Improved relationship between left and right ventricular electrical activation after cardiac resynchronization therapy in heart failure patients can be quantified by body surface potential mapping

Abstract

OBJECTIVES:Few studies have evaluated cardiac electrical activation dynamics after cardiac resynchronization therapy. Although this procedure reduces morbidity and mortality in heart failure patients, many approaches attempting to identify the responders have shown that 30% of patients do not attain clinical or functional improvement. This study sought to quantify and characterize the effect of resynchronization therapy on the ventricular electrical activation of patients using body surface potential mapping, a noninvasive tool.METHODS:This retrospective study included 91 resynchronization patients with a mean age of 61 years, left ventricle ejection fraction of 28%, mean QRS duration of 182 ms, and functional class III/IV (78%/22%); the patients underwent 87-lead body surface mapping with the resynchronization device on and off. Thirty-six patients were excluded. Body surface isochronal maps produced 87 maximal/mean global ventricular activation times with three regions identified. The regional activation times for right and left ventricles and their inter-regional right-to-left ventricle gradients were calculated from these results and analyzed. The Mann-Whitney U-test and Kruskall-Wallis test were used for comparisons, with the level of significance set at p≤0.05.RESULTS:During intrinsic rhythms, regional ventricular activation times were significantly different (54.5 ms vs. 95.9 ms in the right and left ventricle regions, respectively). Regarding cardiac resynchronization, the maximal global value was significantly reduced (138 ms to 131 ms), and a downward variation of 19.4% in regional-left and an upward variation of 44.8% in regional-right ventricular activation times resulted in a significantly reduced inter-regional gradient (43.8 ms to 17 ms).CONCLUSIONS:Body surface potential mapping in resynchronization patients yielded electrical ventricular activation times for two cardiac regions with significantly decreased global and regional-left values but significantly increased regional-right values, thus showing an attenuated inter-regional gradient after the cardiac resynchronization therapy.

Clinical Utility of Body Surface Potential Mapping in CRT Patients

“…[ 8 ] Another BSPM approach based on measurement of QRS duration in 87 body surface unipolar leads showed that regional activation time in the RV increased in biventricular pacing, but it was compensated for by an even greater decrease in activation time in the LV, therefore the effect of CRT could be optimised by decreasing the inter-regional RV–LV gradients. [ 23 , 24 ] In addition, BSPM parameters of ventricular repolarisation dispersion such as T peak –T end interval, T peak –T end integral, and T wave amplitude were reduced compared with sinus rhythm under biventricular pacing, whereas RV or LV pacing resulted in increased dispersion of repolarisation. [ 9 ]…”

Mapeamento do Potencial da Superfície Corporal durante a Despolarização Ventricular em Atletas com Intervalo PQ Prolongado após Exercício

“…Previous studies 16 , 17 , 21 described the BSPM patterns during ventricular depolarization in persons with conduction disturbances in the His-Purkinje system. In patients with a complete right bundle branch block (RBBB), the breakthrough of the excitation on the ventricular subepicardium (which is reflected by the formation of the “saddle” potential distribution on the BSPMs) is noted at 44 ms after the onset of activation of the heart ventricles, in patients with incomplete RBBB – at 38 ms after the onset of ventricular activation.…”

“… 11 - 13 Previously, BSPM was applied in order to investigate the ventricular electrical activation in patients with intraventricular conduction abnormalities. 14 - 17 Studies of ventricular depolarization by means of BSPM in first-degree AV block have not been conducted in athletes.…”

“…[11][12][13] Anteriormente, a BSPM foi aplicada para investigar a ativação elétrica ventricular em pacientes com anormalidades na condução intraventricular. [14][15][16][17] Estudos de despolarização ventricular por meio da BSPM no bloqueio AV de primeiro grau não foram realizados em atletas.…”

Aplicação do Mapeamento Eletrocardiográfico de Superfície por Meio de Exercício em Pequenos Animais

“…During the last three decades, thereby, we developed pioneering studies in all the specialties of Cardiology, including our partnership with colleagues developing doctoral theses at InCor HCFMUSP. [4][5][6][7][8][9][10][11][12][13] The Biomedical Engineering Department of InCor HCFMUSP has been working on the development of a fully nationalized 64-lead BSPM equipment since 2016, with the contribution of the Electrocardiography Unit of InCor.…”