Defibrillator therapy 1997. Prerequisites--results--prospects

BACKGROUND: The first human cardioverter defibrillator implant was performed in 1980. Since then, significant technological improvement has been performed and today, ICDs with multiple diagnostic and therapeutic features are available. We report on 541 patients who underwent ICD implantation between January 1984 and March 1997. Epicardial ICD implant was performed in 209 patients (39%) and 332 patients (61%) received transvenous ICDs. PATIENTS AND RESULTS: Perioperative mortality was 2% (13 patients), significantly more frequent after epicardial (12/209 patients, 6%) than after transvenous implantation (1/332 patients) (p < 0.01). During a mean follow-up of 28 +/- 23 months, 104 patients died (20%), 15 of them (3%) suddenly. 8407 arrhythmic episodes were observed and terminated by antitachycardia pacing in 6655 (79%). Infections occurred in 13 patients (2%), electrode complications in 43 patients (8%) and inappropriate shocks in 84 patients (16%). CONCLUSION: The ICD is an effective approach to treat patients with life-threatening ventricular tachyarrhythmias leading to a low incidence of sudden death. Today, there is a low operative risk and modern ICDs have multiple diagnostic and therapeutic features that allow individual ICD therapy.     

Non-pharmacologic prevention of sudden cardiac death

Non-pharmacologic therapy has revolutionized the management of arrhythmias and prevention of sudden cardiac death (SCD). Of particular importance is the introduction of radiofrequent catheter ablation (RFCA) and implantable cardioverter-defibrillator (ICD). RFCA is effective and useful in the treatment and prevention of SCD, especially in supraventricular tachyarrhythmias related to dual or accessory atrioventricular pathways. There are some limitations in using this method in the prevention of SCD in ventricular tachyarrhythmias. RFCA is very successful, particularly in the treatment of bundle branch reentrant ventricular tachycardia and ventricular tachycardia in patients without structural heart disease. RFCA can be used as a palliative treatment of incessant or frequent VT before and after ICD implantation. Antibradycardia pacing decreases SCD not only by the removal of serious bradyarrhythmias but also by prevention of the occurrence of malignant ventricular tachyarrhythmias induced by bradyarrhythmia. Antitachycardia pacing is used in the prevention of SCD only as a part of ICD device. Implantation of an antitachycardia pacemaker as an isolated permanent treatment of tachycardias is currently almost not used. This method was replaced by RFCA in supraventricular tachyarrhythmias and by ICD in ventricular tachyarrhythmias. ICD is a very perspective non-pharmacologic approach to SCD prevention, particularly as transvenous leads were introduced and device construction was simplified. ICD is indicated especially in patients with spontaneous sustained hemodynamically significant ventricular tachycardia/ventricular fibrillation and when antiarrhythmic drug treatment, RFCA or antitachycardia surgery are ineffective, intolerated, contraindicated or cannot be performed. ICD as the treatment of first choice instead of antiarrhythmic drugs as well as prophylactic ICD implantation in asymptomatic patients at high risk is a subject of discussion. ICD decreases the incidence of SCD significantly. However, the decrease in overall mortality was not verified. Antitachycardia surgery is less frequently used after RFCA, and ICD have been introduced. At present, this therapy is reserved only for the cases of failure of RFCA or the impossibility to use RFCA and ICD. Surgical therapy can be combined also with concommitant surgical correction of associated structural heart disease. Sympathectomy is used in prevention of malignant ventricular tachyarrhythmias and SCD in patients with congenital long Q-T syndrome. Selective left cardiac sympathetic denervation significantly reduces the risk of SCD in these patients but does not remove it completely. Heart transplantation is the last alternative of non-pharmacologic prevention of SCD. It is indicated in cases when all pharmacologic and non-pharmacologic approaches have been exhausted. Heart transplantation is the only effective modality for the improvement of long-term prognosis in patients with malignant ventricular tachyarrhythmias and advanced chronic heart failure.     

