Современные принципы физиологической стимуляции by Max Didenko

Ì.Â.Äèäåíêî, Ê.Í.Øîðîõîâ, Ã.Ã.Õóáóëàâà ÑÎÂÐÅÌÅÍÍÛÅ ÏÐÈÍÖÈÏÛ ÔÈÇÈÎËÎÃÈ×ÅÑÊÎÉ ÝËÅÊÒÐÎÊÀÐÄÈÎÑÒÈÌÓËßÖÈÈ

Ñàíêò-Ïåòåðáóðãñêàÿ Âîåííî-ìåäèöèíñêàÿ àêàäåìèÿ èì. Ñ.Ì.Êèðîâà Ðàññìàòðèâàþòñÿ ñîâðåìåííûå ïðåäñòàâëåíèÿ î ôèçèîëîãè÷åñêîé ýëåêòðîêàðäèîñòèìóëÿöèè, àíàëèçèðóþòñÿ ðåçóëüòàòû ìíîãîöåíòðîâûõ èññëåäîâàíèé, ïðèâîäÿòñÿ ñîáñòâåííûå äàííûå ïî ïðèìåíåíèþ ðåæèìîâ, ìèíèìèçèðóþùèõ ñòèìóëÿöèþ ïðàâîãî æåëóäî÷êà, áèâåíòðèêóëÿðíîé ñòèìóëÿöèè è ñòèìóëÿöèè ìåææåëóäî÷êîâîé ïåðåãîðîäêè. Êëþ÷åâûå ñëîâà: ôèçèîëîãè÷åñêàÿ ýëåêòðîêàðäèîñòèìóëÿöèÿ, áèâåíòðèêóëÿðíàÿ ñòèìóëÿöèÿ, àòðèîâåíòðèêóëÿðíàÿ áëîêàäà, ìåææåëóäî÷êîâàÿ ïåðåãîðîäêà, äèññèíõðîíèÿ, õðîíè÷åñêàÿ ñåðäå÷íàÿ íåäîñòàòî÷íîñòü, ôèáðèëëÿöèÿ ïðåäñåðäèé. The current concepts of physiological cardiac pacing are considered, the results of multi-center studies are analyzed, the results of the authors studies on the use of the regimens minimizing the pacing of the right ventricle, on biventricular pacing, and pacing of inter-ventricular septum are given. Key words: physiological cardiac pacing, biventricular pacing, atrio-ventricular block, inter-ventricular septum, dyssynchrony, chronic heart failure, atrial fibrillation. Ïîíÿòèå «ôèçèîëîãè÷åñêàÿ ýëåêòðîêàðäèîñòèìóëÿöèÿ (ÝÊÑ)» ïðåòåðïåëî çíà÷èòåëüíûå èçìåíåíèÿ çà ïîñëåäíèå íåñêîëüêî ëåò. Åñëè åùå ñîâñåì íåäàâíî äâóõêàìåðíàÿ ÷àñòîòíîàäàïòèâíàÿ ÝÊÑ â ðåæèìå DDDR ñ èìïëàíòàöèåé ýëåêòðîäîâ â óøêî ïðàâîãî ïðåäñåðäèÿ (ÏÏ) è âåðõóøêó ïðàâîãî æåëóäî÷êà (ÏÆ) ìîãëà ñ÷èòàòüñÿ âî âñåõ ñëó÷àÿõ ôèçèîëîãè÷íîé, òî ñåé÷àñ ýòî âîïðîñ ñïîðíûé. Êëèíè÷åñêèå èññëåäîâàíèÿ ïàöèåíòîâ ñ èìïëàíòèðîâàííûìè ýëåêòðîêàðäèîñòèìóëÿòîðàìè äëÿ ëå÷åíèÿ ñèíäðîìà ñëàáîñòè ñèíóñîâîãî óçëà (ÑÑÑÓ) èëè àòðèîâåíòðèêóëÿðíûõ (ÀÂ) áëîêàä ðàçëè÷íîé ñòåïåíè, à òàêæå ñ èìïëàíòèðóåìûìè êàðäèîâåðòåðàìè-äåôèáðèëëÿòîðàìè (ÈÊÄ), ïîêàçàëè ÷òî íàðóøåíèå ñèíõðîííîñòè ýëåêòðè÷åñêîé è ìåõàíè÷åñêîé ñèñòîëû æåëóäî÷êîâ, âûçâàííîå ÝÊÑ èç âåðõóøêè ÏÆ, â îòäàëåííûå ñðîêè óâåëè÷èâàåò ðèñê ðàçâèòèÿ ñåðäå÷íîé íåäîñòàòî÷íîñòè (ÑÍ) è ñìåðòíîñòè. Ïðè ýòîì ðèñê ÑÍ âîçðàñòàåò ñ óâåëè÷åíèåì äîëè æåëóäî÷êîâîé ñòèìóëÿöèè è ó ïàöèåíòîâ ñ èñõîäíî íàðóøåííîé ñîêðàòèòåëüíîé ôóíêöèåé ëåâîãî æåëóäî÷êà (ËÆ). Íåñìîòðÿ íà òî, ÷òî ÝÊÑ â áîëüøèíñòâå ñëó÷àåâ ÿâëÿåòñÿ ñïàñàþùåé æèçíü ïðîöåäóðîé, â ðÿäå ñëó÷àåâ ïðîèñõîäèò óñóãóáëåíèå òå÷åíèÿ ÑÍ. Ïîýòîìó äëÿ äîñòèæåíèÿ ìàêñèìàëüíîé ôèçèîëîãè÷íîñòè íåîáõîäèì èíäèâèäóàëüíûé ïîäõîä äëÿ êàæäîãî êîíêðåòíîãî ïàöèåíòà. Îñíîâûâàÿñü íà ýòèõ äàííûõ, ñåãîäíÿ âðà÷ ïåðåä èìïëàíòàöèåé óñòðîéñòâà äîëæåí îïðåäåëèòü âèä ÝÊÑ (îäíî-, äâóõ- èëè òðåõêàìåðíàÿ), îáëàñòü ïîçèöèîíèðîâàíèÿ ýëåêòðîäîâ â ñåðäöå, à òàêæå âîçìîæíîñòü ìàêñèìàëüíî ñíèçèòü íåìîòèâèðîâàííóþ ñòèìóëÿöèþ æåëóäî÷êîâ. Åäèíñòâåííûì ìåòîäîì ëå÷åíèÿ ñèìïòîìàòè÷íîé áðàäèêàðäèè è ïðîôèëàêòèêè âíåçàïíîé ñìåðòè âûçâàííîé àñèñòîëèåé, âñëåäñòâèå ÑÑÑÓ è ÀÂ áëîêàäû, ÿâëÿåòñÿ ÝÊÑ. Îäíàêî, íåñìîòðÿ íà òî, ÷òî ÝÊÑ ïðèìåíÿåòñÿ â êëèíè÷åñêîé ïðàêòèêå óæå îêîëî 50 ëåò, äî êîíöà íå îïðåäåëåíû íè îïòèìàëüíûé ðåæèì ñòèìóëÿöèè, íè îáëàñòü èç êîòîðîé ñëåäóåò å¸ ïðîâîäèòü.

Ïåðâûå ÝÊÑ áûëè îäíîêàìåðíûìè è íå îáåñïå÷èâàëè ïðåäñåðäíî-æåëóäî÷êîâóþ ñèíõðîíèçàöèè. Äâóõêàìåðíàÿ ÝÊÑ â ðåæèìå DDD/R íà÷àëà ïðèìåíÿòüñÿ îêîëî 20 ëåò íàçàä äëÿ âîññòàíîâëåíèÿ ïðåäñåðäíî-æåëóäî÷êîâîé ñèíõðîííîñòè ó ïàöèåíòîâ ñ ÀÂ áëîêàäàìè è îçíàìåíîâàëà ñåðüåçíûé òåõíè÷åñêèé è êëèíè÷åñêèé ïðîãðåññ. Äîñòàòî÷íî áûñòðî äâóõêàìåðíàÿ ÝÊÑ ðàñïðîñòðàíèëàñü â êëèíè÷åñêîé ïðàêòèêå è ñòàëà íàçûâàòüñÿ «ôèçèîëîãè÷íîé». Îäíàêî, ïðîâåäåííûå êðóïíûå ðàíäîìèçèðîâàííûå êëèíè÷åñêèå èññëåäîâàíèÿ (ÐÊÈ) ó ïàöèåíòîâ ñ ÑÑÑÓ è/èëè ÀÂ áëîêàäàìè ïîêàçàëè, ÷òî ñîõðàíåíèå ïðåäñåðäíî-æåëóäî÷êîâîé ñèíõðîííîñòè ñ ïîìîùüþ ÝÊÑ â ðåæèìå DDD/R íå ñíèæàëî ëåòàëüíîñòü ïî ñðàâíåíèþ ñ ÝÊÑ â ðåæèìå VVI/R è òîëüêî íåçíà÷èòåëüíî óìåíüøàëà âåðîÿòíîñòü ïðîãðåññèðîâàíèÿ ÑÍ â îòäàëåííûå ñðîêè [1, 2, 3]. Ïðè ýòîì â äðóãèõ ÐÊÈ áûëî äîñòîâåðíî ïîêàçàíî, ÷òî ïðåäñåðäíàÿ ÝÊÑ (AAI/R) ñíèæàåò ðèñê ôèáðèëëÿöèè ïðåäñåðäèé (ÔÏ) è ÑÍ, à òàêæå óëó÷øàåò âûæèâàåìîñòü ïî ñðàâíåíèþ ñ ÝÊÑ â ðåæèìàõ VVI/R è DDD/R ó ïàöèåíòîâ ñ ÑÑÑÓ [4, 5]. Îòñóòñòâèå ïðåèìóùåñòâ, êàçàëîñü áû, ôèçèîëîãè÷íîé äâóõêàìåðíîé ÝÊÑ (DDD/R) ïåðåä íåôèçèîëîãè÷íîé ÝÊÑ æåëóäî÷êîâ VVI/R îáúÿñíÿåòñÿ ôàêòîðîì, êîòîðûé ïðèñóù âñåì ðåæèìàì ñòèìóëÿöèè æåëóäî÷êîâ, à èìåííî - àñèíõðîííûì ñîêðàùåíèåì æåëóäî÷êîâ. Ïåðâûå äîêàçàòåëüñòâà ýòîé êîíöåïöèè áûëè ïîêàçàíû â õîäå ðåòðîñïåêòèâíîãî àíàëèçà èññëåäîâàíèÿ «MOST» (Mode Selection Trial), â êîòîðîì ðèñê ãîñïèòàëèçàöèè ïî ïîâîäó ÑÍ è ÔÏ áûë ïðÿìî ïðîïîðöèîíàëåí ñîâîêóïíîé äîëå ÝÊÑ æåëóäî÷êîâ, âûðàæåííîé â ïðîöåíòàõ, è íå çàâèñåë îò ðåæèìà ÝÊÑ [6]. Íàèìåíüøèé ðèñê îòìå÷àëñÿ ó ïàöèåíòîâ ñ DDD/R, íî ïðè ýòîì î÷åíü ìàëåíüêîé äîëåé ÝÊÑ æåëóäî÷êîâ. Òî åñòü, ó ýòèõ ïàöèåíòîâ îáåñïå÷èâàëàñü íå òîëüêî ïðåäñåðäíî-æåëóäî÷êîâàÿ, íî è íå íàðóøàëàñü ìåæ- è âíóòðèæåëóäî÷êîâàÿ ñèíõðîííîñòü. Íåãàòèâíîå âëèÿíèå æåëóäî÷êîâîãî àñèíõðîíèçìà, âûçâàííîãî ÝÊÑ èç âåðõóøêè ÏÆ, òàêæå áûëî ïîêàçà-

