Electrophysiologic and hemodynamic studies in patients resuscitated from cardiac arrest

Fifty-two patients resuscitated from cardiac arrest underwent electrophysiologic studies. The earliest documented arrhythmia at the time of initial or recurrent (18 patients) cardiac arrest was ventricular fibrillation (30 patients) or ventricular tachycardia (20 patients); in 2 patients no arrhythmia was documented before defibrillation. Programmed ventricular stimulation revealed inducible arrhythmias in 33 patients (63 percent). Of the 30 patients with ventricular fibrillation as the initial arrhythmia, 13 had inducible arrhythmias—ventricular fibrillation (4 patients), sustained ventricular tachycardia (6 patients) and nonsustained ventricular tachycardia (3 patients). In the 20 patients with ventricular tachycardia as the initial arrhythmia, sustained ventricular tachycardia was initiated in 17 patients and torsade de pointes in 1. Patients with inducible arrhythmias had longer mean A-H and H-V intervals than those without inducible arrhythmias (91.1 versus 76.6 ms and 62.5 versus 50.3 ms, respectively). Prolonged H-V intervals (17 of 33) and intraventricular conduction defects (18 of 33) were more common in patients with than in those without inducible arrhythmias (4 of 19 and 7 of 19, respectively). Mean cardiac index was lower (2.4 versus 3.9 liters/min per m²), left ventricular end-diastolic pressure higher (17.0 versus 9.4 mm Hg), and ejection fraction lower (36.1 versus 57.2 percent) in the group with inducible arrhythmias than in those in whom no arrhythmia could be induced. These data suggest that (1) ventricular tachycardia often precipitates cardiac arrest; and (2) electrophysiologic testing may provide data on which to base therapy in patients resuscitated from cardiac arrest.     

Management of supraventricular tachyarrhythmias

Supraventricular tachyarrhythmias are common and treatment is based on the frequency and hemodynamic severity caused by these arrhythmias. Empiric therapy with currently available medications often satisfactorily controls symptomatic arrhythmias. Nonpharmocologic therapy with permanent antitachycardia pacemakers, percutaneous catheter ablation or surgery can be effective for selected patients with medically refractory supraventricular tachyarrhythmias after thorough electrophysiologic evaluation. In selected patients with life-threatening supraventricular tachyarrhythmias due to the WPW syndrome, surgical ablation is the therapy of choice.     

Predictive value of ventricular arrhythmias in resuscitated out-of-hospital cardiac arrest victims

Twenty-four hour ambulatory electrocardiograms recorded in 103 survivors of out-of-hospital cardiac arrest were analyzed to find those characteristics of the ventricular premature complex (VPC) which provide the best combination of sensitivity, specificity, and predictive accuracy for subsequent mortality. VPC characteristics were grouped as: (1) frequent (greater than or equal to 25 h-1), (2)bigeminal, (3) multiform, (4) early coupled, (5) pairing, (6) repetitive greater than or equal to 2, (7) repetitive greater than or equal to 3, (8) repetitive greater than or equal to 6, (9) the combination of frequent and repetitive, or (10) complex defined as any multiform, early, bigeminal or repetitive VPC. In an average follow-up period of 43 months, 42 deaths occurred, 17 of which were classified as sudden. Each characteristic was a significant predictor for all causes of subsequent death except early coupled VPCs and repetitive VPCs greater than 6. None of the characteristics reached significance as predictors for sudden death. The number of repetitive VPCs when stratified to none, greater than or equal to 2 and greater than or equal to 3 successive VPCs correlated with mortality in an incremental fashion. The combination of frequent VPCs and repetitive VPCs provided the best combination of sensitivity, specificity and predictive accuracy for death from all causes within five years.     

Should the elderly be resuscitated following out-of-hospital cardiac arrest?

