Patient-initiated transtelephone transmission of electrocardiographic signals in the diagnosis of arrhythmias.

Thirty-one patients who had complained of recurrent palpitations were given transtelephone transmitters of electrocardiographic signals and instructed to use the transmitters while they were having symptoms. From the transcribed electrocardiograms sinus tachycardia was documented in 12 patients, paroxysmal atrial tachycardia in 7, atrial fibrillation in 4, atrial flutter in 3, frequent ventricular premature beats in 4 and ventricular tachycardia in 1. Patient-initiated transtelephone transmission of electrocardiographic signals was found to be an effective means of documenting the nature of symptomatic paroxysmal tachycardia.     

Immediate Effects of Intravenous Verapamil in Cardiac Arrhythmias

Verapamil was administered by intravenous injection to 181 patients with various cardiac arrhythmias. The automaticity of the cardiac pacemaker was slowed in sinus, idionodal, and idioventricular tachycardia. In atrial fibrillation the drug usually slowed the ventricular response and often made it regular. In some cases atrial flutter was converted to sinus rhythm, the ventricular response being reduced in the remainder. Conversion of paroxysmal supraventricular tachycardia to sinus rhythm was consistently achieved. A favourable response occurred in four patients in whom arrhythmias were associated with pre-excitation syndromes. There were no adverse clinical side effects.     

Ablation of Post Transplant Atrial Flutter and Pseudo-fibrillation Using Magnetic Navigation via a Superior Approach

Ablation of cavotricuspid isthmus flutter and atrial tachycardia in a complex substrate has never been reported using remote navigation via superior approach. Venous access was obtained via right internal jugular for ablation and left subclavian for duodecapolar catheter placement into the coronary sinus. In a posttransplant patient presenting with both regular and irregular tachycardia, both cavotricuspid isthmus flutter in the donor and atrial tachycardia in the recipient was mapped using a two catheter approach. Successful ablation of typical atrial flutter and anastomotic block was achieved. This is the first report of successful ablation of cavotricuspid isthmus flutter and posttransplant atrial tachycardia using magnetic navigation via superior approach. Using only two catheters, this approach is logical and feasible in complex substrates with interrupted inferior venous access.     

Confounding factors leading to misdiagnosing ventricular tachycardia as supraventricular in the emergency room

Studies conducted during the last 50 years have proposed electrocardiographic criteria and algorithms to determine if a wide QRS tachycardia is ventricular or supraventricular in origin. Sustained ventricular tachycardia is an uncommon reason for consultation in the emergency room. The latter and the complexity of available electrocardiographic diagnostic criteria and algorithms result in frequent misdiagnoses. Good hemodynamic tolerance of tachycardia in the supine position does not exclude its ventricular origin. Although rare, ventricular tachycardia in patients with and without structural heart disease may show a QRS duration <120 ms. Interruption of tachycardia by coughing, carotid sinus massage, Valsalva maneuver, or following the infusion of adenosine or verapamil should not discard the ventricular origin of the arrhythmia. In patients with regular, uniform, sustained broad QRS tachycardia, the presence of structural heart disease or A-V dissociation strongly suggest its ventricular origin. Occasionally, ventricular tachycardia can present with AV dissociation without this being evident on the 12-lead ECG. Cardiac auscultation, examination of the jugular venous pulse, and arterial pulse palpation provide additional clues for identifying A-V dissociation during tachycardia. This paper does not review the electrocardiographic criteria for categorizing tachycardia as ventricular but rather why emergency physicians misdiagnose these patients.     