ÂÅÑÒÍÈÊ ÀÐÈÒÌÎËÎÃÈÈ, ¹ 48, 2007

59 íî â íåñêîëüêèõ ÐÊÈ, èçó÷àâøèõ ÈÊÄ. Òàê â èññëåäîâàíèè «DAVID» [7] ïðîâåðÿëàñü ãèïîòåçà, î òîì, ÷òî äâóõêàìåðíàÿ ÝÊÑ â ðåæèìå DDD/R ñ ìèíèìàëüíîé ÷àñòîòîé ñòèìóëÿöèè (×Ñ) 70 â 1 ìèí. áóäåò óëó÷øàòü ðåçóëüòàòû ëå÷åíèÿ ÑÍ, ñíèæàòü êîëè÷åñòâî ãîñïèòàëèçàöèé ïî ïîâîäó ÑÍ è ñìåðòíîñòü â ñðàâíåíèè ñ ïîäñòðàõîâî÷íîé ÝÊÑ òîëüêî æåëóäî÷êîâ â ðåæèìå VVI ñ ìèíèìàëüíîé ×Ñ 40 â 1 ìèí. Èíòåðåñíî, ÷òî ýòî èññëåäîâàíèå áûëî îñòàíîâëåíî ïðåæäåâðåìåííî, ò.ê. ñìåðòíîñòü è ãîñïèòàëèçàöèÿ áûëè çíà÷èòåëüíî âûøå â ãðóïïå ñ DDD/R ÝÊÑ. Äîïîëíèòåëüíûé àíàëèç ðåçóëüòàòîâ èññëåäîâàíèÿ «DAVID» ïðîäåìîíñòðèðîâàë òîò æå âûâîä, ÷òî è «MOST» - íàèìåíüøèé ðèñê ïðîãðåññèðîâàíèÿ (äåêîìïåíñàöèè) ÑÍ èëè ñìåðòè áûë ó ïàöèåíòîâ ñ DDD/R ÝÊÑ ñ íèçêîé äîëåé ÝÊÑ æåëóäî÷êîâ [8]. Àíàëèç èññëåäîâàíèÿ «MADIT II» ïðîäåìîíñòðèðîâàë àíàëîãè÷íûå ïðÿìî ïðîïîðöèîíàëüíûå ñâÿçè ìåæäó äîëåé ÝÊÑ æåëóäî÷êîâ è ÑÍ, æåëóäî÷êîâûìè àðèòìèÿìè è ñìåðòíîñòüþ, êîòîðûå íå çàâèñåëè îò íàëè÷èÿ ÈÊÄ è ðåæèìà ÝÊÑ [9]. Âàæíî îòìåòèòü, ÷òî àñèíõðîííîå ñîêðàùåíèå æåëóäî÷êîâ âîçíèêàþùåå ïðè ÝÊÑ èç âåðõóøêè ÏÆ ïîäîáíî ïàòîëîãè÷åñêîìó àñèíõðîíèçìó ïðè ïîëíîé áëîêàäå ëåâîé íîæêè ïó÷êà Ãèñà (ÏÁËÍÏÃ) áåç èçìåíåíèÿ ÀÂ ñèíõðîííîñòè [10]. Ïðè ýòîì õîðîøî èçâåñòíî, ÷òî ÏÁËÍÏÃ è ðàñøèðåíèå êîìïëåêñà QRS ÿâëÿþòñÿ íåçàâèñèìûìè ïðåäèêòîðàìè ñìåðòíîñòè ó ïàöèåíòîâ ñ ñèñòîëè÷åñêîé ÑÍ [11, 12]. Òàêèì îáðàçîì, ñòàíîâèòüñÿ íåîñïîðèìûì ïðàêòè÷åñêèé ñìûñë èçó÷åíèÿ æåëóäî÷êîâîãî àñèíõðîíèçìà, â òîì ÷èñëå ïðè ÝÑ èç âåðõóøêè ÏÆ, è åãî ïàòîëîãè÷åñêîãî âëèÿíèÿ íà ñîêðàòèòåëüíóþ ôóíêöèþ ìèîêàðäà, êîòîðîé óäèâèòåëüíûì îáðàçîì ïðåíåáðåãàëè äåñÿòêè ëåò. ÏÀÒÎÔÈÇÈÎËÎÃÈß ÝÊÑ ÈÇ ÂÅÐÕÓØÊÈ ÏÆ Àñèíõðîííàÿ àêòèâàöèÿ æåëóäî÷êîâ Îïòèìàëüíàÿ íàñîñíàÿ ôóíêöèÿ ËÆ è ýíåðãåòè÷åñêè ýôôåêòèâíîå ñîêðàùåíèå òðåáóåò íîðìàëüíîé ïîñëåäîâàòåëüíîñòè ýëåêòðè÷åñêîé àêòèâàöèè, êîòîðóþ îáåñïå÷èâàåò ñïåöèàëèçèðîâàííàÿ ïðîâîäÿùàÿ ñèñòåìà ñåðäöà. ÝÊÑ èç ëþáîé òî÷êè æåëóäî÷êîâ íàðóøàåò íîðìàëüíóþ (ïðè âîçáóæäåíèè ÷åðåç ñèñòåìó Ãèñà-Ïóðêèíüå) ýëåêòðè÷åñêóþ è ìåõàíè÷åñêóþ ñèñòîëó, òàê êàê èçìåíÿåòñÿ ïîñëåäîâàòåëüíîñòü è çàìåäëÿåòñÿ ñêîðîñòü ïðîâåäåíèÿ ýëåêòðè÷åñêîãî èìïóëüñà ÷åðåç ìèîêàðä. Ëþáàÿ ïîçèöèÿ ýëåêòðîäà äëÿ ÝÊÑ èç îáëàñòè ÏÆ, â òîì ÷èñëå èç åãî âåðõóøêà âûçûâàþò ãåìîäèíàìè÷åñêèå íàðóøåíèÿ ðàáîòû ñåðäöà [13, 14]. Âàæíî îñîçíàòü, ÷òî âåðõóøêà ÏÆ ñòàëà íàèáîëåå ÷àñòîé îáëàñòüþ äëÿ ÝÊÑ æåëóäî÷êîâ, ò.ê. ïîçèöèîíèðîâàòü ïðîäàâàåìûå íà ðûíêå ýëåêòðîäû â ýòó îáëàñòü äîñòàòî÷íî ëåãêî, êðîìå òîãî, îáåñïå÷èâàåòñÿ õîðîøàÿ ñòàáèëüíîñòü ïîëîæåíèÿ è ïîðîãè ñòèìóëÿöèè â áëèæàéøèå è îòäàëåííûå ñðîêè ïîñëå îïåðàöèè. Óõóäøåíèå íàñîñíîé ôóíêöèè ËÆ Åùå â 1925 ãîäó áûëà îïóáëèêîâàíà ðàáîòà, â êîòîðîé áûëî âïåðâûå ïîêàçàíî, ÷òî ñòèìóëÿöèÿ æåëóäî÷êîâ ó ìëåêîïèòàþùèõ ïðèâîäèò ê íåáëàãîïðèÿòíûì ãåìîäèíàìè÷åñêèì ïîñëåäñòâèÿì [15]. Ïîäîáíûå äàííûå áûëè ïîëó÷åíû â ðÿäå äðóãèõ ýêñïåðèìåíòàëüíûõ ðà-

