Correspondence

Sudden Cardiac Arrest Associated with Early Repolarization

N Engl J Med 2008; 359:761-762August 14, 2008

Article

To the Editor:

In their article on sudden cardiac arrest associated with early repolarization, Haïssaguerre and colleagues (May 8 issue)1 refer to the definition of idiopathic ventricular fibrillation that is used by the joint steering committees of the Unexplained Cardiac Registry of Europe and of the Idiopathic Ventricular Fibrillation Registry of the United States. However, the characterization of patients in their study appears to be largely incomplete. Registries,2 necropsy studies,3 and endomyocardial-biopsy studies4 have shown that concealed myocardial diseases — in particular, arrhythmogenic right ventricular cardiomyopathy and myocarditis — may cause sudden death in subjects with apparently normal hearts. In such cases, cardiac magnetic resonance imaging (MRI) and right ventricular angiography (performed cumulatively in only 75% of patients enrolled in the study reported by Haïssaguerre and colleagues) appear to be mandatory, and additional studies, such as three-dimensional electroanatomical mapping5 and endomyocardial biopsy, must be considered in order to rule out structural abnormalities accounting for both electrocardiographic and arrhythmic features.

The lack of data regarding the evolution of cardiac morphology and function during follow-up represents another limitation of the study, since myocardial disorders that are concealed at the time of a first arrhythmic event may be manifested after some years. We agree that the identification of an electrocardiographic marker associated with malignant arrhythmias has relevant diagnostic implications, but we also believe that the identification of a specific arrhythmogenic disease may affect treatment and prognosis.

Maurizio Pieroni, M.D., Ph.D.
Fulvio Bellocci, M.D.
Filippo Crea, M.D.
Catholic University, 00168 Rome, Italy
mauriziopieroni@yahoo.com

5 References

1. 1

   Haissaguerre M, Derval N, Sacher F, et al. Sudden cardiac arrest associated with early repolarization. N Engl J Med 2008;358:2016-2023
   Full Text | Web of Science | Medline

2. 2

   Survivors of out-of-hospital cardiac arrest with apparently normal heart: need for definition and standardized clinical evaluation: consensus statement of the Joint Steering Committees of the Unexplained Cardiac Arrest Registry of Europe and of the Idiopathic Ventricular Fibrillation Registry of the United States. Circulation 1997;95:265-272
   Web of Science | Medline

3. 3

   Corrado D, Basso C, Thiene G. Sudden cardiac death in young people with apparently normal heart. Cardiovasc Res 2001;50:399-408
   CrossRef | Web of Science | Medline

4. 4

   Frustaci A, Bellocci F, Olsen EG. Results of biventricular endomyocardial biopsy in survivors of cardiac arrest with apparently normal hearts. Am J Cardiol 1994;74:890-895
   CrossRef | Web of Science | Medline

5. 5

   Corrado D, Basso C, Leoni L, et al. Three-dimensional electroanatomic voltage mapping increases accuracy of diagnosing arrhythmogenic right ventricular cardiomyopathy/dysplasia. Circulation 2005;111:3042-3050
   CrossRef | Web of Science | Medline

Author/Editor Response

By definition, the diagnosis of idiopathic ventricular fibrillation implies that all other possible causes of ventricular fibrillation have been ruled out. In our study, all patients were screened in accordance with consensus guidelines.1 Right ventricular angiography and MRI were performed in most patients, and the findings were normal. In addition, the patients were followed for a mean of 5 years, and despite regular investigation, no structural heart disease was found in any patient. The role of electoanatomical mapping studies has been highlighted only recently. Corrado et al.2 reported abnormalities in only 65% of patients with established arrhythmogenic right ventricular dysplasia (ARVD).

Endomyocardial biopsy was performed in 16 patients in our study, and the findings were negative in all of them. In a study by Frustaci et al.,3 the diagnosis in the single patient with ARVD was based on electrocardiographic and echocardiographic criteria. The final word on the use of biopsy should be the statement of the cardiology societies: “The indication for endomyocardial biopsy in unexplained, life-threatening ventricular tachyarrhythmias [is] `uncertain,' and it seems there has been little published literature since [1989] to change this classification.”4

Isabelle Nault, M.B., B.S., Ph.D.
Matthew Wright, M.D.
Michel Haïssaguerre, M.D.
Université Bordeaux, 33000 Bordeaux, France
michel.haissaguerre@chu-bordeaux.fr

4 References

1. 1

   Zipes DP, Camm AJ, Borggrefe M, et al. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death -- executive summary: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. J Am Coll Cardiol 2006;48:1064-1108
   CrossRef | Web of Science

2. 2

   Corrado D, Basso C, Leoni L, et al. Three-dimensional electroanatomic voltage mapping increases accuracy of diagnosing arrhythmogenic right ventricular cardiomyopathy/dysplasia. Circulation 2005;111:3042-3050
   CrossRef | Web of Science | Medline

3. 3

   Frustaci A, Bellocci F, Olsen EG. Results of biventricular endomyocardial biopsy in survivors of cardiac arrest with apparently normal hearts. Am J Cardiol 1994;74:890-895
   CrossRef | Web of Science | Medline

4. 4

   Cooper LT, Baughman KL, Feldman AM, et al. The role of endomyocardial biopsy in the management of cardiovascular disease: a scientific statement from the American Heart Association, the American College of Cardiology, and the European Society of Cardiology: endorsed by the Heart Failure Society of America and the Heart Failure Association of the European Society of Cardiology. J Am Coll Cardiol 2007;50:1914-1931
   CrossRef | Web of Science | Medline