Long-duration electrocardiographic recording in 33 patients with obstructive cardiomyopathy

A prospective study of arrhythmias was performed in 33 patients with hypertrophic cardiomyopathy with obstruction by Holter monitoring. The aim of the study was to assess the incidence of "occult" arrhythmias in this condition and to establish a "profile" of high risk patients from clinical, echocardiographic and haemodynamic data. The Holter monitoring demonstrated asymptomatic arrhythmias in 31 of the 33 patients (94%). A supraventricular arrhythmia was detected in 15 cases (45%), including 7 episodes of supraventricular tachycardia (21%). Ventricular arrhythmias were observed in 28 patients (85%), including 5 episodes of ventricular tachycardia (15%). Some patients presented several types of arrhythmia. A number of patients with arrhythmia including short bursts of ventricular tachycardia were asymptomatic during Holter monitoring; conversely, other patients complained of dizziness or syncope but had no arrhythmias. A retrospective study of clinical, echocardiographic and haemodynamic data showed no difference between patients with and patients without arrhythmias. Medium-dose betablocker therapy (propranolol, 110 mg/day) did not seem to protect patients with hypertrophic cardiomyopathy with obstruction from arrhythmias. We conclude that Holter monitoring should form part of the routine evaluation of patients with cardiomyopathy with obstruction, and that potentially dangerous arrhythmias should be treated by anti-arrhythmic agents other than betablockers. This attitude could reduce the incidence of syncope and eventually decrease the risk of sudden death in this condition.     

Long-term medical management of hypertrophic obstructive cardiomyopathy

Twenty-two patients, aged 15 to 61 years, with hypertrophic obstructive cardiomyopathy documented at catheterization were followed up prospectively for 2 to 8 years (mean 5) while receiving “complete” beta receptor blocking doses of propranolol (average dose 462 mg/day). Hypertension, fluid retention, pulmonary disease and arrhythmias were treated as required. Dyspnea, angina, syncope, presyncope and palpitations were graded from 0 to 3 based on severity, and the scores were added to obtain a total score. This group was compared with 14 nonrandomized control patients, aged 17 to 78 years, who were not receiving propranolol and were evaluated retrospectively for a mean follow-up period of 5 years (range 2 to 13). The average total score for the protocol group was initially 7.9 and is now 1.9. No patient died; the condition of all patients is improved, with an average improvement in dyspnea of 58 percent. Eighteen patients are currently asymptomatic during usual daily activities. In contrast, symptoms increased in severity in 13 of the 14 control patients. Their mean score increased from 2.9 to 5.4, and dyspnea increased by 133 percent. Of the 10 control patients treated only medically, 4 died suddenly.

Improvement in protocol patients was independent of the severity of subvalve obstruction. Potentially life-threatening arrhythmias were found in 11 of the 22 protocol patients, including the 3 patients without obstruction at rest. Rhythm disturbance responded to propranolol alone in four patients, but antiarrhythmic drugs or pacemaker insertion, or both, was required in the remaining seven patients. Thus, “complete” beta blockade supplemented by control of arrhythmia is optimal management for hypertrophic obstructive cardiomyopathy. Most patients do not require surgery.     

Utility of mobile cardiac outpatient telemetry for the diagnosis of palpitations, presyncope, syncope, and the assessment of therapy efficacy

Introduction: Continuous mobile cardiac outpatient telemetry (MCOT) may have several advantages over traditional ambulatory monitoring systems in the diagnostic evaluation of symptoms such as palpitations, dizziness, and syncope. However, only limited published data are available showing its advantages.
Methods and Results: We reviewed the records of 122 consecutive patients evaluated using MCOT for palpitations, presyncope/syncope, or to monitor the efficacy of a specific antiarrhythmic therapy. Ten of 17 patients (59%) studied for presyncope/syncope had a diagnosis made with MCOT. Eight of these 17 patients had a previous negative evaluation for presyncope/syncope and five had an event correlated with the heart rhythm during the monitoring period. Nineteen patients monitored for palpitations or presyncope/syncope were asymptomatic during monitoring but had a prespecified arrhythmia detected. When MCOT was used as the first ambulatory monitoring system to evaluate palpitations (n = 18), 73% of patients correlated their symptoms with the underlying cardiac rhythm. Seven of 21 patients monitored for medication titration had dosage adjustments during outpatient monitoring.
Conclusions: MCOT can detect asymptomatic clinically significant arrhythmias, and was especially useful to identify the cause of presyncope/syncope, even in patients with a previous negative workup. This outpatient monitoring system allows patients to undergo daily medication dose titration in the outpatient setting, thus avoiding hospitalization.     