áîò íà æèâîòíûõ è â òå÷åíèè ïîñëåäíèõ ëåò ïðîäåìîíñòðèðîâàíû ó ëþäåé â êëèíè÷åñêèõ èññëåäîâàíèÿõ [14, 16, 17]. Íàèáîëåå âåðîÿòíî, ÷òî îñíîâíàÿ ïðè÷èíà ýòèõ íàðóøåíèé íàñîñíîé ôóíêöèè ñåðäöà ýòî àñèíõðîííàÿ àêòèâàöèÿ æåëóäî÷êîâ [13]. Îêàçàëîñü, ÷òî íàðóøåíèå ýëåêòðè÷åñêîé àêòèâàöèè âåäåò ê äðàìàòè÷íûì íàðóøåíèÿì ìåõàíè÷åñêîé ñèñòîëû, âñëåäñòâèå èçìåíåíèÿ íå òîëüêî ïîñëåäîâàòåëüíîñòè, íî è ñêîðîñòè âîçáóæäåíèÿ ðàçëè÷íûõ îòäåëîâ æåëóäî÷êîâ. Ïðè ýòîì, ñîêðàùåíèå îáëàñòåé ïðèëåãàþùèõ íåïîñðåäñòâåííî ê ýëåêòðîäó ïðèâîäèò ê ðàñòÿæåíèþ åùå íå âîçáóäèâøèõñÿ ðÿäîì ëåæàùèõ ðåãèîíîâ. Äîïîëíèòåëüíîå ðàñòÿæåíèå çàäåðæèâàåò ñîêðàùåíèå è óâåëè÷èâàåò åãî ñèëó â ñîîòâåòñòâèè ñ ìåõàíèçìîì Ôðàíêà-Ñòàðëèíãà. Ýòî ïðèâîäèò ê òîìó, ÷òî áîëåå ýíåðãè÷íî ñîêðàòèâøèåñÿ îáëàñòè ìèîêàðäà âëèÿþò íà ðåãèîíû àêòèâèðîâàâøèåñÿ ðàíüøå, êîòîðûå â ýòîò ìîìåíò ïîäâåðãàþòñÿ ñèñòîëè÷åñêîìó ïàðàäîêñàëüíîìó ðàñòÿæåíèþ. Òàêîå ðåöèïðîêíîå ðàñòÿæåíèå êàðäèîìèîöèòîâ ËÆ ÿâëÿåòñÿ ïðè÷èíîé îñëàáëåííîãî è ýíåðãåòè÷åñêè íå ýôôåêòèâíîãî ñîêðàùåíèÿ [18]. Âñå ýòî íàðóøàåò ôèçèîëîãèþ ðàáîòû ñåðäöà, óõóäøàåò ïåðôóçèþ ìèîêàðäà è óâåëè÷èâàåò ïîòðåáëåíèå êèñëîðîäà ìèîêàðäîì [19, 20, 21, 22]. Ó ìíîãèõ ïàöèåíòîâ (äî 65%) ñ ïîñòîÿííîé ÝÊÑ âåðõóøêè ÏÆ, ó êîòîðûõ íå îòìå÷àåòñÿ àíãèîãðàôè÷åñêèõ ïðèçíàêîâ ïîðàæåíèÿ êîðîíàðíûõ àðòåðèé, ìîãóò ðåãèñòðèðîâàòüñÿ äåôåêòû ïåðôóçèè è äèñêèíåçèÿ ñòåíîê ËÆ [23, 24]. Â íàñòîÿùåå âðåìÿ èìåþòñÿ äîêàçàòåëüñòâà, ÷òî ÝÊÑ èç âåðõóøêè ÏÆ ìîæåò ïðèâîäèòü ê óìåíüøåíèþ âðåìåíè äèàñòîëè÷åñêîãî íàïîëíåíèÿ è èçãíàíèÿ, ñíèæåíèþ ôðàêöèè âûáðîñà ËÆ [16, 23, 24] è äðóãèì íåáëàãîïðèÿòíûì ãåìîäèíàìè÷åñêèì ýôôåêòàì, ÷òî, â êîíå÷íîì ñ÷åòå, íåáëàãîïðèÿòíî âëèÿåò íà îáùóþ íàñîñíóþ ôóíêöèþ ñåðäöà [25]. Ðåìîäåëèðîâàíèå æåëóäî÷êîâ è êëåòî÷íûå èçìåíåíèÿ Ïåðâûå ïðèçíàêè êëåòî÷íîé àäàïòàöèè îòìå÷àþòñÿ óæå ÷åðåç íåñêîëüêî ÷àñîâ ÝÊÑ èç âåðõóøêè ÏÆ [16]. Âîçìîæíî, ÷òî îäíîé èç ïðè÷èí ýòîãî ôåíîìåíà ÿâëÿåòñÿ ñòðóêòóðíîå èçìåíåíèå êàëèåâûõ è êàëüöèåâûõ êàíàëîâ. Ïðè áîëåå ïðîäîëæèòåëüíîé æåëóäî÷êîâîé ÝÊÑ ïðîèñõîäèò äèëàòàöèÿ è àñèììåòðè÷íàÿ ãèïåðòðîôèÿ ËÆ [26, 27]. Ïðè ýòîì áîëåå âûðàæåííàÿ ãèïåðòðîôèÿ íàáëþäàåòñÿ â ðåãèîíàõ ñ áîëåå ïîçäíåé àêòèâàöèåé, êîòîðûå ïîäâåðãàëèñü äîïîëíèòåëüíîìó ðàñòÿæåíèþ ïåðåä ñîêðàùåíèåì, ÷òî ãîâîðèò â ïîëüçó èñêëþ÷èòåëüíîé âàæíîñòè â ïðîöåññå ðåìîäåëèðîâàíèÿ ìèîêàðäà ëîêàëüíîé ìåõàíè÷åñêîé íàãðóçêè [26]. Ãèïåðòðîôèè ìèîêàðäà òàêæå ñïîñîáñòâóåò óâåëè÷åíèå óðîâíÿ êàòåõîëàìèíîâ, âîçíèêàþùåå âñëåäñòâèå ïîâûøåíèÿ ñèìïàòè÷åñêîé àêòèâíîñòè [21]. Àêòèâèðóþùèåñÿ ïîçæå ðåãèîíû ïîäâåðãàþòñÿ ìàêñèìàëüíîé ãèïåðòðîôèè è äåãåíåðàöèè, ïðè êîòîðîé ïðîèñõîäèò ñíèæåíèå ÷óâñòâèòåëüíîñòè áåëêîâ-ðåöåïòîðîâ, ó÷àñòâóþùèõ â ãîìåîñòàçå êàëüöèÿ è ïðîâåäåíèè èìïóëüñà. Ïðè ÝÊÑ èç âåðõóøêè ÏÆ îïèñàíû ÿâëåíèÿ äèñòðîôè÷åñêîé êàëüöèôèêàöèè, äåçîðãàíèçàöèè ìèòîõîíäðèé è ïåðåñòðîéêè êëåòî÷íûõ ìèîôèáðèëë [28]. Îñíîâíûå ìåõàíèçìû ðåìîäåëèðîâàíèÿ æåëóäî÷êîâ è ñíèæåíèÿ íàñîñíîé ôóíêöèè ñåðäöà ïðåäñòàâëåíû íà ðèñ. 1 [29].

ÂÅÑÒÍÈÊ ÀÐÈÒÌÎËÎÃÈÈ, ¹ 48, 2007

Ðèñ. 1. Ìåõàíèçìû ðåìîäåëèðîâàíèÿ æåëóäî÷êîâ è ñíèæåíèÿ íàñîñíîé ôóíêöèè ñåðäöà ïðè ñòèìóëÿöèè èç âåðõóøêè ïðàâîãî æåëóäî÷êà (ïîÿñíåíèÿ â òåêñòå) [29]. ÍÎÂÛÅ ÏÐÈÍÖÈÏÛ ÔÈÇÈÎËÎÃÈ×ÅÑÊÎÉ ÝÊÑ

ìåíòàëüíîé öåëüþ ÝÊÑ ÿâëÿåòñÿ ïðîôèëàêòèêà ñèìïòîìíîé áðàäèêàðäèè, òî íå êàæäûé ñïåöèàëèñò ðåøèòüñÿ ïîæåðòâîâàòü áåçîïàñíîñòüþ ïðè íàëè÷èè ÝÊÑ æåëóäî÷êîâ â ïîëüçó îòíîñèòåëüíî íåâûñîêîãî ðèñêà ðàçâèòèÿ è/èëè ïðîãðåññèðîâàíèÿ ÑÍ èëè ÔÏ. Àëüòåðíàòèâíûì ïîäõîäîì ïðè DDD/R ðåæèìå ÝÊÑ ÿâëÿåòñÿ èñïîëüçîâàíèå äëèííîé ÀÂ çàäåðæêè. Ýòî âî ìíîãèõ ñèòóàöèÿõ ïðèâîäèò ê òîìó æå ýôôåêòó êàê è ïðè AAI/R ÝÊÑ è íèâåëèðóåò ðèñê ïîòåðè ÝÊÑ æåëóäî÷êîâ ïðè âîçíèêíîâåíèè ÀÂ áëîêàäû [5, 31]. Åùå îäíà âîçìîæíîñòü óìåíüøèòü ÝÊÑ æåëóäî÷êîâ - ýòî ïîèñê ñîáñòâåííîãî ÀÂ ïðîâåäåíèÿ èëè ÀÂ ãèñòåðåçèñ. Â íàøåé êëèíèêå íà÷èíàÿ ñ 2005 ãîäà ïðè êîíòðîëüíîì ïðîãðàììèðîâàíèè ó âñåõ ïàöèåíòîâ ñ äâóõêàìåðíîé DDD/R ÝÊÑ è òðàíçèòîðíûìè íàðóøåíèÿìè ÀÂ ïðîâîäèìîñòè óñòàíàâëèâàåòñÿ ÀÂ çàäåðæêà äî 250 ìñ, ðåæèìû ÀÂ ãèñòåðåçèñà, à òàêæå ïîèñêà ñîáñòâåííîãî ÀÂ ïðîâåäåíèÿ â ïðèáîðàõ ðàçëè÷íûõ ïðîèçâîäèòåëåé. Çà 28 ìåñÿöåâ ó 207 ïàöèåíòîâ áûëè âûïîëíåíû âûøåóêàçàííûå ìàíèïóëÿöèè, ïðè ýòîì â ñðîêè îò 3 äî 22 ìåñÿöåâ óäàëîñü ñíèçèòü äîëþ ÝÊÑ æåëóäî÷êîâ â ñðåäíåì íà 48,4%. Ïðè ýòîì, íè ó îäíîãî èç ïàöèåíòîâ íå îòìå÷àëîñü êàêèõ ëèáî íåáëàãîïðèÿòíûõ êëèíè÷åñêè çíà÷èìûõ ïîñëåäñòâèé óâåëè÷åíèÿ ÀÂ çàäåðæêè. Îäíèì èç íîâûõ è ýôôåêòèâíûõ àëãîðèòìîâ äëÿ óìåíüøåíèÿ äîëè ÝÊÑ æåëóäî÷êîâ ÿâëÿåòñÿ ðåæèì èçáèðàòåëüíîé æåëóäî÷êîâîé ÝÊÑ. Îí óìåíüøàåò êîëè÷åñòâåííóþ äîëþ ÝÊÑ æåëóäî÷êîâ ïóòåì çàïðîãðàììèðîâàííîãî óäëèíåíèÿ ÀÂ çàäåðæêè, åñëè ïðåäøåñòâóþùèé êàðäèîöèêë ñîïðîâîæäàëñÿ ñïîíòàííîé ÀÂ ïðîâîäèìîñòüþ. Åñëè ñòèìóëÿòîð íå îáíàðóæèâàåò ñîáñòâåííîãî æåëóäî÷êîâîãî ñîáûòèÿ âî âðåìÿ óäëèíåííîé ÀÂ çàäåðæêè, òî îí âîçâðàùàåòñÿ ê íîðìàëüíîìó âðåìåíè ÀÂ çàäåðæêè [5]. Óâåëè÷åíèå ÀÂ çàäåðæêè îò ïîñòîÿííî çàïðîãðàììèðîâàííîé ìîæåò ñîñòàâëÿòü â çàâèñè-