PURPOSE: Elderly and younger patients who were successfully resuscitated and hospitalized following out-of-hospital cardiac arrest were studied to determine if there was a significant difference in hospital course and long-term survival between the two groups. PATIENTS AND METHODS: The study consisted of 214 consecutive patients, divided into two age groups: elderly (more than 70 years, n = 112) and younger (less than 70 years, n = 102). Hospital charts and paramedic run data were retrospectively reviewed for each patient and findings were compared between the two age groups. RESULTS: Prior to cardiac arrest, 47 of 112 (42 percent) elderly patients had a history of heart failure, compared with 19 of 102 (18 percent) younger patients, and were more commonly taking digitalis (51 percent versus 29 percent) and diuretics (47 percent versus 26 percent). Younger patients, however, more often had an acute myocardial infarction at the time of the cardiac arrest (33 percent versus 16 percent). At the time of cardiac arrest, 83 percent of younger patients demonstrated ventricular fibrillation, compared with 71 percent of the elderly. In contrast, electromechanical dissociation was five times more common in the elderly patients. Although hospital deaths were more common in the elderly (71 percent versus 53 percent), the length of hospitalization and stay in intensive care units were not significantly different between the age groups. The number of neurologic deaths was similar in both age groups, as were residual neurologic impairments. Only five elderly patients and six younger patients required placement in extended-care facilities. Calculated long-term survival curves demonstrated similar survival in both age groups, with approximately 65 percent of hospital survivors alive at 24 months after hospital discharge. CONCLUSION: Resuscitation of elderly patients in whom out-of-hospital cardiac arrest occurs is reasonable and appropriate, according to the findings of this study. Even though elderly patients are more likely than younger patients to die during hospitalization, the hospital stay of the elderly is not longer, the elderly do not have more residual neurologic impairments, and survival after hospital discharge is similar to that in younger patients.     

A resuscitated case of sleep apnea syndrome with cardiac arrest]

A 71-year-old man was noted to habitually snore loudly at night and have a predisposition to somnolence during the daytime. While dozing during the day, he developed cardiac arrest at the time when snoring stopped, and was resuscitated. By means of a respiration monitor, he was diagnosed as having sleep apnea syndrome (SAS) with a combination of obstructive, central, and mixed type. However, neither respiratory insufficiency nor cardiac insufficiency was observed, and there were no abnormal findings on laboratory tests and bronchoscopy. SAS complicated by cardiac arrest is usually seen in cases with concomitant symptoms such as excessive obesity, hypertension, arrhythmia, right heart insufficiency, secondary polycythemia, or mental disorder. The present case abruptly developed cardiac arrest in the absence of such symptoms. This case therefore suggests the importance of screening tests using a respiration monitor during sleep in subjects who have a loud snore or a predisposition to somnolence during the daytime. Although treatment with UPPP alone had no noticeable effect, UPPP treatment combined with sleeping in the lateral position was effective in the present case. The efficacy rate of UPPP has been reported to be 50 to 60%. The early establishment of a method for precise evaluation of the site of obstruction as well as criteria for appropriate application of UPPP are urgently required.     

Invasive strategy in patients with resuscitated cardiac arrest and ST elevation myocardial infarction

Coronary artery disease is the most frequent cause of sudden cardiac death. There is general consensus that immediate coronary angiography with percutaneous coronary intervention(PCI) should be performed in all conscious and unconscious patients with ST-elevation myocardial infarction in post-resuscitation electrocardiogram. In these patients acute coronary thrombotic lesion("ACS" lesion) suitable for PCI is typically present in more than 90%. PCI in these patients is not only feasible and safe but highly effective and there is evidence of improved survival with good neurological outcome. PCI of the culprit lesion is the primary goal while PCI of stable obstructive lesions may be postponed unless post-resuscitation cardiogenic shock is present.     

Amiodarone in the control of supraventricular tachyarrhythmias

The clinical efficacy of amiodarone was observed in a group of 20 patients (9 women and 11 men) with a total 21 supraventricular tachyarrhythmias (16 paroxysms or premature supraventricular beats (PSB) and 5 with established arrhythmias), to whom amiodarone was given during one month: 800 mg/day the first week and 400 mg/day for 3 weeks. An electrocardiogram and a 24 hour Holter were taken before and after treatment. The results observed for paroxysmal arrhytmias and PSB were excellent in 94% and satisfactory in one patient. As for established arrhythmias the results were excellent or satisfactory in 80%. We conclude that ammiodarone is an effective drug with a wide security range in the treatment of supraventricular arrhythmias.     

