Association of accelerated idioventricular rhythm and paroxysmal ventricular tachycardia in acute myocardial infarction

Although previous studies have suggested that accelerated idioventricular rhythm rarely coexists with paroxysmal ventricular tachycardia, this relation has not been systematically evaluated in acute myocardial infarction. To examine this relation, the frequency and characteristics of the two arrhythmias were analyzed by performing 24 hour Holter monitoring during the initial 24 hours of acute myocardial infarction in 52 successive patients. Twenty-four of these patients had documented accelerated idioventricular rhythm; 28 patients did not. Paroxysmal ventricular tachycardia occurred in 83 percent of patients with accelerated idioventricular rhythm but in only 18 percent of patients without this arrhythmia (P < 0.001). The results remained at the same level of significance whether paroxysmal ventricular tachycardia was defined by rates greater than 100, 120 or 140 beats/min. These findings suggest that accelerated idioventricular rhythm complicating acute myocardial infarction is not always benign and is frequently associated with more serious forms of ventricular arrhythmia.     

Association of ventricular extrasystoles and ventricular tachycardia with idioventricular rhythm.

Patients with acute myocardial infarction were monitored for ventricular arrhythmias in the first 48 hours. Idioventricular rhythm (rate less than 100/minute) occurred in 35 out of 224 patients (15.6%) during the first day and in 13 out of 192 patients not receiving treatment on the second day (6.8%). This arrhythmia was frequently preceded by late ventricular extrasystoles, which often showed variation of their coupling intervals to the preceding QRS. Double ventricular extrasystoles separated by larger than or equal to 600 ms were also precursors of idioventricular rhythm. Idioventricular rhythm at times could be described as an escape rhythm, but on other occasions it was undoubtedly an accelerated rhythm. Spontaneous changes in the idioventricular cycle length were frequent on single one-minute electrocardiographic recordings. The rate of the dominant rhythm in patients with episodes of idioventricular rhythm was significantly slower than the heart rate of patients without this arrhythmia. Idioventricular rhythm was more frequent in patients with inferior infarction. Idioventricular rhythm sometimes preceded ventricular tachycardia but there was only a significant association between ventricular tachycardia and idioventricular rhythms with rates of over 75/minute. Irregular idioventricular rhythm frequently accelerated to ventricular tachycardia. It is suggested that the term benign idioventricular rhythm be reserved for those rhythms below 75/minute, and that the term rapid idioventricular rhythm should be used for rhythms between 75 and 120/minute. The rate of idioventricular rhythm is related to the probability of development of life-threatening ventricular arrhythmias during the first 48 hours after myocardial infarction.     

Association of ventricular extrasystoles and ventricular tachycardia with idioventricular rhythm.

Patients with acute myocardial infarction were monitored for ventricular arrhythmias in the first 48 hours. Idioventricular rhythm (rate less than 100/minute) occurred in 35 out of 224 patients (15.6%) during the first day and in 13 out of 192 patients not receiving treatment on the second day (6.8%). This arrhythmia was frequently preceded by late ventricular extrasystoles, which often showed variation of their coupling intervals to the preceding QRS. Double ventricular extrasystoles separated by larger than or equal to 600 ms were also precursors of idioventricular rhythm. Idioventricular rhythm at times could be described as an escape rhythm, but on other occasions it was undoubtedly an accelerated rhythm. Spontaneous changes in the idioventricular cycle length were frequent on single one-minute electrocardiographic recordings. The rate of the dominant rhythm in patients with episodes of idioventricular rhythm was significantly slower than the heart rate of patients without this arrhythmia. Idioventricular rhythm was more frequent in patients with inferior infarction. Idioventricular rhythm sometimes preceded ventricular tachycardia but there was only a significant association between ventricular tachycardia and idioventricular rhythms with rates of over 75/minute. Irregular idioventricular rhythm frequently accelerated to ventricular tachycardia. It is suggested that the term benign idioventricular rhythm be reserved for those rhythms below 75/minute, and that the term rapid idioventricular rhythm should be used for rhythms between 75 and 120/minute. The rate of idioventricular rhythm is related to the probability of development of life-threatening ventricular arrhythmias during the first 48 hours after myocardial infarction.     

