Sunao Tawara : further musings on his tribulations in providing the basis for the modern-day understanding of cardiac electrophysiology.

Sunao Tawara, who was born in 1873 and died in 1952, is considered the father of modern cardiac electrophysiology. He published his monumental monograph describing the atrioventricular conduction axis in 1906. He achieved this task in the face of multiple tribulations as a doctoral student working in a cultural environment that was not his own. Although his letters underscoring the publication of the monograph have been published, little emphasis has been placed on the potential problems he encountered in bringing his task to fruition. For example, it was not until the final 6 months of his studies that he resolved the issue of the connection between the atrioventricular bundle and the so called "Purkinje cardiomyocytes". His exchanges with his mentor, Ludwig Aschoff, emphasized that the difficulties he encountered in making the connection caused him quite some turmoil. We believe that this issue, and others that he identified in his correspondence, are worthy of further attention.

Introduction to noninvasive cardiac mapping.

From the dawn of the twentieth century, the electrocardiogram (ECG) has revolutionized the way clinical cardiology has been practiced, and it has become the cornerstone of modern medicine today. Driven by clinical and research needs for a more precise understanding of cardiac electrophysiology beyond traditional ECG, inverse solution electrocardiography has been developed, tested, and validated. This article outlines the important progress from ECG development, through more extensive measurement of body surface potentials, and the fundamental leap to solving the inverse problem of electrocardiography, with a focus on mathematical methods and experimental validation.

Historical perspectives of cardiac electrophysiology.

The diagnosis and treatment of clinical electrophysiology has a long and fascinating history. From earliest times, no clinical symptom impressed the patient (and the physician) more than an irregular heart beat. Although ancient Chinese pulse theory laid the foundation for the study of arrhythmias and clinical electrophysiology in the 5th century BC, the most significant breakthrough in the identification and treatment of cardiac arrhythmias first occurred in this century. In the last decades, our knowledge of electrophysiology and pharmacology has increased exponentially. The enormous clinical significance of cardiac rhythm disturbances has favored these advances. On the one hand, patients live longer and thus are more likely to experience arrhythmias. On the other hand, circulatory problems of the cardiac vessels have increased enormously, and this has been identified as the primary cause of cardiac rhythm disorders. Coronary heart disease has become not just the most significant disease of all, based on the statistics for cause of death. Arrhythmias are the main complication of ischemic heart disease, and they have been directly linked to the frequently arrhythmogenic sudden death syndrome, which is now presumed to be an avoidable "electrical accident" of the heart. A retrospective look--often charming in its own right--may not only make it easier to sort through the copious details of this field and so become oriented in this universe of important and less important facts: it may also provide the observer with a chronological vantage point from which to view the subject. The study of clinical electrophysiology is no dry compendium of facts and figures, but rather a dynamic field of study evolving out of the competition between various ideas, intentions and theories.

The role of electrophysiology study in risk stratification of sudden cardiac death.

Patients with ischemic heart disease and left ventricular systolic dysfunction are at high risk of sudden cardiac death. However, most of these high-risk patients will never develop potential fatal ventricular arrhythmias. Thus, modalities that stratify patients according to their risk of sudden cardiac death are needed. The electrophysiology study has, for decades, been used to prognosticate on patients' risk of sudden cardiac death. Recent data from the Multicenter Unsustained Tachycardia Trial (MUSTT) and Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) demonstrate that in patients with ischemic heart disease and left ventricular systolic dysfunction, an electrophysiology study can help identify patients who are at high risk of sudden cardiac death. However, in these patient populations, the prognostic ability of an electrophysiology study is only modest and the negative predictive value is poor. In the future, combining the results of noninvasive modalities with invasive electrophysiology testing may improve our prognostic ability. Furthermore, expanding the role of the electrophysiology study to include therapeutic ablations may alter a patient's future risk of sudden cardiac death.