Response to cardiac resynchronization therapy is determined by intrinsic electrical substrate rather than by its modification.
Int J Cardiol
; 270: 143-148, 2018 Nov 01.
Article
em En
| MEDLINE
| ID: mdl-29895424
ABSTRACT
BACKGROUND:
Electrocardiographic mapping (ECM) expresses electrical substrate through magnitude and direction of the activation delay vector (ADV). We investigated to what extent the response to cardiac resynchronization therapy (CRT) is determined by baseline ADV and by ADV modification through CRT and optimization of left ventricular (LV) pacing site.METHODS:
ECM was performed in 79 heart failure patients (4 RBBB, 12 QRSâ¯<â¯120â¯ms, 23 non-specific conduction delay [NICD] and 40 left bundle branch block [LBBB]). 67 patients (QRSâ¯≥â¯120â¯ms) underwent CRT implantation and in 26 patients multiple LV pacing site optimization was performed. ADV was calculated from locations/depolarization times of 2000 virtual epicardial electrodes derived from ECM. Acute response was defined as ≥10% LVdP/dtmax increase, chronic response by composite clinical score at 6â¯months.RESULTS:
During intrinsic conduction, ADV direction was similar in patients with QRSâ¯<â¯120â¯ms, NICD and LBBB, pointing towards the LV free wall, while ADV magnitude was larger in LBBB (117⯱â¯25â¯ms) than in NICD (70⯱â¯29â¯ms, Pâ¯<â¯0.05) and QRSâ¯<â¯120â¯ms (52⯱â¯14â¯ms, Pâ¯<â¯0.05). Intrinsic ADV accurately predicted the acute (AUCâ¯=â¯0.93) and chronic (AUCâ¯=â¯0.90) response to CRT. ADV change by CRT only moderately predicted response (highest AUCâ¯=â¯0.76). LV pacing site optimization had limited effects +3⯱â¯4% LVdP/dtmax when compared to conventional basolateral LV pacing.CONCLUSION:
The baseline electrical substrate, adequately measured by ADV amplitude, strongly determines acute and chronic CRT response, while the extent of its modification by conventional CRT or by varying LV pacing sites has limited effects.Palavras-chave
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Base de dados:
MEDLINE
Assunto principal:
Mapeamento Potencial de Superfície Corporal
/
Terapia de Ressincronização Cardíaca
/
Insuficiência Cardíaca
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article