Ïîíèìàíèå ïàòîëîãè÷åñêîãî âëèÿíèÿ íà ñåðäå÷íóþ ãåìîäèíàìèêó ÝÊÑ èç âåðõóøêè ÏÆ ïîäâèãàåò íàñ íà èçó÷åíèå è êëèíè÷åñêîå ïðèìåíåíèå ñïîñîáîâ, óìåíüøàþùèõ ýòè ýôôåêòû. Íàøà öåëü - ñâåäåíèå ê ìèíèìóìó è êàê ìîæíî áëèæå ê 0% ÝÊÑ ÏÆ, òàê êàê âàæåí êàæäûé ïðîöåíò ñíèæåíèÿ äîëè ñòèìóëÿöèè [6]. Íà ñåãîäíÿøíèé äåíü êàæäûé ñïåöèàëèñò ïî ÝÊÑ ìîæåò îñóùåñòâëÿòü ôèçèîëîãè÷íóþ ÝÊÑ òðåìÿ ñïîñîáàìè. Ïåðâûé âêëþ÷àåò â ñåáÿ âûáîð ðåæèìà ÝÊÑ è èíòåðâàëîâ ÀÂ çàäåðæêè äëÿ ìèíèìèçàöèè áåñïîëåçíîé æåëóäî÷êîâîé ÝÊÑ, îñîáåííî ó ïàöèåíòîâ ñ íåíàðóøåííûì èëè òðàíçèòîðíî èçìåíåííûì ÀÂ ïðîâåäåíèåì. Âòîðîé ñïîñîá çàêëþ÷àåòñÿ â ïîçèöèîíèðîâàíèè æåëóäî÷êîâîãî ýëåêòðîäà â àëüòåðíàòèâíûå îáëàñòè ÏÆ, íàïðèìåð, â ìåææåëóäî÷êîâóþ ïåðåãîðîäêó (ÌÆÏ), îñîáåííî ó ïàöèåíòîâ, êîòîðûì àáñîëþòíî ïîêàçàíî ïðîâåäåíèå ÝÊÑ æåëóäî÷êîâ â ñâÿçè ñ íàðóøåííûì ïðîâåäåíèåì ïî ÀÂ óçëó è/èëè íîæêàì ïó÷êà Ãèñà. È òðåòèé - ïðîâåäåíèå áèâåíòðèêóëÿðíîé ÝÊÑ ó ïàöèåíòîâ ñî ñíèæåííîé íàñîñíîé ôóíêöèåé ìèîêàðäà. Ìèíèìèçàöèÿ ÝÊÑ ÏÆ ïðè ïîìîùè âûáîðà ðåæèìîâ ÝÊÑ è ÀÂ çàäåðæåê Åñëè ÀÂ ïðîâåäåíèå íå èçìåíåíî èëè íàðóøàåòñÿ òðàíçèòîðíî íàì íåîáõîäèìî ïðîäóìàòü 4 îáñòîÿòåëüñòâà: 1) ïðîôèëàêòèêà ñèìïòîìàòè÷íîé áðàäèêàðäèè; 2) îñóùåñòâëåíèå õðîíîòðîïíîé ïîääåðæêè (ïðè íåîáõîäèìîñòè); 3) ñîõðàíåíèå ïðåäñåðäíî-æåëóäî÷êîâîé ñèíõðîíèè; 4) ñîõðàíåíèå íîðìàëüíîé ïîñëåäîâàòåëüíîñòè àêòèâàöèè æåëóäî÷êîâ. Ñàìûì ïðîñòûì ðåøåíèåì ìîæåò ñòàòü èñïîëüçîâàíèå îäíîêàìåðíîãî ïðåäñåðäíîãî óñòðîéñòâà èëè ïåðåïðîãðàììèðîâàíèå äâóõêàìåðíîãî â Ðèñ. 2. Äåìîíñòðàöèÿ ðàáîòû àëãîðèòìà èçáèðàòåëüîäíîêàìåðíûé ïðåäñåðäíûé ðåæèì AAI/R. Ñ îäíîé íîé æåëóäî÷êîâîé ñòèìóëÿöèè («refined ventrical ñòîðîíû, ýòî ïîçâîëèò ñ óñïåõîì ïðîâîäèòü ëå÷åíèå pacingTM», Vitatron, Ãîëëàíäèÿ) âî âðåìÿ ñóòî÷íîãî áðàäèêàðäèè ó ïàöèåíòîâ ñ ÑÑÑÓ áåç íàðóøåíèé ìîíèòîðèðîâàíèÿ ó ïàöèåíòà ñ òðàíçèòîðíûì íàðóÀÂ ïðîâîäèìîñòè, ñ äðóãîé - ýòîò ðåæèì íåïðèìå- øåíèåì ÀÂ ïðîâîäèìîñòè, ãäå As - ñîáñòâåííîå (äåíèì ó ïàöèåíòîâ ñ çàðåãèñòðèðîâàííîé òðàíçèòîð- òåêòèðîâàííîå) ïðåäñåðäíîå ñîáûòèå; Vp - ñòèìóëèíîé èëè ïîñòîÿííîé ÀÂ áëîêàäîé. Êðîìå òîãî, èçâå- ðîâàííûé æåëóäî÷êîâûé êîìïëåêñ; Vs - ñîáñòâåííîå ñòíî, ÷òî â 50% ñëó÷àåâ ÀÂ áëîêàäà ìàíèôåñòèðóåò (äåòåêòèðîâàííîå) æåëóäî÷êîâîå ñîáûòèå; AVD ñèíêîïàëüíûì ñîñòîÿíèåì [5, 30]. À òàê êàê ôóíäà- ïðåäñåðäíî-æåëóäî÷êîâàÿ çàäåðæêà. ÂÅÑÒÍÈÊ ÀÐÈÒÌÎËÎÃÈÈ, ¹ 48, 2007

Ðèñ. 3. Äåìîíñòðàöèÿ ðàáîòû ðåæèìà «MVPTM» (Medtronic, ÑØÀ). Ïðåäñòàâëåí ãðàôèê äîëè ñòèìóëÿöèè ïðåäñåðäèé è æåëóäî÷êîâ (â ïðîöåíòàõ). Ïåðâàÿ êîðîòêàÿ ñòðåëêà îáîçíà÷àåò èìïëàíòàöèþ ïðèáîðà è íà÷àëî ðàáîòû ðåæèìà «MVPTM». Äëèííàÿ ïðåðûâèñòàÿ ñòðåëêà - âûêëþ÷åíèå ðåæèìà íà 10 äíåé. Äàëåå îïÿòü êîðîòêàÿ ñïëîøíàÿ ñòðåëêà - ïîâòîðíîå âêëþ÷åíèå MVP. Ïðè âûêëþ÷åíèè ðåæèìà MVP äîëÿ ñòèìóëÿöèè æåëóäî÷êîâ âîçðîñëà ïðèìåðíî äî 60% â ñóòêè, à ïðè âêëþ÷åíèè çíà÷èòåëüíî ñíèçèëàñü, à åùå ÷åðåç ìåñÿö äîñòèãëà ïðàêòè÷åñêè 0%. Îáîçíà÷åíèÿ: % Pacing/day - äîëÿ ñòèìóëÿöèè æåëóäî÷êîâ èëè ïðåäñåðäèé çà ñóòêè âûðàæåííàÿ â ïðîöåíòà; Atrial - ïðåäñåðäíàÿ; Ventricular - æåëóäî÷êîâàÿ.

