples from each heart were obtained from the right ventricle and from the epicardium (outermost 1-2 mm. portion) and endocardium of the left ventricle. These samples were analyzed for sodium and potassium by flame photometry, after being freed of all removable fat and blood vessels. The results were expressed in mEq 100 Gm. of fat-free and water-free tissueThe left ventricle had significantly (15 per cent) more potassium than the right; while the right ventricle had significantly (30 per cent) more sodium than the left. The left ventricular epicardium had significantly more sodium than the endocardium, but an equal concentration of potassiumThe higher sodium concentration in the outer ventricular layer (epicardium) was interpreted to mean that this area probably had relatively more extracellular fluid as a result of the squeezing action of the intramyocardial pressureThe higher sodium content of the right ventricle was thought to be due only partly to a greater amount of extracellular space. The possibility that some of this sodium in the right ventricle must be intracellular could not be eliminated because of the lower potassium content of this ventricle and the previous studies demonstrating a reciprocal relationship between these ionsThe difference in potassium content between left and right ventricles was considered to indicate a difference in the potassium of the muscle cells themselves, and consequently, as a reflection of differences in cellular metabolism and activity. Some physiologic qualities of the normal right ventricle that differ from the left ventricle were cited as possible effects of these cellular chemical differences. (Summary)

Cardiovascular disease incidence in some asian-pacific countries

A cooperative survey of general hospitals in Australia, India and the Philippines during 1954-1956 showed that the cardiovascular incidence and distribution pattern in the Philippines was intermediate between those of Australia and India in a similar manner as the Philippines is, culturally speaking, intermediate between the two. However, no good correlation was observed between the cardiovascular incidence of hypertensive and arteriosclerotic heart diseases with the reported values of serum cholesterol and dietary fats in these countries. (Summary and Conclusions)