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Biomedical subjects

E Andries

Publications and source records attributed to E Andries.

At least 19 recordsLinked to original sources
PubMed1998

Different humoral responses during head-up tilt testing among patients with neurocardiogenic syncope.

Neurocardiogenic dysfunction is believed to result from activation of ventricular mechanoreceptors. To asses other humoral and circulatory mechanisms activated during vasovagal syncope, epinephrine, norepinephrine, renin, and aldosterone levels were measured during head-up tilt testing. Twenty-three patients referred because of vasovagal syncope underwent passive head-up tilt testing (80 degrees). Blood samples were taken at baseline, after 30 minutes of supine rest and at syncope. Five patients (four men, one woman; mean age 46 +/- 27 years) had cardioinhibitory syncope. Seven patients (five men, two women; mean age 40 +/- 12 years) had vasodepressor syncope. Eleven patients (eight men, three women; mean age 55 +/- 21 years) had negative results of head-up tilt tests. Among patients with cardioinhibitory syncope, norepinephrine concentration rose significantly from baseline to syncope (0.44 +/- 0.12 ng/ml versus 1.14 +/- 0.72 ng/ml; p < 0.05), whereas no significant change was observed in epinephrine (0.08 +/- 0.03 ng/ml versus 2.74 +/- 2.85 ng/ml; p = not significant [NS]), renin (5.68 +/- 3.03 pg/ml versus 19.58 +/- 11.47 pg/ml; p = NS), or aldosterone concentration (66.60 +/- 16.10 ng/ml versus 109.00 +/- 44.70 ng/ml; p = NS). Patients with vasodepressor syncope had a significant rise in renin (9.03 +/- 4.56 pg/ml versus 52.53 +/- 41.63 pg/ml; p < 0.05) and aldosterone concentration (95.43 +/- 103.03 ng/ml versus 249.57 +/- 191.54 ng/ml; p < 0.05), whereas no change in level of epinephrine (0.12 +/- 0.12 ng/ml versus 0.28 +/- 0.33 ng/ml; p = NS) or norepinephrine (0.60 +/- 0.26 ng/ml versus 0.86 +/- 0.53 ng/ml; p = NS) was detected. Among patients with negative results of tilt tests, levels of renin (7.94 +/- 7.19 pg/ml versus 27.71 +/- 18.50 pg/ml; p < 0.01) and aldosterone (64.64 +/- 28.33 ng/ml versus 160.91 +/- 79.58 ng/ml; p < 0.01) rose significantly, whereas no change was seen in epinephrine (0.12 +/- 0.14 ng/ml versus 0.23 +/- 0.31; p = NS) or norepinephrine concentration (0.54 +/- 0.21 ng/ml versus 0.82 +/- 0.52; p = NS). Patients with cardioinhibitory syncope were characterized by a rise in norepinephrine level and blunted activation of the renin-angiotensin-aldosterone axis at syncope. Unlike patients with cardioinhibitory syncope, the renin-angiotensin-aldosterone axis is activated in patients with vasodepressor syncope and patients with a negative result of head-up tilt test without a statistically significant increase in catecholamine levels. Patients with cardioinhibitory syncope have higher epinephrine levels at syncope compared with patients with a negative result of head-up tilt test and patients with vasodepressor syncope.

Adult↗
PubMed1998

Neck pounding during sinus rhythm: a new clinical manifestation of dual atrioventricular nodal pathways.