Implantable cardioverter defibrillator utilization among device recipients presenting exclusively with syncope or near-syncope

INTRODUCTION: Implantable cardioverter defibrillators (ICDs) are occasionally used in presumed high-risk patients with electrocardiographically undocumented syncope, although the incidence of ventricular tachyarrhythmias in this population is not well defined. METHODS AND RESULTS: We studied 33 consecutive patients receiving an ICD (67% nonthoracotomy and 70% tiered therapy) after electrophysiologic testing for unmonitored "syncope" (n = 29) or "near-syncope" (n = 4). Atherosclerotic heart disease was present in 24 (73%); mean left ventricular ejection fraction (LVEF) was 0.39 +/- 0.15; and sustained monomorphic ventricular tachycardia (SMVT) was inducible in 18 (55%). Over a median follow-up of 17 months (range 4 to 61), 12 patients (36%) received > or = 1 appropriate ICD discharge triggered by SMVT (cycle length 230 to 375 msec) in 10 and ventricular flutter or fibrillation in 2--without concomitant antiarrhythmic medication in 8 of 12 cases. Inducible SMVT and LVEF < or = 0.35 were statistically significant, independent predictors of an appropriate ICD discharge (P < 0.02 and P < 0.03, respectively). Estimated 1-year cumulative survival free of appropriate discharge was 34% versus 87%, respectively, in patients with versus without inducible SMVT (P < 0.02), and 18% versus 56%, respectively, in patients with LVEF < or = 0.35 versus LVEF > 0.35 (P < 0.03). CONCLUSION: In this highly select, multicenter population of ICD recipients with electrocardiographically undocumented syncope, a substantial incidence of appropriate device discharges was observed, particularly in patients with inducible SMVT and LVEF < or = 0.35. These findings support the notion that, in patients with LV dysfunction and inducible SMVT, ventricular tachyarrhythmias are likely to account for episodes of syncope or near-syncope.     

Incidence of implantable defibrillator discharges after coronary revascularization in survivors of ischemic sudden cardiac death

Coronary revascularization has been suggested as sole therapy for secondary prevention of sudden cardiac arrest associated with ischemia. The use of implantable defibrillators (ICD) in combination with coronary revascularization for this patient population is unclear. Among 412 consecutive patients receiving an ICD, 23 (6%) were identified as sudden cardiac arrest survivors who were noninducible with programmed stimulation and had unstable angina or ischemia on a functional study; they underwent successful coronary revascularization. During a follow-up of 34 +/- 18 months, 10 (43%) of the 23 patients received ICD shocks (8 +/- 8 per patient, range 1 to 22 shocks), and nine of the 10 patients had syncope/presyncope associated with at least one ICD discharge. Patients with ICD discharges were compared with those without ICD discharges, and no clinical characteristics were statistically different between the two groups. In conclusion, revascularization alone may be inadequate therapy for survivors of sudden cardiac arrest associated with ischemia who are noninducible with programmed stimulation, and clinical variables cannot predict which patients are likely to have recurrent malignant ventricular arrhythmias.     

Therapy of ventricular tachyarrhythmia with implantable cardioverters/defibrillators--mortality and complications using epicardial electrodes

Technical improvements of third generation implantable cardioverter defibrillators (ICD) like antitachycardia pacing modalities lead to an extended use of ICDs, not only in patients with aborted sudden cardiac death, but also in patients with hemodynamically tolerable ventricular tachycardia. In addition, anticipated results of current prospective studies might indicate the prophylactic use of ICDs in patients with high risk for sudden cardiac death, but without documented ventricular tachyarrhythmias. This report reviews mortality and complications associated with the ICDs with epicardial defibrillation leads. Mortality is separated in cardiac death, sudden cardiac, arrhythmogenic "not so sudden" cardiac death, and overall mortality. Pulmonary complications and infections are related to the underlying disease and the surgical procedure. Device- and lead-related complications, high defibrillation thresholds, pacemaker interactions, inappropriate shocks, arrhythmic effects, syncope, and psychosocial problems are reported, respectively.     