65,4±28,4% äî 11,2±5,6%. Ê ñîæàëåíèþ, óâåëè÷èòü ÀÂ çàäåðæêó äî áåñêîíå÷íîñòè íåâîçìîæíî, â ñâÿçè ñ ôóíäàìåíòàëüíûìè ïðàâèëàìè è îñîáåííîñòÿìè ïðîãðàììèðîâàíèÿ âðåìåííûõ èíòåðâàëîâ ïðè äâóõêàìåðíîé ÝÊÑ (ìàêñèìàëüíàÿ ÷àñòîòà ÝÊÑ, ñëåïîé ïåðèîä è äð.), à òàêæå âîçìîæíûìè íàðóøåíèÿìè äåòåêöèè ÔÏ. Îäíîé èç íåäàâíî ïîÿâèâøèõñÿ âîçìîæíîñòåé äëÿ îáåñïå÷åíèÿ ìàêñèìàëüíî ôèçèîëîãè÷íîé ÝÊÑ ÿâëÿåòñÿ ðåæèì óïðàâëåíèÿ æåëóäî÷êîâîé ñòèìóëÿöèåé («MVPTM») [32, 33]. Àëãîðèòì ðàáîòû ðåæèìà çàêëþ÷àåòñÿ â àâòîìàòè÷åñêîì ïåðåêëþ÷åíèè êàðäèîñòèìóëÿòîðà èç ðåæèìà AAI/R â ðåæèì DDD/R è îáðàòíî â çàâèñèìîñòè îò íàëè÷èÿ èëè îòñóòñòâèÿ ñïîíòàííîãî ÀÂ ïðîâåäåíèÿ. Òàêèì îáðàçîì, æåëóäî÷êîâàÿ ÝÊÑ îñóùåñòâëÿåòñÿ òîëüêî ïðè íåîáõîäèìîñòè, âî âðåìÿ óõóäøåíèÿ ÀÂ ïðîâåäåíèÿ. Â òîæå âðåìÿ, ïåðèîäè÷åñêîå ñêàíèðîâàíèå ñîáñòâåííîãî ÀÂ ïðîâåäåíèÿ â ðåæèìå DDD/R äåëàåò âîçìîæíûì àâòîìàòè÷åñêèé ïåðåõîä îáðàòíî â ðåæèì AAI/R. Ýòîò ðåæèì ïîçâîëÿåò áåçîïàñíî è ýôôåêòèâíî ñíèçèòü ïðîöåíò ÝÊÑ æåëóäî÷êîâ äî 0,5% ó ïàöèåíòîâ ñ ÑÑÑÓ è äî 1,6% ó áîëüíûõ ñ ïðåõîäÿùåé ÀÂ áëîêàäîé [34, 35]. Ìû èñïîëüçîâàëè ðåæèì MVP ó 4-õ ïàöèåíòîâ. Ïðè ýòîì îòìåòèëè çíà÷èòåëüíîå ñíèæåíèå äîëè ÝÊÑ æåëóäî÷êîâ, ó 3-õ áîëüíûõ ïðàêòè÷åñêè äî 0% (ðèñ. 3). Ñëåäóåò ïîìíèòü, ÷òî âêëþ÷åííûé ðåæèì MVP äîïóñêàåò âîçìîæíîñòü íàëè÷èÿ î÷åíü áîëüøîãî ÀÂ èíòåðâàëà è/èëè ïîòåðè ÀÂ ñèíõðîíèçàöèè â îäíîì êàðäèîöèêëå, ÷òî íå ÿâëÿåòñÿ íàðóøåíèåì ðàáîòû ÝÊÑ, îäíàêî ìîæåò áûòü ÷óâñòâèòåëüíî äëÿ ïàöèåíòà. Êðîìå òîãî, íå ðåêîìåíäóåòñÿ âêëþ÷àòü ýòîò ðåæèì ó ïàöèåíòîâ ñ ïîëíîé ÀÂ áëîêàäîé.

ìîñòè îò ïðåäïî÷òåíèé âðà÷à 60, 80, 100 èëè 120 ìñ. Ñêàíèðîâàíèå íà íàëè÷èå ñïîíòàííîé ÀÂ ïðîâîäèìîñòè îñóùåñòâëÿåòñÿ ïîñëå 30, 60 èëè 120 ñòèìóëèðîâàííûõ æåëóäî÷êîâûõ ñîáûòèé (â çàâèñèìîñòè îò çàïðîãðàììèðîâàííîé âåëè÷èíû). Ïîñëå ñåðèè ñòèìóëèðîâàííûõ æåëóäî÷êîâûõ êîìïëåêñîâ ñòèìóëÿòîð àâòîìàòè÷åñêè ïðîäëåâàåò ÀÂ çàäåðæêó äëÿ îäíîãî êàðäèîöèêëà íà çàïðîãðàììèà á ðîâàííóþ âåëè÷èíó. Åñëè âî âðåìÿ ïðîäëåííîé ÀÂ çàäåðæêè íå äåòåêòèðóåòñÿ íè îäíîãî æåëóäî÷êîâîãî ñîáûòèÿ, ñòèìóëÿòîð âîçâðàùàåòñÿ ê íîðìàëüíîé ÀÂ çàäåðæêå. Åñëè âî âðåìÿ ñêàíèðóþùåé óäëèíåííîé ÀÂ çàäåðæêè äåòåêòèðóåòñÿ ñïîíòàííîå æåëóäî÷êîâîå ñîáûòèå, ñòèìóëÿòîð ïðîäîëæàåò ðàáîòàòü ñ óâåëè÷åííîé ÀÂ çàäåðæêîé äî ñëåäóþùåãî ñòèìóëèðîâàííîãî æåëóäî÷êîâîãî êîìïëåêñà, ÷òî è îáåñïå÷èâàåò íîðìàëüíóþ ïîñëåäîâàòåëüíîñòü àêòèâàöèè æåëóäî÷êîâ ïðè òðàíçèòîðíûõ Ðèñ. 4. Äåìîíñòðàöèÿ ñèñòåìû äëÿ èìïëàíòàöèè ýëåêòðîäîâ â ðàçëè÷íûå íàðóøåíèÿõ ÀÂ ïðîâîäè- îòäåëû ñåðäöà ñ ïîìîùüþ ñèñòåìû «Select Secure» (Medtronic, ÑØÀ) íà àíàòîìè÷åñêîì ïðåïàðàòå (ïåðåäíÿÿ ñòåíêà âûõîäíîãî îòäåëà ÏÆ è ïåðåìîñòè (ðèñ. 2). Îïûò íàøåé êëèíèêè äíåáîêîâàÿ ñòåíêà ÏÏ óäàëåíû): à - â ïîëîñòè ÏÆ âèçóàëèçèðóåòñÿ ñïåöèâ èñïîëüçîâàíèè àëãîðèòìà àëüíûé óïðàâëÿåìûé èíòðîäüþññåð, âíóòðè êîòîðîãî íàõîäèòüñÿ òîíêèé (4 èçáèðàòåëüíîé æåëóäî÷êî- F) áèïîëÿðíûé ýëåêòðîä, ïîçèöèîíèðîâàííûé â âåðõíèõ îòäåëàõ ÌÆÏ â âîé ÝÊÑ íàñ÷èòûâàåò 31 âûõîäíîì òðàêòå ÏÆ; á - ïîñëå òîãî êàê ýëåêòðîä çàôèêñèðîâàí èíòðîäüþñïàöèåíòà, ïðè ýòîì óäàëîñü ñåð óäàëÿåòñÿ. Îáîçíà÷åíèÿ: ÏÏ - ïðàâîå ïðåäñåðäèå; Àî - àîðòà, ËÏ - ëåâîå óìåíüøèòü äîëþ ñòèìóëÿ- ïðåäñåðäèå; ËÀ - ëåãî÷íàÿ àðòåðèÿ; ÏÆ - ïðàâûé æåëóäî÷åê; ÌÆÏ - ìåææåöèè æåëóäî÷êîâ â ñðåäíåì ñ ëóäî÷êîâàÿ ïåðåãîðîäêà; ËÆ - ëåâûé æåëóäî÷åê. ÂÅÑÒÍÈÊ ÀÐÈÒÌÎËÎÃÈÈ, ¹ 48, 2007

62 Àëüòåðíàòèâíûå îáëàñòè ïîçèöèîíèðîâàíèÿ ýëåêòðîäà Àëüòåðíàòèâíûå îáëàñòè ñòèìóëÿöèè ÏÆ ïðèìåíÿþòñÿ ó ïàöèåíòîâ, êîòîðûì àáñîëþòíî ïîêàçàíà æåëóäî÷êîâàÿ ÝÊÑ äëÿ ïðåäîòâðàùåíèÿ ñèìïòîìàòè÷íîé áðàäèêàðäèè. Îòñóòñòâèå èëè íåíàäåæíîå ÀÂ ïðîâåäåíèå, à òàêæå íàëè÷èå ïîñòîÿííîé ôîðìû ÔÏ òðåáóþò íàäåæíîé ÝÊÑ æåëóäî÷êîâ. Äëÿ óëó÷øåíèÿ íàñîñíîé ôóíêöèè ñåðäöà â òàêèõ ñëó÷àÿõ èñïîëüçóåòñÿ ñòèìóëÿöèÿ ÌÆÏ èç ÏÆ èëè ñòèìóëÿöèÿ ïó÷êà Ãèñà. Â ïîñëåäíèå ãîäû ïîçèöèîíèðîâàíèå ýëåêòðîäîâ â ðàçëè÷íûå îáëàñòè ÏÆ ñòàëî áîëåå ðåàëüíî â êëèíè÷åñêèõ óñëîâèÿõ [36] áëàãîäàðÿ ïîÿâëåíèþ íîâûõ ñïåöèàëüíûõ óñòðîéñòâ äëÿ èìïëàíòàöèè ýëåêòðîäîâ â ðàçëè÷íûå îòäåëû ÏÆ (ðèñ. 4à,á). Íà èçó÷åíèå àëüòåðíàòèâíûõ âåðõóøêå îáëàñòåé â ÏÆ áûëî íàïðàâëåíî äîñòàòî÷íî ìíîãî èññëåäîâàíèé, òàê êàê ñèñòåìû äëÿ ÝÊÑ ïðîùå è ÷àùå âñåãî èìïëàíòèðóþòñÿ òðàíñâåíîçíûì äîñòóïîì. Ê ñîæàëåíèþ, áûëî ïîêàçàíî, ÷òî â ïîëîñòè ÏÆ íåò îáëàñòè, êîòîðàÿ áû íå óõóäøàëà íàñîñíóþ ôóíêöèþ ñåðäöà [14]. Òåì íå ìåíåå, íàèáîëåå îïòèìàëüíûì ÿâëÿåòñÿ âåðõíèé îòäåë ÌÆÏ â îáëàñòè âûõîäíîãî òðàêòà ÏÆ. [14, 37]. Ëþáîïûòíî, ÷òî ïðè ïåðâîé èìïëàíòàöèè ÝÊÑ ó ÷åëîâåêà ýëåêòðîä áûë ïîçèöèîíèðîâàí èìåííî â ÌÆÏ [38]. Ñòèìóëÿöèÿ ÌÆÏ îáîñíîâàíà äëÿ èñïîëüçîâàíèÿ íà ïðàêòèêå. Â áëèæàéøèå è îòäàëåííûå ñðîêè îíà íå õóæå ïî ñòàáèëüíîñòè è ýôôåêòèâíîñòè â ñðàâíåíèè ñ âåðõóøêîé ÏÆ, êðîìå òîãî, èìååò íèçêèé ðèñê ïåðôîðàöèè ñåðäöà, ñòèìóëÿöèè äèàôðàãìàëüíîãî íåðâà è ïîçâîëÿåò äîñòàòî÷íî ëåãêî óäàëÿòü ýëåêòðîä ïðè çàìåíå [19]. Íàø îïûò èìïëàíòàöèè ýëåêòðîäà â ÌÆÏ (ðèñ. 5à,á) íàñ÷èòûâàåò 23 ïàöèåíòà. Ìû íå îòìåòèëè äîñòîâåðíûõ ðàçëè÷èé â èíòðàîïåðàöèîííûõ è ïîñëåîïåðàöèîííûõ ýëåêòðîôèçèîëîãè÷åñêèõ ïîêàçàòåëÿõ â ñðàâíåíèè ñ êëàññè÷åñêîé èìïëàíòàöèåé â âåðõóøêó ÏÆ. Òîëüêî îäíîìó (âòîðîìó) ïàöèåíòó áûëà âûïîëíåíà ðåïîçèöèÿ ýëåêòðîäà â ïåðâûå ñóòêè ïîñëå îïåðàöèè â ñâÿ-