OBJECTIVE: To determine the clinical and electrophysiological characteristics of patients with paroxysmal palpitations and neck pounding during sinus rhythm. METHODS: Clinical, electrocardiographic, and electrophysiological characteristics of six patients with paroxysmal palpitations and neck pounding during sinus rhythm were studied in basal conditions and when symptomatic. Response to treatment was observed. RESULTS: Baseline ECGs were normal (four patients) or had first degree atrioventricular block with intermittent PR shortening. During symptoms, narrow QRS rhythms were seen without visible P waves (three patients) or with P waves partially hidden in the QRS complex (three patients). Dual atrioventricular nodal pathways were found in all five patients who had electrophysiological studies. In these patients the slow pathway conduction time was long enough (mean (SD), 425 (121) ms) for ventricular activation after slow pathway conduction during sinus rhythm to coincide with the next atrial depolarisation, causing neck pounding during exercise (four patients) or at rest (two patients). Tachycardia was not induced in any patient. Medical treatment aggravated symptoms in three patients. A pacemaker was successfully used in two. CONCLUSIONS: Neck pounding during sinus rhythm is a clinical manifestation of dual atrioventricular nodal pathways. Medical treatment may aggravate symptoms but a pacemaker may offer definitive relief.

Adult↗
PubMed1997

Hemodynamic deterioration following radiofrequency ablation of the atrioventricular conduction system.

Radiofrequency ablation of the atrioventricular conduction system (ACS) has become an established therapy for patients with drug refractory atrial fibrillation. We observed eight patients with hemodynamic deterioration after radiofrequency ablation of the atrioventricular conduction system. As we found hemodynamic deterioration related to worsening mitral regurgitation, we compared the clinical history, electrophysiological, and echocardiographic data from the patients with hemodynamic deterioration and worsening mitral regurgitation (group 1) to those without hemodynamic deterioration and stable mitral regurgitation after the procedure (group 2). Eight out of 108 patients (7.4%) undergoing ablation of the ACS deteriorated hemodynamically with acute pulmonary edema in three and congestive heart failure in five patients occurring at a mean of 3 and 8 weeks, respectively, after the procedure. Three of these patients were referred for mitral valve surgery. Two patients underwent ablation using a left-sided approach. A right-sided approach was used in five patients. In one patient, a left- and right-sided approach was used. Compared to group 2 patients, group 1 patients had significantly higher left ventricular end-diastolic diameters (64 +/- 6 mm vs 56 +/- 9 mm) at baseline despite similar fractional shortening (32% +/- 11% vs 34% +/- 13%), left ventricular end-systolic diameters (43 +/- 9 mm vs 36 +/- 7 mm) and degree of mitral regurgitation (1.4 +/- 1.1 vs 1.4 +/- 0.7) on echocardiographic analysis. Thus, hemodynamic deterioration together with progression of mitral regurgitation is a potential complication of ablation of the ACS (up to 7.4%). Patients with high left ventricular end-diastolic diameters and moderate mitral regurgitation at baseline seem prone to this complication.

Adult↗
PubMed1997

Ventricular fibrillation and sudden death after radiofrequency catheter ablation of the atrioventricular junction.

Two hundred thirty-five patients underwent RF catheter ablation of AV conduction for symptomatic drug refractory AF (84%), atrial flutter (9%), and atrial tachycardia (7%). In the first 100 patients, postablation pacing was not prospectively set at any specific rate and was always < or = 70 beats/min. In the next 135 patients, postablation pacing was prospectively set at 90 beats/min for 1-3 months. Six of the first 100 patients (6%) had VF or sudden death after the RF procedure and none (0%) of the next 135 patients did (P < 0.05). One of the six patients had recurrent VF 4 days after the ablation. Five patients were successfully resuscitated and one patient died. There were no statistically significant differences between patients with and without (aborted) sudden death or between the first 100 and the next 135 patients with respect to age, sex, underlying heart disease, EF, number of RF applications, or left-or right-sided approach of the procedure. VF mostly occurred during episodes of slow ventricular escape rhythms or during slow ventricular pacing. We conclude that malignant ventricular arrhythmias and sudden death are possible complications of RF ablation of the AV function. The mechanism of these complications could have a bradycardia dependent nature and it seems that the occurrence of malignant arrhythmias can be prevented by temporarily pacing the heart at relatively fast rates immediately after ablation.