Echocardiographic and electrocardiographic evaluation of the effects of propranolol and verapamil in obstructive hypertrophic cardiomyopathy

The purpose of this study is to compare M-mode echocardiographic and electrocardiographic modifications obtained by short-term therapy (6 weeks) with high doses (480 mg/day) of propranolol or verapamil in six patients with hypertrophic obstructive cardiomyopathy. Propranolol prevents heart rate acceleration and reduces significantly the echocardiographic obstruction index during provocative testing with isoprenaline, when verapamil doesn't. However verapamil seems to be more able than propranolol to suppress ventricular arrhythmias as demonstrated in Holter monitoring. Evaluation of each patient suffering from hypertrophic obstructive cardiomyopathy with echocardiography and 24-hours electrocardiography would permit to better define appropriate therapy.     

Diagnostic efficacy of 24-hour electrocardiographic monitoring for syncope

The effectiveness of an open referral electrocardiographic monitoring service in identifying an arrhythmogenic cause for syncope was evaluated. Over 5 years, 7,364 patients of all ages underwent ambulatory 24-hour electrocardiographic (Holter) monitoring using a 2-channel recorder. Of these, 1,512 (20.5%) were referred because of syncope. During monitoring, 15 patients had syncope and 7 of the episodes were related to an arrhythmia, usually ventricular tachycardia. Presyncope was reported in 241 patients, with a related arrhythmia in 24. Thus, an arrhythmia-related symptom that could be diagnostic was present in only 2% of the patients monitored. However, syncope or presyncope without an associated arrhythmia might be considered a negative diagnostic clue and occurred in 225 (15%). High-grade atrioventricular block was present in 15 and ventricular tachycardia in 116; only 6 (5%) reported associated symptoms. An age-related incremental increase in atrial and ventricular arrhythmias was found. In 415 of the 1,004 patients (41%) aged 60 years or more, arrhythmias that are conventionally associated with sinoatrial disease were recorded. Using stringent diagnostic criteria, the sick sinus or tachybradycardia syndrome was present in 33 (3%). Many older patients (70%) were taking drugs that could be arrhythmogenic, hypotensive or both. It is concluded that an open referral 24-hour ambulatory monitoring service rarely results in identifying relevant symptom-related arrhythmias in patients with syncope. H records many asymptomatic arrhythmias that can compound rather than resolve the diagnostic problem in older patients, because the data obtained could lead to unnecessary therapy. An iatrogenic cause for syncope should always be considered.     

Prognostic determinants in hypertrophic cardiomyopathy. Prospective evaluation of a therapeutic strategy based on clinical, Holter, hemodynamic, and electrophysiological findings.

BACKGROUND. Patients with hypertrophic cardiomyopathy (HCM) frequently have arrhythmias and hemodynamic abnormalities and are prone to sudden death and syncope. An important need exists for improved risk stratification and definition of appropriate investigation and therapy. METHODS AND RESULTS. The relation of 31 clinical, Holter, cardiac catheterization, and electrophysiological (EP) variables to subsequent cardiac events in 230 HCM patients was examined by multivariate analysis. Studies were for cardiac arrest (n = 32), syncope (n = 80), presyncope (n = 52), ventricular tachycardia (VT) on Holter (n = 36), a strong family history of sudden death (n = 9), and palpitations (n = 21). Nonsustained VT on Holter was present in 115 patients (50%). Sustained ventricular arrhythmia was induced in 82 patients (36%). Seventeen cardiac events (eight sudden deaths, one cardiac arrest, and eight syncope with defibrillator discharges) occurred during a follow-up of 28 +/- 19 months. The 1-year and 5-year event-free rates were 99% and 79%, respectively. Two variables were significant independent predictors of subsequent events: sustained ventricular arrhythmia induced at EP study (beta, 3.5; p = 0.002) and a history of cardiac arrest or syncope (beta, 2.9; p less than 0.05). Only two of 66 patients without symptoms of impaired consciousness had a cardiac event (3-year event-free rate, 97%). In contrast, nonsustained VT on Holter was associated with a worse prognosis only in patients with symptoms of impaired consciousness: 11 of 79 symptomatic patients with VT on Holter (14%) had events versus only four of 85 symptomatic patients without VT on Holter (5%) (p = 0.057). Notably, none of 51 patients without symptoms of impaired consciousness in whom VT was not induced at EP study had a cardiac event. CONCLUSIONS. In HCM, VT on Holter is of benign prognostic significance in the absence of symptoms of impaired consciousness and inducible VT, and sustained VT induced at EP study, especially when associated with cardiac arrest or syncope, identifies a subgroup at high risk for subsequent cardiac events.     

