[CRT-FORUM] 47E Non-responders. Dr. Perez Riera

[CRT-INFO]

Dearest friend and brilliant young electrophysiologist Dr, Raed Abu 
Sham'a from the suffered Palestine
Cardiac resynchronization therapy non-responders and "worse than 
non-responders"

CRT is an effective treatment strategy in patients with severe LV 
dysfunction and those with evidence of electro-mechanical dyssynchrony. 
Although CRT is used for treatment of refractory HF in patients with low 
EF and cardiac dyssynchrony, there are a substantial number of 
non-responders. Unfortunately, 20-30% of patients are non-responders 
or"worse than non-responders" to CRT. This indicates that, in addition 
to cardiac dyssynchrony, there are other factors affecting response to 
CRT. Pre-implant identification of these factors appears of crucial 
importance in order to finalize the CRT to those patients who have the 
highest probability of a positive response. Unresolved issues are the 
identification of these non-responders and the efficacy of CRT in 
patients with mechanical dyssynchrony without electrical dyssynchrony 
and in NYHA functional class I/II patients with EF ?35%. CRT assists 
patients with HF by improving LV dyssynchrony, but there are significant 
numbers of non-responders, 1 reason being that the QRS duration is used 
as the only surrogate determinant of mechanical dyssynchrony, so an 
effective indicator of LV dyssynchrony is required. Discordance of 
systole in regional myocardial segments may present as mechanical 
dyssynchrony in the LV and could be used as an alternative to QRS 
duration. Quantitative assessment of dyssynchrony may be possible using 
ECG-gated SPECT myocardial perfusion imaging (2). Additionally, the main 
potential benefit of 3D and 4D echocardiography in electrophysiology lie 
in real-time guidance of complex ablation procedures and precise 
assessment of cardiac dyssynchrony.
Elevated erythropoietin levels in the absence of anemia and renal 
insufficiency effectively correlate with functional impairment and 
severe symptoms, which impair quality of life in patients undergoing CRT 
(3).
In patients with ischemic dilated cardiomyopathy the average global 
longitudinal strain evaluated by speckle-tracking strain echo (2DSE) is 
strongly associated with total scar burden assessed by contrast-enhanced 
magnetic resonance, and is an excellent independent predictor of 
response to CRT(4).
A prompt rise in systolic blood pressure just after CRT was observed 
more often in responders than in non-responders, and systolic blood 
pressure rise ?5 mmHg was the only significant independent predictor of 
a CRT responder(5).
The Cardiac Contractility Modulation (CCM) consist in an additional 
CCM-implantation contra-lateral to the existing CRT system (OPTIMIZER 
III, Impulse Dynamics, Orangeburg, NY, USA). CCM delivers non-excitatory 
high-energy stimulatory impulses during the absolute refractory period, 
thus improving contractility LV dp/dt) by stimulating the septum with 
two screw-in leads and one additional atrial lead for triggering the 
impulses. CCM is feasible and could be applied with calculated risks as 
a possible useful adjunct in CRT non-responders when no other options 
are available; however, mortality and event rates are high in this very 
sick population(6).

References

1) Storti C, Longobardi M, Buzzi MP, Negro MC, Pilun EB, Baldi A, 
Falcone C. [Non-pharmacological therapy of decompensated heart failure: 
cardiac resynchronization therapy. G Ital Cardiol (Rome). 2008 Oct;9(10 
Suppl 1):123S-128S.
2) Keida T, Ohira H, Fujita M, Chinen T, Nakamura K, Kato T, Sakakibara 
N, Ihara Z, Takami M. Quantitative Assessment of Dyssynchrony Using 
ECG-Gated SPECT Myocardial Perfusion Imaging Prior to and Following 
Cardiac Resynchronization Therapy. Circ J. 2009 Jan 9. [Epub ahead of print]
3) Jazrawi A, Clifford S, Machado C, Daccarett M. Erythropoietin levels 
in cardiac resynchronization therapy responders. Int J Cardiol. 2009 Jan 
28. [Epub ahead of print]
4) Andrea A, Caso P, Scarafile R, Riegler L, Salerno G, Castaldo F, 
Gravino R, Cocchia R, Del Viscovo L, Limongelli G, Di Salvo G, Ascione 
L, Iengo R, Cuomo S, Santangelo L, Calabrò R. Effects of global 
longitudinal strain and total scar burden on response to cardiac 
resynchronization therapy in patients with ischaemic dilated 
cardiomyopathy. Eur J Heart Fail. 2009 Jan; 11: 58-67.
5) Tanaka Y, Tada H, Yamashita E, Sato C, Irie T, Hori Y, Goto K, 
Iwamoto J, Manni H, Yokokawa M, Naito S, Oshima S, Taniguchi K. Change 
in blood pressure just after initiation of cardiac resynchronization 
therapy predicts long-term clinical outcome in patients with advanced 
heart failure. Circ J. 2009 Feb; 73:288-294.
6) Nägele H, Behrens S, Eisermann C. Cardiac contractility modulation in 
non-responders to cardiac resynchronization therapy. Europace. 2008 Dec; 
1013:1375-80.

All the best for all

Andrés Ricardo Pérez Riera.MD
Chief of electrovectorcardiographic sector. ABC’s Medical School, ABC 
Foundation, Santo André, São Paulo, Brazil Riera at uol.com.br
> Dear Colleagues and teachers
>
> Dearest Prof Pérez Riera and Prof Levine
>
> Greetings
>
> CRT represent a state-of-art therapy for patients with advanced heart
> failure maintained on optimal medical therapy and have 
> electrocardiographic
> evidence of dyssynchrony. This therapy sometimes complicated by rapid
> clinical deterioration which may lead to SCD, frequent hospitalization,
> decreased in NYHA functional class or worsening of quality of life score.
> These patients are considered as non-responders, but the reality that 
> these patient are "worse than non-responders" as they deteriorated.
> Do we have any predictors for this group of patients which may help in
> avoiding implantation of such patients? This may help in decreasing the
> percentage of non-responders.
>
> Warm Regards
>
> Raed Abu Sham'a, MD
> Palestine
>
>


-- 
Dr. Sergio Dubner
President of Scientific Committee

Dr. Edgardo Schapachnik
President of Steering Committee