Improved Detection and Analysis of Sensed and Paced Events in Dual Chamber Pacemakers with Extended Memory Function A Prospective Multicenter Trial in 626 Patients

Patients and Methods: This prospective study analyzed the incidence of atrial arrhythmias in a population of 626 patients in 173 medical centers of eleven European countries and Japan with indication for a dual chamber pacemaker system. The accuracy of the new Automatic Interpretation for Diagnosis Assistance (AIDA) program which is included in Chorus pacemakers was evaluated and the AIDA analysis was compared to and proven with Holter monitoring. Data stored in the pacemakers' memories for the first 24 hours (D1) were compared with simultaneously recorded 24-hour surface electrocardiograms, and data stored over the following 28 days (D28) were examined against reported intercurrent symptoms. Results: At D1, atrial arrhythmias were detected by AIDA in 60 out of 626 patients (12%), consisting of atrial fibrillation (n = 29), atrial flutter (n = 4), and miscellaneous arrhythmias (n = 17), and closely corroborated by Holter monitoring (sensitivity 93.7%, specificity 94.9%). At D28, 149 out of 386 patients (49%) had had episodes of automatic mode switch prompted by atrial arrhythmias. Symptoms were reported by 81 patients (54%), 92 (62%) had no histories of atrial arrhythmias, and 57 patients (38%) were neither symptomatic nor had histories of atrial arrhythmias. An inverse relationship was found between the number of atrial paced events and the occurrence of atrial arrhythmias (p < 0.001). A history of atrial arrhythmias and older age were associated with a higher risk of atrial arrhythmias (p < 0.05). In contrast, gender, hypertension, concomitant heart disease, or type of atrial lead fixation system were not related with the occurrence of atrial arrhythmias. Conclusion: AIDA allowed to confirm, or disprove, the occurrence of atrial arrhythmias as a source of symptoms reported during long-term follow-up. It could also be used to examine the efficacy of antiarrhythmic therapy, and be of assistance when weighing the needs for anticoagulation in patients experiencing asymptomatic atrial arrhythmias. Patienten und Methode: Die vorliegende prospektive Studie untersucht die Inzidenz von Vorhofarrhythmien in einer Population von 626 Patienten mit der Indikation zur Implantation eines Zwei-Kammer-Schrittmachersystems, durchgeführt in 173 medizinischen Zentren in elf europäischen Ländern und in Japan. Die Genauigkeit des neuen Programms zur Automatischen Interpretation der Diagnose-Analyse (Automatic Interpretation for Diagnosis Assistance, AIDA) für Chorus-Herzschrittmacher wurde evaluiert und die AIDA-Analyse mit dem Langzeitelektrokardiogramm (Holter) verglichen und überprüft. Die im Schrittmacher gespeicherten Daten der ersten 24 Stunden (D1) wurden mit einem simultan aufgezeichneten 24-Stunden-Langzeitelektrokardiogramm verglichen. Die Daten der folgenden 28 Tage (D28) wurden in Bezug auf die vom Patienten angegebenen Symptome untersucht. Ergebnisse: Im Zeitraum von D1 wurden bei 60 von 626 Patienten (12%) Vorhofarrhythmien mit dem AIDA-Programm erfasst, bei denen es sich um Vorhofflimmern (n = 29), Vorhofflattern (n = 4) und gemischte Vorhofarrhythmien (n = 17) handelte. Die Auswertung der Langzeitelektrokardiogramme bestätigte die Diagnose mit einer Sensitivität von 93,7% und einer Spezifität von 94,9%. Im Zeitraum von D28 zeigten 149 von 386 Patienten (49%) eine Episode einer Vorhofarrhythmie, die zu einem Wechsel in den Fallback-Modus führte. Symptome wurden von 81 Patienten (54%) angegeben: 92 Patienten (62%) hatten bisher in der Vorgeschichte keine Vorhofarrhythmien, 57 Patienten (38%) hatten bisher weder Symptome noch Vorhofarrhythmien. Eine inverse Beziehung zwischen der Anzahl stimulierter Vorhofereignisse und dem Auftreten von Vorhofarrhythmien konnte nachgewiesen werden (p < 0,0001). Eine Historie von Vorhofarrhythmien sowie höheres Lebensalter waren assoziiert mit einem höheren Risiko für das Auftreten von Vorhofarrhythmien (p < 0,05). Im Gegensatz dazu zeigte sich für die Faktoren Geschlecht, Bluthochdruckkrankheit, begleitende Herzerkrankung oder die Art der Fixierung der Vorhofelektrode (passiv oder aktiv) kein Bezug zum Auftreten von Vorhofarrhythmien. Schlussfolgerung: Das AIDA-Programm erlaubt das Auftreten von Vorhofarrhythmien als Ursache von Symptomen in der Nachsorge zu bestätigen oder zu widerlegen. Es kann auch genutzt werden, um die Effektivität einer antiarrhythmischen Therapie zu untersuchen und die Notwendigkeit einer Antikoagulation bei Patienten mit asymptomatischen Vorhofarrhythmien abzuwägen.     