The Utility of Holter Monitoring Compared to Loop Recorders in the Evaluation of Syncope and Presyncope

Background: Holter monitoring is frequently used to assess patients with syncope, but rarely provides a diagnosis. Newer loop recorders provide the opportunity for prolonged electrocardiographic monitoring to enhance diagnostic yield. Methods: The results of 232 Holter monitors and 81 loop recordings performed for the investigation of syncope or presyncope were reviewed for indication, patient demographics, and presence and type of symptoms and/or arrhythmias. The results were classified as (1) symptom‐arrhythmia correlation, (2) clinically useful information (group 1 plus those excluding arrhythmic syncope, and those demonstrating asymptomatic serious arrhythmias) and (3) unhelpful (asymptomatic and no serious arrhythmias). Results: Loop recorders provided a symptom‐arrhythmia correlation in 11.1% of patients compared to only 0.4% in the Holter group (P < 0.0001). Clinically useful information was obtained in 54.3% of loop patients compared to 27.6% in the Holter group (P < 0.0001). Technical problems occurred in 0.4% of the Holter patients and in 3.7% of loop patients (P = 0.05). Classification was difficult in seven patients in the Holter group; two experienced symptoms during sinus rhythm but also had a serious asymptomatic arrhythmia, and five patients had 6–10 beats of asymptomatic ventricular tachycardia at a rate < 160 beats/min. Conclusion: Loop recording was well tolerated and superior to Holter monitoring in providing a symptom‐arrhythmia correlation or clinically useful information in patients with syncope and presyncope. An initial approach with a loop‐recording device should be employed in these patients.     

High risk for sudden death identified by electrocardiographic loop recording in a patient with hypertrophic cardiomyopathy without major risk factors

Recurrent presyncope is occasionally reported by patients with hypertrophic cardiomyopathy (HC). However, it is difficult to identify on 24-hour Holter recordings the mechanisms responsible for these infrequent symptoms. We report the case of a patient with HC with recurrent presyncope and without major sudden death risk factors, in whom electrocardiographic loop recording identified life-threatening arrhythmias as the mechanism responsible for these symptoms. Documentation of these arrhythmias justified implantation of a cardioverter-defibrillator in the absence of other risk factors.     

Diagnostic utility of memory equipped transtelephonic monitors

The diagnostic utility of memory-equipped transtelephonic electrocardiographic monitors was evaluated in a series of 31 patients referred for evaluation of unexplained syncope (16), presyncope (8), or palpitations (7). Previous nondiagnostic workups included 4 +/- 1 days (mean +/- standard error of the mean) of 24-hour Holter and/or in-hospital telemetric monitoring per patient. The duration of monitoring averaged 31 +/- 2 days per patient. Electrocardiographic recordings were made during a typical symptom episode in 9 of 31 (29%) patients, including 0 of 16 with syncope, 3 of 8 (37%) with presyncope, and 6 of 7 (86%) with palpitations (p less than .001). The probability of recording typical symptoms was strongly influenced by their previous frequency. Potentially causal arrhythmias were documented in 5 of 7 (71%) patients with palpitations, but in none of the other symptom subgroups (p less than .001). Monitoring led to changes in therapy in only two patients. During followup of 9 +/- 1 months, symptoms continued in 4 of 16 (25%) with syncope, 7 of 8 (87%) with presyncope, and 7 of 7 (100%) with palpitations (p = .001). The diagnostic utility of these devices thus appears to be low in patients with previously unexplained syncope or presyncope. The yield was high in those monitored for palpitations, which may be in part attributable to the greater frequency of symptoms observed in this group.     