经食道心房调搏术及食道心电图在心律失常中的应用

目的:分析经食道心房调搏术(TEAP)及食道内心电图(EECG)在心律失常中的应用价值。方法:选取2018年6月至2019年12月于我院行食道心电图及经食道调搏的患者189例,其中男80例,女109例,年龄11~83岁。结果:54例为房室结折返性心动过速(AVNRT),34例为房室折返性心动过速(AVRT),8例为房性心动过速(AT),4例为心房扑动(AF),6例为心房颤动(Af),5例为室性心过速,78例为室早或其他。共105例心律失常患者拟行食道心房调搏终止心动过速,所有AVNRT和AVRT患者及17例AT患者经食道心房调搏S1S1成功转为窦律,50例AVNRT、32例AVRT、6例AT、3例AF及2例VT患者通过射频消融术成功根治。其中1例11岁AT患者因无法耐受食道调搏,未能转为窦律,患者经静推普罗帕酮后次日转为窦律。共97例患者拟行食道心房调搏诱发,共49例诱发出心动过速,1例左后分支型室速经静滴异丙肾上腺素后诱发心动过速,且仍需静滴异丙肾上腺素后经心房食道调博终止心动过速,后经射频消融术成功根治。结论:TEAP及EECG可用于复杂心律失常的诊断及治疗,是一种相对安全、临床容易掌握的技术,值得推广。     

Pacemaker lead-related macroreentrant atrial tachycardia

Macroreentrant atrial circuits are frequently associated with scarring. Previous reports have shown the possible development of scar tissue that is adjacent to pacemaker (PM) leads. However, reports of PM lead-related reentrant tachycardia are scarce. We report the case of a 63-year-old woman who presented with macroreentrant atrial tachycardia (MAT), related to the atrial trajectory of an old single-lead ventricular PM, that was successfully treated with radiofrequency ablation after a conventional electrophysiological study ruled out isthmus-dependent atrial flutter and provided sufficient data to confirm this diagnosis. This report presents a case of MAT originating around the trajectory of a PM lead, probably because of scar tissue that developed adjacent to the lead. Experimental studies have already shown that interstitial atrial fibrosis may develop adjacent to a ventricular single-lead. This finding suggests that MAT develops in patients with this specific condition. Recognizing this condition is important for managing these arrhythmias and performing safe ablation with the preservation of PM lead integrity.     

Non-Synchronized Direct-Current Countershock in Cardiac Arrhythmias

One hundred and thirty-two direct-current shocks were administered to 82 patients in an attempt to convert supraventricular tachyarrhythmias. Sinus rhythm was restored in 74 patients. In at least seven instances the shock was delivered during the T wave. Ventricular fibrillation did not occur. One episode of ventricular tachycardia and one of third-degree heart block followed countershock and terminated spontaneously. Excessive digitalis was considered to be a contributing factor in these two arrhythmias. Non-synchronized countershock is considered a safe and effective method of converting atrial fibrillation and flutter.     

Ventricular tachycardia due to cardiac ischaemia: assessment by exercise electrocardiography

Although ventricular tachycardia is a well-known complication of myocardial ischaemia and may be provoked by exercise, many patients may appreciate only the angina and be unaware of the unduly rapid heart rate that precipitates it. Exercise testing is needed to show this arrhythmia and to enable treatment to be started.Twenty-three patients were found to have chronic ischaemic heart disease complicated by ventricular tachycardia. Six patients with old myocardial infarction had ventricular tachycardia at rest which required conversion to sinus rhythm; 17 patients developed ventricular tachycardia only when they exercised. In 12 of these 17 patients coronary angiography showed disease of the anterior descending branch of the left coronary artery; other vessels were usually also affected. Although beta-adrenergic blocking drugs increased exercise tolerance, ventricular tachycardia still occurred when the heart rate on exercise reached a level similar to that before treatment. In five patients coronary artery bypass surgery was performed because of angina and exercise-induced ventricular tachycardia. Exercise tolerance was increased in all three patients who underwent exercise tests after operation, and in two of these patients, both of whom were known to have patent grafts, ventricular tachycardia was abolished.If part of the beneficial effect of coronary bypass surgery is preventing life-threatening ventricular arrhythmias it is essential to detect these, and ambulatory monitoring and stress testing have a complementary role.     