Repeated blackout in a patient with accelerated idioventricular rhythm]

There has been no report that Accelerated Idioventricular rhythm (AIVR) causes a syncope attack. The patient described in this report is very rare because AIVR chronic without any heart diseases has been observed for 13 years, and because it is considered that AIVR is closely associated with his repeated blackouts. A 62-year-old male was admitted to our hospital because of repeated syncopal attacks. He reported that he occasionally felt lightheaded after strenuous lifting and pushing or pulling against resistance. We found that AIVR could produce a remarkable arterial pressure drop partly because of ventricular asynergy and loss of timed atrial contribution. Furthermore, we observed syncopal attacks during Valsalva maneuver and found abnormalities of baroreceptor reflex (Lack of reflex tachycardia and weakened evershoot phenomenon). It is concluded that AIVR is not a benign arrhythmia in this patient because it has been a possible cause of syncope attack due to systemic arterial pressure drop and baroreceptor abnormalities.     

Multiform accelerated idioventricular rhythm in acute myocardial infarction: electrocardiographic characteristics and response to verapamil

Thirteen patients with acute myocardial infarction with multiform accelerated idioventricular rhythm (AIVR) occurring during the first 12 hours of monitoring in the coronary care unit are described. This arrhythmia, similar to the more common uniform AIVR, was intermittent, did not cause hemodynamic compromise, and was not related to more serious ventricular arrhythmias. There was no correlation between the bundle branch block pattern of the multiform AIVR and the electrocardiographic location of the myocardial infarction, but there was a perfect correlation between the frontal plane electrical axis of the multiform AIVR and the electrocardiographic location of the myocardial infarction. The presence of fusion beats between the different forms of AIVR suggests multifocality rather than multiformity. Intravenous verapamil (3 to 5 mg bolus) was administered to 6 patients with multiform AIVR in whom the arrhythmias were persistent enough to allow the evaluation of the effect of verapamil on the arrhythmia. Verapamil caused no change in the rate of AIVR in 1 patient, but in a second patient it decreased the rate by 20 beats/min. In 4 patients, verapamil abolished the arrhythmia: in 2 patients carotid sinus pressure (induced sinus slowing) allowed the emergence of the AIVR at a lower rate, and in the remaining 2 patients the arrhythmia was not observed.     

Physician interpretation of electrocardiographic artifact that mimics ventricular tachycardia

BACKGROUND: Patients who are misdiagnosed with ventricular tachycardia because of electrocardiographic artifact may be subjected to unnecessary procedures. The purpose of this study was to determine how often electrocardiographic artifact is misdiagnosed as ventricular tachycardia. METHODS: Physicians (n = 766) were surveyed with a case simulation that included a two-lead electrocardiographic monitor tracing of artifact simulating a wide-complex tachycardia. RESULTS: The rhythm strip was not recognized as artifact by 52 of the 55 internists (94%), 128 of the 221 cardiologists (58%), and 186 of the 490 electrophysiologists (38%). One hundred fifty-six of the 181 electrophysiologists (88%), 67 of the 126 cardiologists (53%), and 14 of the 15 internists (31%) who misdiagnosed the rhythm as ventricular tachycardia recommended an invasive procedure for further evaluation or therapy. CONCLUSIONS: This physician survey suggests that electrocardiographic artifact that mimics ventricular tachycardia may frequently result in patients being subjected to unnecessary invasive cardiac procedures. Physicians should include artifact in their differential diagnosis of wide complex tachycardias to minimize unneeded procedures.     

An accurate electrocardiographic algorithm for differentiation of tremor-induced pseudo-ventricular tachycardia and true ventricular tachycardia

Tremor-induced electrocardiographic artifacts could be misdiagnosed as ventricular tachycardia (VT). However, there has been no electrocardiographic algorithm effectively differentiating pseudo-VT. In this study, we used 3 electrocardiographic "signs": "Sinus" sign, "Spike" sign, and "Notch" sign, and created an electrocardiographic algorithm. The algorithm was prospectively tested in 98 electrocardiographs (37 tremor-induced pseudo-VT and 61 true VT) Thirty-six out of 37 (97.3%) tremor-induced pseudo-VTs could be accurately diagnosed. In conclusion, this is the first study to systemically analyze the tremor-induced pseudo-VT. Our new electrocardiographic algorithm provides a useful tool for a rapid and accurate diagnosis.     

