Introduction: Cardiac resynchronization therapy (CRT) has proven important beneficial effects in left ventricular (LV) failure with reduced ejection fracti-on (EF).Upgrade from a simple pacemaker (PM) to a biventricular one in patients with bradyarrhythmias with a high percent of right ventricular (RV) pacing is normally recommended when/if they develop a reduced LV EF. Preliminary evidence show that CRT may be beneficial also for RV failure secondary to high afterload, but consistent data to sustain and recommend this approach is still lacking.
Objective: To report the case of a patient with dominantly RV failure secondary to severe pulmonary hyper tension (PH), in which upgrade from a single chamber to a biventricular PM had significant beneficial effects.
Case presentation: The 76-year-old male patient, with advanced chronic obstructive lung disease, implanted 9 years before with a single chamber PM for low rate permanent atrial fibrillation had had multiple hospitalizations for decompensated heart failure (dominantly right) in the last year. The ECG and PM interrogation showed atrial fibrillation with >98% RV pacing. Echocardiography revealed a normal sized LV with a moderately reduced EF, intra- and interventricular dyssynchrony, paradoxic interventricular septum movement, moderate degenerative and functional mitral regurgitation, a dilated RV with reduced systolic function, moderate to severe tricuspid regurgitation with severe PH (evaluation performed in a compensated state). The PM was upgraded to biventricular when replaced for battery depletion. The patient’s clinical status im-proved significantly. He had no decompensated heart failure hospitalization during the first year of CRT. PM interrogation revealed 100% biventricular pacing. The ECG showed a reduction in paced QRS with from 160 ms to 130 ms. Echocardiographic reevaluation after 6 months of CRT revealed an improved LVEF (from ~40-45% to 50%), with a near normal interventricular septum contraction (trace signs of right side compression), without significant residual inter and/or intraventricular dyssynchronism. Mitral regurgitation improved from moderate to mild. Tricuspid regurgitation improved from moderate-severe to moderate with a decrease in tricuspid regurgitation gradient from 46mmHg to 35mmHg. Right ventricular systolic function also im-proved with a tricuspid annulus plane systolic excursi-on (TAPSE) increase from 1.4 to 1.6 cm.
Conclusions: Biventricular pacing may have signifi-cant beneficial effects even in patients with pulmonary lung disease and dominantly RV dysfunction. One of the pulmonary hypertension components was solved in this patient by improving LV function and mitral regurgitation. The better contraction synchrony led to an improvement in RV preload and afterload resulting in RV function improvement. The case is worth men-tioning as it reports an unusual case of CRT, with poor data in the literature in this regard.