A new diagnostic concept in cardiac pacing for the evaluation of the incidence of atrial arrhythmias. Results of the AIDA study]

An international, prospective, multicentre trial (AIDA) was undertaken from October 1995 to March 1997. The object was to compare the diagnosis of atrial arrhythmias (AA) by the automatic interpretation of the memory functions of dual chamber pacemakers with that of 24 hour Holter monitoring at day 1. The second objective was to assess the incidence and symptomatology of the AA during follow-up at Day 28. In France, 226 patients implanted with Chorus, Chorus II and Chorus RM pacemakers were included in the study (148 men, 70.5 +/- 10.8 years) for the following indications: AVB (atrioventricular block)/bundle branch block (47.3%), sinus mode dysfunction (10.2%), bradycardia-tachycardia syndrome (10.2%), AVB + sinus node dysfunction + cardia-tachycardia syndrome (19.5%), other (2.2%). AA were documented in 34.5% of patients before implantation. Of the 226 patients analysed at Day 1, 23 (10.2%) had at least one episode of AA diagnosed simultaneously by Holter monitoring and the automatic interpretation (AIDA). These AA were atrial fibrillation (15 patients), atrial flutter (2 patients) and atrial tachycardia (6 patients). The sensitivity of the AIDA programme for detecting AA was 92% and the specificity 97%. Of the 156 patients evaluated at Day 28, the programme diagnosed AA in 78 patients (50%), 34 of which (21.8%) were asymptomatic and without previously documented AA. The results of the AIDA study confirmed the excellent sensitivity and specificity of the memory functions of these cardiac pacemakers for analysis of AA. They seem to be very common during the follow-up of pacemaker-equipped patients. This new diagnostic concept will facilitate the programming and study of the efficacy of anti-arrhythmic therapy prescribed during long-term follow-up.     

Prevalence of atrial arrhythmia in 48 hypertensive patients: research of predictive criteria]

We studied atrial arrhythmias during a continue prospective work in 48 hypertensive patients referred to the OMS criteria. Hypertension was confirmed by a blood pressure ambulatory monitoring and stress testing blood pressure trend. All cardiovascular drugs were stopped at admission. Patients with associated valvular or coronary artery disease were excluded from analysis. In all patients, we realized a twelve lead-ECG, stress testing, 24 hour Holter monitoring, a blood pressure ambulatory monitoring, two-dimensional echocardiography with Doppler study and cardiac radio-nuclide angiography with diastolic function study. Atrial arrhythmias were considered significant if more than 100 premature atrial beats (PAB) and/or more than three successive PAB were present during Holter monitoring. Significant atrial arrhythmias were found in 39.5% of patients (group II, n = 19), not significant in 60.5% of patients (group I, n = 29). The duration of hypertension was longer in group II (140 vs 66 months, p < 0.05). There was no difference between the two populations considering left atrial size or blood pressure level. Furthermore, we were surprised to find a normal E/A ratio on mitral Doppler recording in patients with atrial arrhythmias (1.23 vs 0.9; p < 0.05). Others diastolic parameters didn't significantly differ. Left ventricular mass index was similar in the two groups but patients with atrial arrhythmias had more asymmetric hypertrophy (1.23 vs 1.13 septum/posterior wall ratio: p < 0.05). Conclusion: atrial arrhythmias in our study seem to be more dependent from duration of HTA and left ventricular asymmetric structure than from left atrial size.(ABSTRACT TRUNCATED AT 250 WORDS)     