çè ñ åãî äèñëîêàöèåé. Â ïîñëåäóþùåì ìû ïðèøëè ê âûâîäó, ÷òî èìïëàíòàöèÿ â ýòó îáëàñòü òðåáóåò ïîâûøåííûõ òðåáîâàíèé ê èíòðàîïåðàöèîííîé ïðîâåðêå ñòàáèëüíîñòè ýëåêòðîäà è ê îïûòó îïåðàòîðà. Ïðè ÝõîÊÃ ñ òêàíåâîé äîïïëåðîãðàôèåé îòìå÷àëîñü äîñòîâåðíî ìåíüøå ÿâëåíèé æåëóäî÷êîâîé àñèíõðîíèè è íàðóøåíèé âíóòðèñåðäå÷íîé ãåìîäèíàìèêè. Òåõíèêà èìïëàíòàöèè ýëåêòðîäà è âûáîð ïîçèöèè â îáëàñòè ÌÆÏ òðåáóþò îñîáîãî âíèìàíèÿ. Òàê, íàïðèìåð, ðÿä èññëåäîâàíèé ïîêàçàë îáîñíîâàííîñòü èñïîëüçîâàíèÿ øèðèíû êîìïëåêñà QRS äëÿ îïòèìèçàöèè ïîëîæåíèÿ ýëåêòðîäà è óìåíüøåíèÿ ïàãóáíîãî âëèÿíèÿ íà ôóíêöèþ ËÆ [39, 40]. ×åì óæå êîìïëåêñ QRS, òåì ëó÷øå äëÿ âíóòðèñåðäå÷íîé ãåìîäèíàìèêè. Ïðè ýòîì ïîêàçàíî, ÷òî óçêèé QRS îáóñëîâëåí âîçáóæäåíèåì ñîáñòâåííîé ñèñòåìû ïó÷êà Ãèñà ïðè ñòèìóëÿöèè ÌÆÏ [41]. ÝÊÑ îáëàñòè ïó÷êà Ãèñà îáåñïå÷èâàåò èäåíòè÷íóþ íîðìàëüíîé ïîñëåäîâàòåëüíîñòü âîçáóæäåíèÿ æåëóäî÷êîâ è íå ðàñøèðÿåò êîìïëåêñ QRS. Ó ïàöèåíòîâ áåç çíà÷èìûõ íàðóøåíèé äèñòàëüíîãî ïðîâåäåíèÿ, ïîñëå ïðîêñèìàëüíîé êàòåòåðíîé àáëàöèè ÀÂ ñîåäèíåíèÿ ïî ïîâîäó òàõèñèñòîëè÷åñêîé ôîðìû ÔÏ, ÝÊÑ â îáëàñòè ïó÷êà Ãèñà íå íàðóøàåò ïîñëåäîâàòåëüíîñòü àêòèâàöèè ËÆ è åãî íàñîñíóþ ôóíêöèþ [42, 43]. Îäíàêî òåõíèêà è ìåòîäîëîãèÿ èìïëàíòàöèè â ýòó îáëàñòü â íàñòîÿùåå âðåìÿ äàëåêà îò èäåàëà, ÷òî òðåáóåò äàëüíåéøåãî ñîâåðøåíñòâîâàíèÿ è ïðîâåäåíèÿ êðóïíûõ ìíîãîöåíòðîâûõ èññëåäîâàíèé. Îïðåäåëåííîé ïåðñïåêòèâíîñòüþ îáëàäàåò ìåòîäèêà ñòèìóëÿöèè èçîëèðîâàííîãî ó÷àñòêà ïðàâîãî ïðåäñåðäèÿ â îáëàñòè êîìïàêòíîé ÷àñòè ÀÂ ñîåäèíåíèè [44]. Áèâåíòðèêóëÿðíàÿ ÝÊÑ ïåðâîíà÷àëüíî èñïîëüçîâàëàñü äëÿ êîððåêöèè ìåææåëóäî÷êîâîé è âíóòðèæåëóäî÷êîâîé àñèíõðîíèè ó ïàöèåíòîâ ñ ÑÍ äëÿ óëó÷øåíèÿ ñîêðàòèòåëüíîé ôóíêöèè ìèîêàðäà. Õîðîøî èçâåñòíî, ÷òî ïðè ÝÊÑ èç âåðõóøêè ÏÆ ïîñëåäîâàòåëüíîñòü âîçáóæäåíèÿ òàêàÿ æå, êàê è ïðè ÏÁËÍÏÃ. Áûëî ïîêàçàíî, ÷òî ÝÊÑ èç âåðõóøêè ÏÆ â çíà÷èòåëüíîé ñòåïåíè óñóãóáëÿåò íàñîñíóþ ôóíêöèþ ñåðäöà, è ÷åì âûøå äîëÿ ÝÊÑ òåì ñèëüíåå ñòðàäàåò ñîêðàòèìîñòü à á (ðèñ. 6) [29]. Ïîýòîìó íåóäèâèòåëüíî, ÷òî ó ïàöèåíòîâ ñ ÑÍ è ïîçèöèîíèðîâàííûì ðàíåå ýëåêòðîäîì â âåðõóøêå ÏÆ èìïëàíòàöèÿ ýëåêòðîäà äëÿ ñòèìóëÿöèè ËÆ (óñîâåðøåíñòâîâàíèå äî áèâåíòðèêóëÿðíîé ñèñòåìû) ïðèâîäèò ê óëó÷øåíèþ ñîêðàòèòåëüíîé ôóíêöèè ìèîêàðäà è ðåçóëüòàòîâ ëå÷åíèÿ [45]. Èññëåäîâàíèå âíóòðèñåðäå÷íîé ãåìîäèíàìèêè ïîêàçàëî, ÷òî ëó÷øèå ïîêàçàòåëè íàáëþäàþòñÿ ïðè áèâåíòðèêóëÿðíîé ÝÊÑ èëè ÝÊÑ òîëüêî ËÆ, â ñðàâíåíèè ñî ñòèìóëÿöèåé â ëþáîé îáëàñòè ÏÆ, îñîáåííî ó ïàöèåíòîâ ñ íàðóøåííîé Ðèñ. 5. Èíòðàîïåðàöèîííûå ðåíòãåíîãðàììû ïàöèåíòà ñ ñîêðàòèòåëüíîé ôóíêöèåé ìèîêàðäà [14]. èìïëàíòèðîâàííûìè ýëåêòðîäàìè â óøêî ÏÏ è ÌÆÏ â âûõîäÂ ýòîì æå èññëåäîâàíèè áûëî ïîêàçàíî, íîì îòäåëå ÏÆ â ïðÿìîé (à) è ëåâîé áîêîâîé (á) ïðîåêöèÿõ. Ó ÷òî ó ïàöèåíòîâ ñ íàðóøåííîé ñîêðàòèýòîãî æå ïàöèåíòà ðàíåå áûëî âûïîëíåíî ñòåíòèðîâàíèå òåëüíîé ôóíêöèåé ìèîêàðäà ÝÊÑ èç ëþïåðåäíåé ìåææåëóäî÷êîâîé àðòåðèè. Â ëåâîé áîêîâîé ïðîåêöèè áîé òî÷êè ÏÆ ïðèâîäèò ê óõóäøåíèþ íàõîðîøî âèäíî ÷òî ýëåêòðîä íàïðàâëåí ê ìåææåëóäî÷êîâîé ïåðåãîðîäêå è ñîîòâåòñòâåííî ê ñòåíòó â ÏÌÆÀ. Îáîçíà÷åíèÿ: ñîñíîé ôóíêöèè ìèîêàðäà, îäíàêî ýòîãî íå îòìå÷àëîñü ó ïàöèåíòîâ áåç íàðóøåíèé ÏÏ - ïðàâîå ïðåäñåðäèå; ÌÆÏ - ìåææåëóäî÷êîâàÿ ïåðåãîðîäêà; âíóòðèñåðäå÷íîé ãåìîäèíàìèêè. ÏÌÆÀ - ïåðåäíÿÿ ìåææåëóäî÷êîâàÿ àðòåðèÿ. ÂÅÑÒÍÈÊ ÀÐÈÒÌÎËÎÃÈÈ, ¹ 48, 2007