Premature Ventricular Contractions and Non-sustained Ventricular Tachycardia: Association with Sudden Cardiac Death,Risk Stratification,and Management Strategies

Premature ventricular contractions (PVCs) and non-sustained ventricular tachycardia (NSVT) are frequently encountered and a marker of electrocardiomyopathy. In some instances, they increase the risk for sustained ventricular tachycardia, ventricular fibrillation, and sudden cardiac death. While often associated with a primary cardiomyopathy, they have also been known to cause tachycardia-induced cardiomyopathy in patients without preceding structural heart disease. Medical therapy including beta-blockers and class III anti-arrhythmic agents can be effective while implantable cardiac defibrillators (ICD) are indicated in certain patients. Radiofrequency ablation (RFA) is the preferred, definitive treatment in those patients that improve with anti-arrhythmic therapy, have tachycardia-induced cardiomyopathy, or have certain subtypes of PVCs/NSVT. We present a review of PVCs and NSVT coupled with case presentations on RFA of fascicular ventricular tachycardia, left-ventricular outflow tract ventricular tachycardia, and Purkinje arrhythmia leading to polymorphic ventricular tachycardia.     

A Model for Mechano-Electrical Feedback Effects on Atrial Flutter Interval Variability

Atrial flutter is a supraventricular arrhythmia, based on a reentrant mechanism mainly confined to the right atrium. Although atrial flutter is considered a regular rhythm, the atrial flutter interval (i.e., the time interval between consecutive atrial activation times) presents a spontaneous beat-to-beat variability, which has been suggested to be related to ventricular contraction and respiration by mechano-electrical feedback. This paper introduces a model to predict atrial activity during atrial flutter, based on the assumption that atrial flutter variability is related to the phase of the reentrant activity in the ventricular and respiratory cycles. Thus, atrial intervals are given as a superimposition of phase-dependent ventricular and respiratory modulations. The model includes a simplified atrioventricular (AV) branch with constant refractoriness and conduction times, which allows the prediction of ventricular activations in a closed-loop with atrial activations. Model predictions are quantitatively compared with real activation series recorded in 12 patients with atrial flutter. The model predicts the time course of both atrial and ventricular time series with a high beat-to-beat agreement, reproducing 96±8% and 86±21% of atrial and ventricular variability, respectively. The model also predicts the existence of phase-locking of atrial flutter intervals during periodic ventricular pacing and such results are observed in patients. These results constitute evidence in favor of mechano-electrical feedback as a major source of cycle length variability during atrial flutter.     

Ischemic Ventricular Tachycardia Presenting as a Narrow Complex Tachycardia

This report describes a patient presenting with a narrow complex tachycardia in the context of prior myocardial infarction and impaired ventricular function. Electrophysiological studies confirmed ventricular tachycardia and activation and entrainment mapping demonstrated a critical isthmus within an area of scar involving the His-Purkinje system accounting for the narrow QRS morphology. This very rare case shares some similarities with upper septal ventricular tachycardia seen in patients with structurally normal hearts, but to our knowledge has not been seen previously in patients with ischemic heart disease.     

Effect of chronic stimulation of the negative and positive emotionogenic centers of the hypothalamus on development of cardiac arrhythmias]

Chronic experiments were conducted on 46 rabbits; a study was made of the changes in cardiac activity arising in prolonged (up to 1--2 weeks) electric stimulation of the ventro-median nuclei of the hypothalamus. Disturbances of the cardiac rhythm in the form of tachycardia, atrial flutter and fibrillation, ventricular extrasystole and paroxysmal ventricular tachysystole occurred mostly during the first days of stimulation and ceased after inderal infusion. Functional "weakness" of the cardiac pacemakers was revealed in the animals subjected to 1--2-week stimulation of the ventromedian nuclei. This was indicated by the post-stimulation suppression of the pacemaker automaticity and the appearance of Liciani's periods. Disturbances of the cardiac rhythm originating in stimulation of the ventromedian nuclei ceased in stimulation of the lateral hypothalamic field.     

