[CRT-FORUM] 15E. Right bundle branch block and CRT. Dr. Paul Levine

[CRT-INFO]

Dr. Perez makes some excellent points.  I would like to cite a reference 
with respect to VERBS - Ventricular Endocardial Right Bifocal 
Stimulation.  Dr. Jose Pachon and colleagues have a superb article 
reviewing this topic published in 2001.
Pachon J C, et al, Ventricular Endocardial Right Bifocal Stimulation in 
the treatment of severe dilated cardiomyopathy heart failure with wide 
QRS, PACE 2001; 24: 1369-1376
 
If either Dr. Juan, Enrique or Jose Pachon are participating in this 
symposium, perhaps they might offer some additional comments with 
respect to VERBS and its potential role in the treatment of Chagasic 
cardiomyopathy.
 
With respect to RBBB, over the years, I have treated a number of 
patients for sick sinus syndrome who have concomitant RBBB and have 
normalized the QRS complex by careful programming of the paced and 
sensed AV delays to force intentional fusion.   This has not been 
subjected to formal clinical study and in the patients in whom I have 
used this technique, their ventricular function was basically normal.    
 
The concept of using fusion to improve hemodynamics was first reported 
(that I am aware of) at the VIIth World Symposium on Cardiac Pacing in 
1983 in Vienna by de Teresa and colleagues.  They studied 4 patients 
with chronic LBBB who had undergone aortic valve surgery.  They were 
doing poorly in the post-operative period and taking advantage of 
temporary LV epicardial pacing lead and insertion of a temporary 
endocardial right atrial lead, they carefully timed ventricular pacing 
(LV lead pacing) with the P wave and intrinsic conduction to result in 
fusion with normalization of the QRS and improvement in hemodynamics.    
 
 
 
Paul A. Levine MD, FHRS, FACC, CCDS
Vice President, Medical Services
St, Jude Medical CRMD
Tel: 1-818-493-2900 Fax: 1-818-362-2242
plevine at sjm.com
Clinical Professor of Medicine - Loma Linda University School of Medicine
Clinical Associate Professor of Medicine -UCLA
 
> Dear colleague Marcos Souza From Belo Horizonte Minas Gerais  Brazil: 
> It is unclear whether benefits of CRT extend to patients with right 
> branch bundle block (RBBB) or a paced QRS at baseline despite QRS>120 
> ms. Very recently, O'Connor et al (1) in a preliminary report suggests 
> that similar reverse remodeling can be observed in Complete RBBB 
> (CRBBB) patients as patients with LBBB after CRT. The authors studied 
> 4 consecutive patients with CRBBB advanced ischemic HF, EF ≤35%) and 
> intraventricular asynchrony ≥50 ms scheduled for CRT. Dobutamine 
> stress echocardiography  was performed within the week before CRT. 
> Viability was defined as increased wall thickening during dobutamine 
> stress echocardiography. Viability in the region of LV pacing lead was 
> defined as the presence of viability in 2 contiguous segments. 
> Response was defined by LV reverse remodeling (i.e. ≥15% reduction in 
> LV end-systolic volume) 3-6 months after CRT.
> Three patients demonstrated LV reverse remodeling at follow-up. 
> Responders showed LV end-systolic volume decrease of -31+/-16% from 
> baseline to follow-up whereas no change was observed in the non 
> responder patient. Similar LV asynchronism was found in all patients. 
> All responders had viability in ≥2 segments in the region of LV 
> pacing. Intraventricular asynchrony and CRBBB, viability in the region 
> of pacing lead may help to predict response to CRT in patients with HF.
>
> In patients with CRBBB (N= 62 patients: 10% of all universe) 
> undergoing CRT had low rates of symptomatic and echocardiographic 
> response, and their survival free from orthotopic heart 
> transplantation or ventricular assist device placement was 
> significantly worse than in patients with LBBB (N=412; 65%),. Patients 
> with conventionally paced QRS (N=412; 65%), experienced an 
> intermediate response(2).
> From 29 patients (mean age 61.5) with predominant  chagasic 
> cardiomyopathy cardiac resynchronization therapy was effective for 
> patients with conventional pacemakers and advanced HF as it yields a 
> high rate of response (86.2%), significantly improves LVEF and reduces 
> QRS duration(3).
> Finally, Studies have demonstrated a beneficial effect of right 
> ventricular  bifocal pacing, using two leads at different positions, 
> in Chagas disease patients who developed both severe dilated 
> cardiomiopathy and chronic AF.
>
> References
>
> 1)    O'Connor K, Sénéchal M, Lancellotti P, Dubois M, Magne J, 
> Champagne J, Philippon F, Pierard L, O'Hara G. Usefulness of cardiac 
> resynchronisation therapy in patients with right bundle branch block: 
> Is viability an important piece of the puzzle? Int J Cardiol. 2009 Jan 
> 23. [Epub ahead of print]
> 2)    Adelstein EC, Saba S. Usefulness of baseline 
> electrocardiographic QRS complex pattern to predict response to 
> cardiac resynchronization. Am J Cardiol. 2009 Jan 15;103(2):238-42.
> 3)    Silva RT, Martinelli Filho M, Lima CE, Martins DG, Nishióka SA, 
> Pedrosa AA, Crevelari ES, Costa R, Sosa EA, Ramires JA. Functional 
> behavior of patients with conventional pacemakers undergoing cardiac 
> resynchronization. Arq Bras Cardiol. 2008 Feb;90:138-143.
>
> All the best
> Andrés Ricardo Pérez Riera MD, chief of electrovectorcardiology sector
> ABC Faculty of Medicine (FMABC), Discipline of Cardiology, Foundation 
> of ABC (FUABC), Santo André, São Paulo, Brazil.
>
>> Dear colleagues,
>>
>> congratulations to all participants and specially to organizers!
>>
>> I would like a review or a discussion about ressyncronization therapy 
>> in patients with right bundle branch block, specially in Chagas disease,
>>
>> thank you,
>>
>> Marcos Sousa - Mater Dei hospital and Federal University of Minas Gerais
>>
>> Belo Horizonte, Minas Gerais,  Brazil
>>
>
>


-- 
Dr. Sergio Dubner
President of Scientific Committee

Dr. Edgardo Schapachnik
President of Steering Committee