Bronchodilator response to salbutamol after chronic dosing with salmeterol or placebo

OBJECTIVES: We report the occurrence of cardiac events during long-term follow-up in patients with hypertrophic cardiomyopathy (HCM) after cardioverter-defibrillator implantation. BACKGROUND: The identification of patients at high risk for sudden death and the prevention of recurrence of sudden death in HCM represents a difficult problem. METHODS: We retrospectively analyzed the occurrence of cardiac events during follow-up of 13 patients with HCM who received an implantable cardioverter-defibrillator (ICD) because of aborted sudden death (n = 10) or sustained ventricular tachycardia (n = 3) (group I). Findings were compared with those in 215 patients with an ICD and other structural heart disease or idiopathic ventricular fibrillation (group II). RESULTS: After a mean (+/-SD) follow-up period of 26+/-18 months, 2 of 13 patients in group I received appropriate shocks. The calculated cumulative incidence of shocks was 21% in group I and 66% in group II after 40 months (p < 0.05). We observed a low incidence of recurrence of ventricular tachycardia/fibrillation during follow-up in patients with HCM. No deaths occurred. CONCLUSIONS: Our data suggest that ventricular tachyarrhythmias may not always be the primary mechanism of syncope and sudden death in patients with HCM. The ICD seems to have a less important impact on prognosis in patients with HCM than in patients with other etiologies of aborted sudden death.     

The effects of cocaine preexposure on the acquisition of cocaine-induced taste aversions

OBJECTIVES: This study investigated the role of programmed ventricular stimulation (PVS) for arrhythmia risk prediction in patients with idiopathic dilated cardiomyopathy (IDC) and spontaneous nonsustained ventricular tachycardia (VT). BACKGROUND: Nonsustained VT in patients with IDC has been associated with a high incidence of sudden cardiac death. METHODS: Over the course of 4 years, 34 patients with IDC, a left ventricular (LV) ejection fraction < or = 35%, and spontaneous nonsustained VT underwent PVS. All patients were prospectively followed for 24+/-13 months. RESULTS: Sustained ventricular arrhythmias were induced in 13 patients (38%). Sustained monomorphic VT was induced in three patients (9%), and polymorphic VT or ventricular fibrillation (VF) in another 10 patients (29%). No sustained ventricular arrhythmia could be induced in 21 study patients (62%). Prophylactic implantation of third-generation defibrillators (ICDs) with electrogram storage capability was performed in all 13 patients with inducible sustained VT or VF, and in nine of 21 patients (43%) without inducible sustained VT or VF. There were no significant differences between the additional use of amiodarone, d,I-sotalol, and beta-blocker therapy during follow-up in patients with and without inducible VT or VF. During 24+/-13 months of follow-up, arrhythmic events were observed in nine patients (26%) including sudden cardiac deaths in two patients and ICD shocks for rapid VT or VF in seven patients. Arrhythmic events during follow-up occurred in four of 13 patients with inducible ventricular arrhythmias compared with five of 21 patients without inducible ventricular arrhythmias at PVS (31% vs. 24%, p=NS). CONCLUSION: PVS does not appear to be helpful for arrhythmia risk stratification in patients with IDC, a left ventricular ejection fraction < or =35%, and spontaneous nonsustained VT. Due to the limited number of patients, however, the power of this study is too small to exclude moderately large differences in outcome between patients with IDC with and without inducible VT or VF.     

Implantable defibrillator diagnostic storage capabilities: evolution, current status, and future utilization

There has been a rapid and significant evolution in the stored diagnostic information available from implantable cardioverter defibrillators (ICDs). The diagnostic information available in current generation ICDs has greatly enhanced the clinicians' ability to determine the rhythm triggering device therapy as well as to identify potential problems with the ICD system. Furthermore, this information may be useful in identifying triggers of ventricular arrhythmias in patients at high risk for sudden death. The history, evolution, value, and limitations of the stored diagnostic capabilities of implantable defibrillators are discussed.     

