European Heart Journal Advance Access originally published online on May 4, 2005
European Heart Journal 2005 26(14):1447-1448; doi:10.1093/eurheartj/ehi317
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Enhancement of perfusion reserve by cardiac resynchronization therapy
Department of Cardiology
6D 120
VU University Medical Center
De Boelelaan 1117
1081 HV Amsterdam
The Netherlands
Tel: +31 20 4442244
Fax: +31 20 4442446
E-mail address: p.knaapen{at}vumc.nl
Department of Nuclear Medicine and PET Research
6D 120
VU University Medical Center
De Boelelaan 1117
1081 HV Amsterdam
The Netherlands
Department of Cardiology
6D 120
VU University Medical Center
De Boelelaan 1117
1081 HV Amsterdam
The Netherlands
With great interest, we read the recent work by Lindner et al.,1 which investigated the effects of cardiac resynchronization therapy (CRT) on regional resting myocardial oxidative metabolism and perfusion. Even though the observed homogenizing effects of CRT on regional metabolism are not new and confirmatory of previously reports,2,3 the studied patient population is by far the largest to date. Owing to the large sample size, subgroup analysis was feasible, which hinted at a more favourable effect of CRT in non-ischaemic patients than in ischaemic patients.
Among others, the authors conclude that ‘... studies have to clarify whether long-term CRT is able to improve perfusion and metabolism on a global level suggesting regression of cardiomyopathy’. We would like to point out that our group has recently addressed this issue by demonstrating a (reversible) enhancement of global perfusion reserve during CRT.3 In line with the results of Lindner et al.,1 ischaemic heart failure patients tended to improve to a lesser extent than non-ischaemic patients, although the sample size in our study was too small to be able to perform a reliable subgroup analysis. Furthermore, the level of augmentation seemed to be related to the degree of reduction in wall stress, which in turn was related to the degree of reverse remodelling.
Impairment of perfusion reserve is a hallmark of both ischaemic and non-ischaemic cardiomyopathy and an independent prognostic marker for an unfavourable outcome.4 Regardless of its aetiology, impairment of perfusion reserve is believed to cause repetitive stunning (intermittent periods of ischaemia), leading to chronic reversible left ventricular dysfunction.4,5 In fact, signs of ischaemia have been observed in patients with idiopathic dilated cardiomyopathy, making the term ‘non-ischaemic’ cardiomyopathy a matter of debate.5
Although the benefit of biventricular pacing is related to mechanical resynchronization of the interventricular septum and lateral free wall, it is likely that enhancement of perfusion reserve and its subsequent reduction of ischaemic episodes also play a role in the recovery of function associated with CRT. In our opinion, this demonstrates, at least in part, a true regression of cardiomyopathy.
References
- Lindner O, Vogt J, Kammeier A, Wielepp P, Holzinger J, Baller D, Lamp B, Hansky B, Korfer R, Horstkotte D, Burchert W. Effect of cardiac resynchronization therapy on global and regional oxygen consumption and myocardial blood flow in patients with non-ischaemic and ischaemic cardiomyopathy. Eur Heart J 2005; 26:70–76.
[Abstract/Free Full Text] - Ukkonen H, Beanlands RS, Burwash IG, de Kemp RA, Nahmias C, Fallen E, Hill MR, Tang AS. Effect of cardiac resynchronization on myocardial efficiency and regional oxidative metabolism. Circulation 2003;107:28–31.
[Abstract/Free Full Text] - Knaapen P, van Campen LM, de Cock CC, Gotte MJ, Visser CA, Lammertsma AA, Visser FC. Effects of cardiac resynchronization therapy on myocardial perfusion reserve. Circulation 2004; 110:646–651.
[Abstract/Free Full Text] - Neglia D, Michelassi C, Trivieri MG, Sambuceti G, Giorgetti A, Pratali L, Gallopin M, Salvodori P, Sorace O, Carpeggiani C, Poddighe R, L'Abbate A, Parodi O. Prognostic role of myocardial blood flow impairment in idiopathic left ventricular dysfunction. Circulation 2002; 105:186–193.
[Abstract/Free Full Text] - van den Heuvel AF, van Veldhuisen DJ, van der Wall EE, Blanksma PK, Siebelink HM, Vaalburg WM, van Gilst WH, Crijns HJ. Regional myocardial blood flow reserve impairment and metabolic changes suggesting myocardial ischemia in patients with idiopathic dilated cardiomyopathy. J Am Coll Cardiol 2000;35:19–28.
[Abstract/Free Full Text]
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