Insulin tolerance test causes hypokalaemia and can provoke cardiac arrhythmias

We report the observation and analysis of a new adverse event during the insulin tolerance test (ITT) and propose additional safety procedures. An 8-year-old girl with growth hormone insufficiency had a cardiac arrest due to ventricular flutter when she was tested for growth hormone deficiency by the ITT. Severe hypokalaemia (K+ 2.6 mmol/l) was observed after resuscitation. Ergometry ECG revealed catecholaminergic polymorphic ventricular tachycardia, a hereditary arrhythmogenic disease. Consecutive measurements of serum potassium during ITT in 29 short children (21 boys) with growth failure revealed a mean decrease of serum potassium by 1.1 +/- 0.4 mmol/l with the nadir at 30 min after the insulin bolus. Hypokalaemia (serum potassium < 3.5 mmol/l) occurred in all but one child; severe hypokalaemia (serum potassium < 2.9 mmol/l) was measured in every third child. This observation indicates that acute hypokalaemia which is induced by insulin and catecholamine excess occurs frequently in ITT. The case shows that the combination of acute hypokalaemia and the adrenergic counterregulation in ITT is a strong trigger of cardiac arrhythmias, which can become life-threatening if the child has an arrhythmogenic disease. Therefore, we recommend ECG monitoring during ITT to enhance the detection of cardiac arrhythmias. In addition, in the case of a comatose child during ITT the determination of the glucose and potassium level as well as adequate treatment are necessary.     

Idiopathic fascicular ventricular tachycardia

Idiopathic fascicular ventricular tachycardia is an important cardiac arrhythmia with specific electrocardiographic features and therapeutic options. It is characterized by relatively narrow QRS complex and right bundle branch block pattern. The QRS axis depends on which fascicle is involved in the re-entry. Left axis deviation is noted with left posterior fascicular tachycardia and right axis deviation with left anterior fascicular tachycardia. A left septal fascicular tachycardia with normal axis has also been described. Fascicular tachycardia is usually seen in individuals without structural heart disease. Response to verapamil is an important feature of fascicular tachycardia. Rare instances of termination with intravenous adenosine have also been noted. A presystolic or diastolic potential preceding the QRS, presumed to originate from the Purkinje fibers can be recorded during sinus rhythm and ventricular tachycardia in many patients with fascicular tachycardia. This potential (P potential) has been used as a guide to catheter ablation. Prompt recognition of fascicular tachycardia especially in the emergency department is very important. It is one of the eminently ablatable ventricular tachycardias. Primary ablation has been reported to have a higher success, lesser procedure time and fluoroscopy time.     

Right Ventricular Endomyocardial Fibrosis Presenting With Ventricular Tachycardia And Apical Thrombus - An Interesting Presentation

Endomyocardial fibrosis is a progressive disease of unknown origin affecting children and young adults. It involves inflow portion of right and/or left ventricle and apex. It may be associated with thrombus. Literature regarding right ventricular endomyocardial fibrosis with thrombus is scarce. Here we report a rare case of right ventricular endomyocardial fibrosis presenting as ventricular tachycardia and echocardiographic evidence of apical thrombus. Interestingly there was no pulmonary involvement or evidence of deep venous thrombosis. This case also underscores the importance of urgent echocardiography in diagnosis of obscure cases of ventricular tachycardia.     

SUPRASTERNAL NOTCH ECHOCARDIOGRAPHY AND ATRIAL ARRHYTHMIAS

Anterior-posterior single-crystal echocardiography has been used in atrial flutter and in sinus rhythm after cardioversion to demonstrate anterior movement of the posterior left atrial wall, representing the effects of atrial flutter and sinus contractions.(1) This is thought to be the first report of characteristic superior movement of the inferior left atrial wall during atrial flutter, atrial tachycardia, and sinus rhythm by single-crystal suprasternal notch echocardiography.     