Favorable results of implantable cardioverter-defibrillator implantation in patients older than 70 years

BACKGROUND: The clinical results of implantable cardioverter-defibrillator (ICD) implantation in the elderly have received limited documentation. As the longevity of the U.S. population has increased, so has the need for ICD implantation in the elderly. We evaluated the efficacy and outcome of ICD implantation in elderly patients (>70 years) compared with younger patients. METHODS: The case records of all consecutive patients who underwent ICD implantation at our institution between 1986 and 1994 were reviewed. Of a total of 238 patients, 78 patients were 70 years of age or older and 160 patients were younger than 70 years of age. RESULTS: The mean age of the younger group was 58 years and that of the elderly group was 74 years. There were no statistical differences in the presence of coronary artery disease, left ventricular systolic function, the inducibility of arrhythmias, or the history of sudden cardiac death. The hospital morbidity rate was similar in both groups (6.9% in the younger group and 7.7% in the elderly group; p = not significant). The operative mortality rate was 1.9% for the younger group and 1.3% for the elderly group (p = not significant). At a mean follow-up of 33 +/- 26 months, Kaplan-Meier survival curves demonstrated similar survival rates, with 93%, 82%, and 65% of the patients alive at 1, 3, and 6 years, respectively. CONCLUSIONS: Implantable cardioverter-defibrillator implantation was equally effective in the treatment of patients older than 70 years as in younger patients. No differences in theoretic survival or morbidity were observed.     

Predictors of sudden cardiac death in hypertrophic cardiomyopathy

Patients with hypertrophic cardiomyopathy (HC) die suddenly. Proposed risk factors for sudden cardiac death (SCD) in HC are youth, a family history of SCD, syncope, and ventricular tachycardia. Hemodynamic variables have not convincingly proved to be risk factors for SCD. Therefore, this study was designed to examine predictors of SCD in a large number of patients with HC during long-term follow-up periods. The relation of studied variables (clinical, electrocardiographic, echocardiographic, hemodynamic, and exercise test findings) to SCD in 309 patients with HC who were initially diagnosed during 1971 through 1994 (mean follow-up 9.4 years) was examined by multivariate analysis. SCD occurred in 28 patients. Independent predictors of SCD were a smaller difference between peak and rest systolic blood pressure during exercise testing (p=0.006), and higher left ventricular outflow tract pressure gradient at rest (p=0.003). Exercise-related SCD occurred in 8 patients and exercise-unrelated SCD in 20 patients (mean age 28 vs 47 years, p <0.05). Thus, patients of exercise-related SCD were younger and had smaller increases in systolic blood pressure during exercise testing, whereas patients with exercise-unrelated SCD were older and had higher left ventricular outflow tract pressure gradient.     

Potential benefit from implantable cardioverter-defibrillator therapy in patients with and without heart failure

BACKGROUND: Whether patients with heart failure derive a benefit from therapy with implantable cardioverter-defibrillators (ICDs) has been questioned. The purpose of this study was to investigate whether New York Heart Association (NYHA) functional class had an impact on the potential benefit from ICD therapy as assessed from data stored in the memory of ICDs. METHODS AND RESULTS: Between 1989 and 1996, 603 patients (77% men; 59% with coronary artery disease and 16% with dilated cardiomyopathy; age, 57+/-13 years; ejection fraction, 44+/-18%) were treated with an ICD with extended memory function (storage of electrograms and/or RR intervals from treated episodes) in combination with endocardial lead systems. The stages of heart failure (NYHA functional class I through III) at implantation were correlated with overall mortality and the recurrence of fast ventricular tachyarrhythmias (>240 bpm) during follow-up. The potential benefit of the device was estimated as the difference between overall mortality and the hypothetical death rate had the device not been implanted. The latter was based on the recurrence of fast and, without termination by the devices, presumably fatal ventricular tachyarrhythmias. In the overall group, a significant difference between hypothetical death rate and overall mortality was observed (13.9%, 23.5%, and 26.6% at 1, 3, and 5 years, respectively) that suggested a benefit from ICD implantation. In patients in NYHA class I, the estimated benefit, which increased over time, was 15.2%, 29.2%, and 35.6% after 1, 3, and 5 years, respectively. In patients in NYHA class II or III, the estimated benefit increased until the third year (21.8% and 21.9%, respectively) and then remained constant until the fifth year (22.9% and 23.8%, respectively). Even those patients in NYHA class III with a history of decompensated heart failure benefited from ICD implantation. CONCLUSIONS: Analysis of stored ECG data suggests that in patients with a history of ventricular tachycardia or ventricular fibrillation, ICD therapy may lead to a prolongation of life in NYHA classes I through III. The initial benefit is greatest in patients in NYHA class II and class III, but the estimated benefit might persist longest for patients in NYHA class I.     

