Heart rate variability in idiopathic dilated cardiomyopathy: characteristics and prognostic value.

OBJECTIVES: This study was designed to evaluate heart rate variability (HRV) in patients with idiopathic dilated cardiomyopathy (IDC), to determine its correlation with hemodynamic variables and ventricular arrhythmias and to evaluate its prognostic value in IDC. BACKGROUND: Previous studies have shown that HRV could predict arrhythmic events in patients after infarction, but the characteristics of HRV in IDC have not been fully established. METHODS: Time domain analysis of HRV on 24-h electrocardiographic (ECG) recording was performed in 93 patients with IDC, and results were compared with those in 63 control subjects. RESULTS: Patients with IDC, even those without congestive heart failure, had significantly lower values for HRV than those of control subjects. HRV was related to left ventricular shortening fraction (R = 0.5, p = 0.0001) and to peak oxygen uptake (R = 0.53, p = 0.01). HRV was not different in patients with runs of ventricular tachycardia or in patients with late potentials on the signal-averaged ECG. During a mean follow-up period (+/-SD) of 49.5 +/- 35.6 months, patients with reduced HRV had an increased risk of cardiac death or heart transplantation (p = 0.006). On multivariate analysis, cardiac events were predicted by increased left ventricular end-diastolic diameter (p = 0.0001), reduced standard deviation of all normal to normal RR intervals (p = 0.02) and increased pulmonary capillary wedge pressure (p = 0.04). CONCLUSIONS: Decreased HRV in patients with IDC is related to left ventricular dysfunction and not to ventricular arrhythmias. Analysis of HRV can identify patients with IDC who have an increased risk of cardiac death or heart transplantation.

Prognostic value of heart rate variability for sudden death and major arrhythmic events in patients with idiopathic dilated cardiomyopathy.

OBJECTIVE: This study was designed to evaluate the prognostic value of heart rate variability for sudden death, resuscitated ventricular fibrillation or sustained ventricular tachycardia in patients with idiopathic dilated cardiomyopathy. BACKGROUND: Previous studies have shown that heart rate variability could predict arrhythmic events and sudden death in postinfarction patients, but the prognostic value of heart rate variability for arrhythmic events or sudden death in patients with idiopathic dilated cardiomyopathy has not been established. METHODS: Time and frequency domain analysis of heart rate variability on 24-h electrocardiographic (ECG) recording was assessed in 116 patients with idiopathic dilated cardiomyopathy (91 men, aged 51+/-12 years, left ventricular ejection fraction 34+/-12%). RESULTS: Mean follow-up (+/-SD) was 53+/-39 months. Sixteen patients reached one of the defined study end-points (sudden death, resuscitated ventricular fibrillation or sustained ventricular tachycardia) during follow-up. Using multivariate analysis, only reduced standard deviation of all normal-to-normal intervals (SDNN) (p = 0.02) and ventricular tachycardia during 24-h ECG recording (p = 0.02) predicted sudden death and/or arrhythmic events. For SDNN, a cutoff level of 100 ms seemed the best for the risk stratification. CONCLUSIONS: Decrease in heart rate variability is an independent predictor of arrhythmic events and sudden death in idiopathic dilated cardiomyopathy, whether the mechanism of sudden death is ventricular tachyarrhythmia or not.

Persistent fetal dispersion of the atrioventricular node. Association with the Wolff-Parkinson-White syndrome.

Symptomatic supraventricular tachycardias developed in a 58-year-old man not long before he also was found to have metastatic cancer. During electrophysiological studies, type A Wolff-Parkinson-White syndrome was defined and at least four different forms of supraventricular tachycardias were documented. When he died of his cancer, autopsy studies included special examination of his heart and its conduction system. There was a slender connection between the left atrium and left ventricle posterior to the margo obtusus, composed of ordinary working myocardial cells. There was also persistent fetal dispersion of the atrioventricular (AV) node within the central fibrous body, forming a suitable anatomical substrate for reentrant tachycardias originating entirely there. The anatomical and electrophysiological findings are discussed relative to the question of surgery in such patients, since cutting the lateral AV connections might eliminate the delta wave but not the supraventricular tachycardias.

Long-term prognostic value of time domain analysis of signal-averaged electrocardiography in idiopathic dilated cardiomyopathy.

