Prediction of arrhythmic events after myocardial infarction based on signal-averaged electrocardiogram and ejection fraction

BACKGROUND

Trials on implantable cardioverter-defibrillators (ICD) for patients after acute myocardial infarction (AMI) have highlighted the need for risk assessment of arrhythmic events (AE). The aim of this study was to evaluate risk predictors based on a novel approach of interpreting signal-averaged electrocardiogram (SAECG) and ejection fraction (EF).

METHODS

SAECG, interpreted with a new index, and EF were prospectively evaluated to predict AE in 144 patients with AMI.

RESULTS

During the mean follow-up period of 4.1 years, 19 AE occurred. The new SAECG index showed a sensitivity of 84%, a specificity of 62%, a positive predictive value (PPV) of 25%, and a negative predictive value (NPV) of 96%. A combination of a normal new SAECG index and an EF >35% resulted in a sensitivity of 100%, a specificity of 47%, a PPV of 22%, and a NPV of 100%; this corresponded to an AE incidence rate of 0%. When both tests were abnormal, the AE incidence rate was 21.3%.

CONCLUSIONS

This is the first contemporary study reporting predictive values based on a combination of SAECG and EF. If confirmed in an appropriately designed and powered trial, this novel approach might be used to identify both patients at very low risk for AE not requiring further risk assessment and patients at high risk in whom ICD implantation can be considered without further risk assessment.

Comparison of different approaches for optimization of atrioventricular and interventricular delay in biventricular pacing

AIMS

It has been shown that optimizing atrioventricular (AV) and interventricular (VV) delay improves cardiac performance in patients with biventricular pacemakers. However, there is no standard method for optimization available yet. The aim of this study was to compare echocardiographic parameters-displacement imaging, A wave duration, and aortic velocity time integral (VTI)-and acoustic cardiography derived electromechanical activation time (EMAT) using different approaches of AV and VV delay optimization. We tested whether the initial optimization of the AV interval followed by VV optimization at that optimal AV interval or initial optimization of the VV interval followed by AV optimization at the determined optimal VV interval was accurate and consistent, and how this compared to testing every conceivable combination of AV and VV intervals available.

METHODS AND RESULTS

A group of 20 patients with biventricular pacemakers was included. Displacement imaging, A wave duration, and aortic VTI were determined at different combinations of AV (100, 150, 200, 250 ms) and VV (RV40, 0, LV40 ms) intervals. If AV duration was determined first, displacement imaging identified the best setting in 8/20, aortic VTI in 10/20, A duration in 13/20, and EMAT in 18/20 patients. With VV duration determined first, the best setting was more difficult to identify regardless of the method used. There was a poor agreement in optimal AV and VV delays of the different methods, and there was no single patient in whom all four methods yielded the same delay combination.

CONCLUSION

It is advisable to measure a full grid of AV and VV delays to identify optimal settings rather than optimizing one of the two delays first. Different techniques for delay optimization resulted in different optimal delay combinations.

Precordial low voltage in patients with ascites

AIMS

Electrocardiographic (ECG) changes in patients with ascites are not well studied. The aim of this study was to evaluate ECG changes in patients with ascites.

METHODS AND RESULTS

Prospective analysis of patients with ascites who were referred for paracentesis. Three ECGs were recorded before paracentesis. ECG 1 was a standard 12-lead ECG. For ECG 2 the precordial leads were placed 1 intercostal space (ICS) and for ECG 3, 2 ICS cranially. The sums (Sigma) of the QRS in ECG1 were compared with ECG 2 and 3. In six patients the same ECG protocol was performed after removal of ascites. Ten hospitalized patients without ascites served as controls. Twenty patients with ascites were analysed. Limbs leads low voltage was present in 11 patients and precordial low voltage in four patients. Cranial placement of the precordial electrodes increased SigmaQRS in all patients with ascites. The most prominent voltage changes appeared in the leads V4-V6 (+62%). Paracentesis of ascites normalized precordial leads low-voltage, while limbs leads low voltage remained. Cranial placement of the precordial electrodes in patients without ascites decreases SigmaV1-V6.

