Concealed accessory pathways: Historical notes

Concealment of an accessory pathway is caused by its ability to conduct retrogradely only. This variant of accessory pathway conduction could not be confirmed until invasive electrophysiology was introduced in the 1970s. As a rule, it is reported that concealed accessory pathways were predicted from animal experiments in 1971. However, even earlier studies suggested an accessory pathway or mechanisms comparable to those of the Wolff-Parkinson-White syndrome to be the cause of supraventricular tachycardias even though preexcitation during sinus rhythm had been lacking. Such interpretations were derived from clinical considerations, from patients having lost their ventricular preexcitation spontaneously, and from the disappearance of the delta wave after drug administration. Some authors postulated but did not provide the correct interpretation. Even a few contributions published before the paper of Wolff, Parkinson, and White in 1930 are worth considering in this context.

[The history of Wolf-Parkinson-White syndrome and evolution of surgical methods for its management]

Wolf-Parkinson-White syndrome (WPW syndrome) affects roughly 1% of the population. It usually occurs in subjects with normal heart function but may combine with congenital cardiac failure and cardiomyopathy. Paroxysmal tachycardia is recorded in 40-80% of he WPW patients, largely in the form of reciprocal tachycardia related to circulation of excitation in the atrioventricular junction and Kent's bundle. Development and improvement of surgical methods for the management of supraventricular tachycardia became possible with the advent of transcatheter registration of electrical activity in different heart regions and programmed heart stimulation techniques. Catheter-assisted methods for the treatment of cardiovascular disorders including arrhythmia have been extensively used in recent decades. Transvenous fulguration is one of them replaced at present by radiofrequency ablation (RFA). The discovery of WPW syndrome made possible a new approach to the the problem of sudden death in young age. Treatment of this syndrome by RFA of additional atrioventricular junction in the last 20 years permitted not only to manage the syndrome itself but also to ensure practically complete recovery of the patients.

[WPW cases in the literature prior to the publication of Wolff, Parkinson and White in 1930]

In 1930, Wolff, Parkinson and White described the clinical entity of what is today known as the preexcitation or WPW syndrome. In the preceding literature, the authors found four comparable cases. Later on, seven further cases published prior to 1930 were discovered. An analysis of the altogether eleven cases displays that, in addition to the anomalous ECG in sinus rhythm, nearly all typical electrocardiographic findings during the tachyarrhythmias are found in this early literature. As tachycardia ECGs especially help to understand the mechanism of the WPW syndrome, the question is discussed whether already Wolff, Parkinson and White would have been able to give the correct interpretation of the mechanism if they had taken into consideration their own tachycardia ECGs as well as those known to them from the literature.

[A concise history of the Wolff-Parkinson-White syndrome]

In a paper entitled Bundle-branch block with short P-R interval in healthy young people prone to paroxysmal tachycardia (Am Heart J 1930; 5: 685-704), Dr. Louis Wolff (1898-1972), Sir John Parkinson (1885-1976) and Paul Dudley White (1886-1973) described an intricate syndrome. Prior case reports had already pointed out the essentials of this entity, which has borne the eponym (WPW syndrome) since the publication by Levine and Beeson (Am Heart J 1941; 22: 401-409). It was long thought that the first patient with a short PR interval, delta-wave-induced widening of the QRS complex and paroxysmal supraventricular tachycardia (PSVT) was described by Cohn and Fraser in the prestigious cardiological journal edited by Sir Thomas Lewis (1881-1945) in London, UK (Heart 1913/1914; 5: 93-107). Shortly afterwards, Dr János Angyán (1886-1969), a school-founder chairman of medicine (1923-1959) at the University of Pécs, Hungary, also published a clear-cut case of intermittent WPW syndrome in the German periodical Zentralblatt für Herz- und Gefässkrankheiten (1914; 6: 345-349]. In fact, Angyán should be considered the first Hungarian "cardiologist" who dealt steadily with heart diseases and rhythm disturbances. Quite reently, thanks to the activities of Dr Georg von Knorre, Rostock (PACE 2005; 28: 228-230) we have learnt that the earliest documented case of ECGs with ventricular preexcitation and PSVT ("Herzjagen") was published by August Hoffmann (1862-1929) in the 2 Nov 1909 issue of Münchener Medizinische Wochenschrift (56: 2259-2262; Figures 10 and 11). Hoffmann worked as an internist/neurologist and was director of the university hospital in Düsseldorf, Germany. The first successful surgical division of an atrioventricular accessory pathway (bundle of Kent), by Sealy and his coworkers at the Duke University Medical Center in 1967, led to the modern era of curative transcatheter ablation for WPW patients by radiofrequency alternative current or, nowadays, by transvenous cryoablative catheter techniques. Our current knowledge and day-to-day clinical practice is the result of marvelous contributions from numerous dedicated scientists in diverse disciplines in many countries.