The aim of this study was to evaluate the long-term prognostic value of signal-averaged electrocardiography (SAECG) in idiopathic dilated cardiomyopathy (IDC). Time domain analysis of SAECG was assessed in 131 patients with angiographically confirmed IDC (age 52+/-12 years; 108 men; left ventricular ejection fraction 33+/-12%) using specific criteria in 44 patients with bundle branch block. Late potentials (LP) on SAECG were present in 27% of the patients. Patients with LP had a similar left ventricular ejection fraction and a similar left ventricular end-diastolic diameter than patients with a normal SAECG. With a follow-up of 54+/-41 months, 24 patients suffered cardiac death and 19 had major arrhythmic events (sudden death, resuscitated ventricular fibrillation, or sustained ventricular tachycardia). Patients with LP had an increased risk of all-cause cardiac death (RR 3.3, 95% confidence interval 1.5 to 7.5, p = 0.004) and of arrhythmic events (RR 7.2, 95% confidence interval 2.6 to 19.4, p = 0.0001). Using multivariate analysis, only LP on SAECG (p = 0.001), reduced SD of all normal-to-normal intervals (SDNN) (p = 0.002), increased pulmonary capillary wedge pressure (p = 0.005), and history of sustained ventricular tachyarrhythmia (p = 0.02) predicted cardiac death. A history of previous sustained ventricular tachyarrhythmia (p = 0.0001), reduced SDNN (p = 0.003), and LP on SAECG (p = 0.006) were the only independent predictors of major arrhythmic events. Results were not altered when considering separately patients with or without bundle branch block, or after exclusion of patients with a history of sustained ventricular tachyarrhythmia. This study is one of the first to suggest that LP on SAECG is an independent predictor of all-cause cardiac death and is of high interest for arrhythmia risk stratification in IDC.

Effect of verapamil on heart rate variability in subjects with normal hearts.

Heart rate variability on 24-hour electrocardiographic recording was assessed in 23 patients without structural heart disease before and after 2 months of oral treatment with verapamil prescribed for paroxysmal atrioventricular nodal reentrant tachycardia. Verapamil had no significant effect on overall heart rate variability in the frequency domain, but it increased ultra low frequency power and decreased the low-frequency/high-frequency ratio, deemed to be a marker of sympathetic activity.

Effect of verapamil on QT interval dynamicity.

Using measurements of QT/RR slopes with a computerized Holter system, QT interval dynamicity was evaluated in 19 patients with normal structural heart before and 2 months after oral treatment with verapamil prescribed for paroxysmal atrioventricular nodal reentrant tachycardia. Verapamil significantly shortened QT at low heart rates, mainly in the diurnal period, and this characteristic may explain, in part, the previously reported protective effect of verapamil against torsades de pointes.

Association between heart rate-corrected QT interval and coronary risk factors in 2,894 healthy subjects (the DESIR Study). Data from an Epidemiological Study on the Insulin Resistance syndrome.

In the prospective Data from an Epidemiological Study on the Insulin Resistance Syndrome, 2,894 healthy subjects aged 30 to 64 years had determinations of fasting glucose, insulin, serum lipid and fibrinogen concentrations, blood pressures, body mass index, and waist-hip ratio, as well as tobacco and alcohol consumptions and physical activity. A 12-lead electrocardiogram with automatic measurement of the QT interval was recorded and the formula used for heart rate correction was based on the best-fit regression between QT and heart rate. The QT duration was influenced by glucose homeostasis in both sexes, and increased in men with physical activity; there was a dose-effect relation for men who smoked.

Significance of late ventricular potentials in myotonic dystrophy.

In 39 patients with myotonic dystrophy, we found a high percentage of infrahissian cardiac conduction abnormalities (51%) and late potentials (46%), whereas spontaneous and inducible ventricular arrhythmias were rare. These results suggest that the prolongation of QRSD and the duration of the low-amplitude signal on the signal-averaged electrocardiogram were related to delayed activation of the His and Purkinje tissue rather than true late potentials.

Diagnosis of arrhythmogenic right ventricular cardiomyopathy by fourier analysis of gated blood pool single-photon emission tomography.

To evaluate the diagnostic performance of Fourier phase analysis of gated blood pool single-photon emission computed tomography (GBP SPECT) in arrhythmogenic right ventricular (RV) cardiomyopathy, 18 patients with confirmed arrhythmogenic RV cardiomyopathy underwent GBP SPECT and x-ray cineangiography. Results were compared with data obtained with GBP SPECT in 10 control subjects. This 3-dimensional method demonstrated good correlation with cineangiography for measurements of RV enlargement and extent of the disease; RV and left ventricular segments were analyzed with the same accuracy. Tomographic abnormalities were significant decreased RV ejection fraction, RV dilatation, nonsynchronized contraction of the ventricles, increased RV contraction dispersion, presence of segmental RV wall motion disorders and/or phase delays, and occasionally regional left ventricular abnormalities. RV-delayed phase areas were always present in our population. A scoring system with RV criteria was proposed to diagnose RV disease. Because Fourier analysis of GBP SPECT provides ventricular morphologic information for the right ventricle with the same accuracy as for the left ventricle, it may replace planar radionuclide studies. Therefore, this method is helpful in patients with a strong clinical suspicion of arrhythmogenic RV cardiomyopathy, and should be used as a screening method before right ventriculography.