Aged↗
PubMed1996

A prophylactic implantable cardioverter-defibrillator?

Antiarrhythmic drugs have systematically failed to improve--or have even worsened prognosis--when given prophylactically to "high-risk" patients without previous spontaneous sustained ventricular arrhythmias. In patients who have had > or = 1 episode(s) of near sudden cardiac death or sustained ventricular arrhythmias, randomized studies against placebo have been considered unethical. Therefore, no information exists on the value of treatment with antiarrhythmic drugs in the prevention of sudden death in these patients. Sudden death is quite predictable and almost expected in some situations. The number of "very high risk" patients is small, but the incidence of sudden death among them is very high. A prophylactic implantable cardioverter-defibrillator (ICD) can be easily justified in them. Unfortunately, the greatest absolute number of sudden deaths occurs in patients from a very large population with a rather low risk for sudden death. Truly unexpected cardiac death is most frequently caused by the first acute ischemic event in a previously asymptomatic individual. While the causes of sudden cardiac death are multiple, the final link is frequently the same: ventricular fibrillation. This arrhythmia can be effectively recognized and treated by an ICD, irrespective of its initiating cause. The time when an ICD will be given prophylactically to a truly asymptomatic individual may never come, but there is an urgent need to implant this device prophylactically in patients who are clearly at risk for sudden death. There are medical, ethical, statistical, technical, practical, financial, and even philosophical obstacles involved in the concept of a prophylactic ICD, but they can be solved, because this therapy is effective. Deciding on the benefits of a prophylactic ICD is a probabilistic issue analogous to deciding on mass vaccination against a preventable infection. To the political community, the decision to accept a prophylactic ICD is too much a matter of expenses, because the benefits may not seem that obvious to them. To the device industry, the cleaves between doctors and politicians have to be the best stimuli to come along with cost-effective technology acceptable to both sides.

Death, Sudden, Cardiac↗
PubMed1995

New developments and treatment strategies in patients with supraventricular tachyarrhythmias.

The mechanisms, clinical presentation and therapy of supraventricular tachycardias are discussed. The therapy has changed from palliation by means of anti-arrhythmic drugs into definitive cure by ablation of the arrhythmia substrate. Radiofrequency energy causes tissue damage by heating and appears to be a safe method for catheter ablation of supraventricular tachycardias. We report a 97% success rate for radiofrequency ablation of 195 accessory atrioventricular pathways thereby curing these patients from circus-movement tachycardia and paroxysmal atrial fibrillation. Complications occurred in 3% of patients. One hundred seventy-two patients with atrioventricular nodal reentrant tachycardia, caused by reentry within dual AV-nodal pathways, were treated by selectively ablating one of the pathways with non-inducibility of the arrhythmia afterwards in 97% of the cases. Nine percent of patients had a recurrence but were successfully treated in a second session. The procedure was complicated by complete AV-block in 4% of patients. The disappointing medical treatment of atrial fibrillation and the fact that atrial fibrillation can be the cause of a reversible form of heart failure (tachycardiomyopathy), induced the clinical application of alternative forms of treatment. Ablation of the normal atrioventricular conduction system by using radiofrequency energy was performed with a 100% success rate in 121 patients. After implantation of a ventricular pacemaker it is possible to control and regulate the ventricular rhythm leading to rate control and amelioration of ventricular performance.

Atrial Fibrillation↗
PubMed1995

At what time are implantable defibrillator shocks delivered? Evidence for individual circadian variance in sudden cardiac death.

