Download Influence of right ventricular pacing on right ventricular systolic

Influence of right ventricular pacing on right ventricular systolic function
Background and aim of the study:
Even though right ventricle pacing is irreplaceable therapeutic modality, the question of it´s influence on
myocardial contractility remains remains unresolved.
Aim of this prospective study is to inquire, whether right ventricle pacing worsens the right ventricle
systolic function and, if need be, which position of the right ventricle pacing lead is more favorable with
regard to the right ventricle systolic function.
We have also tested the ability of real time 3D transthoracic echocardiography (TTE) to verify the
position of the pacing lead.
Methods:
30 patients were included in the study in the period since March 2013 to March 2015. This population
was randomly divided in to two groups: with apical and septal position of the lead (11 and 19 pts.). Apical
position was chosen by the implanting physician in case of provocation of electric instability by the septal
position or in case of unsatisfactory electric parameters in the septal position of the lead. To verify the lead
position, real-time 3D echo on Philips IE33 machine was used, besides the more usual methods
(fluoroscopy and ECG).
For evaluation of the systolic function of the right ventricle we have used tricuspid annulus plain systolic
excursions (TAPSE) and tricuspid annulus systolic velocity (TASV) parameters. Values under 16 mm of
TAPSE and under 10 cm/s of TASV were considered decreased.
The percentage of ventricular pacing (VP) was red from the external programmers.
Used pacing modes were DDD, DDDR, VVI, VVIR, AAI-DDD and AAIR-DDDR.
The time of follow up was 2-26 months, average 8.1 months.
Demographic parameters of the population:
Population consists of 19 male and 11 female patients, aged 45-93 years, average age was 74 years. There
were 11 apical and 19 septal lead positions. 6 pacemakers were one chamber and the rest (24) were two
chamber devices. The average percentage of ventricular pacing (VP) was 62%. 14 patients were dependend
on the pacemaker with VP of 99% or more.
Statistical analysis:
In order to inquire, whether or not, there is a significant decrease of TAPSE and TASV values, in all
patients with right ventricle pacing, we have used the pair t-test. We have studied the differences (d) in the
pair couples of TAPSE and TASV 1 and 2 (first and second measured values) and we have tested the zero
hypothesis H0, that the values of pair couples do not differ systematically in one direction. The normality
of the selected samples was verified by the Chisq test of the good concurrence and also by the
Kolmogorov-Smirnov test. The measured values of TAPSE: d=0.8±0,848, i.e. Confidence interval (CI) for
d is (-0.05; 1.65), and for TASV d=0.483±0.694 i.e. CI for d is (-0,216;1,15).
Pair test showed, that there is not a significant difference – decrease of the values of both parameters –
TAPSE p=0.0746 and TASV p=0,19055.
We have also studied influence of the lead position on the difference between first and second
measurement: The difference between pair values of TAPSE and TASV in two independent groups of
patients, that is, group with apical (n=11) and group with non-apical (n=19) lead position. We have used
non-parametrical Mann-Whitney test. H0: Lead position does not influence the differences of the values in
the given two groups – H0 is not rejected on the level of significance 5% with p=0.2 for TAPSE and p=0.11
for TASV.
Results:
1. Pair test showed, that there is not a significant difference – decrease of the values of both parameters –
TAPSE and TASV in all patients with right ventricle pacing and
2. non-parametrical Mann-Whitney test showed, that H0 (Lead position does not influence the differences of
the values in the given two groups) is not rejected on the level of significance 5%, p=0.2 for TAPSE and
p=0.11 for TASV.
3. There was not a single patient, in whom there would be a decline of any studied parameter under the limit
of normal values, given by the American Society of Echocardiography (1).
4. In all patients included in the study, it was possible to visualize the ventricular lead with the use of
transthoracic echo. Since the real time 3D echo is able to show a longer part of the lead at the same time
than 2D TTE, it provided either better information than 2D or at least the same. Real-time 3D TTE often
provides a better visualization of the lead insertion in to the myocardium.
Discussion:
The right ventricle pacing has been used for more than 5 decades and this method significantly prolongs
and improves the quality of life of the population. Yet, one of the possible side effects is worsening of the
systolic function of the left ventricle (LV). This question has been discussed for more than 20 years. 14
randomized trials were performed, of which, some suggest a negative influence of the apical right
ventricular pacing on the LVEF. Strongest evidence of this has been brought for patients who had systolic
dysfunction of the LV already before the implantation.