CONCLUSION

We describe a phenomenon of precordial voltage changes in patients with ascites, not reported in the literature yet. By placing the precordial electrodes 1 and 2 ICS cranially the voltage changes can be 'corrected' and this should be done in all patients prior to further diagnostic workup. Removal of the ascites normalizes the precordial leads low voltage.

ECG changes following cardioversion and defibrillation

PRINCIPLES

changes of the QRS amplitude following defibrillation or cardioversion have never been reported in humans.

METHODS

prospective analysis of patients externally cardioverted or defibrillated for ventricular and supraventricular tachyarrhythmias. Patients with coronary artery disease (CAD) and acute coronary syndrome (ACS) formed group A and patients without CAD but with external cardioversion/defibrillation formed group B. Patients in the control group (group C) experienced a shock by an Internal Cardioverter Defibrillator (ICD). All patients underwent the same study protocol: serial ECG's were recorded and sums (Sigma) of the QRS amplitude created separately for the precordial and peripheral leads. Sigma were then compared with baseline values and changes indicated as percentage (%).

RESULTS

We included a total of 45 patients in our study: 21 patients (47%) in group A, 11 patients (24%) in group B and 13 patients (29%) in group C. Median age was 66 years in group A, 55 in group B and 52 in group C. In group A mean change of the R amplitude was -35% in precordial and -16% in the peripheral leads. In group B mean change of the R amplitude was -16% in the precordial and -2% in the peripheral leads. The QRS amplitude changed -23% in the precordial leads in group A and -14% in group B. 13 patients with external defibrillation or cardioversion of group A + B and all patients of the control group (n = 13) showed no voltage changes. The most pronounced R and QRS attenuation was seen in patients with acute coronary syndrome, CAD and those in whom manual chest compressions had been necessary. Changes appeared after a mean period of 23 hours and returned to normal after a mean of 62 hours.

CONCLUSIONS

we report the phenomenon of reversible voltage loss after external defibrillation or cardioversion. A possible explanation for this phenomenon might be tissue oedema in the chest area after electrical and traumatic injury. An alternative reason might be myocardial stunning. The exact pathophysiological mechanism leading to reversible voltage attenuation remains unclear and needs further exploration in studies with a larger sample of patients.

ECG changes following cardioversion and defibrillation

PRINCIPLES

changes of the QRS amplitude following defibrillation or cardioversion have never been reported in humans.

METHODS

prospective analysis of patients externally cardioverted or defibrillated for ventricular and supraventricular tachyarrhythmias. Patients with coronary artery disease (CAD) and acute coronary syndrome (ACS) formed group A and patients without CAD but with external cardioversion/defibrillation formed group B. Patients in the control group (group C) experienced a shock by an Internal Cardioverter Defibrillator (ICD). All patients underwent the same study protocol: serial ECG's were recorded and sums (Sigma) of the QRS amplitude created separately for the precordial and peripheral leads. Sigma were then compared with baseline values and changes indicated as percentage (%).

RESULTS

We included a total of 45 patients in our study: 21 patients (47%) in group A, 11 patients (24%) in group B and 13 patients (29%) in group C. Median age was 66 years in group A, 55 in group B and 52 in group C. In group A mean change of the R amplitude was -35% in precordial and -16% in the peripheral leads. In group B mean change of the R amplitude was -16% in the precordial and -2% in the peripheral leads. The QRS amplitude changed -23% in the precordial leads in group A and -14% in group B. 13 patients with external defibrillation or cardioversion of group A + B and all patients of the control group (n = 13) showed no voltage changes. The most pronounced R and QRS attenuation was seen in patients with acute coronary syndrome, CAD and those in whom manual chest compressions had been necessary. Changes appeared after a mean period of 23 hours and returned to normal after a mean of 62 hours.

CONCLUSIONS

we report the phenomenon of reversible voltage loss after external defibrillation or cardioversion. A possible explanation for this phenomenon might be tissue oedema in the chest area after electrical and traumatic injury. An alternative reason might be myocardial stunning. The exact pathophysiological mechanism leading to reversible voltage attenuation remains unclear and needs further exploration in studies with a larger sample of patients.

