European Heart Journal Advance Access published online on June 27, 2008
European Heart Journal, doi:10.1093/eurheartj/ehn291
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Long-term survival in patients undergoing cardiac resynchronization therapy: the importance of atrio-ventricular junction ablation in patients with permanent atrial fibrillation: reply
Department of Cardiology
IRCCS Istituto Clinico Humanitas
Via Manzoni 56 Rozzano (Milan) 20089
Italy
Tel: +39 02 82224 4622
Fax: +39 02 8224 3690
Email: maurizio.gasparini{at}humanitas.it
As Drs Foley and Leyva pointed out in their letter, device features such as ventricular rate regularization and ventricular trigger mode may be important to regularize heart rate trying to maximize biventricular capture in atrial fibrillation (AF) patients treated with cardiac resynchronization therapy (CRT). In our patient series1 of permanent AF patients with preserved atrio-ventricular junction (AVJ), ventricular trigger mode as well as ventricular rate regularization/stabilization features, such as Conducted AF ResponseTM or Ventricular Rate RegularizationTM, were activated once available. For Guidant devices, these features were incorporated in the devices from 2001 onwards, whereas for Medtronic models these were included only from 2003. It seems rather surprising, as mentioned in the letter by Foley and Levya, that in the Khadjooi study (covering up to 6.8 years of follow-up), ventricular trigger mode could have been activated in all AF patients, even those implanted before 2001.
These perplexities are further confirmed through the comparison between the survival curve of our study,1 in which the device features were activated once available, and the Khadjooi study,2 in which these features were reported to have been activated in all AF patients. In fact, survival from death from any cause was found to be very similar between the two AF groups with preserved AV conduction (Figure 1, survival curve C, dashed red for Gasparini et al. vs. B, solid blue for Khadjooi). These two clinically similar groups, although coming from different clinical realities, presented identical long-term outcome. In this context, either there were little or no differences in the rate regularization features activated between these groups, or any differences did not translate into important effects on outcome. When the Kaplan–Meier survival curve of permanent AF patients treated with AVJ ablation (Figure 1, curve D, dotted green for Gasparini et al.) derived from our experience is compared with the two other curves of patients with preserved AVJ conduction (Figure 1, curve C, dashed red for Gasparini et al., and B, solid blue for Khadjooi et al.), the significant protective effects of AVJ ablation on all-cause mortality become striking. Even though yearly mortality rate for the AF population is not explicitly specified in the Khadjooi study (Figure 1, curve B, solid blue), the survival pattern of this group is superposed to that of our experience (Figure 1, curve C, dotted red) and therefore yearly mortality may be estimated to be around 14 per 100 patients-year compared with a significantly lower incidence (4.6 per 100 patients-year) of events in the ablated AF group (Figure 1, curve D, dotted green).
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Paraphrasing the editorial article3 accompanying our previous article4 on this topic, indeed we all are ‘desperately seeking a randomized clinical trial of resynchronization therapy for patients with heart failure and atrial fibrillation’. Such a trial should evaluate the AVJ ablation approach compared with combined use of medication and device rate-control features such as ventricular trigger mode. In the meantime, the current evidence (including the comparison of these survival curves) supports, in our view, the recourse to AVJ ablation to optimize resynchronization effect in this heart failure patient population.
References
- Gasparini M, Auricchio A, Metra M, Regoli F, Fantoni C, Lamp B, Curnis A, Vogt J, Klersy C, for the Multicentre Longitudinal Observational Study (MILOS) Group. Long-term survival in patients undergoing cardiac resynchronization therapy: the importance of atrio-ventricular junction ablation in patients with permanent atrial fibrillation. Eur Heart J (2008) April 4 [Epub ahead of print].
- Khadjooi K, Foley PW, Anthony J, Chalil S, Smith R, Frenneaux M, Leyva F. Long-term effects of cardiac resynchronization therapy in patients with atrial fibrillation. Heart (2008) 94:874–883.
[Abstract/Free Full Text] - Steinberg JS. Desperately seeking a randomized trial of resynchronization therapy for patients with heart failure and atrial fibrillation. J Amer Coll Cardiol (2006) 48:744–746.
[Free Full Text] - Gasparini M, Auricchio A, Regoli F, Fantoni C, Kawabata M, Galimberti P, Pini D, Ceriotti C, Gronda E, Klersy C, Fratini S, Klein HH. Four-year efficacy of cardiac resynchronisation therapy on exercise tolerance and disease progression: the importance of performing atrioventricular junction ablation in patients with atrial fibrillation. J Am Coll Cardiol (2006) 48:734–743.
[Abstract/Free Full Text]
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