Circannual variation of malignant ventricular tachyarrhythmias in patients with implantable cardioverter-defibrillators and either coronary artery disease or idiopathic dilated cardiomyopathy

We studied the possible relation between the frequency of ventricular tachyarrhythmic events and thermal stress in patients with an implantable cardioverter-defibrillator (ICD) living in a locally limited area under homogeneous climatic conditions. The frequency of tachyarrhythmic events was correlated with the thermal stress level according to the "Klima Michel Model," a complete thermophysiologic model that calculates "felt-temperature" values on the basis of the outdoor temperature and further meteorologic data. During a mean follow-up time of 40 +/- 17 months (range 4 to 72), 761 ventricular tachyarrhythmic events occurred in 50 of 138 consecutive ICD recipients. Analysis of the monthly felt-temperature levels and the mean circannual variation of the registered ventricular arrhythmias suggested that very cold and very hot conditions may be associated with an increased frequency of ventricular tachyarrhythmias. This finding was confirmed by calculation of the sum of tachyarrhythmias on all 2,039 days of the follow-up period divided into 5-degree-step felt-temperature classes. Thus, thermal stress may be 1 factor triggering the occurrence of ventricular tachyarrhythmias in patients with cardiac disease and suppressed cardiac function. Part of the increase in cardiac mortality under above-average hot and cold atmospheric conditions may be attributed to ventricular arrhythmic events.     

Inferior alveolar nerve function after mandibular osteotomies

Many patients with an implanted cardioverter defibrillator (ICD) also receive antiarrhythmic drug therapy. Although an expanding number of patients are receiving ICD therapy, many will not have received previous antiarrhythmic treatment. For patients with an ICD, infrequent arrhythmias and a low probability of inappropriate device discharges, no antiarrhythmic therapy is required. However, for those patients who require an antiarrhythmic drug, amiodarone is a reasonable first choice because of safety in patients with poor LV function. It may be particularly useful for patients with high density ventricular arrhythmias. However, the interactions between ICDs and antiarrhythmic therapy requires close monitoring in order that patient benefit can be optimised, and this review focuses on those interactions.     

Effects of passive tilt and submaximal exercise on spectral heart rate variability in ventricular fibrillation patients without significant structural heart disease

It has been shown that tilt and exercise elicit significant changes in autonomic activity in normal subjects and that submaximal exercise causes a greater reduction in heart rate variability (HRV) in animals susceptible to ventricular fibrillation (VF). Whether there is an abnormal HRV response to tilt and exercise in patients at risk of sudden cardiac death (SCD) remains unknown. Short-term HRV before and during passive tilt and exercise was studied in 12 survivors of out-of-hospital cardiac arrest with documented VF and compared with 12 age- and sex-matched normal controls. No patient had significant structural heart disease or left ventricular dysfunction. HRV was computed as total-frequency (TF, 0.01 to 1.00 Hz), low-frequency (LF, 0.04 to 0.15 Hz) and high-frequency (HF, 0.15 to 0.40 Hz) components. There was no significant difference between normal controls and SCD survivors in HRV before or during tilt or submaximal exercise testing. The HF component was significantly decreased during tilt compared with that in the supine position in both normal controls (5.85 +/- 0.61 vs 5.08 +/- 0.95 In(msec2), p = 0.005) and patients (5.58 +/- 1.49 versus 4.74 +/- 1.18 In(msec2), p = 0.003). There was again no significant change in the TF or LF components during tilt in either patients or controls. All frequency components were significantly decreased during submaximal exercise testing in both patients and controls. However, there was no significant difference in any of these tilt- and exercise-induced changes in HRV between normal controls and SCD survivors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of metoprolol and sotalol in preventing ventricular tachyarrhythmias after the implantation of a cardioverter/defibrillator

