Right-to-left ventricular diastolic delay in chronic thromboembolic pulmonary hypertension is associated with activation delay and action potential prolongation in right ventricle.
BACKGROUND
Delayed left ventricle (LV)-to-right ventricle (RV) peak shortening results in cardiac output reduction in patients with chronic thromboembolic hypertension (CTEPH) and other types of pulmonary arterial hypertension. Why the synchrony between LV and RV is lost is unknown. We hypothesized that RV electrophysiological remodeling, notably, conduction slowing and action potential prolongation, contribute to this loss in synchrony.


RESULTS
We conducted epicardial mapping during pulmonary endarterectomy in 26 patients with CTEPH and compared these findings with clinical, hemodynamic, and echocardiographic variables. We consecutively placed a multielectrode grid on the epicardium of the RV free wall and LV lateral wall. These regions corresponded to RV and LV areas where echocardiographic Doppler sample volumes were placed to measure RV-to-LV diastolic interventricular delay. RV and LV epicardial action potential duration was assessed by measuring activation-recovery interval. Onset of diastolic relaxation of RV free wall with respect to LV lateral wall (diastolic interventricular delay) was delayed by 38+/-31 ms in patients with CTEPH versus -12+/-13 ms in control subjects (P<0.001), because, in patients with CTEPH, RV completed electric activation later than LV (65+/-20 versus 44+/-7 ms, P<0.001) and epicardial action potential duration, as assessed by activation-recovery interval measurement, was longer in RV free wall than in LV lateral wall (253+/-29 versus 240+/-22 ms, P<0.001).


CONCLUSIONS
Additive effects of electrophysiological changes in RV, notably, conduction slowing and action potential prolongation, assessed by epicardial activation-recovery interval, contribute to diastolic interventricular delay in patients with CTEPH.
Heart Failure Research Center, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
Maxim
M
Hardziyenka
Maria E
ME
Campian
Berto J
BJ
Bouma
André C
AC
Linnenbank
H A C M Rianne
HA
de Bruin-Bon
Jaap J
JJ
Kloek
Allard C
AC
van der Wal
Jan
J
Baan
Edouard M
EM
de Beaumont
Herre J
HJ
Reesink
Jacques M T
JM
de Bakker
Paul
P
Bresser
Hanno L
HL
Tan
D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D018780:Body Surface Potential Mapping / Q000379:methods; D003971:Diastole / Q000502:physiology; D015150:Echocardiography, Doppler; D004691:Endarterectomy; D005260:Female; D006329:Heart Conduction System / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging / Q000503:physiopathology*