Transient left anterior and septal fascicular blocks after self‐expandable percutaneous transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is indicated in severe symptomatic aortic stenosis, when there is intermediate‐high surgical risk, or a condition considered inoperable, as in the case of “porcelain aorta” that could turn clamping or cannulation of the ascending aorta hazardous in open‐heart surgery. Among the complications of this less invasive procedure, intraventricular conduction disorders subsequent to the procedure stand out. TAVI causes worsening of intraventricular dromotropic disorders in more than 75% of the cases, with the presence of preexisting right bundle branch block and first‐degree atrioventricular block, deep prosthesis implant, male gender, size of the aortic annulus smaller than the prosthesis, and porcelain aorta being predictive of requirement for permanent pacemaker implant.     

Transient left septal and anterior fascicular block associated with type 1 electrocardiographic Brugada pattern

The left septal fascicular block (LSFB) or blockage of the middle fibers of the left bundle branch is probably caused mainly by - in the developed world - the proximal obstruction of the left anterior descending artery (LAD) before its first anterior septal perforator branch (S₁). The association of transient LSFB and left anterior fascicular block (LAFB) - left bifascicular block - and the electrocardiographic type 1 Brugada pattern (BrP) has not been described in the literature yet.     

Transient prominent anterior QRS forces in the setting ST segment elevation coronary syndrome: Left septal fascicular block

Numerous successive publications have shown that transient prominent anterior QRS forces (PAF) in the setting of acute coronary syndrome (ACS) is suggestive of critical proximal obstruction of left anterior descending coronary artery (LAD) before its first septal perforator branch (S₁). Transient ischemia of the left septal fascicle resulting in left septal fascicular block has been proposed as the causative mechanism. We present a case of acute inferior ST-elevation myocardial infarction caused by acute proximal occlusion of the right coronary artery associated with proximal critical obstruction of the left anterior descending coronary artery.     

Left anterior fascicular block secondary to coronary artery spasm

Spasm of the left anterior descending coronary artery occurredduring cardiac calheterization in a 52 year old patient witha history of syncope and a chest pain syndrome. The main featureof coronary spasm was left axis deviation consistent with leftanterior fascicular block. Electrical axis reverted to normalityafter sublingual nitroglycerin. Coronary angiography was repeatedand showed a normal coronary artery tree. This report documentsaxis shift as a feature of coronary spasm and supports the conceptofischemic left anterior hemiblock.     

Isolated left posterior fascicular block associated with acquired ventricular septal defect

Isolated left posterior fascicular block in the absence of associated right bundle-branch block is a rare electrocardiographic finding. In view of its anatomy and the fact that it receives a dual blood supply, the posterior fascicle of the left bundle branch appears to be less vulnerable than the anterior fascicle or the right bundle. Mechanical disruption of the posterior fascicle can produce isolated left posterior fascicular block. This has been demonstrated in animal models. However, such occurrence has not been noted in humans. We present two cases of inferior wall myocardial infarction, complicated by rupture of the inferior septum, resulting in isolated left posterior fascicular block. The development of isolated left posterior fascicular block complicating myocardial infarction may, therefore, serve to alert to the possible underlying septal rupture.     

Congenital tricuspid valve stenosis with atrial septal defect and left anterior fascicular block

Congenital tricuspid valve stenosis in the absence of other valvular abnormalities is rare. In this report we describe a patient with congenital tricuspid valve stenosis, ostium secundum atrial septal defect, and electrocardiographic left anterior fascicular block, who presented with paradoxical emboli. This case, as well as previous case reports, suggests that congenital tricuspid stenosis with ostium secundum atrial septal defect is associated with left anterior fascicular block.     

Kearns-Sayre syndrome: electro-vectorcardiographic evolution for left septal fascicular block of the his bundle

The Kearns-Sayre syndrome is a neuromyopathic disorder associated with mitochondrial abnormalities and characterized by the triad of chronic external ophthalmoplegia, atypical pigmentary retinopathy, and progressive conduction system disorders. Ragged red muscle fibers that seem to contain an excess of altered mitochondria are observed. The disease affects both sexes alike, during the first or the second decade of life.The following manifestations are observed: central bilateral sensorineural deafness, pyramidal signs, ataxia, asymmetrical ptosis, external ophthalmoplegia, and progressive muscular weakness secondary to myopathy associated with a significant increase of proteins of cephalorachidian liquid. A variety of endocrinopathies may occur.     