ECG in the diagnosis of supraventricular tachyarrhythmias

The development of catheter ablation techniques during the last decade provided new data about the mechanism of supraventricular tachyarrhythmias and at the same time, set new requirements for their classification. An accurate diagnosis of individual SVT can usually be made during an electrophysiologic study that precedes catheter ablation. Nevertheless, clinically acceptable differential diagnosis of SVT can be based on analysis of a standard 12-lead electrocardiogram. This may prove useful especially when selecting optimum antiarrhythmic drug according to a suspected mechanism of arrhythmia. At the same time, electrocardiogram during SVT serves as a recording of clinical arrhythmia for catheter ablation. At present, SVTs are divided into 3 main categories: 1. atrial tachyarrhythmias confined solely to atrial tissue, 2. tachycardias involving the AV junction, and 3. AV reentrant tachycardias involving one or more accessory connections with an electric impulse travelling between atria and ventricles. The first category can be further subdivided into: a) macroreentrant atrial tachycardias related to the presence of macroscopic anatomical or functional barriers; b) focal atrial tachycardias arising from a focus of abnormal automaticity or microreentry in the atrium; c) the syndrome of inappropriate sinus tachycardia resulting most probably from hypersensitivity to adrenergic stimulation; d) atrial fibrillation based on the existence of multiple wandering wavelets in the atria. Electrocardiographic differential diagnosis is predominantly based on an analysis of the standard 12-lead ECG. Principal diagnostic features include the presence and timing of the P waves in relation to the QRS complex. Additional criteria comprise the presence or absence of AV block during the tachycardia, an axis orientation of the P waves and their morphology, the appearance of QRS alternans or frequency of tachycardia.     

Long-term outcome of patients with hypertrophic cardiomyopathy successfully resuscitated after cardiac arrest

This study describes the long-term outcome of 33 patients with hypertrophic cardiomyopathy who experienced a cardiac arrest but were successfully resuscitated. Cardiac arrest occurred at ages 9 to 62 years (mean 32); five patients survived multiple (two or three) arrests. A variety of treatments were administered; 18 patients with left ventricular outflow tract obstruction underwent ventricular septal myotomy-myectomy or mitral valve replacement and also received drug therapy; 15 patients received medical therapy alone. To date, 22 (67%) of the 33 patients have survived after the initial cardiac arrest for periods of 17 months to 22 years (mean 7 years); 12 patients have survived for greater than or equal to 5 and 6 for greater than or equal to 10 years. Of the 22 survivors, 16 have remained asymptomatic or only mildly symptomatic over the period of follow-up; 6 others have become severely symptomatic with heart failure, including 3 with evidence of left ventricular wall thinning and cavity enlargement. Eight patients ultimately died of natural cardiac causes (suddenly or of progressive heart failure) 7 months to 8.4 years (mean 4 years) after their initial cardiac arrest. Actuarial patient survival was 97 +/- 3%, 74 +/- 9% and 61 +/- 11% after 1, 5 and 10 years, respectively. Event-free rate (defined as actuarial survival without recurrent cardiac arrest of death) was 83 +/- 7%, 65 +/- 9% and 53 +/- 11%, respectively. For this group of patients with hypertrophic cardiomyopathy who were treated in a nonsystematic fashion with a variety of therapeutic strategies, the long-term outcome after surviving a cardiac arrest was variable.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of diltiazem in supraventricular paroxysmal tachyarrhythmias

Diltiazem (0.3 mg/kg body weight intravenous in 2 minutes) was administered to 40 patients (24 males, 16 females, mean age 51.55 years) with paroxysmal supraventricular tachyarrhythmias: 7 patients with atrial fibrillation, 6 patients with atrial flutter, 25 patients with paroxysmal supraventricular tachycardia, 2 patients with uncommon atrioventricular reciprocating tachycardia. In patients with atrial fibrillation intravenous diltiazem produced a significant decrease of ventricular response (from 160 +/- 11 to 113.57 +/- 10.34--p less than 0.01). In patients with atrial flutter intravenous diltiazem produced variable effects: an increase in atrio-ventricular block (from 2:1 to 3:1 atrio-ventricular conduction (2 patients); conversion to sinus rhythm (1 patient); change to atrial fibrillation (1 patient); no appreciable change of the basic rhythm (2 patients). In paroxysmal supraventricular tachycardia patients conversion to sinus rhythm occurred in 20/22 patients (91%) treated with intravenous diltiazem (mean conversion time 4.69 minutes). In the 2 patients with uncommon atrioventricular nodal reciprocating tachycardia diltiazem increased P'-R and R-P' intervals without appreciable change of the basic rhythm. No serious side effects from drug administration were noted. Intravenous diltiazem appears to be as a highly effective medication in conversion or control of paroxysmal supraventricular tachyarrhythmias.     

Esmolol in the treatment of supraventricular tachyarrhythmias

Infusion of esmolol, an ultra short acting beta-blocker was used in the acute management of 48 patients with supraventricular tachyarrhythmias. Following acute control of the heart rate, patients received maintenance of esmolol infusion for 6 h when they were transferred to alternate oral antiarrhythmic agents. Prompt control of heart rate (mean +/- SD, 15 +/- 8.8 mins) was achieved in 85% of patients with esmolol at a dose rate of 80 +/- 59 micrograms/kg/min. Ninety percent of these subjects were successfully transferred to alternate oral therapy. Five subjects experienced transient side effects. Esmolol was highly effective and particularly suitable for the acute management of patients with supraventricular tachyarrhythmias.     