["Torsades de pointe" and reentry induced by anti-arrhythmia agents]. / Torsades de pointe et rentrées provoquées par les antiarythmiques.

Some anti-arrhythmic agents which have a stabilising effect on the membrane, particularly those belonging to Group I of Vaughan William's classification, are likely to cause rythmic disturbances by a re-entry phenomenon (atrial flutter 1/1, premature ventricular contractions, ventricular tachycardia, "torsades de pointe", even fatal ventricular fibrillation). The quinidines have been the most often condemned due to their effect on the action potential and on the speed of conduction. The fact that these re-entry phenomena are more frequent at therapeutic doses than at high or toxic doses suggests an individual susceptibility and the interaction of various predisposing factors: renal insufficiency, potassium depletion, pre-existing conduction disturbances, potentialsing drugs. In order to prevent these incidents it is advisable not to prescribe such anti-arrhythmic agents for susceptible patients, to control individual tolerance and to watch for the first ECG signs of conduction disturbances or of re-entry, such as premature contraction with fixed coupling. Treatment consists in an electrosystolic stimulus and the possible administration of potassium and bretylium.

[Wolff-Parkinson-White syndrome and longitudinal dissociation of the atrioventricular node. Anatomical and electrophysiological correlates]. / Syndrome de Wolff-Parkinson-White et dissociation longitudinale du noeud de Tawara. Corrélations entre l'anatomie et l'électrophysiologie.

A 58 year old man who died of metastatic carcinoma had undergone electrophysiological investigation 4 years previously for a Wolff-Parkinson-White syndrome (Rosenbaum Type A, Frank and Boineau Type IV) associated with supraventricular tachycardia (SVT) at 180/mn, atrial fibrillation and flutter and slow junctional (or low atrial) rhythm at 70-80/mn. Atrial extrasystoles or appropriate atrial stimulation not only induced and terminated the SVT but also the junctional rhythm and allowed passage from one arrhythmia to another. These studies showed the presence of a left lateral Kent bundle responsible for orthodromic SVT with retrograde conduction through the accessory pathway, and suggested that the junctional rhythm might be due to longitudinal dissociation of the AV node. Autopsy findings confirmed the presence of the left posterolateral Kent bundle in an almost horizontal position, parallel to the mitral annulus (it might therefore have escaped eventual surgical section) and the longitudinal dissociation of the AV node.

[The heart and hyperkalemia]. / Coeur et hyperkaliémie.

Hyperkalaemia is a common and serious clinical condition in medical and surgical intensive care units. It is mainly encountered in patients with overt or latent cardiac and/or renal failure, and often aggravated by dietetic and therapeutic mismanagement. Hyperkalaemia depresses cardiac contractility, automaticity, conductivity and excitability, leading to ECG changes which must be recognized before clinical cardiovascular deterioration occurs if treatment is to be given to reverse an irremediably fatal evolution: ST-T changes and widening of the QRS with axial deviation shortly precede sinoatrial, intraatrial and atrioventricular block, the characteristic appearances of atrial standstill and ventricular and junctional hyperexcitability. The ECG changes faithfully follow the rise in serum potassium with few exceptions, such as associated electrolytic and acid-base disturbances (usually acidosis). Treatment must be administered as soon as a rise in potassium is observed. It may be administered intravenously (hypertonic glucose and insulin, calcium gluconate, furosemide, buffer solution and, above all, sodium bicarbonate or hypertonic saline) or orally (cation exchange resin). Renal dialysis may be required secondarily.

[Chronic idiopathic binodal block. Occurrence, course and pathogenesis]. / Le bloc binodal chronique idiopathique. Fréquence, aspects évolutifs et hypothèses pathogéniques.

The incidence of binodal, sinoatrial (SA) and atrioventricular (AV), block was determined in a series of 362 patients, 90 of whom had chronic sinoatrial block (group I), 162 suprahisian, infrahisian or diffuse AV block (group II), 38 with paroxysmal supraventricular tachycardia (group III), and 70 with slow atrial fibrillation, 54 of whom were studied in sinus rhythm (group IV). Electrophysiological investigation revealed: overt or latent AV block in 71% of group I, 48% of group III, and 100% of group IV; overt or latent SA block in 40 to 61% of group II, 87% of group III and 78% of group IV; paroxysmal atrial fibrillation in 61% of group I, 25% of group II and 50% of group IV; intra-atrial block in 26% of group I, 20% of group II, 16% of group III and 31% group IV. An ECG syndrome associating binodal block and disturbances or atrial conduction and excitability is suggested. The pathogenesis and anatomical basis are discussed, the prime lesion of which may be fibrosis of the atrial tissues which may ultimately result in partial or total atrial standstill.