Arrhythmia in hypertrophic cardiomyopathy: exercise and 48 hour ambulatory electrocardiographic assessment with and without beta adrenergic blocking therapy

Submaximal treadmill exercise electrocardiography and 48 hour ambulatory electrocardiographic monitoring were performed in 30 patients with hypertrophic cardiomyopathy both with and without beta adrenergic blocking therapy. During ambulatory electrocardiographic monitoring 1 patient (3 percent) had no arrhythmia, 14 patients (46 percent) had supraventricular tachycardia or paroxysmal atrial fibrillation, 13 (43 percent) had multiform or paired ventricular extrasystoles and 8 (26 percent) had ventricular tachycardia. The frequency of these ventricular arrhythmias was almost identical with and without beta adrenergic blocking drugs (mean dose in "propranolol equivalents" 280 mg daily). With beta blocking therapy fewer patients had supraventricular tachycardia; however, the difference was not significant. During exercise testing 18 patients (60 percent) had ventricular extrasystoles and 3 patients (10 percent) had paired ventricular extrasystoles and the frequency was almost identical with and without beta adrenergic blocking therapy. No routine echocardiographic or hemodynamic measurement predicted the serious ventricular arrhythmias. It is concluded that asymptomatic ventricular arrhythmia is a common occurrence in patients with hypertrophic cardiomyopathy and its frequency is not reduced with beta adrenergic blocking therapy. Because occult arrhythmia may be the cause of sudden death it is important to detect it in these patients so that an effort can be made to improve prognosis with specific antiarrhythmic treatment.     

Potentially lethal arrhythmias and their management in hypertrophic cardiomyopathy

The prevalence of potentially lethal arrhythmias (PLA) in groups of patients with hypertrophic cardiomyopathy has been assessed, but the rate at which they develop (their incidence) during long-term follow-up has not been reported. Therefore, conduction system disease (CSD) (sick sinus syndrome and His-ventricular disease), ventricular couplets and ventricular tachycardia (VT) detected by routine electrocardiograms, periodic 24-hour Holter monitoring and periodic exercise stress testing were studied in 50 patients treated with large doses of β-adrenergic blocking drugs who were followed for 2 to 14 years (mean 5.9). Sixteen PLAs detected at the beginning of observation were excluded from actuarial analysis for new PLAs. Twenty-one patients had 24 new PLAs (7 with CSD, 1 patient with sustained supraventricular tachycardia, 6 with ventricular couplets and 10 with VT); only 43% of these PLAs were heralded by new symptoms. In 6 patients, the arrhythmia caused symptoms and was identified by a routine electrocardiogram. The 3 patients with His-ventricular disease presented with syncope and required electrophysiologic confirmation of this diagnosis. In only 1 patient was a PLA (ventricular couplets) detected only by exercise testing. All other ventricular arrhythmias were detected by Holter monitoring. The incidence of CSD in 47 patients free of this condition at entry was 5% at 5 years and 33% at 10 years. The incidence of ventricular couplets or VT in 39 patients free of these at entry was 26% at 5 years and 75% at 10 years, and the incidence of VT only was 18% at 5 years and 40% at 10 years. The incidence of all categories of new PLAs in the 50 patients was 32% at 5 years and 81% at 10 years. Because new PLAs are frequent during long-term follow-up and most cannot be detected adequately without surveillance, periodic Holter monitoring—at least on an annual basis—is recommended.     

The diagnosis of cardiac arrhythmias: a prospective multi-center randomized study comparing mobile cardiac outpatient telemetry versus standard loop event monitoring

Introduction: Ambulatory electrocardiographic monitoring systems are frequently used in the outpatient evaluation of symptoms suggestive of a cardiac arrhythmia; however, they have a low yield in the identification of clinically significant but infrequent, brief, and/or intermittently symptomatic arrhythmias. The purpose of this study was to compare the relative value of a mobile cardiac outpatient telemetry system (MCOT) with a patient-activated external looping event monitor (LOOP) for symptoms thought to be due to an arrhythmia.
Methods and Results: The study was a 17-center prospective clinical trial with patients randomized to either LOOP or MCOT for up to 30 days. Subjects with symptoms of syncope, presyncope, or severe palpitations who had a nondiagnostic 24-hour Holter monitor were randomized. The primary endpoint was the confirmation or exclusion of a probable arrhythmic cause of their symptoms. A total of 266 patients who completed the monitoring period were analyzed. A diagnosis was made in 88% of MCOT subjects compared with 75% of LOOP subjects (P = 0.008). In a subgroup of patients presenting with syncope or presyncope, a diagnosis was made in 89% of MCOT subjects versus 69% of LOOP subjects (P = 0.008). MCOT was superior in confirming the diagnosis of clinical significant arrhythmias, detecting such events in 55 of 134 patients (41%) compared with 19 of 132 patients (15%) in the LOOP group (P < 0.001).
Conclusions: MCOT provided a significantly higher yield than standard cardiac loop recorders in patients with symptoms suggestive of a significant cardiac arrhythmia.     