Drug and electrical therapy of supraventricular tachyarrhythmias

This article reviews current pharmacological and electrical approaches to the restoration of sinus rhythm in patients who suffer from atrial fibrillation and atrial flutter. Spontaneous conversion to sinus rhythm occurs in a high proportion of atrial fibrillation of < 24 h duration. Among patients presenting with atrial fibrillation, which was clinically estimated to have lasted < 48 h, the likelihood of cardioversion-related clinical thromboembolism is low, which supports the current practice of early cardioversion without anticoagulation. Antiarrhythmic drugs effective in terminating atrial fibrillation of short duration are those which possess class IA, IC and III properties. Electrical transthoracic cardioversion by using different electrode positions and additional pressure over the electrodes during shock delivery is a highly effective and well-tolerated method in restoration of sinus rhythm even in patients under conscious sedation. Immediate spontaneous reinitiation of atrial fibrillation can occur in a significant proportion of patients undergoing electrical cardioversion and can be reduced after a pretreatment with antiarrhythmic drugs. In patients with failed external cardioversion, internal low energy cardioversion offers an effective option for restoring sinus rhythm. After cardioversion in a high proportion of patients antiarrhythmic drugs are necessary to prevent atrial fibrillation from recurring. A serial cardioversion approach can prevent the evolution of permanent atrial fibrillation in a subgroup of patients. Overdrive atrial pacing is an effective and minimally invasive procedure for termination of atrial flutter. The acute administration of class IA, IC and III antiarrhythmic drugs increases the success rate of this method in restoring sinus rhythm.     

Clinical,electrophysiologic and hemodynamic profile of patients resuscitated from prehospital cardiac arrest

Of 352 prehospital cardiac arrest patients studied during a three year period, the initial mechanism recorded by rescue personnel was ventricular fibrillation in 220 (62 per cent), ventricular tachycardia in 24 (7 per cent) and bradyarrhythmias or asystole in 108 (31 per cent). Early survival was best in the group with ventricular tachycardia (16 of 24 patients resuscitated and survived hospitalization—67 per cent); the prognosis was worst in the group with bradyarrhythmias asystole (nine of 108 admitted to the hospital alive—none survived hospitalization); and 51 of 220 patients with ventricular fibrillation (23 per cent) were resuscitated and survived subsequent hospitalization, a significantly better outcome than previously reported for ventricular fibrillation.Central nervous system damage accounted directly or indirectly for 28 of 48 in-hospital deaths (59 per cent), and hemodynamic abnormalities for 31 per cent. Only five in-hospital deaths (10 per cent) were primary arrhythmic. The majority of survivors had evidence of left ventricular hemodynamic abnormalities (mean left ventricular end-diastolic pressure = 17.80 ± 8.99 mm Hg; mean cardiac index = 2.62 ± 0.72 liters/min/m²; mean ejection fraction = 38.58 ± 17.55 per cent), but approximately one third of the surviving patients had normal left ventricular function. Early in-hospital electrophysiologic data demonstrated persistent, drug-resistant complex ventricular arrhythmias during the first 72 hours; but intracardiac electrophysiologic studies elicited specific patterns only in patients with ventricular tachycardia, whose arrhythmias were reproducible in five of six patients studied. The risk of recurrent ventricular fibrillation in the first 72 hours was predicted better by coexistent conducting system abnormalities, than by the persistent ventricular arrhythmia alone.We conclude that the electrical mechanism of prehospital cardiac arrest provides early prognostic information, that early survival rates are improving and that one third of the discharged survivors have normal indices of left ventricular function. The presence of conducting system abnormalities identifies a subgroup at high risk for in-hospital recurrent ventricular fibrillation.     

Patient-activated transvenous cardiac stimulation for the treatment of supraventricular and ventricular tachycardia

Recurrent, drug-refractory sustained tachycardias present a difficult management problem. After invasive electrophysiologic study and extensive antiarrhythmic drug testing, a permanent transvenous lead system and radiofrequency stimulator that required patient activation for burst pacing were implanted in eight patients with refractory Supraventricular tachycardia and in nine patients with refractory ventricular tachycardia. In a follow-up period of 2 to 28.5 months (mean 12) each patient has successfully terminated multiple episodes of recurrent tachycardia without complicatlon. This therapeutic approach has allowed a reduction in antiarrhythmic drug dosage and adverse effects, has obviated the need for frequent hospital admissions resulting from recurrent tachycardia, and has met with excellent patient acceptance.