The purpose of this prospective study was to evaluate, on an intention-to-treat basis, the efficacy of d,l-sotalol and metoprolol with regards to the recurrence of arrhythmic events after implantable cardioverter defibrillator (ICD) implantation. After ICD implantation, 70 patients were randomly assigned to treatment with either metoprolol (mean dosage 104+/-37 mg/day in 35 patients) or d,l-sotalol (mean dosage 242+/-109 mg/day in 35 patients). During follow up ventricular tachycardia (VT), fast VT, and ventricular fibrillation (VF) episodes were calculated. Metoprolol treatment led to a marked reduction in the recurrence of arrhythmic events. Actuarial rates for absence of VT recurrence at 1 and 2 years were significantly higher in the metoprolol group compared with the d,l-sotalol group (83% and 80% vs 57% and 51%, respectively, p=0.016). The actuarial rates for absence of fast VT or VF were 80% in the metoprolol group compared with 46% in the d,l-sotalol group (p=0.002). During a follow up of 26+/-16 months, there were 3 deaths in the metoprolol group compared with 6 deaths in the d,l-sotalol group. Actuarial rates of overall survival were not significantly different in the 2 groups (91% vs 83%, p=0.287). In this prospective, randomized, controlled study the recurrence rate of ventricular tachyarrhythmias in patients treated with metoprolol was lower than in patients treated by d,l-sotolol.     

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In 41 survivors of acute myocardial infarction (AMI) a prospective study was performed in 2 sequential phases. In phase 1, the role of baroreflex sensitivity and heart rate variability as predictors of inducible and spontaneous sustained ventricular tachyarrhythmias was evaluated. In phase 2, the effects of transdermal scopolamine on baroreflex sensitivity, spectral and nonspectral measures of heart rate variability were investigated. At a mean follow-up of 10 +/- 3 months after AMI, 5 of 41 patients (12%) developed a late arrhythmic event. Of these, all (100%) had inducibility of sustained monomorphic ventricular tachycardia at programmed stimulation compared with 3 of 36 patients (8%) without events (p < 0.0001). At multivariate analysis, baroreflex sensitivity had the strongest relation to both inducibility of sustained monomorphic ventricular tachycardia (p < 0.0001) and occurrence of arrhythmic events (p < 0.0001). Of 41 patients, 28 (68%) consented to undergo phase 2 of the investigation. Baroreflex sensitivity significantly (p < 0.00001) increased after transdermal scopolamine as well as heart rate variability indexes. Of these, the mean of SDs of normal RR intervals for 5-minute segments (p < 0.0001) and the total power (p < 0.0001) had the most significant improvement after scopolamine. The present investigation confirms that assessment of autonomic function is an essential part of arrhythmic risk evaluation after AMI. Transdermal scopolamine, administered to survivors of a recent AMI, reverses the autonomic indexes that independently predict arrhythmic event occurrence. On the basis of these data, transdermal scopolamine could be a potential useful tool in the prophylaxis of life-threatening ventricular arrhythmias after AMI.     

Peroxidase activity of liver microsomal vitamin D 25-hydroxylase and cytochrome P450 1A2 catalyzes 25-hydroxylation of vitamin D3 and oxidation of dopamine to aminochrome