Ðèñ. 6. Ãðàôèê èçìåíåíèÿ íàñîñíîé ôóíêöèè ñåðäöà ó ïàöèåíòîâ ñ ÑÍ ïðè åñòåñòâåííîì òå÷åíèè çàáîëåâàíèÿ è ïðè ÝÊÑ èç âåðõóøêè ÏÆ. Îáîçíà÷åíèÿ: ÑÍ - õðîíè÷åñêàÿ ñåðäå÷íàÿ íåäîñòàòî÷íîñòü; ÝÊÑ - ýëåêòðîêàðäèîñòèìóëÿöèÿ; ÏÆ ïðàâûé æåëóäî÷åê. Ó ïàöèåíòîâ áåç íàðóøåíèé ôóíêöèè ïðîâîäÿùåé ñèñòåìû ñåðäöà è ñîêðàòèìîñòè ìèîêàðäà ÝÊÑ ËÆ ñîïðîâîæäàåòñÿ ìåíüøèì êîëè÷åñòâîì ïîáî÷íûõ ýôôåêòîâ, ÷åì ÝÊÑ èç âåðõóøêè ÏÆ [13, 46]. Âàæíî îòìåòèòü, ÷òî ó ïàöèåíòîâ ñ íàëè÷èåì è îòñóòñòâèåì ÏÁËÍÏÃ îïòèìàëüíûìè äëÿ ÝÊÑ, ñ òî÷êè çðåíèÿ ëåâîæåëóäî÷êîâîé ãåìîäèíàìèêè, ÿâëÿþòñÿ ðàçëè÷íûå îòäåëû ËÆ. Òàê â èññëåäîâàíèÿõ íà æèâîòíûõ [47] è ó äåòåé [48] ïðîäåìîíñòðèðîâàíî, ÷òî íàèëó÷øèå ïàðàìåòðû âíóòðèñåðäå÷íîé ãåìîäèíàìèêè íàáëþäàþòñÿ ïðè ÝÑ èç âåðõóøå÷íûõ îòäåëîâ ïåðåãîðîäêè ËÆ èëè ýïèêàðäèàëüíîé ïîâåðõíîñòè âåðõóøêè ËÆ. Ëåâîæåëóäî÷êîâàÿ ÝÊÑ ìîæåò áûòü äîñòîéíîé çàìåíîé êëàññè÷åñêîé òåõíèêè â ïåäèàòðè÷åñêîé ïðàêòèêå, òàê êàê ýëåêòðîä â âåðõóøêó ËÆ ìîæíî èìïëàíòèðîâàòü ýïèêàðäèàëüíî ÷åðåç ìèíèòîðàêîòîìèþ, à, êàê èçâåñòíî, ýïèêàðäèàëüíûé äîñòóï ó äåòåé èñïîëüçóåòñÿ äîñòàòî÷íî ÷àñòî. Íåñìîòðÿ íà ÿâíûå ïðåèìóùåñòâà ïåðåä ÝÊÑ èç ÏÆ áèâåíòðèêóëÿðíîé ÝÊÑ è ÝÊÑ ËÆ, â íàñòîÿùåå âðåìÿ ðóòèííàÿ èìïëàíòàöèÿ òàêèõ òèïîâ ÝÊÑ áîëüøèíñòâó ïàöèåíòàì íåöåëåñîîáðàçíà è íåïðàêòè÷íà. Ýòî ñâÿçàíî ñ áîëåå âûñîêèì âðåìåíåì îïåðàöèè è ôëþîðîñêîïèè, ñíèæåííîé ïðîäîëæèòåëüíîñòüþ ðàáîòû áàòàðåè, áîëåå âûñîêîé öåíîé ïðîöåäóðû è ÷àñòîòîé îñëîæíåíèé, òàêèõ êàê äèñëîêàöèÿ ýëåêòðîäà, à òàêæå ìåíüøåé íàäåæíîñòüþ ïðîâåäåíèÿ ÝÊÑ â îòäàëåííûå ñðîêè. ÒÀÊÒÈÊÀ ÂÛÁÎÐÀ ÎÏÒÈÌÀËÜÍÎÉ ÝËÅÊÒÐÎÊÀÐÄÈÎÑÒÈÌÓËßÖÈÈ Ïîëó÷åííûå, â ïîñëåäíèå ãîäû, äàííûå î âëèÿíèè ðàçëè÷íûõ âàðèàíòîâ ÝÊÑ íà ñåðäå÷íóþ ãåìîäèíàìèêó çàñòàâëÿþò çàäóìàòüñÿ îá îäíîì èç âûñêàçûâàíèé Ãèïïîêðàòà - «Ïðåæäå âñåãî - íå íàâðåäè». Íà ñåãîäíÿøíèé äåíü îñíîâíûìè öåëÿìè ïîñòîÿííîé ÝÊÑ äîëæíû ÿâëÿòüñÿ íå òîëüêî ïðîôèëàêòèêà ñèìïòîìíîé áðàäèêàðäèè, íî è ìàêñèìàëüíàÿ ôèçèîëîãè÷íîñòü ëå÷åíèÿ äëÿ óìåíüøåíèÿ âåðîÿòíîñòè ïàãóáíîãî

âëèÿíèÿ ÝÊÑ. Ñîâðåìåííàÿ ÝÊÑ òðåáóåò îáäóìàííîãî èíäèâèäóàëüíîãî ïîäõîäà ê âûáîðó ðåæèìà ÝÊÑ è îáëàñòè ïîçèöèîíèðîâàíèÿ ýëåêòðîäîâ äëÿ ìàêñèìàëüíîãî óìåíüøåíèÿ ïîáî÷íûõ ýôôåêòîâ. Â íàøåé êëèíèêå ìû èñïîëüçóåì àëãîðèòì ïîäáîðà òèïà ÝÊÑ è îáëàñòè èìïëàíòàöèè ýëåêòðîäîâ îñíîâàííûé íà îöåíêå âíóòðèæåëóäî÷êîâîãî è ÀÂ ïðîâåäåíèÿ, à òàêæå â çàâèñèìîñòè îò ñîêðàòèòåëüíîé ôóíêöèè ìèîêàðäà è òÿæåñòè ÑÍ (ðèñ. 7). Íàïðèìåð, åñëè åùå 57 ëåò íàçàä ïàöèåíòêå 60 ëåò, ñ áðàäè-òàõè ôîðìîé ÑÑÑÓ ñîïðîâîæäàþùåéñÿ ñèìïòîìíîé áðàäèêàðäèåé, à òàêæå ðåäêèìè ïàðîêñèçìàìè ÔÏ, èìåþùåé ÀÂ áëîêàäó I ñòåïåíè è òðàíçèòîðíóþ II ñòåïåíè, áûë áû ðåêîìåíäîâàí äâóõêàìåðíûé ïðèáîð DDDR ñ èìïëàíòàöèåé ýëåêòðîäîâ â âåðõóøêó ÏÆ è óøêî ÏÏ, òî ñåãîäíÿ ñàìûì ôèçèîëîãè÷íûì áóäåò âûáîð ïðèáîðà DDDRP, èìåþùåãî ðåæèìû ìèíèìèçàöèè ÝÊÑ æåëóäî÷êîâ, è èìïëàíòàöèÿ ýëåêòðîäîâ â îáëàñòü ïó÷êà Áàõìàíà (â ìåæïðåäñåðäíîé ïåðåãîðîäêå) è ÌÆÏ äëÿ ñòèìóëÿöèè æåëóäî÷êîâ. ÇÀÊËÞ×ÅÍÈÅ Òàêèì îáðàçîì, äëÿ òîãî ÷òîáû «íå íàâðåäèòü» ïàöèåíòó è îñóùåñòâëÿòü ìàêñèìàëüíî âîçìîæíóþ ôèçèîëîãè÷åñêóþ ÝÊÑ, íåîáõîäèìî: 1) îáåñïå÷èâàòü ÀÂ ñèíõðîííîñòü ïðè íàðóøåíèè ÀÂ ïðîâîäèìîñòè; 2) ñîõðàíÿòü èñõîäíóþ àêòèâàöèþ æåëóäî÷êîâ, ó ïàöèåíòîâ ñ íåíàðóøåííûì èëè ñ òðàíçèòîðíûìè íàðóøåíèÿìè ÀÂ ïðîâîäèìîñòè, ìàêñèìàëüíî èñïîëüçóÿ ïðåäñåðäíûå ðåæèìû ÝÊÑ è àëãîðèòìû ìèíèìèçàöèè ÝÊÑ æåëóäî÷êîâ; 3) îïòèìèçèðîâàòü ïîñëåäîâàòåëüíîñòü àêòèâàöèè (åñëè ñòèìóëÿöèÿ æåëóäî÷êîâ íåîáõîäèìà) ïóòåì âûáîðà îï-

Ðèñ. 7. Àëãîðèòì ïîäáîðà òèïà ÝÊÑ è îáëàñòè èìïëàíòàöèè ýëåêòðîäîâ. Ó ïàöèåíòîâ ñ íàðóøåííûì âíóòðèæåëóäî÷êîâûì ïðîâåäåíèåì ïðîâåðÿåòñÿ ìåõàíè÷åñêàÿ æåëóäî÷êîâàÿ àñèíõðîíèÿ ïî äàííûì ýõîêàðäèîãðàôèè. Îáîçíà÷åíèÿ: ÝÊÑ - ýëåêòðîêàðäèîñòèìóëÿöèÿ; ÝÑ - ýëåêòðîñòèìóëÿöèÿ; ÏÆ - ïðàâûé æåëóäî÷åê; ËÆ - ëåâûé æåëóäî÷åê; ÑÐÒ - ñåðäå÷íàÿ ðåñèíõðîíèçèðóþùàÿ òåðàïèÿ; ÌÆÏ - ìåææåëóäî÷êîâàÿ ïåðåãîðîäêà; ÑÍ - õðîíè÷åñêàÿ ñåðäå÷íàÿ íåäîñòàòî÷íîñòü; ýíäî - ýíäîêàðäèàëüíûé; ýïè - ýïèêàðäèàëüíûé.

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64 òèìàëüíîé îáëàñòè ïîçèöèîíèðîâàíèÿ ýëåêòðîäà, èç êîòîðûõ íàèáîëåå äîñòóïíîé ÿâëÿåòñÿ ÌÆÏ; 4) èñïîëüçîâàòü áèâåíòðèêóëÿðíóþ ÝÊÑ ó áîëüíûõ ñî ñíèæåííîé ñîêðàòèòåëüíîé ôóíêöèåé ìèîêàðäà è õðî-

íè÷åñêîé ñåðäå÷íîé íåäîñòàòî÷íîñòüþ, îñîáåííî ó ïàöèåíòîâ ñ íàðóøåíèåì âíóòðèæåëóäî÷êîâîé ïðîâîäèìîñòè (øèðîêèé QRS) èëè ñ óñòàíîâëåííûì ðàíåå ýëåêòðîäîì âåðõóøêå ÏÆ.