Fetal arrhythmias: Diagnosis and management

This article reviews important features for improving the diagnosis and management of fetal arrhythmias. The normal fetal heart rate ranges between 110 and 160 beats per minute. A fetal heart rate is considered abnormal if the heart rate is beyond the normal ranges or the rhythm is irregular. The rate, duration, and origin of the rhythm and degree of irregularity usually determine the potential for hemodynamic consequences. Most of the fetal rhythm disturbances are the result of premature atrial contractions (PACs) and are of little clinical significance. Other arrhythmias include tachyarrhythmias (heart rate in excess of 160 beats/min) such as atrioventricular (AV) reentry tachycardia, atrial flutter, and ventricular tachycardia, and bradyarrhythmias (heart rate <110 beats/min) such as sinus node dysfunction, complete heart block (CHB) and long QT syndrome (which is associated with sinus bradycardia and pseudo-heart block).     

起搏器术后新发房性心律失常的影响因素分析

目的:探讨起搏器术后新发房性心律失常的发生情况及其相关影响因素。方法:选择2006年1月至2007年12月于沈阳军区总医院首次植入永久起搏器的107例患者,男性50例,平均年龄65.0±11.9岁,术前通过追问病史及相关检查均排除房性心律失常(房颤、房扑、房速),术后平均随访3.9年,观察新发房性心律失常情况。按术后是否出现房性心律失常,将患者分为新发房性心律失常组和无房性心律失常组,比较两组患者术前和术后心脏超声结果的变化、心室起搏比例、起搏部位及起搏模式,并通过logistic回归分析起搏器术后发生房性心律失常的影响因素。结果:新发房性心律失常组26例(24.3%),其中房颤17例(15.9%),房扑2例(1.9%),房速7例(6.5%);无房性心律失常组81例。与无房性心律失常组比较,新发房性心律失常组左房内径明显增加(P=0.040)、二尖瓣返流程度较重(P=0.032)及左室射血分数明显下降(P=0.001),心室起搏百分比(VP%)显著升高(P=0.017)。心尖部起搏患者房性心律失常的发生率明显高于间隔部起搏(33.3%vs 16.9%,P<0.05),双腔起搏组患者房性心律失常发生率明显低于单腔起搏器组(18.7%vs 37.5%,P<0.05)。Logistic回归分析显示术后新发房性心律失常的发生与高比例的心室起搏(P=0.006)、VVI(R)起搏模式(P=0.014)及右心室起搏电极导线植于心尖部(P=0.024)显著相关。结论:起搏模式、心室起搏百分比、起搏部位是起搏器术后发生房性心律失常的影响因素。     

Catheter ablation of ventricular tachycardia originating from the left posterior papillary muscle guided by the shadow of a multipolar catheter

A 62-year-old man without structural heart disease underwent electrophysiological testing for ventricular tachycardia (VT). Hemodynamically unstable VT was induced after isoproterenol (ISP) provocation. Electroanatomical mapping using a multipolar catheter identified the earliest activation originating from the posterior papillary muscle (PPM) where prepotentials preceding the local ventricular electrogram were observed. Irrigated radiofrequency current guided by the shadow of a multipolar catheter eliminated the VT. This case suggested that multipolar catheters may be helpful for identifying tachycardia origins arising from the PPM.     

An approach to catheter ablation of cavotricuspid isthmus dependent atrial flutter

Much of our understanding of the mechanisms of macro re-entrant atrial tachycardia comes from study of cavotricuspid isthmus (CTI) dependent atrial flutter. In the majority of cases, the diagnosis can be made from simple analysis of the surface ECG. Endocardial mapping during tachycardia allows confirmation of the macro re-entrant circuit within the right atrium while, at the same time, permitting curative catheter ablation targeting the critical isthmus of tissue located between the tricuspid annulus and the inferior vena cava. The procedure is short, safe and by demonstration of an electrophysiological endpoint - bidirectional conduction block across the CTI - is associated with an excellent outcome following ablation. It is now fair to say that catheter ablation should be considered as a first line therapy for patients with documented CTI-dependent atrial flutter.