Benjamin M. Kaplan

Tachycardia-bradycardia syndrome (so-called “sick sinus syndrome”): Pathology, mechanisms and treatment☆

Abstract The tachycardia-bradycardia syndrome consists of paroxysmal atrial fibrillation, flutter or tachycardia followed by sinoatrial block or sinus arrest resulting in Stokes-Adams attacks. Detailed histologie findings of the conduction system of 2 patients with this entity correlated well with the clinical observation of cardiac rhythm disturbances in the sinus node, atria and atrioventricular (A-V) junction. Eight other patients with the syndrome were studied clinically. The mechanisms (as revealed by the electrocardiogram) producing the bradycardia phase include depression of pacemaker function (arrest) or of conduction (exit block) of the sinus impulse, or both, plus depression of A-V junctional impulse formation. Proper therapy usually requires electrical pacing in conjunction with administration of digitalis or propranolol, or both. Our findings suggest that the term “sick sinus syndrome” is an inaccurate and inappropriate synonym for the tachycardia-bradycardia syndrome.

Serial Electrocardiograms After Myocardial Infarction

Excerpt Recently we have had the opportunity to assess the value of serial electrocardiograms in middle-aged men after acute myocardial infarction. This evaluation was conducted as part of a prospe...

Complete AV Block Following Mediastinal Radiation Therapy: Electrocardiographic and Pathologic Correlation and Review of the World Literature

The clinical, features, serial electrocardiograms, and autopsy findings of a patient with symptomatic complete AV block, who had received mediastinal radiation therapy 81/2 years previously, are presented. The cardiac histopathology disclosed immense fibrosis of the conduction system and of the atria and ventricles. The enormous amount of fibrosis was similar in location and intensity to that observed in our previously reported patient (Cohen et al., Arch Intern Med 1981;141:676-679) who had undergone mediastinal radiation. We conclude that the severe fibrosis was primarily due to radiation, rather than secondary to atherosclerotic coronary artery disease, which also has been described as a consequence of mediastinal radiotherapy. This patientÆs serial electrocardiograms disclosed evidence of complete block both in the AV nodal area and infra His system, which correlated well with the histopathology. The characteristic clinical features of patients with symptomatic complete AV block post mediastinal radiation therapy are presented, along with a review of the world literature.

The Tachycardia-Bradycardia Syndrome

The tachycardia-bradycardia syndrome (paroxysmal atrial fibrillation, flutter, or tachycardia followed by sinoatrial block or sinus arrest resulting in Stokes-Adams attacks) is an important clinical entity that requires familiarity by the clinician. Pathologic studies and physiologic mechanisms as revealed in the electrocardiogram indicate multiple disturbances in the conduction system of the heart (sinus node, atria, and atrioventricular junctional tissues). The electrocardiogram establishes the diagnosis. Pacemaker implantation with supplementary drugs has provided a satisfactory means of therapy. With proper treatment the prognosis of patients with the tachycardia-bradycardia syndrome has improved to the extent that the primary determinant of mortality is no longer the arrhythmia, but the underlying cardiac and/or systemic pathology.

Murmurs Associated with Mitral Annular Calcification and Aortic Sclerosis

Background: Auscultation of patients with mitral annular calcification on echocardiography revealed a particular constellation of findings. Objective: To test the hypothesis that a particular auscultatory constellation provides a high degree of certainty in diagnosing the combination of mitral annular calcification and aortic sclerosis so often found in the elderly. Methods: Two groups of patients were studied to evaluate the particular auscultatory constellation under consideration which consisted of: (1) a harsh ejection systolic murmur heard from the 2nd right interspace to the cardiac apex and usually loudest between the 3rd left interspace and the apex; (2) the murmur radiates from the apex towards the left axilla and radiates poorly or not at all from the 2nd right interspace to the neck, and (3) the 2nd heart sound at the cardiac base is normal in intensity, and no ejection clicks are present. Group 1 consisted of patients with mitral annular calcification on echocardiographic examination, and group 2 consisted of patients in whom the particular constellation of auscultatory findings was present and who were then referred for echocardiographic assessment. Results: The particular auscultatory constellation under investigation allowed the diagnosis of the presence of the combination of mitral annular calcification and aortic sclerosis with substantial accuracy. Conclusion: The findings in this exploratory study suggest that the pathologic combination of mitral annular calcification and aortic sclerosis can be diagnosed with a reasonably high degree of certainty in elderly patients, if the particular auscultatory configuration is identified.

Mechanisms and Treatment of the Tachycardia-Bradycardia Syndrome (the So-Called Sick Sinus Syndrome) with Correlative Pathology.

Excerpt The tachycardia-bradycardia syndrome consists of paroxysmal atrial fibrillation, flutter, or tachycardia followed by sinoatrial (SA) block or sinus arrest resulting in Stokes-Adams attacks....