Five of a kind N.M. van Hemel
Case reports attempt to deliver messages that exceed the limits of our knowledge of mechanisms, diagnosis and treatment of a disease. In contrast to large-scale randomised dinical trials with their unavoidable 'Editorials' that put the results into perspective, the power of case reports relies on the unexpected observation, event or unorthodox therapy. These eyecatchers usually reflect a unique experience that precludes any reproducibility. For this reason they do not fulfill our empirical concepts of science as formulated by the 19th century French scientist and physician Claude Bernard,' and therefore rarely justify an editorial. Furthermore, because of the uniqueness of the case report, its message for daily practice does not appear to have general applicability. The common denominator of the five case reports in this issue (one ofwhich is presented as an imaging) encompasses the 12-lead ECG, rhythm and conduction disturbances, and several sorts of contemporary electrical therapy to suppress or eradicate the consequences of these cardiac disorders. These reports demonstrate the intellectual and manual skills of the authors who are all very faniliar with invasive arrhythmia techniques, and show passion for this diagnostic and therapeutic field. Although at a first glance the messages of these reports appear to be quite different, the eventual diagnostic and therapeutic approaches reflect five of a kind. Two reports address abnormal venous access to the desired site of cardiac pacing due to a persistent left superior cardiac vein. The authors have shown us that despite anatomical deviations, the ICD and biventricular pacemaker can be inserted properly, provided the operator immediately recognises the anomalous venous route taken by the guiding catheter. Venous angiography appears to be indispensable for proceeding with this procedure. Two reports emphasise the anatomical distance between the site ofthe trigger, or between the location of the haemodynamic deterior-
ation due to arrhythmias, and the location of the arrhythmia, representing examples of cardiac 'crossover' ofthe arrhythmia substrate and its consequences. In the case of the hidden left-sided Wolff-ParkinsonWhite syndrome, the trigger was surgery to the right ventricle. In the case of the right atrial tachycardias, the consequence was transient failure ofthe left ventricle. In the fifth case we are invited to consider whether implantable electrical therapy should be supplied to prolong the life expectancy ofpatients incapacitated by a neuromuscular disorder of a progressive nature: technically feasible, it is the ethical problem that dictates our decision here. This issue has been highlighted by recent data from a large multicentre prospective cohort register that demonstrate the inadequacy of the implanted conventional pacemaker to treat significant conduction disturbances inherent to myotonic dystrophy, to reduce the risk of sudden cardiac death in those patients.2 This observation supports the consideration for ICD therapy, and in patients fulfilling Madit II criteria ICD biventricular pacing, and not conventional pacing ifconduction disorders require pacing.
The contributions of these five case reports to our knowledge are similar. Precise documentation and a careful search for the nature and site ofthe arrhythmia substrate is the only way to determine the appropriate therapy. These reports also show that to date, treatment of complex arrhythmias requires specialised experience accumulated in well-equipped centres. Case reports do evoke our curiosity and despite the lack of reproducibility, the five reports in this issue can certainly affect our daily thinking and decision-making and therefore gain more applicability than first assumed. To quote Claude Bernard 'In experimentation it is always necessary to start from a particular fact and proceed to the generalisation... But above all one must observe'. U References
N.M. van Hemel Emeritus Professor of Cardiology
Correspondence to: N.M. van Hemel E-mail: [email protected]
Netherlands Heart Journal, Volume 14, Number 7/8, August 2006
1 C. Bernard. An introduction to the studyofexperimental medicine. Translated from the French by Henry Copley Green, with an introduction by Lawrence J. Henderson. Impressum, NewYork, Dover Publications, 1957. 2 Nair GV, Lowe MR, Bhakta D, Dusa AC, Groh WJ. Pacemakers do not protect from sudden death in patients with myotonic dystrophy. Heart Rhythm 2006;3(Suppl 1):S102.