History of Wolff-Parkinson-White syndrome

While Drs. Wolff, Parkinson, and White fully described the syndrome that bears their names in 1930, prior case reports had already described the essentials. Over the ensuing century this syndrome has captivated the interest of anatomists, clinical cardiologists, and cardiac surgeons. Stanley Kent described lateral muscular connections over the atrioventricular (AV) groove, which he felt were the normal AV connections. The normal AV connections were, however, clearly described by His and Tawara. True right-sided AV connections were initially described by Wood et al., while Ohnell first described left free wall pathways. David Scherf is thought to be the first to describe our current understanding of the pathogenesis of the Wolff-Parkinson-White (WPW) syndrome in terms of a reentrant circuit involving both the AV node--His axis as well as the accessory pathway. This hypothesis was not universally accepted and many theories were applied to explain the clinical findings. The basics of our understandings were established by the brilliant work of Pick, Langendorf, and Katz who by using careful deductive analysis of ECGs were able to define the basic pathophysiological processes. Subsequently, Wellens and Durrer applied invasive electrical stimulation to the heart in order to confirm the pathophysiological processes. Sealy and his colleagues at Duke University Medical Center were the first to successfully surgically divide an accessory pathway and ushered in the modern area for curative therapy for these patients. Morady and Scheinman were the first to successfully ablate an accessory pathway (posteroseptal) using high-energy direct-current shocks. Subsequently, Jackman, Kuck, Morady, and a number of groups proved the remarkable safety and efficiency of catheter ablation for pathways in all locations using radiofrequency energy. More recently, Gallob et al. first described the gene responsible for a familial form of WPW. The current ability to cure patients with WPW is due to the splendid contributions of individuals from diverse disciplines from throughout the world.

The Earliest Published Electrocardiogram Showing Ventricular Preexcitation

When in 1930, Wolff, Parkinson, and White published what is today known as the WPW, or preexcitation syndrome, they, and subsequently others, found few comparable cases in the preceding literature. Among these the report of Cohn and Fraser, published in 1913, was the earliest. However, another even earlier documentation in a 1909 article by Hoffmann escaped notice till now. The ECG of a patient with paroxysmal tachycardia reveals a short PR interval and a delta-wave-induced widening of the QRS complex, even though the reproduced tachycardia was not preexcitation related. The interpretation of this poorly reproduced ECG can be confirmed by another and more detailed description of the patient in an electrocardiography textbook published in 1914 by the same author. Thus, the earliest publication of an ECG showing ventricular preexcitation now can be dated back to 1909. Moreover, the Hoffmann monograph contains two additional examples of the WPW syndrome not noticed until now. All three cases published by Hoffmann had their first ECG recordings in 1912 or earlier.

Cardiac Surgery for Arrhythmias

Cardiac arrhythmia surgery was initiated in 1968 with the first successful division of an accessory AV connection for the Wolff-Parkinson-White Syndrome. Subsequent surgical procedures included the left atrial isolation procedure and the right atrial isolation procedure for automatic atrial tachycardias, discrete cryosurgery of the AV node for AV nodal reentry tachycardia, the atrial transection procedure, corridor procedure and Maze procedure for atrial fibrillation, the right ventricular disconnection procedure for arrhythmogenic right ventricular tachycardia, the encircling endocardial ventriculotomy, subendocardial resection procedure, endocardial cryoablation, the Jatene procedure, and the Dor procedure for ischemic ventricular tachycardia. Because of monumental strides in the treatment of most refractory arrhythmias by endocardial catheter techniques during the past decade, the only remaining viable surgical procedures for cardiac arrhythmias are the Maze procedure for atrial fibrillation and the Dor procedure for ischemic ventricular tachycardia. Nevertheless, the 25-30 years of intense activity in the field of cardiac arrhythmia surgery provided the essential foundation for the development of these catheter techniques and represent one of the most exciting and productive eras in the history of medicine. In one short professional career, we have witnessed the birth of arrhythmia surgery, its adolescence as an "esoteric" specialty, its prime as an enlightening yet exhausting period, and finally its waning years as a source of knowledge and wisdom on which better methods of treatment have been founded. One could hardly ask for a more rewarding experience.

Catheter ablation of the accessory pathways of the Wolff-Parkinson-White syndrome and its variants

The basis of arrhythmias in the Wolff-Parkinson-White (WPW) syndrome and its variants is the presence of accessory atrioventricular connections. Those variants include the concealed form of the WPW syndrome, the permanent form of junctional reciprocating tachycardia, and Mahaim preexcitation. In all forms of symptomatic WPW syndrome, catheter ablation of the accessory atrioventricular connections using radiofrequency current has become the treatment of choice. This review traces the development of this therapy, outlines the basics of the technique, summarizes the results reported in the largest series, indicate remaining areas of controversy, and discusses the indications and limitations of radiofrequency ablation therapy.

Will C. Sealy, MD: the father of arrhythmia surgery--the story of the fisherman with a fast pulse

The development of clinical electrophysiology and arrhythmia surgery has a long and interesting history. On May 2, 1968, Dr. Will C. Sealy, with the electrophysiologists at Duke University, performed the first successful ablation of a pathway in a patient with Wolff-Parkinson-White syndrome using an epicardial approach. Thereafter, he and his colleagues developed improved endocardial techniques to ensure ablation of even multiple and complex anatomic pathways. From this work the impulse to perform these procedures spread worldwide, and a school of arrhythmia surgeons sprouted. For these and other accomplishments, Dr. Sealy clearly became the Father of Arrhythmia Surgery. The story is told herein.

Surgical cure of cardiac arrhythmia. 1969

The first surgical procedure undertaken for the intended purpose of curing a patient with recurrent tachycardia was performed by Sealy in 1968, and the report of that operation was published in The Annals of Thoracic Surgery in 1969. The first attempted accessory bundle ablation was successful, marked the beginning of cardiac arrhythmia surgery, and has set the standard against which other methods of arrhythmia control must be measured.

Wolff-Parkinson-White syndrome: long follow-up and an Anglo-American historical note

A patient who developed palpitation in 1917 was later found to have the Wolff-Parkinson-White syndrome and survived to the age of 86, when he died of emphysema. Shortly before he first presented, a report of another patient had been published that can now retrospectively be recognized as containing the first tracings from a case of the Wolff-Parkinson-White syndrome; its coauthors were a distinguished American cardiologist, Alfred E. Cohn, who had worked with Sir Thomas Lewis, and his British research fellow, Francis R. Fraser.