心外膜室性心动过速的心电图特征

心外膜室速的心电图有其共同表现：QRS 时限≥200 ms,但也有部分时限≤120 ms;起始部有假性Δ波≥34 ms;电轴多数左偏,胸前导联移行在 V2以后;V2导联 R 波达峰值时间延长≥85 ms;最短 RS 时间≥121 ms。识别左心室起源的心外膜室速：Ⅰ导联呈 Q 波的基底、心尖部室速;Ⅱ、Ⅲ、aVF 导联无 Q 波的基底部室速;Ⅱ、Ⅲ、aVF 导联呈 Q 波的基底上部、心尖部室速;最大转折指数可识别左室流出道心外膜室速,当最大转折指数≥0．55可识别远离主动脉窦的心外膜室速。识别右心室起源的心外膜室速：Ⅰ导联呈 Q 波且右室前壁导联呈 QS,预示心外膜室速可能性大;Ⅱ、Ⅲ、aVF 导联起始 Q 波,可在同步电生理标测时观察到位于右心室心外膜起源的室速。但不同部位及不同病因的室速又有其特殊性,术前通过体表心电图进行较为精确的定位对室速消融有一定的指导意义。     

Resetting of ventricular tachycardia with electrocardiographic fusion: incidence and significance

The incidence and significance of fusion of the QRS complex during resetting of sustained ventricular tachycardias (VTs) was determined in 53 VTs induced by programmed stimulation in 46 patients with prior myocardial infarction. All 53 VTs were reset with one or two extrastimuli delivered at the right ventricular apex (RVA); 29 (54.7%) demonstrated fusion of the VT QRS complex coincident with the extrastimulus resetting the VT. Activation time at the RVA during VT (measured from the onset of the VT QRS complex to the first rapid deflection of the RVA electrogram) was longer in VT reset with fusion compared with those without fusion (91 +/- 30 vs 33 +/- 32 msec; p less than .001). A right bundle branch block VT QRS morphology and a rightward and inferior axis were more common in VT reset with electrocardiographic (ECG) fusion. Additionally, the shortest return cycle following the extrastimulus resetting the VT was shorter in VT reset with ECG fusion compared with those without (327 +/- 66 vs 423 +/- 84 msec; p less than .001). Fusion of the endocardial electrogram recorded at the site of VT origin was noted in 11 of 15 VTs that were reset while a recording catheter was positioned at this site, including all eight VTs with evidence of surface ECG fusion and three of seven VTs without fusion. Seventeen VTs were reset from the right ventricular outflow tract as well as the RVA; eight demonstrated QRS fusion at both sites, five from the right ventricular outflow tract only, and four from neither site.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hoffmayer心电图积分识别ARVC室早／室速

目的探讨应用Hoffmayer心电图积分鉴别致心律失常性右室心肌病（arrhvthmogenic right ventricular cardiomyopathy,ARVC）和特发f生右室流出道室早／室速的临床意义。方法收集2009年9月至2013年5月就诊于北京大学人民医院患者中,心电图表现为右室流出道起源室早／室速患者57例。其中明确诊断为ARVC患者4例,经电生理检查及射频消融治疗成功的特发性右室流出道室早／室速患者53例。由两位电生理医生在不知道确切诊断的情况下,依据Hoffmayer心电图积分对上述患者的心电图进行分析,计算总积分≥5分,各单项积分诊断ARVC伴发的室早／室速的敏感度、特异度、阳性预测值、阴性预测值及诊断符合率。结果Hoffmayer心电图积分≥5分诊断ARVC伴发室早／室速的敏感度75％,特异度96．23％,阳性预测值60％,阴性预测值98％、诊断符合率94．7％。结论Hoffmayer积分≥5可有效鉴别右室流出道室早／室速是ARVC伴发的还是特发性的。应用此项积分具有简单、快速、敏感度及特异度均较高的优点,具较高的临床应用价值。