Electro‐vectorcardiographic demonstration of rate‐independent transient left posterior fascicular block

Left posterior fascicular block (LPFB) is a rare intraventricular conduction disorder of rare occurrence, especially as an isolated entity. Its transient form is even rarer and maybe rate‐independent or rate‐dependent intermittent LPFB (phase 3 block, tachycardia‐dependent and phase 4 block or bradycardia‐dependent). We present a case of a young adult male whose baseline ECG/VCG showed the typical LPFB pattern. A treadmill stress test revealed rate‐independent intermittent LPFB with random occurrence. Imaging exams ruled out structural heart disease. To our knowledge, this is the first case in the literature of a rate‐independent intermittent LPFB with no underlying structural heart disease.     

The tetrafascicular nature of the intraventricular conduction system

The existence of a tetrafascicular intraventricular conduction system remains debatable. A consensus statement ended up with some discrepancies and, despite agreeing on the possible existence of an anatomical left septal fascicle, the electrocardiographic and vectorcardiographic characteristics of left septal fascicular block (LSFB) were not universally accepted. The most important criteria requested to confirm the existence of LSFB is its intermittent nature. So far, our group has published cases of transient ischemia‐induced LSFB and phase 4 or bradycardia‐dependent LSFB. Finally, anatomical, anatomopathological, histological, histopathological, electrocardiographic, vectorcardiographic, body surface potential mapping, and electrophysiology studies support the fact that the left bundle branch divides into three fascicles or a “fan‐like interconnected network.”     

左间隔支阻滞与QRS时限诊断左室舒张性心力衰竭的临床价值

目的观察左间隔支阻滞和常规心电图QRS时限评估充血性心力衰竭患者舒张功能的价值。方法75例符合NYHAⅡ-Ⅳ级充血性心力衰竭(CHF)患者为观察对象(男39例,女36例,平均年龄69.3±13.4岁)。采用多普勒-超声心动图(Doppler-Echo)为诊断标准,以左室射血分数(LVEF)≥50%及<50%分为左室舒张性心力衰竭(DHF)和收缩性心力衰竭(SHF)两组。分别评价QRS时限,左间隔支阻滞以及将两项指标合并后在诊断DHF时的敏感性和特异性。结果DHF组QRS时限(n=31,QRS=92±23ms)显著短于SHF组(n=44,QRS=124±27ms,p<0.01)。作为DHF的预测指标,尽管QRS时限≤100ms特异性高(95.45%),但敏感性较差(61.29%);而QRS时限≤120ms敏感性显著高于100ms(87.10%,与61.29%),其特异性显著高于QRS时限≤140ms(81.82%与43.18%);同样,左间隔支阻滞敏感性高而特异性较差(分别为90.32%及61.36%)。将QRS时限≤120ms与左间隔支阻滞两项指标作为联量检测标准,尽管敏感性下降(87.10%,90.32%与83.87%),但特异性则有显著性提高(81.82%,61.36%与86.36%,p<0.01)。结论鉴于QRS时限≤120ms与左间隔支阻滞联合诊断标准的特异性高于各单项指标,故可用于左室舒张性心衰的临床诊断。     

Electro‐vectorcardiographic demonstration of bifascicular block associated with ventricular preexcitation

Down syndrome occurs more frequently in the offsprings of older pregnant women and may be associated with atrioventricular septal defect. This refers to a broad spectrum of malformations characterized by a deficiency of the atrioventricular septum and abnormalities of the atrioventricular valves caused by an abnormal fusion of the superior and inferior endocardial cushions with the midportion of the atrial septum and the muscular portion of the ventricular septum.     

Isolated anomaly of the left anterior descending coronary artery

An isolated anomaly of the left anterior descending coronary artery arising from the right sinus of Valsalva is described. A review of the literature shows that isolated anomalies of this vessel are very rare. However, the inability to visualize this vessel from the left sinus of Valsalva warrants careful search of the right sinus.     

Isolated left posterior fascicular block: A reliable marker for inferior myocardial infarction and associated severe coronary artery disease

The electrocardiographic (ECG) pattern of isolated left posterior fascicular block (LPFB) is a rare condition. It seems that true LPFB is often not recognized, whereas in cases of simple QRS axis of +60d? to+100d? in the frontal plane, the diagnosis of LPFB is made erroneously. Both facts rely on controversial and partially misleading opinions in the literature. Therefore, a retrospective and prospective study was performed in order to determine the prevalence of LPFB and to correlate its presence to the underlying disease. Retrospective study: Of a cohort of 830 patients referred in 1988 to a cardiologic laboratory for invasive investigation of certain or suspected coronary artery disease (CAD), 163 patients had an old inferior myocardial infarction (IMI). Nine patients (5.5%) showed the typical pattern of LPFB; eight of these had three-vessel disease. The diagnosis of IMI had been made only in one case before entry of the patient into the hospital, since LPFB generally masks IMI. Prospective study: 2502 ECGs were investigated, 1710 from a department of cardiology and 792 from two departments of internal medicine. Six LPFBs were detected (0.24%), all associated with IMI and four of them with three-vessel CAD. It is concluded that LPFB is a rare but clinically important intraventricular conduction disturbance. Its appearance is reliably connected with IMI and generally reflects severe three-vessel CAD, requiring invasive investigation.     