Drug treatment of hypertrophic cardiomyopathy

Both, beta-receptor blocking agents and calcium-antagonists have been proven to be very effective in the treatment of idiopathic hypertrophic cardiomyopathy. In the vast majority of patients they lead to a significant reduction of the predominant clinical symptoms--angina and dyspnea--or even abolish them. Since beta-blockers primarily act on the contractile behaviour of the left ventricle they are especially suited in the obstructive form of the disease where they reduce outflow tract obstruction. In contrast, calcium-antagonists seem to mainly influence diastolic muscle mechanics by increasing diastolic distensibility, and thus may be indicated in the nonobstructive forms of hypertrophic cardiomyopathy. In cases with severe, life-threatening arrhythmias especially if associated with syncope, an antiarrhythmic therapy is mandatory.     

Sudden death and obstructive hypertrophic cardiomyopathy

Sudden death is the most common cause of death in obstructive hypertrophic cardiomyopathies. Ventricular arrhythmias appear to be involved most frequently. The typical clinical picture is that of a young, asymptomatic male subject with a family history of sudden death and obstructive hypertrophic cardiomyopathy. The electrocardiogram at rest, the left ventricular pressure gradient, and the width of the septum are not good predictive criteria. Holter monitoring with the discovery of a run of ventricular tachycardia is the only method which identifies a subgroup at high risk for sudden death. Treatment with beta blockers does not protect patients with obstructive hypertrophic cardiomyopathy from sudden death and only combined therapy with an antiarrhythmic agent can control ventricular rhythm disturbances and decrease the number of sudden deaths in this condition.     

Study of the arrhythmogenicity of cardiomyopathies. Hypertrophic cardiomyopathies

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)     

Symptoms of hypertrophic cardiomyopathy,with special emphasis on syncope and postprandial exacerbation of symptoms

We undertook a prospective study of the symptoms of hypertrophic cardiomyopathy with the aim of profiling symptomatic morbidity in detail, determining the prevalence of anxiety and depression, and describing the prevalence and associations of syncope and postprandial symptom exacerbation. A questionnaire was administered to consecutive outpatients;70 with hypertrophic cardiomyopathy, 43 with coronary artery disease, 32 with idiopathic dilated cardiomyopathy, and to 40 normal subjects. Hypertrophic cardiomyopathy patients underwent exercise testing, echo-cardiography, and Holter monitoring. Hypertrophic cardiomyopathy patients had a high frequency of cardiac symptoms and, on average, had a level of symptomatic morbidity equivalent to that of chronic stable angina and dilated cardiomyopathy. There was no evidence for an excess of anxiety (14%) or depression (6%) in patients with hypertrophic cardiomyopathy. Syncope and presyncope, especially provoked by exertion or posture change, were characteristic and common symptoms in hypertrophic cardiomyopathy. A history of syncope was associated with an abnormal blood pressure response to exercise in over 50% of cases that may be the mechanism of syncope in some. Postprandial exacerbation of symptoms occurred in over one-third of hypertrophic cardiomyopathy patients, half of coronary disease patients, and infrequently in dilated cardiomyopathy. Hypertrophic cardiomyopathy patients with postprandial symptoms had a greater frequency of angina, were more symptomatic, and had a reduced exercise capacity, suggesting that postprandial symptoms are a marker for more severe disease.     

Role of ambulatory ECG in a cardiology department

Ambulatory electrocardiographic monitoring has become an important clinical tool for the diagnosis and management of patients with symptoms suggesting cardiac arrhythmias or ischemic heart disease. Holter monitoring (H) is widely used in the evaluation of patients with recent myocardial infarction, angina pectoris, hypertrophic cardiomyopathy, dilated cardiomyopathy, long QT syndrome, sinus node dysfunction. The role of H monitoring in defining prognosis in many of these heart disease is not well established. Holter monitoring is also used to evaluate the results of antiarrhythmic and antianginal drug therapy. Application of quantitative H monitoring to define drug efficacy has revealed that antiarrhythmic drugs may have a proarrhythmic effect and that a withdrawal syndrome can follow the abrupt cessation of antianginal and antiarrhythmic drugs. There are no consistent data about the optimal duration of monitoring to detect and quantify ventricular arrhythmias and ischemic attacks. We think that the appropriate duration of monitoring must be adjusted to the single patient, considering: a) the frequency and severity of symptoms; b) the cardiac lesion (s) and functional class; c) the goal of H. When used appropriately H can be a cost-effective tool and may prevent hospitalizations.     