OBJECTIVES: This study sought to determine the long-term risk of sudden cardiac death in patients with hemodynamically stable sustained ventricular tachycardia complicating coronary artery disease. BACKGROUND: The prognosis and risk of sudden cardiac death in patients with a history of myocardial infarction and ventricular tachyarrhythmias have not been clearly defined. Prior studies are limited by a short follow-up period and by inclusion of patients with heterogeneous cardiac diseases and presenting arrhythmias. METHODS: A retrospective cohort analysis was performed on data from 124 patients, followed up for a mean of 36 +/- 30 months, who received electrophysiologically guided therapy for hemodynamically stable ventricular tachycardia after remote myocardial infarction. RESULTS: Seventy-eight patients were treated pharmacologically (medical group), and 46 patients underwent map-guided subendocardial resection (surgical group). Nine patients (7.3%) died suddenly, 5 (4.0%) died of noncardiac causes, 9 (7.3%) died of a perioperative complication, and 20 (23.4%) died of other cardiac causes. At 1, 2 and 3 years, sudden death occurred at cumulative rates of 2 +/- 1%, 3 +/- 2% and 7 +/- 3%, whereas total mortality was 20 +/- 4%, 28 +/- 4% and 32 +/- 5% (mean +/- SD). Sudden cardiac death (p = 0.047) and total mortality (p = 0.036) were higher in patients with multivessel disease and were similar for both treatment groups. CONCLUSIONS: Although the overall mortality in postinfarction patients presenting with hemodynamically stable ventricular tachycardia treated with electrophysiologically guided antiarrhythmic therapy is high, the risk of sudden death in these patients appears to be low (average 2.4%/year).     

Prognostic value of ventricular arrhythmia in hypertensive patients

OBJECTIVE: Hypertensive left ventricular hypertrophy (LVH) is associated with increased risk of arrhythmias and mortality. However, no clinical study demonstrated a significant relation between ventricular arrhythmias and mortality in systemic hypertension. DESIGN AND METHODS: To evaluate the prognostic value of arrhythmogenic markers in systemic hypertension, we included between 1987 and 1993. 214 hypertensive patients, 59.1 +/- 12.8 years old, without symptomatic coronary disease, myocardial infarction, systolic dysfunction, electrolyte disturbances or antiarrhythmic therapy. At inclusion, an ECG, a 24 h Holter ECG (204 patients) with Lown classification of ventricular arrhythmias, an echocardiography (reliable in 187 patients) with left ventricular mass index and ejection fraction calculation, a SAECG (125 patients, enrolled after 1988) with ventricular late potentials (LP) were recorded. QT interval dispersion (QTd) was calculated on 12 leads standard ECG and LVH was appreciated. RESULTS: At baseline echocardiographic LVH was recorded in 63 patients (33.7%) with normal ejection fraction (75 +/- 7.4%). Non-sustained ventricular tachycardia (Lown IVb) was found in 33 pts (16.2%) and LP in 27 patients (21.6%). After a mean follow up of 42.4 +/- 26.8 months, all-cause mortality was 11.2% (24 patients); 17 patients died of cardiac causes (7.9%); of these 9 patients (4.2%) died suddenly. In univariate analysis, age, strain pattern of LVH, advanced Lown classes and abnormal QT dispersion (> 80 ms) were significantly related to global, cardiac and sudden death (p < or = 0.01). Left ventricular mass index was closely related to cardiac mortality (p = 0.002). LP failed to predict mortality. In multivariate analysis, only Lown class IVb was an independent predictor of global and cardiac mortality, increasing the risk of global death 2.6 fold [1.2-6.0] (CI 95%) and the risk of cardiac death 3.5 fold [1.2-9.7] (CI 95%). CONCLUSIONS: In hypertensive patients the presence of non-sustained ventricular tachycardia on 24 h Holter has a prognostic value.     

Sudden cardiac death: a retrospective and prospective study

Since the inception of mobile coronary care units (MCCU), patients with sudden cardiac death (SCD) saved by advanced emergency medical technicians (EMT-A) can be studied retrospectively and prospectively. Forty-eight cases of SCD found in ventricular fibrillation (VF) were successfully resuscitated. Only 32% had a myocardial infarction. Most survivors were New York Heart Association (NYHA) class I or II. All class IV survivors with severe congestive heart failure died within 45 days. All class II survivors had angina as the limiting factor. Of all patients with VF, 23% survived. Eighty percent of survivors were class I or II and have resumed previous lifestyles. No clear cut symptom complex was identified. Rescue response time was generally less than five minutes. Intracardiac medications were administered without complications. Empirical administration of sodium bicarbonate correlated poorly with arterial blood gas determinations.