Continuous Arrhythmia Monitoring in Pediatric and Adult Patients With Left Ventricular Noncompaction

Patients with left ventricular noncompaction (LVNC) are at risk of clinically significant arrhythmias and sudden death. We evaluated whether implantable loop recorders could detect significant arrhythmias that might be missed in these patients during annual Holter monitoring.Selected pediatric and adult patients with LVNC who consented to implantable loop recorder placement were monitored for 3 years (study duration, 10 April 2014–9 December 2019). Fourteen subjects were included (age range, 6.5–36.4 yr; 8 males). Of 13 patients who remained after one device extrusion, one underwent implantable cardioverter-defibrillator placement. Four patients (31%) had significant arrhythmias: atrial tachycardia (n=2), nonsustained ventricular tachycardia (n=1), and atrial fibrillation (n=1). All 4 events were clinically asymptomatic and not associated with left ventricular ejection fraction. In addition, a high frequency of benign arrhythmic patterns was detected.Implantable loop recorders enable continuous, long-term detection of important subclinical arrhythmias in selected patients who have LVNC. These devices may prove to be most valuable in patients who have LVNC and moderate or greater ventricular dysfunction.     

Cardiac arrhythmias during the combined use of intravenous aminophylline and terbutaline in status asthmaticus

The purpose of this study was to evaluate prospectively the occurrence of cardiac arrhythmias during the combined therapy with intravenous aminophylline and terbutaline in 29 consecutive patients with status asthmaticus. The 24-hour Holter recordings were performed during continuous intravenous infusions of aminophylline (0.56 +/- 0.20 mg/kg/h) and terbutaline (0.034 +/- 0.014 microgram/kg/min). Serum theophylline concentration was 12.1 +/- 3.8 micrograms/ml and never reached the toxic level (greater than 20 micrograms/ml). Premature ventricular contractions (PVCs) were absent in 35 percent of patients and 48 percent had rare unifocal PVCs (less than 10/h). Only 17 percent of patients (five of 29) exhibited severe ventricular arrhythmias: PVCs greater than 10/h (n = 3), multifocal PVCs (n = 1); and a short run of ventricular tachycardia (n = 1). Serious supraventricular arrhythmias occurred in only 7 percent of patients (two of 29) who developed sustained runs of atrial tachycardia. These arrhythmias were always clinically well tolerated and spontaneously resolved without any antiarrhythmic treatment. We conclude that severe arrhythmias are rarely observed during combined therapy with aminophylline and terbutaline in status asthmaticus.     