ËÈÒÅÐÀÒÓÐÀ 1. Connolly SJ, Kerr CR, Gent M, et al. Canadian Trial of Physiological Pacing Investigators Effects of physiological pacing versus ventricular pacing on the risk of stroke and death due to cardiovascular causes N Engl J Med 2000;342:1385-1391. 2. Lamas GA, Lee KL, Sweeney MO, et al. MOST Investigators Ventricular pacing or dual chamber pacing for sinus node dysfunction N Engl J Med 2002;346:1854-1862. 3. Toff WD, Camm AJ, Skehan JD, United Kingdom Pacing and Cardiovascular Events Trial (UKPACE) Investigators Single-chamber versus dual-chamber pacing for high-grade atrioventricular block N Engl J Med 2005;353:145-155. 4. Andersen HR, Nielsen JC, Rhomsen PEB, Mortensen PT, Vesterlund T, Pedersen AK. Long-term follow-up of patients from a randomized trial of atrial versus ventricular pacing for sick-sinus syndrome Lancet 1997;350:12101216. 5. Nielsen JC, Kristensen L, Andersen HR, Mortensen PT, Pedersen O, Pedersen AK. A randomized comparison of atrial and dual-chamber pacing in 177 consecutive patients with sick sinus syndromeechocardiographic and clinical outcome. J Am Coll Cardiol 2003;42:614-623. 6. Sweeney MO, Hellkamp AS, Ellenbogen KA, et al. Adverse effect of ventricular pacing on heart failure and atrial fibrillation among patients with normal baseline QRS duration in a clinical trial of pacemaker therapy for sinus node dysfunction Circulation 2003;23:2932-2937. 7. The DAVID Trial Investigators Dual-chamber pacing or ventricular backup pacing in patients with an implantable defibrillatorthe Dual Chamber and VVI Implantable Defibrillator (DAVID) trial. JAMA 2002;288:3115-3123. 8. Sharma AD, Rizo-Patron C, Hallstrom AP, et al. DAVID Investigators Percent right ventricular pacing predicts outcomes in the DAVID Trial Heart Rhythm 2005;2:830834. 9. Steinberg JS, Fischer A, Wang P, et al. The clinical implications of cumulative right ventricular pacing in the Multicenter Automatic Defibrillator Trial II J Cardiovasc Electrophysiol 2005;16:359-365. 10. Vassalo JA, Cassidy DM, Miller JM, Buxton AE, Marchlinski FE, Josephson ME. Left ventricular endocardial activation during right ventricular pacingeffect of underlying heart disease. J Am Coll Cardiol 1986;7:12281233. 11. Baldasseroni S, Opasich C, Gorini M, et al. Italian Network on Congestive Heart Failure Investigators Left bundle branch block is associated with increased 1-year sudden and total mortality rate in 5,517 outpatients with congestive heart failurea report from the Italian network on congestive heart failure. Am Heart J 2002;143:398-405. 12. Schneider JF, Thomas Jr HE, Kreger BE, et al. Newly acquired left bundle branch blockthe Framingham study. Ann Intern Med 1979;90:303-310.

13. Prinzen FW, Peschar M. Relation between the pacing induced sequence of activation and left ventricular pump function in animals Pacing Clin Electrophysiol 2002;25:484-498. 14. Lieberman R, Padeletti L, Schreuder J, et al. Ventricular pacing lead location alters systemic hemodynamics and left ventricular function in patients with and without reduced ejection fraction J Am Coll Cardiol 2006;48:16341641. 15. Wiggers C. The muscular reactions of the mammalian ventricles to artificial surface stimuli Am J Physiol 1925;73:346-378. 16. Nahlawi M, Waligora M, Spies SM, Bonow RO, Kadish AH, Goldberger J. Left ventricular function during and after right ventricular pacing J Am Coll Cardiol 2004;44:1883-1888. 17. Tantengco MV, Thomas RL, Karpawich PP. Left ventricular dysfunction after long-term tight ventricular apical pacing in the young J Am Coll Cardiol 2001;37:20932100. 18. Baller D, Wolpers H-G, Zipfers J, Bretschneider H-J. Comparison of the effects of right atrial, right ventricular apex, and atrioventricular sequential pacing on myocardial oxygen consumption and cardiac efficiencya laboratory investigation. Pacing Clin Electrophysiol 1988;11:394403. 19. Prinzen FW, Augustijn CH, Arts T, Allessi MA, Reneman RS. Redistribution of myocardial fiber strain and blood flow by asynchronous activation Am J Physiol 1990;259:H300-H308. 20. Prinzen FW, Hunter WC, Wyman BT, et al. Mapping of regional myocardial strain and work during ventricular pacingexperimental study using magnetic resonance imaging tagging. J Am Coll Cardiol 1999;33:1735-1742. 21. Lee MA, Dae MW, Langberg JL, et al. Effects of longterm right ventricular pacing on left ventricular perfusion, innervation, function and histology J Am Coll Cardiol 1994;24:225-232. 22. Delhaas T, Arts T, Prinzen FW, Reneman RS. Regional fiber stress-fiber strain as estimate of regional oxygen demand in the canine heart J Physiol (Lond) 1994;477:481496. 23. Tse H-F, Lau CP. Long-term effect of right ventricular pacing on myocardial perfusion and function J Am Coll Cardiol 1997;29:744-749. 24. Nielsen JC, Bottcher M, Nielsen TT, Pedersen AK, Andersen HR. Regional myocardial blood flow in patients with sick sinus syndrome randomized to long-term single chamber or dual chamber pacing effect of pacing mode and rate J Am Coll Cardiol 2000;35:1453-1461. 25. Zile M, Blaustein A, Shimizu G, et al. Right ventricular pacing reduces the rate of left ventricular relaxation and filling J Am Coll Cardiol 1987;10:702-709. 26. Prinzen FW, Cheriex EC, Delhaas T, et al. Asymmet-

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65 ric thickness of the left ventricular wall resulting from asynchronous electric activationa study in dogs with ventricular pacing and in patients with left bundle branch block. Am Heart J 1995;130:1045-1053. 27. Van Oosterhout MFM, Prinzen FW, Arts T, et al. Asynchronous electrical activation induces asymmetrical hypertrophy of the left ventricular wall Circulation 1998;98:588595. 28. Spragg DD, Leclercq C, Loghmani M, et al. Regional alterations in protein expression in the dyssynchronous failing heart Circulation 2003;108:929-932. 29. Sweeney MO, Prinzen FW. A new paradigm for physiologic ventricular pacing J Am Coll Cardiol 2006;47:282288. 30. Andersen HR, Nielsen JC, Thomsen PEB, et al. Atrioventricular conduction during long-term follow-up of patients with sick sinus syndrome Circulation 1998;98:13151321. 31. Nielsen JC, Pedersen AK, Mortensen PT, Andersen HR. Programming a fixed long atrioventricular delay is not effective in preventing ventricular pacing in patients with sick sinus syndrome Europace 1999;1:113-120. 32. Sweeney MO, Shea JB, Fox V, et al. Randomized trial of a new atrial-based minimal ventricular pacing mode in dual chamber implantable cardioverter-defibrillatorsMVP. Heart Rhythm 2004;1:160-167. 33. Savoure A, Frohlig G, Galley D, et al. A new dualchamber pacing mode to minimize ventricular pacing Pacing Clin Electrophysiol 2005;28(Suppl 1):S43-S46. 34. Gillis AM, Pererfellner H, Israel CW, et.al. Reduction of unnecessary ventricular pacing due to the Managed Ventricular Pacing (MVP) mode in pacemaker patients: benefit for both sinus node disease (SND) and AV block (AVB) indications. Heart Rhythm. 2005; Abstract AB21-1 35. Sweeney MO, Ellenbogen KA, Casavant D, et al. Multicenter, Prospective, Randomized Safety and Efficacy Study of a new atrial-based managed ventricular pacing Mode (MVP) in dual chamber ICDs. J Cardiovasc Electrophysiol 2005; 16: 811 17. 36. Yee R, Klein GJ, Krahn AC, Skanes AC. Selective site pacing: tools and training. Pacing Clin Electrophysiol 2004;27:894 6. 37. De Cock CC, Giudici MC, Twisk J. Comparison of the haemodynamic effects of right ventricular outflow-tract pacing with right ventricular apex pacinga quantitative review. Europace 2003;5:275-278.

38. Furman S, Schwedel JB. An intracardiac pacemaker for Stokes-Adams Seizures. N Engl J Med 1959;261:943 8. 39. Tse HF, Yu C, Wong KK, et al. Functional abnormalities in patients with permanent right ventricular pacingthe effect of sites of electrical stimulation. J Am Coll Cardiol 2002;40:1451-1458. 40. Victor F, Mabo P, Mansour H, et al. A randomized comparison of permanent septal versus apical right ventricular pacing: short-term results. J Cardiovasc Electrophysiol 2006;17:238 42. 41. Laske TG, Skadsberg ND, Hill AJ, Klein GJ, Isizzo PA. Excitation of the intrinsic conduction system through his and interventricular septal pacing. Pacing Clin Electrophysiol 2006;29:397 405. 42. Occhetta E, Bortnik M, Magnani A, et al. Prevention of ventricular desynchronization by permanent para-Hisian pacing after atrioventricular node ablation in chronic atrial fibrillation: a crossover, blinded, randomized study versus apical right ventricular pacing. J Am Coll Cardiol 2006;47:1938 45. 43. Deshmukh P, Casavant DA, Romanyshyn M, Anderson K. Permanent, direct His-bundle pacing: a novel approach to cardiac pacing in patients with normal HisPurkinje activation. Circulation 2000;101: 869 77. 44. Lu F, Iaizzo PA, Benditt DG, et al. Isolated Atrial Segment Pacing: An Alternative to His Bundle Pacing After Atrioventricular Junctional Ablation (J Am Coll Cardiol 2007;49:1443 9. 45. Leon A, Greenberg M, Kanuru N, et al. Cardiac resynchronization in patients with congestive heart failure and chronic atrial fibrillationeffect of upgrading to biventricular pacing after chronic right ventricular pacing. J Am Coll Cardiol 2002;39:1258-1263. 46. Leclercq C, Walker S, Linde C, et al. Comparative effects of permanent biventricular and right-univentricular pacing in heart failure patients with chronic atrial fibrillation Eur Heart J 2002;23:1780-1787. 47. Peschar M, de Swart H, Michels KJ, Reneman RS, Prinzen FW. Left ventricular septal and apex pacing for optimal pump function in canine hearts J Am Coll Cardiol 2003;41:1218-1226. 48. Vanagt WY, Verbeek XA, Delhaas T, Mertens L, Daenen WJ, Prinzen FW. The left ventricular apex is the optimal site for pediatric pacingcorrelation with animal experience. Pacing Clin Electrophysiol 2004;27:837-843.

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