室壁激动时间对下壁心肌梗塞合并左前分支阻滞的诊断价值

对７例单纯广泛下壁心肌梗塞和１３例下壁心肌梗塞合并左前分支传导阻滞患者的室壁激动时间（ＶＡＴ）比较分析，结果发现，单纯广泛下壁心肌梗塞组ＶＡＴａＶＲ均小于ＶＡＴａＶＬ，而下壁心肌梗塞合并左前分支传导阻滞组ＶＡＴａＶＲ均大于ＶＡＴａＶＬ。揭示ＶＡＴ在判断下壁心肌梗塞是否伴有左前分支传导阻滞时具有一定的临床价值。     

Double left anterior descending coronary artery arising from the left and right coronary arteries: a rare congenital coronary artery anomaly

Double left anterior descending coronary artery arising from the left and right coronary arteries is a very rare congenital coronary artery anomaly. In this report, we describe a patient with double left anterior descending coronary artery originating from the left and right coronary arteries. To the best of our knowledge, dual connection of the left anterior descending coronary artery to the left and right coronary arteries has been described in only five patients.     

Simultaneous transesophageal Doppler assessment of coronary flow reserve in the left anterior descending artery and coronary sinus allows differentiation between proximal and non-proximal left anterior descending artery stenoses.

AIM AND METHODS: The role of simultaneous transesophageal Doppler assessment of coronary flow reserve (CFR) in the left anterior descending artery (LAD) and coronary sinus (CS) in the diagnostics of hemodynamically significant LAD stenoses of various localization was studied in 16 CAD patients with angiographically proven >50% stenotic atherosclerosis of the LAD (nine--in the proximal third, seven--in the mid and/or distal third) and 23 healthy volunteers (all men). Dipyridamole was used as a stress agent. The diastolic phase of coronary flow in the LAD and the antegrade phase of coronary flow in the CS were analyzed. CFR in the LAD and CS was calculated in two ways: one--as ratio of peak hyperemic flow velocity to the peak baseline blood flow velocity (CFR by Vp); two--as ratio of volume hyperemic blood flow velocity to the volume baseline blood flow velocity (CFR by VBF). The level of the CFR <2 in both ways of calculation was diagnosed as reduced. RESULTS: It was found that in CAD patients with LAD proximal stenosis the values of CFR in the LAD were significantly lower than those in healthy individuals by both Vp (1.87 +/- 0.43 and 3.54 +/- 0.82; P<0.001) and VBF (1.79 +/- 0.77 and 3.85 +/- 1.25; P<0.01). In proximal stenosis CFR in the LAD by Vp was significantly lower than that in non-proximal stenosis (1.87 +/- 0.43 and 3.31 +/- 1.44; P<0.05). Sensitivity and specificity of CFR <2 in the LAD by Vp in the diagnostics of LAD proximal stenosis were 56% and 97%, respectively; and CFR <2 in the LAD by VBF--89% and 93%, respectively. In CAD patients with both proximal and non-proximal LAD stenoses CFR in the CS by Vp was significantly lower than that in healthy volunteers and was 1.74 +/- 0.53, 1.63 +/- 0.30 and 2.56 +/- 0.87; P<0.05, respectively. Sensitivity and specificity of CFR <2 in the CS by Vp in the diagnostics of hemodynamically significant LAD stenoses were 75% and 70%, respectively. The values of CFR in the CS by VBF in CAD patients and healthy volunteers did not differ significantly. CONCLUSIONS: Thus, simultaneous evaluation of CFR in the LAD and CS makes it possible to diagnose hemodynamically significant LAD stenoses and to differentiate between proximal and non-proximal impairments.     

Exercise-induced left fascicular block: A forgotten sign of coronary disease

A 55-year-old patient presented with stable angina pectoris with normal physical examination on rest electrocardiogram and cardiac echocardiogram. Treadmill test revealed exercise-induced left posterior fascicular block, which is an uncommon and easily unnoticed marker of coronary artery disease. A dobutamine stress echocardiogram was performed, with a clearly positive result. Coronary angiography revealed critical stenosis in the right coronary artery.