Holter monitoring in syncope: diagnostic yield in octogenarians

OBJECTIVES: To determine the diagnostic yield of Holter monitoring in very old adults (≥80) with syncope. DESIGN: A Holter study was considered diagnostic if the arrhythmia explained syncope (atrioventricular (AV) block, sinus node dysfunction, atrial fibrillation with severe bradycardia or tachycardia, supraventricular or ventricular tachycardia). SETTING: A tertiary care center in Switzerland over a period of 10 years. PARTICIPANTS: Four hundred seventy‐five Holter studies were performed in individuals aged 80 and older (median age 84, 65% female, mean left ventricular ejection fraction (LVEF) 0.56 ± 0.1%). MEASUREMENTS AND RESULTS: Fifty‐three Holter studies (11%) were diagnostic. The detected arrhythmias were AV block (n=13), sinus node dysfunction (n=13), binodal disease (n=2), atrial fibrillation with slow or rapid ventricular response (n=21), ventricular tachycardia (n=3) and supraventricular tachycardia (n=1). Forty participants (8%) received a pacemaker, and one received an implantable cardioverter‐defibrillator because of the results of Holter monitoring. The yield of Holter monitoring was significantly greater (all P<.01) in the presence of heart disease (17%) and low LVEF (22%), in men (17%) and in participants aged 90 and older (20%). Heart disease (odds ratio (OR)=3.2, 95% confidence interval (CI)=1.7–6.1), male sex (OR=2.1, 95% CI=1.1–3.8), and aged 90 and older (OR=2.4, 95% CI=1.2–5.1) remained independent predictors for a high diagnostic yield of Holter monitoring. Furthermore, Holter monitoring was helpful in excluding arrhythmias as a cause of syncope in an additional 10% of cases. CONCLUSION: The diagnostic value of Holter monitoring in participants aged 80 and older with syncope was 11.2%. Its yield was higher in men and in the presence of structural heart disease and was 20% in individuals aged 90 and older.     

Limited Clinical Utility of Holter Monitoring in Patients with Palpitations or Altered Consciousness: Analysis of 8973 Recordings in 7394 Patients

Aims: To determine the clinical utility of 24 hour Holter monitoring by measuring the frequency of candidate arrhythmias recorded during the investigation of palpitations and altered consciousness. Methods: Of 9,729 Holter recordings, reports were available in 8,973 (92.2%) performed in the 7394 patients who comprise the study group. The mean age of the study group was 66 ± 19 years and 56.4% were women. Results: The most common indications were altered consciousness (41.7%) and palpitations (36.2%). Among patients with palpitations and sinus rhythm (n=2688), recordings were normal in 2247 (83.6%). Abnormalities included paroxysmal atrial fibrillation (PAF, 6.6%), narrow complex tachycardia (NCT, 2.8%) nonsustained or sustained ventricular tachycardia (NSVT/VT, 2.6%). Among patients with altered consciousness (n=3075), recordings were normal in 2589 (84.2%). Abnormalities included PAF (9.5%), NCT (2.6%), NSV/VT (0.2%), pause >2.8s (2.2%) and high degree AV block (1.3%). The diagnostic yield of Holter monitoring was particularly low in patients aged ≤50 years, of whom 93.1% had palpitations and 95.3% had altered consciousness had normal recordings. Conclusions: The diagnostic utility of Holter monitoring in patients being investigated for palpitations and altered consciousness is very limited, particularly in young patients for whom alternative diagnostic methods should be considered.     

Is there an association of atrial septal aneurysm with arrhythmias?

An association of atrial septal aneurysm (ASA) with cardiac arrhythmias has been described, and it has been suggested that undulating movements of the aneurysm initiate these arrhythmias, thereby causing arterial embolism. In this prospective study, all available electrocardiograms were reviewed and Holter monitoring was performed in 50 consecutive patients with echocardiographic diagnosis of ASA in order to assess the relationship between the occurrence of arrhythmias, morphologic characteristics of ASA and arterial embolism. Significant arrhythmias were identified in 26 (52%) patients (supraventricular n = 15, ventricular n = 6, both n= 5). Patients with arrhythmias were older (65 +/- 12 vs. 54 +/- 13 years, p = 0.005), frequently had palpitations (21/26 vs. 1/24, p < 0.0001) and an abnormal resting electrocardiogram (18/26 vs. 5/24, p < 0.001). By echocardiography, patients with arrhythmias had a larger left atrial (42.8 +/- 7.4 vs. 35.3 +/- 4.6 mm, p < 0.0001) and left ventricular enddiastolic diameter (53.8 +/- 5.6 vs. 49.7 +/- 4.1, p < 0.01) and a higher prevalence of associated mitral valve prolapse (12/26 vs. 4/24, p = 0.05). Potential cardiovascular causes for arrhythmia other than ASA were present in the great majority of patients with documented arrhythmias (24/26 vs. 7/24, p < 0.0001). The base diameter of ASA was larger in patients with arrhythmias (25.5 +/- 6.2 vs. 21.4 +/- 3.4, p < 0.01) and correlated with a larger left atrial diameter (r = 0.72, p < 0.0001). Concerning the mobility of ASA (maximal protrusion or phasic excursion), there was no significant difference between the two patient groups. Arterial embolism, however, predominantly occurred in ASA patients without arrhythmias (16/24 vs. 9/26, p < 0.05). In conclusion, the majority of patients with ASA and arrhythmias has underlying structural heart disease other than ASA which may be responsible for the arrhythmias observed. Arrhythmias in association with ASA do not play a major role as a mechanism for arterial embolism.     

