Atrial Electrical and Structural Changes Associated with Longstanding Hypertension in Humans: Implications for the Substrate for Atrial Fibrillation

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Extraido de J Cardiovasc Electrophysiol, Vol. 22, pp. 1317-1324, December 2011

 

Atrial Remodeling inHuman Hypertension.

 Introduction: Hypertension (HT) is the most common modifiable
risk factor for atrial fibrillation (AF), yet little is known of the atrial
effects of chronic HT in humans.We aimed to characterize the electrophysiologic
(EP) and electroanatomic (EA) remodeling of the right atrium (RA) in patients
with chronically treated systemic HT and left ventricular hypertrophy (LVH) without
a history of AF.

 Methods and Results:

Twenty patientswith (systolicBP145±10mmHg)and without (BP 119±11mmHg, P < 0.01) systemic HT underwent detailed
conventional EP and EA voltage and activation mapping. We measured RA
refractoriness at the coronary sinus and high septum at cycle lengths (CLs) 600
and 450 ms, and RA conduction velocities, activation times, and voltages at a
global and regional level at CLs 600 ms and 300 ms. HT was associated with
slowing of global (73 ± 17 cm/s vs 96 ± 12 cm/s in controls, P < 0.01) and regional conduction velocity
particularly in the posterior RA (70 ± 17 cm/s vs 96 ± 12 cm/s in controls, P < 0.01) at the crista terminalis
(fractionation and double potentials in HT 72% ± 4 vs 43% ± 23 in controls, P = 0.04). Mean RA voltage was similar between the 2
groups, however HT was associated with an increase in areas of low voltage (<0.5mV; HT 13% vs controls 9%, P = 0.04). Sustained AF was induced in 30% HT patients and
no controls.

 Conclusion: Chronically treated systemic HT with LVH is
accompanied by atrial remodeling characterized by: (i) global conduction
slowing, (ii) regional conduction delay particularly at the crista terminalis, and
(iii) increased AF inducibility. These changes may in part be responsible for
the increased propensity to AF associated with systemic HT.

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