Esophagus imaging for radiofrequency ablation of atrial fibrillation using a dual-source computed tomography system: Preliminary observations

OBJECTIVE

The very recent introduction of dual-source computed tomography (DSCT) has significantly improved the temporal resolution of ECG-gated multidetector-row cardiac computed tomography (CT). The aim of the present study was to evaluate whether with a DSCT visualization of the esophagus is feasible without any use of contrast in the esophagus.

MATERIALS AND METHODS

A total of 20 patients were evaluated. Ten patients underwent examination with a DSCT scanner without a gastric tube. In another ten patients, which served as control group, a CT scan was performed with a radio-opaque gastric tube prior to circumferential pulmonary vein isolation (in seven patients with a 16-slice CT and in three patients with a DSCT).

RESULTS

In the control group the gastric tube and the left atrium were reconstructed and were well visualized in all ten patients in the electro-anatomic mapping system, independently whether 16-row CT or DSCT scan was used. In the study group integration of the esophagus into the electro-anatomic mapping system was not feasible, due to the lacking contrast counterpart the surrounding tissue.

CONCLUSIONS

Even with the newest generation of DSCT scanner it is not possible to integrate the esophagus image into the 3-D electroanatomic mapping system without contrast by whatever means. However placing a conventional gastric tube before performing the CT scan allowed visualization and integration of the esophagus into the 3-D electro-anatomical map in all patients.

End-of-life Decisions in ICD Patients with Malignant Tumors

BACKGROUND

The results of multiple implantable cardioverter-defibrillator (ICD) studies have demonstrated a survival benefit in specific high-risk populations, leading to the expansion of ICD implantation rates worldwide. Because the ICD reduces the incidence of sudden cardiac death, patients with these devices more often die of non-arrhythmic causes. For those with a malignancy, little is known about their preferences for disabling ICD therapy.

METHODS

The objective of the present study was to evaluate whether patients with an ICD and a malignant tumor desire deactivation of their ICD in order to have a death without ICD interventions, which are life-prolonging, bothersome, and prevent a peaceful death. All deceased patients having had an ICD implanted at our institution were retrospectively analyzed with respect to whether the option of disabling ICD therapy had been discussed and whether the ICD had been deactivated.

RESULTS

Two hundred and seventy-two patients received an ICD at our institution between January 1, 1994, and January 31, 2007. Thirty-six of the patients have died, and of these eight had a malignant tumor. In six of these eight patients (75%) the option of disabling their ICD therapy was discussed extensively; none wished to abandon the possibility of terminating a malignant arrhythmia by the ICD.

CONCLUSIONS

With the use of ICDs, patients with heart failure are more frequently protected from arrhythmic death, and consequently treating physicians are increasingly confronted with ICD patients presenting with a malignant tumor or other noncardiac terminal disease. In these situations, dialogue between the treating physician and the patient about the possibility of withdrawing ICD therapy is important to terminal care. The physician must be aware that the patient's attitude may contrast with his/her own, and that the patient may be resolute in maintaining ICD protection from arrhythmic death.

Visualizing Pacemaker-Induced Phrenic Nerve Stimulation with Acoustic Cardiography

This case study illustrates that acoustic cardiography--a simple non-invasive test--can be applied in any diagnostic setting as well as during biventricular pacemaker implantation to ensure that the pacemaker settings are not leading to phrenic nerve stimulation.

Early Pacemaker Battery Depletion Caused by a Current Leak in the Output Circuitry: Rectification not Exchange

Malfunction of a dual chamber system pacemaker due to a current leak in the output circuitry leading to a rapid decline in battery longevity is described. Serial pulse amplitude alterations in defined device configurations enabled location of the defect in the 2.5-V output voltage level; the current leak disappeared in the 5-V output voltage level, and recurred in the 7.5-V output voltage level which combines both 2.5-V and 5-V output circuitries. Reprogramming of pulse amplitudes rectified device malfunction. Circuitry reprogramming of pacemakers with faulty unexplained high battery current can circumvent early replacement in management of device malfunction.