Predictive value of presyncope in patients monitored for assessment of syncope

BACKGROUND: The purpose of this study was to assess the diagnostic value of recording the cardiac rhythm during presyncope in patients undergoing monitoring for undiagnosed syncope. METHODS AND RESULTS: Eighty-five patients (age, 59 +/- 18 years; 44 men, 41 women) with recurrent unexplained syncope underwent prolonged monitoring with an implantable loop recorder. Patients were examined for syncope, which was either recurrent or associated with at least 2 presyncopal episodes. Patients had a mean of 5.1 +/- 5.5 syncopal episodes in the previous 12 months, and 70% of patients had symptoms for >2 years. Sixty-two (73%) patients had recurrent symptoms during a 12-month follow-up period. Of 150 recurrent events captured by the implantable loop recorder, there were 38 (25%) episodes of syncope and 112 (75%) episodes of presyncope. Syncope alone recurred in 12 patients, presyncope in 25, and both in 16. An arrhythmia was present in 64% of syncopal events (bradycardia in 16, tachycardia in 2) versus 25% for presyncopal events (bradycardia in 7, tachycardia in 3, P =.001). An arrhythmia was detected in 9 (56%) of the 16 patients with both syncope and presyncope, which was present in all recorded episodes of syncope compared with 6 of 9 presyncopal episodes. Patient-related failure to freeze the device after symptoms occurred in 21 (36%) of 59 syncopal events compared with 15 (12%) of 127 presyncopal events (P =.0001). CONCLUSIONS: Syncope is more likely to be associated with an arrhythmia than is presyncope in patients undergoing extended monitoring. Presyncope is a nonspecific end point that is frequently associated with sinus rhythm. Patients undergoing extended monitoring for syncope should continue to be monitored after an episode of presyncope unless an arrhythmia is detected.     

Placement of moricizine in the selection of antiarrhythmic drug therapy

The selection of antiarrhythmic drug therapy requires a careful assessment of the benefits of ventricular arrhythmia suppression compared with the risks of antiarrhythmic drug use. Since reduction in sudden cardiac death from ventricular arrhythmia suppression has not been demonstrated, the only indications for antiarrhythmic drug suppression involve the reduction of hemodynamic symptoms such as syncope (a major benefit) or the reduction of nonhemodynamic symptoms such as palpitations or dizziness (a minor benefit). Noncardiac adverse effects and organ toxicity as well as cardiac side effects must be considered when antiarrhythmic drug therapy is initiated. For reduction of nonhemodynamically important symptoms in patients with benign or potentially lethal ventricular arrhythmias, beta blockers are chosen as first-line therapy. Because of moricizine's relatively high effectiveness in suppressing ventricular arrhythmias and its low potential for noncardiac adverse effects and organ toxicity as well as a low incidence of induced proarrhythmia and heart failure, moricizine is selected as the next drug in line. All other class I antiarrhythmic drugs either have been shown to have the potential for increasing sudden cardiac death or have major rates of noncardiac adverse effects or organ toxicity that preclude their use in these patient groups except in special circumstances. In patients with malignant ventricular arrhythmias who present with hemodynamic consequences such as syncope or worse, moricizine also is preferred as an initial drug for consideration. When compared to drugs with class IA and IB action, moricizine has comparable efficacy yet lower rates of noncardiac adverse effects, organ toxicity, proarrhythmia and heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Value of Holter monitoring in assessing cardiac arrhythmias in symptomatic patients.

Holter electrocardiographic monitoring in 55 symptomatic patients with syncope, palpitations or dizziness uncovered significant arrhythmias in 30 patients (55 percent). By providing an observation period of at least 24 hours including a period of sleep, the procedure aided detection and diagnosis in both symptomatic and asymptomatic patients of transient arrhythmias or conduction abnormalities not documented by routine electrocardiograms. Bradyarrhythmias accounted for the majority of arrhythmias recorded in 21 or 30 symptomatic patients (70 percent); 15 had sinus bradycardia (35 to 55 beats/min) alone and 6 also had long episodes of sinus arrest of up to 5 seconds. Two had sinus bradycardia with periods of atrioventricular block with Wenckebach phenomenon. Five patients had a tachycardia-bradycardia syndrome; three had other episodic arrhythmias and one had pacemaker failure. In 15 (60 percent) of the 25 patients without arrhythmias, monitoring did not document the cause of symptoms. Holter monitoring is of considerable value in assessing the efficacy and adequacy of drug treatment, especially in patients with known heart disease, and in detecting pacemaker malfunction. However, very long periods of monitoring may be needed to make a diagnosis in those with only sporadic symptoms.