BACKGROUND: As in myocardial infarction and transient ischaemia, out-of-hospital sudden cardiac death has an increased morning incidence. However, sudden death occurring in hospital is evenly distributed over the 24 h period suggesting that there might be subgroups of patients with atypical circadian patterns of sudden death. Patients who received an implantable defibrillator constitute an ideal group for studies of circadian patterns of sudden death since this generation of devices are able to store the exact time when defibrillation occurred. METHODS: The distribution of sudden death aborted by the implantable defibrillator was analysed during the 24 h period for 87 presumed appropriate shocks delivered in a group of 22 patients, 18 men and four women, 58.7 +/- 11.9 years old and with a mean left ventricular ejection fraction of 39.4 +/- 17.6%. RESULTS: Each patient received an average of 4.42 +/- 3.04 shocks during a mean follow-up of 9.4 +/- 5.6 months. Apart from a clear tendency for shocks to occur during the morning hours (42% of total shocks), five of 16 patients who received multiple shocks also showed a trend to repeat the shocks around the same period during the day. CONCLUSION: Our results support the accepted view that changes in autonomic tone in the early morning play a role in the circadian variations of sudden death. Sudden death not only occurs more frequently in the morning hours, but it also clusters in certain periods for individual patients.

Adult↗
PubMed1995

A fast and reliable algorithm to localize accessory pathways based on the polarity of the QRS complex on the surface ECG during sinus rhythm.

BACKGROUND: Many criteria have been published to localize accessory pathways from the 12-lead ECG during sinus rhythm. This study analyzed whether the localization of an accessory pathway could be predicted by using the polarity of the QRS complex during sinus rhythm on the surface ECG, instead of the delta wave polarity as used in many reports. METHODS: The ECGs of 140 patients with an overt and single accessory pathway were evaluated. Eight localizations were taken into account. The precise location was previously known from successful radiofrequency ablation sites. RESULTS: In 128 patients (92%), the new algorithm allowed an accurate diagnosis of the site of implantation of the accessory pathway. CONCLUSION: Analysis of the polarity of the QRS complex on five electrocardiographic leads provides an easy, fast and reliable way to localize accessory pathways during sinus rhythm.

Algorithms↗
PubMed1995

[Radiofrequency catheter ablation of atrial tachycardia].

BACKGROUND AND OBJECTIVE: Radiofrequency catheter ablation has proved to be highly effective for the treatment of supraventricular tachycardia originating in the AV node or related to atrioventricular accessory pathways. However, experience with ablation of atrial tachycardia is more limited. The purpose of our study was to analyse the success and safety of radiofrequency ablation of atrial tachycardias. STUDY POPULATION: Ten symptomatic patients with drug refractory atrial tachycardia. Symptoms included palpitations, dizziness, chest pains, shortness of breath, syncope. Five patients had reduced left ventricular ejection fraction (tachycardiomyopathy). METHODS: Radiofrequency device - Medtronic ATAKRR with temperature monitoring. Temperature ranges from 50 degrees C to 70 degrees C were considered optimal to ablation. Ablation catheter - 7 F CardiorhythmR with a 4 mm2 deflectable tip. Heparin was given intravenously during the procedure (5000 IU bolus + 1000 IU/h). Acetylsalicylic acid 160 mg/day for 1 month after the procedure. Antiarrhythmic drugs were discontinued after the procedure. The sites for ablation were defined during tachycardia by the earliest endocardial atrial activation as compared to the onset of the surface P wave. Criteria of success: Abolition of the tachycardia followed by the inability to reinduce the tachycardia. FOLLOW-UP: Clinical, ECG and 2D ECHO evaluation in the outpatient's clinic. No complications occurred during the procedure. No reccurrences of the tachycardia were observed during the follow-up. All 5 patients with reduced ejection fraction before ablation had normal left ventricular function during follow-up. CONCLUSION: Radiofrequency catheter ablation is a safe and effective treatment for drug refractory atrial tachycardia.

Catheter Ablation↗
PubMed1995

Diagnosis and treatment of tachycardias with a long BP interval.