Psychological Distress in Patients with ICD Recall

BACKGROUND

Multiple clinical trials have shown that a properly functioning implantable cardioverter-defibrillator (ICD) is capable of interrupting sudden death caused by ventricular tachyarrhythmias. However, ICDs are complex medical devices, and they do not always perform as expected or they may fail completely. Exposure of ICD recipients to professional or media reports that their specific device type is potentially malfunctioning could negatively influence their psychological status.

METHODS

This study aimed to evaluate and quantify psychological distress in patients implanted with an ICD-recall device. Thirty patients implanted with ICD-recall devices (ICD-recall group) and 25 patients with unaffected ICD devices (ICD-control group) were interviewed using the Brief Symptom Inventory (a psychological self-report symptom scale).

RESULTS

Mean values of all primary psychiatric distress symptom dimensions and global indices were within the normal range for both the ICD-recall and the ICD-control group. New York Heart Association (NYHA)class was a predictor of higher distress symptoms in all categories, independently of the ICD group. NYHA II group patients tended toward higher stress levels than the NYHA I group, but only somatization was significantly different. An upward, but not significant, trend in 7 of the 12 scales was associated with symptomatic shock experience.

CONCLUSION

This study demonstrates that psychological distress was not significantly increased in patients recently informed about a potential malfunction of their device.

WITHDRAWN: Enlargement of the Right Atrium - Diverticulum or Aneurysm?

The publisher regrets that this was an accidental duplication of an article that has already been published in Eur. J. Echocardiogr., 4 (2003) 223-225, . The duplicate article has therefore been withdrawn.

ECG changes amongst patients with alcohol withdrawal seizures and delirium tremens

INTRODUCTION

Alcohol withdrawal seizures and delirium tremens (DT) are serious complications of alcohol dependence. The prevalence of arrhythmias and other electrocardiographic (ECG) changes occurring in these clinical situations is not well studied.

METHODS

We performed a retrospective analysis of clinical data and ECG's from patients discharged between 1995 and 2005 with the diagnosis of DT (ICD-Code F10.4) or alcohol withdrawal seizures (F10.3). Measurement of the ECG intervals was done in lead II. The corrected QT interval (QTc) was obtained using Bazett's formula.

RESULTS

49 patients (38 males; 11 females) with a mean age of 48 years were included in the study. 23 patients with DT and 16 with convulsions were admitted to the hospitals. Ten patients developed DT while being hospitalised for other reasons. The QTc interval was prolonged (>440 ms and >460 ms in males and females, respectively) in 31 patients (63%). Five patients (10%) developed tachyarrhythmias (two torsade de pointes, one sustained ventricular tachycardia, two supraventricular tachycardia, one atrial fibrillation). All returned to sinus rhythm after appropriate treatment.

CONCLUSIONS

Tachyarrhythmias are common amongst patients with severe alcohol withdrawal syndromes. The majority of the patients had an acquired long QT syndrome which led to a torsade de pointes in two cases. No patient died in the hospital and all were discharged in sinus rhythm. Clinicians should possibly avoid QT prolonging drugs and carefully monitor the rhythm in patients with severe alcohol withdrawal syndromes.

ECG changes amongst patients with alcohol withdrawal seizures and delirium tremens

INTRODUCTION

Alcohol withdrawal seizures and delirium tremens (DT) are serious complications of alcohol dependence. The prevalence of arrhythmias and other electrocardiographic (ECG) changes occurring in these clinical situations is not well studied.

METHODS

We performed a retrospective analysis of clinical data and ECG's from patients discharged between 1995 and 2005 with the diagnosis of DT (ICD-Code F10.4) or alcohol withdrawal seizures (F10.3). Measurement of the ECG intervals was done in lead II. The corrected QT interval (QTc) was obtained using Bazett's formula.

RESULTS

49 patients (38 males; 11 females) with a mean age of 48 years were included in the study. 23 patients with DT and 16 with convulsions were admitted to the hospitals. Ten patients developed DT while being hospitalised for other reasons. The QTc interval was prolonged (>440 ms and >460 ms in males and females, respectively) in 31 patients (63%). Five patients (10%) developed tachyarrhythmias (two torsade de pointes, one sustained ventricular tachycardia, two supraventricular tachycardia, one atrial fibrillation). All returned to sinus rhythm after appropriate treatment.

