LA TERAPIA ELETTRICA DELLO SCOMPENSO CARDIACO.
Valentino Ducceschi
U.O. Cardiologia, P.O. Pellegrini, ASL NA1 Centro.
La terapia dello scompenso cardiaco refrattario al trattamento farmacologico mediante la resincronizzazione elettrica cardiaca è stata ipotizzata per la prima volta agli inizi degli anni ’80 epr poi essere introdotta successivamente nella pratica clinica negli anni ’90. Essa mira a ristabilire la sincronia elettromeccanica della sistole cardiaca, migliorando la performance contrattile del miocardio dissinergico dei pz affetti da insufficienza cardiaca di qualunque eziologia. Comune in questa patologia sono infatti i disturbi della conduzione intraventricolare, specialmente il blocco di branca sx, che vanno considerati causa e/o effetto della severa dilatazione ventricolare coesistente. Si intuisce quindi come la correzione di eventuali dissincronie di contrazione di alcune pareti ventricolari, ottenuta mediante una loro stimolazione diretta “anticipata”, risulta in una sistole elettromeccanica più omogenea dal punto di vista temporale, con evidenti benefici per il pz in termini di qualità di vita, sopravvivenza a lungo termine e più in generale in termini di morbidità. I dispositivi attualmente impiantabili possono avere la sola funzione di pacing resincronizzante (CRT-P) o, più comunemente, anche la funzione di defibrillatore (CRT-D).
Si riportano quindi le ultime linee guida internazionali rivedute e corrette nel Recommendations for CRT in Patients With Systolic Heart Failur2012 DBT
Focused Update Recommendations
Class I
1. CRT is indicated for patients who have LVEF less than or equal to 35%,
sinus rhythm, LBBB with a QRS duration greater than or equal to 150 ms,
and NYHA class II, III, or ambulatory IV symptoms on GDMT. (Level of Evidence:
A for NYHA class III/IV16–19; Level of Evidence: B for NYHA class II20,21)
Modified recommendation (specifying CRT in patients with LBBB
of _150 ms; expanded to include those with NYHA
class II symptoms).
Class IIa
1. CRT can be useful for patients who have LVEF less than or equal to 35%, sinus
rhythm, LBBB with a QRS duration 120 to 149 ms, and NYHA class II, III, or
ambulatory IV symptoms on GDMT.16–18,20–22 (Level of Evidence: B)
New recommendation
2. CRT can be useful for patients who have LVEF less than or equal to 35%,
sinus rhythm, a non-LBBB pattern with a QRS duration greater than or equal
to 150 ms, and NYHA class III/ambulatory class IV symptoms on
GDMT.16–18,21 (Level of Evidence: A)
New recommendation
3. CRT can be useful in patients with atrial fibrillation and LVEF less than or
equal to 35% on GDMT if a) the patient requires ventricular pacing or
otherwise meets CRT criteria and b) AV nodal ablation or pharmacologic rate
control will allow near 100% ventricular pacing with CRT.23–26,26a,48
(Level of Evidence: B)
Modified recommendation (wording changed to indicate benefit
based on ejection fraction rather than NYHA class; level of
evidence changed from C to B).
4. CRT can be useful for patients on GDMT who have LVEF less than or equal
to 35% and are undergoing new or replacement device placement with
anticipated requirement for significant (_40%) ventricular pacing.25,27–29
(Level of Evidence: C)
Modified recommendation (wording changed to indicate benefit
based on ejection fraction and need for pacing rather than
NYHA class); class changed from IIb to IIa).
Class IIb
1. CRT may be considered for patients who have LVEF less than or equal to
30%, ischemic etiology of heart failure, sinus rhythm, LBBB with a QRS
duration of greater than or equal to 150 ms, and NYHA class I symptoms on
GDMT.20,21 (Level of Evidence: C)
New recommendation
2. CRT may be considered for patients who have LVEF less than or equal to
35%, sinus rhythm, a non-LBBB pattern with QRS duration 120 to 149 ms,
and NYHA class III/ambulatory class IV on GDMT.21,30 (Level of Evidence: B)
New recommendation
3. CRT may be considered for patients who have LVEF less than or equal to
35%, sinus rhythm, a non-LBBB pattern with a QRS duration greater than or
equal to 150 ms, and NYHA class II symptoms on GDMT.20,21 (Level of
Evidence: B)
New recommendation
Class III: No Benefit
1. CRT is not recommended for patients with NYHA class I or II symptoms and
non-LBBB pattern with QRS duration less than 150 ms.20,21,30 (Level of
Evidence: B)
New recommendation
2. CRT is not indicated for patients whose comorbidities and/or frailty limit
survival with good functional capacity to less than 1 year.19 (Level of
Evidence: C)
Modified recommendation (wording changed to include cardiac
as well as noncardiac comorbidities).
Rispetto alle linee guida precedent, si osserva un’ estensione delle indicazioni “raccomandate” ai pz in fibrillazione atriale, con turbe e generiche della conduzione intraventricolare (QRS > 150 msec) e paucinstomatici ma con severa compromissione della funzione contrattile ventricolare sx.
BIBLIOGRAFIA
2012 ACCF/AHA/HRS Focused Update of the 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines Circulation 2012; 126