[Adult familial idiopathic binodal block]. / Le bloc binodal idiopathique et familial de l'adulte.

Four brothers with a maximum age difference of 20 years, the eldest of whom has been re-examined after a 10 year interval, have sinoatrial block, a supra-hisian atrioventricular block and paroxysmal atrial arrhythmias which have led to partial atrial standstill in the eldest: left anterior hemiblock is also present in the two youngest brothers. The condition is very well tolerated. This family is compared to the other 12 reported cases of familial idiopathic binodal block in the adult, an autosomal dominant condition with variable penetration. The diagnosis is reserved and justifies endocavitary investigation of the sinus node function and atrioventricular conduction in the four brothers and the most exposed members of their family. The mechanism of the condition is unknown. It seems to arise from variable degrees of nonspecific of the nodal and atrial tissues.

[Paroxysmal sinoatrial tachycardia. Apropos of 44 cases]. / Les tachycardies sino-auriculaires paroxystiques. A propos de 44 cas.

44 cases of paroxysmal sinoatrial tachycardia (PAT) due to reentry within the sinus node or between the sinus node and the atrium are reported; these tachycardias are usually quite well tolerated clinically as the rhythm is rarely faster than 140/min and they are often degraded by functional AV block. They can be triggered and terminated by one (or two) atrial stimuli, and reduced by carotid sinus massage but relapse in the short term. They often alternate with a disturbance of atrial excitability in patients who also have binodal disease. Their diagnosis implies endocavitary investigation showing sinusal anterograde atrial activation and atrial and ventricular stimulation to differentiate them from other types of paroxysmal tachycardia, especially those due to reentry involving concealed right sided Kent bundles. Studies of sinus node function by atrial extrastimulus techniques in 38 patients usually showed an isolated and prolonged Zone I followed, without a transitional plateau, by a Zone IV of sinus echos during which the tachycardia could be triggered. This type of tachycardia, without doubt as common as junctional tachycardia, may respond to treatment with Quinidine, Amiodarone, Verapamil, or beta-blockers, associated with permanent pacing in cases of binodal block.

[Retrograde ventriculo-auricular heart conduction in 126 patients with or without supra-ventricular paroxysmal tachydardia, with or without ventricular preexcitation]. / Etude de la conduction rétrograde ventriculo-auriculaire chez 126 patients normaux ou souffrant de tachycardies supra-ventriculaires paroxystiques avec ou sans préexcitation ventriculaire.

Ventriculo-atrial (VA) conduction was studied by ventricular stimulation at increasing rate and atrial mapping in 126 patients either without ventricular preexcitation (WPW) and supraventricular tachycardia (SVT) (Group I: 60 cases) or with the WPW syndrome with or without SVT (Group II: 30 cases) or with SVT without WPW (Group III: 53 cases) or with short PR intervals (Group IV: 3 cases). In Group I, 22 patients had VA block, 10 had concealed accessory pathways and 28 had nodal VA conduction. In Group II, 2 patients had VA block, 6 had nodal VA conduction and 22 had preferential retrograde conduction through the Kent bundle. In Group III, 9 patients had concealed Kent bundles and 24 had nodal retrograde conduction. In Group IV, the results were varied. The characteristics of retrograde VA conduction are therefore often different from those of anterograde conduction. 52 attacks of SVT were recorded; in the 18 cases of Group II, 5 septal, 3 right lateral, 8 left lateral Kent bundles and 2 intranodal reentries were demonstrated. In the 33 cases of SVT without overt WPW (Group III) a concealed accessory pathway was demonstrated in 9 cases. In all, approximately a half (25 out of 52) of all SVT were due to reentry involving an accessory pathway which was concealed in about one third of cases (9 out of 25) and more often situated on the left border than on the right or in the septum.

[Comparison of the efficacy of moricizine and disopyramide in the treatment of ventricular extrasystoles]. / Comparaison de l'efficacité de la moracizine et du disopyramide dans le traitement des extrasystoles ventriculaires.