CONCLUSIONS

Tachyarrhythmias are common amongst patients with severe alcohol withdrawal syndromes. The majority of the patients had an acquired long QT syndrome which led to a torsade de pointes in two cases. No patient died in the hospital and all were discharged in sinus rhythm. Clinicians should possibly avoid QT prolonging drugs and carefully monitor the rhythm in patients with severe alcohol withdrawal syndromes.

Value of Different Follow-Up Strategies to Assess the Efficacy of Circumferential Pulmonary Vein Ablation for the Curative Treatment of Atrial Fibrillation

BACKGROUND

The objective of this study was to compare transtelephonic ECG every 2 days and serial 7-day Holter as two methods of follow-up after atrial fibrillation (AF) catheter ablation for the judgment of ablation success. Patients with highly symptomatic AF are increasingly treated with catheter ablation. Several methods of follow-up have been described, and judgment on ablation success often relies on patients' symptoms. However, the optimal follow-up strategy objectively detecting most of the AF recurrences is yet unclear.

METHODS

Thirty patients with highly symptomatic AF were selected for circumferential pulmonary vein ablation. During follow-up, a transtelephonic ECG was transmitted once every 2 days for half a year. Additionally, a 7-day Holter was recorded preablation, after ablation, after 3 and 6 months, respectively. With both, procedures symptoms and actual rhythm were correlated thoroughly.

RESULTS

A total of 2,600 transtelephonic ECGs were collected with 216 of them showing AF. 25% of those episodes were asymptomatic. On a Kaplan-Meier analysis 45% of the patients with paroxysmal AF were still in continuous SR after 6 months. Simulating a follow-up based on symptomatic recurrences only, that number would have increased to 70%. Using serial 7-day ECG, 113 Holter with over 18,900 hours of ECG recording were acquired. After 6 months the percentage of patients classified as free from AF was 50%. Of the patients with recurrences, 30-40% were completely asymptomatic. The percentage of asymptomatic AF episodes stepwise increased from 11% prior ablation to 53% 6 months after.

CONCLUSIONS

The success rate in terms of freedom from AF was 70% on a symptom-only-based follow-up; using serial 7-day Holter it decreased to 50% and on transtelephonic monitoring to 45%, respectively. Transtelephonic ECG and serial 7-day Holter were equally effective to objectively determine long-term success and to detect asymptomatic patients.

Perception of Atrial Fibrillation Before and After Radiofrequency Catheter Ablation

Background— The objective of this study was to assess the incidence and impact of asymptomatic arrhythmia in patients with highly symptomatic atrial fibrillation (AF) who qualified for radiofrequency (RF) catheter ablation.

Methods and Results— In this prospective study, 114 patients with at least 3 documented AF episodes together with corresponding symptoms and an ineffective trial of at least 1 antiarrhythmic drug were selected for RF ablation. With the use of CARTO, circumferential lesions around the pulmonary veins and linear lesions at the roof of the left atrium and along the left atrial isthmus were placed. A continuous, 7-day, Holter session was recorded before ablation, right after ablation, and after 3, 6, and 12 months of follow-up. During each 7-day Holter monitoring, the patients recorded quality and duration of any complaints by using a detailed symptom log. More than 70 000 hours of ECG recording were analyzed. In the 7-day Holter records before ablation, 92 of 114 patients (81%) had documented AF episodes. All episodes were symptomatic in 35 patients (38%). In 52 patients (57%), both symptomatic and asymptomatic episodes were recorded, whereas in 5 patients (5%), all documented AF episodes were asymptomatic. After ablation, the percentage of patients with only asymptomatic AF recurrences increased to 37% ( P <0.05) at the 6-month follow-up. An analysis of patient characteristics and arrhythmia patterns failed to identify a specific subset who were at high risk for the development of asymptomatic AF.

Conclusions— Even in patients presenting with highly symptomatic AF, asymptomatic episodes may occur and significantly increase after catheter ablation. A symptom-only–based follow-up would substantially overestimate the success rate. Objective measures such as long-term Holter monitoring are needed to identify asymptomatic AF recurrences after ablation.