The differential diagnosis of tachycardias with a long RP interval is reviewed and the methods of treatment of these arrhythmias catheter ablation are described. Electrocardiographic and electrophysiologic criteria for the correct diagnosis of atrial tachycardia, circus movement tachycardia using retrogradely an accessory pathway with decremental conduction properties and the uncommon form of atrioventricular nodal reentrant tachycardia are discussed. First results of our institution of radiofrequency catheter ablation of atrial tachycardias and circus movement tachycardias using retrogradely an accessory pathway with decremental conduction properties are presented. We concluded that both electrocardiographic and electrophysiologic criteria give a better understanding of the mechanism and arrhythmic site which are important markers for a safe and successful ablation procedure.

Catheter Ablation↗
PubMed1994

The differential diagnosis on the electrocardiogram between ventricular tachycardia and preexcited tachycardia.

The 12-lead surface electrocardiogram is a simple and useful tool for the differential diagnosis of regular wide QRS complex tachycardia. However, criteria do not as yet exist to discriminate between ventricular tachycardia and supraventricular tachycardia with anterograde conduction over an accessory pathway (preexcited tachycardia). Therefore, we designed a new stepwise approach with three criteria for the electrocardiographic differential diagnosis between ventricular tachycardia and preexcited tachycardia and prospectively studied 267 regular tachycardias with electrophysiologically proven mechanism and a wide QRS complex (> or = 0.12 s): 149 consecutive ventricular tachycardias and 118 consecutive preexcited regular tachycardias. Underlying heart disease was old myocardial infarction in 133 of 149 (89%) ventricular tachycardias. The patients presenting with preexcited tachycardia had no additional structural heart disease. Atrial fibrillation with preexcited QRS complex was not included. The criteria favoring ventricular tachycardia were: (1) presence of predominantly negative QRS complexes in the precordial leads V4 to V6, (2) presence of a QR complex in one or more of the precordial leads V2 to V6, and (3) AV relation different from 1:1 (more QRS complexes than P waves). The final sensitivity and specificity of these three consecutive steps to diagnose ventricular tachycardia were 0.75 and 1.00, respectively. This new stepwise approach is sensitive and highly specific for the differential diagnosis between ventricular tachycardia in coronary artery disease and preexcited regular tachycardia.

Coronary Disease↗
PubMed1994

Cardiac depolarization and repolarization in Wolff-Parkinson-White syndrome.

Delta wave and QRS complex polarities have been extensively studied in preexcitation syndromes. However, only limited data exist about ventricular depolarization and repolarization in the setting of maximal preexcitation in relation to the site of insertion of the accessory pathway. Therefore this study was designed to systematically analyze cardiac depolarization and repolarization in patients with maximal preexcitation. We analyzed the polarity of the QRS complex and T wave on the frontal plane on the conventional 12-lead electrocardiogram in 118 patients with maximal preexcitation. Fast atrial pacing was used to provoke maximal ventricular preexcitation. The 32 patients with a left lateral accessory pathway showed right-axis deviation of the QRS complex (110 +/- 20 degrees) with a left-axis deviation of the T-wave axis (-40 +/- 25 degrees). The 54 patients with a posteroseptal accessory pathway had a left axis of the QRS complex (-50 +/- 20 degrees) with a right-axis deviation of the T-wave axis (95 +/- 15 degrees). The 11 patients with a right lateral accessory pathway had a left axis of the QRS complex (-40 +/- 20 degrees) and a right axis of the T wave (110 +/- 10 degrees). In 7 patients with a left anterolateral accessory pathway and 14 patients with a right anteroseptal accessory pathway, the axis of the QRS complex was 50 +/- 25 degrees and 45 +/- 20 degrees, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Inappropriate sinus tachycardia following radiofrequency ablation of AV nodal tachycardia: incidence and clinical significance.

The incidence and consequences of inappropriate sinus tachycardia following modification of the AV nodal area with radiofrequency energy were prospectively studied in a consecutive series of 118 patients. Twelve (10%) patients developed this complication, which persisted less than 1 week in all but three patients. Inappropriate sinus tachycardia was only observed after fast pathway ablation. Only four patients required temporary treatment with a beta blocker.

Adolescent↗