In a systematic review and meta-analysis of 14 RCTs for a total of 754 patients, those randomized to RV
non-apical pacing had greater LVEF at the end of follow-up especially those with a baseline LVEF <45%
and with a follow-up length >12 months. No significant difference was observed in RCTs of patients
whose baseline LVEF was preserved. Results were inconclusive with respect to exercise capacity,
functional class, quality of life and survival. This Task Force is unable to give definite recommendations
until the results of larger trials become available. (2)
Pacing of the right ventricle myocardium, other than the His-Purkinje conduction system can cause a
decrease in stroke volume and abnormal relaxation of the LV (3).
Some studies demonstrate, that long term RV pacing, causes LV remodeling with asymetric hypertrophy
and dilatation, mitral regurgitation, decrease in myocardial perfusion and decrease in ejection fraction (4)
Worsening of the systolic function of the right ventricle plays a major role in the morbidity and mortality
of patients with cardiopulmonary disease. Despite that, there has been to date, to the best of our knowledge,
only one work, studying the influence of the RV pacing on the RV function and this was a retrospective
analysis of 96 pts. Prevalence of the RV dysfunction in this population was 4%, but, one of the limitations
of this study is, that the RV function was not evaluated before the implantation (4).
Evaluation of the RV function: Even though RV has more complex anatomy and kinetics, parameters
TAPSE and TASV are easy to obtain, and have a very good reliability and reproducibility. The use of
TAPSE as a parameter, evaluating the right ventricle systolic function has been repeatedly verified by a
series of studies correlating TAPSE with MRI or radionuclide ventriculography. Values of 16 mm and
more are, according to the current guidelines, considered normal. (1). Another parameter, assessing the
quality contractions of longitudinal fibres is St or TASV (tricuspid annular systolic velocity), obtained by
the pulse-tissue Doppler ultrasound of the lateral margin of the tricuspid annulus. Again, the correlation of
TASV with right ventricle ejection fraction has been confirmed by multiple radionuclide and MR imaging
studies. In both of these parameters, a strong prognostic information - like in patients with heart failure or
patients with pulmonary artery hypertension - has been proved. That is why these parameters are
recommended for the routine evaluation of the right ventricle systolic function.
Studies, focusing on the negative impact of right ventricular pacing on the systolic function of the heart,
were always evaluating LVEF, which parameter has also it´s limitations, like imperfect reproducibility,
especially in the case of suboptimal image quality.
The author is aware of the fact, that parameters of RV function are not applicable to the assessment of
LV function, but, even though left and right ventricles are anatomically two different parts of one organ,
histologically they constitute integrity of one syncytium and thus, should there be a strong and clear
evidence, that RV function is really not worsened by the RV pacing from any site, it would constitute
certain questioning of the concept of negative influence of the RV pacing on the myocardial function as a
whole.
Conclusion: Based on these data, it seems unlikely, that right ventricle pacing influences the right
ventricular systolic function.
At the same time we have confirmed, that TTE is a very good method for determining the ventricular
lead position by it´s direct visualization.
Literature:
1. Rudski LG, Lai WW, Afilalo J, et al. Guidelines for the Echocardiographic Assessment of the Right
Heart in Adults: A Report from the American Society of Echocardiography Endorsed by the European
Association of Echocardiography, a registered branch of the European Society of Cardiology and the
Canadian Society of Echocardiography. J Am Soc Echocardiogr 2010; 23: 685-713.)
2. 2013 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. European Heart Journal
(2013) 34, 2281–2329 doi:10.1093/eurheartj/eht150. (2)Shimony A, Eisenberg MJ, Filion KB, Amit G,
Beneficial effect of right ventricular pacing non-apical pacing vs. apical pacing: a systematic review and
meta-analysis of randomized-controlled trials. Europace 2012; 14: 81-91.)
3. Lee MA, Dae MW, Griffin JC, et al. Effects of long-term right ventricular apical pacing on left
ventricular perfusion, innervation, function and histology. J Am Coll Caardiol 1994; 24: 225-232
4. Tse HF, Lau CP. Long –term effect of right ventricular pacing on myocardial perfusion and function. J
Am Coll Cardiol 1997; 29: 744-9, Tantengco MV, Thomas RL, Karpawich PP. Left ventricular
dysfunction after long-term right ventricular apical pacing in the young. J Am Coll Cardiol 2001; 37: 2093100)
5. Pornwalee Porapakkham et. al. Impact of Right Ventricular Pacing on Right ventricular funcion, J Med
Assoc Thai 2012; 95 (Suppl. 8): S44-S50