Moricizine chlorhydrate (Ethmozine), a relatively unknown antiarrhythmic agent in France, is a derivative of Phenothiazine, related to the Vaughan-Williams Class IB drugs. A randomised, double-blind, crossover trial with Disopyramide 600 mg/day after a placebo period in 10 patients with ventricular extrasystoles, half of whom had underlying cardiac disease, showed that moricizine 750 mg/day significantly reduced (p less than 0.05) the overall number of ventricular extrasystoles by 81 +/- 46% (disopyramide 72 +/- 69%; NS) and that this drug is effective in 2/3 of patients by suppressing 70 to 100% of ventricular extrasystoles, whereas disopyramide was effective in only 40% of the same patients and never gave better results than Moricizine. Cardiac and extracardiac tolerance of Moricizine was good in this study, confirming previously reported results and its superiority when compared with disopyramide (20% of unwanted effects in this series).

[Proarrhythmic effects of antiarrhythmic drugs]. / Les effets proarythmiques des antiarythmiques.

The proarrhythmic effects of antiarrhythmic drugs are complications which have been described over several decades but the mechanisms (reentry, increased automaticity, ectopic faci, induced repetitive activity, vagal or adrenergic triggers) and the predisposing factors (underlying cardiac disease, previous severe arrhythmia, metabolic disorders, ischaemia, etc...) have only recently been identified. The appreciation of their true frequency poses problems of methodology (mode of recruitment, therapeutic converse proof), of definitions and depends to a great extent on the methods of detection used. Their severity cannot be denied and has been demonstrated both in experience of isolated cases and in recent prospective studies, the conclusions of which must be interpreted critically. Proarrhythmic effects may be observed at atrial (vagal or sympathetic arrhythmias, 1/1 flutter, acceleration of atrial fibrillation in preexcitation syndromes), junctional (artificial unidirectional block created by the antiarrhythmic drug which may be very effective at higher dosages: biphasic effect) or ventricular (aggravation of ventricular extrasystoles, torsades de pointe, ventricular tachycardia/fibrillation) levels. It is curious that no antiarrhythmic drug seems to be statistically less exposed to this type of complication which may result from phenomena of toxicity or idiosyncrasy. Given the potential gravity measures must be taken to prevent this complication, by observing simple rules (respect of contraindication, use of progressive dosage regimens, avoidance of loading doses, elimination of predisposing factors and abstention from dangerous therapeutic associations) and by carefully following up high risk patients.

[Nosology of atrial fibrillation. Attempt at clarification]. / Nosologie de la fibrillation auriculaire. Essai de clarification.

Atrial fibrillation is the subject of much clinical interest as it is the arrhythmia responsible for the greatest number of hospital admissions. The arrhythmia working group of the French Society of Cardiology held a symposium on atrial fibrillation in order to establish certain definitions and to assess the value of a classification of atrial fibrillation. This was also the occasion to review a number of known facts and points which remain obscure, concerning this common arrhythmia. A therapeutic strategy is proposed.

[Study of the arrhythmogenicity of cardiomyopathies. Hypertrophic cardiomyopathies]. / Etude du potentiel arythmogène des myocardiopathies. Les myocardiopathies hypertrophiques.

Forty-four cases of hypertrophic cardiomyopathy (23 men, 21 women; 55 +/- 15 years) referred for evaluation of chest pain (28 cases), dyspnoea (26 cases), palpitations (25 cases), dizziness (11 cases) and syncope (4 cases), were investigated prospectively between February 1983 and February 1989. The cardiomyopathy was concentric (N = 16), obstructive (N = 24) or apical (N = 4) and the diagnosis confirmed by angiography. Twenty-four hour Holter monitoring showed no ventricular extrasystoles in 43% of patients: the others had Grade I (25%), Grade III (2%), Grade 4A (14%) or 4B (16%) ventricular arrhythmias with diurnal predominance in half the cases. Patients with greater than or equal to Grade III ventricular extrasystoles had greater left axis deviation but did not differ from the others from the hemodynamic point of view. Exercise stress testing induced an isolated ventricular arrhythmia in 23% of patients and repetitive extrasystoles in 23%. The prevalence of surface late ventricular potentials was no greater in these patients than in normal subjects (4% vs 1%; NS). Programmed ventricular stimulation (N = 37) induced a repetitive response in only 25% of patients, with only two cases of sustained monomorphic ventricular tachycardia. There were no correlations between the results of programmed ventricular stimulation and those of Holter monitoring, exercise stress testing or late ventricular potential recording, but patients with inducible ventricular tachycardia or fibrillation had proportionally more syncopal episodes and greater than or equal to Grade III ventricular extrasystoles on Holter monitoring, but the difference was not statistically significant in this series.(ABSTRACT TRUNCATED AT 250 WORDS)