Roelke M, Garan H, McGovern B A, Ruskin J N
Massachusetts General Hospital, Boston 02114.
J Am Coll Cardiol. 1994 Jan;23(1):117-22. doi: 10.1016/0735-1097(94)90509-6.
This study was designed to analyze stored intracardiac electrograms generated during spontaneous monomorphic ventricular tachycardia to examine the possible mechanisms responsible for the initiation of ventricular tachycardia in a group of postinfarction patients.
Implantable cardioverter-defibrillators capable of storing electrograms during an arrhythmic event provide an intracardiac electrogram analog to Holter ambulatory electrocardiographic monitoring. Such electrograms are of value in arrhythmia diagnosis and in determining the appropriateness of implantable cardioverter-defibrillator therapy and may aid in understanding the initiation of ventricular arrhythmias.
We studied 73 stored electrograms in 22 postinfarction patients with spontaneous monomorphic ventricular tachycardia. Premature depolarizations before tachycardia were classified by morphology and number. Electrogram morphology was compared with the morphology of the baseline rhythm and ventricular tachycardia. Prematurity was assessed by the coupling interval and a calculated prematurity ratio.
During baseline rhythm, ectopic activity was present in 30 (41%) of 73 stored episodes. Ventricular tachycardia was preceded by a short-long-short sequence in 14% of episodes and by a rapid ventricular rhythm in 5.5% of episodes. The onset of ventricular tachycardia was marked by single premature depolarizations in 33 episodes (45%), by pairs in 16 (22%) and by multiple complexes in 24 (33%). Morphology was similar to that of the ensuing tachycardia in 35 episodes (48%). The mean coupling interval was 364 ms, and the mean prematurity ratio was 0.56. In all 10 episodes (14%) where the prematurity ratio was < 0.40, a short-long-short sequence was responsible. When classified by morphology, the mean prematurity ratio of depolarizations dissimilar to ventricular tachycardia (0.53) was significantly less than that of the morphologically similar group (0.60, p = 0.035).
In this select group of postinfarction patients with recurrent sustained monomorphic ventricular tachycardia treated with implantable cardioverter-defibrillators, ventricular tachycardia was most often preceded by late-coupled premature depolarizations. Not infrequently, a short-long-short sequence occurred before tachycardia. Premature depolarizations with a morphology different from that of the tachycardia occurred earlier in the cardiac cycle than did those with a morphology similar to that of the tachycardia. These findings may reflect different mechanisms of ventricular tachycardia initiation.
本研究旨在分析在自发性单形性室性心动过速期间产生的存储于心内的电图，以探讨一组心肌梗死后患者室性心动过速起始的可能机制。
能够在心律失常事件期间存储电图的植入式心脏复律除颤器提供了一种类似于动态心电图监测的心内电图。此类电图在心律失常诊断以及确定植入式心脏复律除颤器治疗的适宜性方面具有价值，并且可能有助于理解室性心律失常的起始。
我们研究了22例有自发性单形性室性心动过速的心肌梗死后患者的73份存储电图。根据形态和数量对心动过速前的过早去极化进行分类。将电图形态与基础心律和室性心动过速的形态进行比较。通过耦合间期和计算得出的过早率来评估提前程度。
在基础心律期间，73次存储发作中有30次（41%）存在异位活动。14%的发作中室性心动过速之前有短 - 长 - 短序列，5.5%的发作中有快速室性心律。33次发作（45%）中室性心动过速的起始以单个过早去极化标记，16次（22%）以成对出现，24次（33%）以多个复合波出现。35次发作（48%）中形态与随后的心动过速相似。平均耦合间期为364毫秒，平均过早率为0.56。在过早率<0.40的所有10次发作（14%）中，短 - 长 - 短序列起作用。按形态分类时，与室性心动过速形态不同的去极化的平均过早率（0.53）显著低于形态相似组（0.60，p = 0.035）。
在这组接受植入式心脏复律除颤器治疗的有复发性持续性单形性室性心动过速的心肌梗死后患者中，室性心动过速最常由晚耦合的过早去极化引发。心动过速之前经常出现短 - 长 - 短序列。形态与心动过速不同的过早去极化在心动周期中比形态与心动过速相似的过早去极化更早出现。这些发现可能反映了室性心动过速起始的不同机制。
