Page 23 - Delaware Medical Journal August 2015

SCIENTIFIC ARTICLE
The etiology of this worsening in
LV function may be explained by
the tendency of RV pacing to cause adverse LV remodeling that results in a reduction in the LVEF and increased LV dimensions which may lead to functional mitral regurgitation.9 Mitral regurgitation in return leads to further LV dilation and worsening ejection fraction. Worsening mitral regurgitation in this setting may represent the earliest signs of pacemaker- induced cardiomyopathy. In extreme cases, the resulting mitral regurgitation can be very acute and severe requiring urgent intervention. The impact of RV pacing on pulmonary artery pressure can probably be explained by the worsening mitral regurgitation in patients who are pacemaker dependent. Long standing worsening of mitral regurgitation will result in increased left atrial pressure that will eventually result with development of new or worsening of existent pulmonary hypertension.
RV pacing is not to be the optimal setting for pacing in pacer dependent patients with LV dysfunction.10 Biventricular pacing is superior to RV pacing in this pacer dependent patients with normal LV function.9,10 The impact of high RV pacing
REFERENCES
on LV dimension and function that was well established coupled with worsening mitral regurgitation that was established in our study may further suggest considering biventricular pacing as an alternative and superior pacing option in pacer dependent patients regardless of the baseline degree of LV dysfunction or at least increase the urge for additional randomized studies in this population.
Our study has several limitations. First,
the retrospective design of our study represents only an observation input about the impact of RV pacing without offering
a control cohort. Second, the settings of pacemaker programming differed between different operators. Third, we were unable to provide independent standardized reading of echocardiographic results, as although described echocardiography methodology was recommended in our echo to these recommendations. Fourth, we
were unable to explore the impact of RV pacing mode VVI-R vs. DDD-R on the
LV function and pulmonary hypertension. Finally, all echocardiography were obtained on routine follow-up, no information is available regarding whether the patients were ventricular paced or not at the time of follow-up echo. Despite these limitations,
our study represents probably one of
the largest retrospective patient cohorts evaluating the impact of apical RV pacing on left ventricle, mitral, and tricuspid valve as well as pulmonary hypertension.
CONCLUSION
PPM or ICD lead implantation worsens
LV function and pulmonary hypertension in patients with high frequency of RV pacing frequency. This is probably caused by the mechanical dyssynchrony induced by
RV pacing.
CONTRIBUTING AUTHORS
■ ZAHER FANARI, MD is a Cardiology Fellow at Christiana Care Health System in Newark, Del.
■ SUMAYA HAMMAMI, MD, MPH is associated with the Department of Cardiology at Christiana Care Health System in Newark, Del.
■ MUHAMMAD BARAA HAMMAMI, MD is associatedwiththeDepartment ofCardiology at Christiana Care Health System in Newark, Del.
■ SAFA HAMMAMI, MD is associated with the Department of Cardiology at Christiana Care Health System in Newark, Del.
■ MOSSAAB SHURAIH, MD is associated with the Texas Heart Institute in Houston, Texas.
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