Suspected cardiac syncope in elderly patients: use of the 12-lead electrocardiogram to select patients for holter monitoring.

BACKGROUND: Results of 24-hour Holter monitoring in elderly patients are often unhelpful, since the prevalence of asymptomatic arrhythmias increases and their prognostic significance is unclear. We investigated the value of the resting electrocardiogram (ECG) in predicting significant findings on 24-hour Holter recordings in those suspected of having cardiac syncope. OBJECTIVE: To see whether the resting 12-lead ECG can be used as a screening tool to select elderly patients suspected of having cardiac syncope for 24-hour ECG monitoring. METHOD: Comparison of resting 12-lead ECGs and 24-hour Holter tapes in 145 consecutive elderly outpatients suspected of having a cardiac cause for falls, dizziness, or syncope. RESULTS: Four of 30 normal ECGs (13%) showed an abnormality on Holter monitoring as compared with 55 of the 115 abnormal ECGs (47.8%; chi = 11.7143, p < 0.005). In the 'normal' group the 4 abnormal Holter recordings all showed short runs of supraventricular tachycardia, and no intervention resulted. The 115 abnormal resting ECGs showed either ischaemia (n = 27), dysrhythmia (n = 28), sinus bradycardia (n = 22), or conduction defects (n = 38). The 55 of these which showed abnormalities on Holter recordings occurred mostly where the resting ECG showed dysrhythmia (n = 14/28; 50%), bradycardia (n = 19/22; 86.4%), and conduction defect (n = 17/38; 44.7%). Seven patients had complete heart block on Holter, and all had conduction defects on resting ECG (p < 0.0004). Fifteen patients had pauses of longer than 3 s on Holter; all had conduction defect, bradycardia, or dysrhythmias on resting ECG (p < 0.0045). Sixteen patients were paced because of complete heart block or pauses on Holter recordings, and all had either bradycardia or conduction defects on resting ECG, resulting in complete resolution of their symptoms. CONCLUSIONS: Patients with suspected cardiac syncope and normal resting ECGs are unlikely to reveal significant abnormalities on single 24-hour Holter monitoring. Cardiac event recorder or prolonged Holter monitoring may be required in patients with strong clinical history. Those with abnormal ECGs, in particular sinus bradycardia and conduction defects, are highly likely to have significant abnormalities on 24-hour ECG monitoring.     

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.     

Evaluation of pacemaker telemetry as a diagnostic feature for detecting atrial tachyarrhythmias in patients with sick sinus syndrome.

AIM: The aim of the present study was to validate pacemaker telemetry as a diagnostic feature for detecting atrial tachyarrhythmias (AT) during pacemaker treatment in patients with sick sinus syndrome (SSS). METHODS AND RESULTS: Patients with SSS and bradytachy syndrome (n = 28, 20 women), mean age 71 +/- 10.3 years, were included. The patients were treated with AAIR (n = 14) or DDDR pacing. At a routine follow-up visit pacemaker telemetry was reset and the patients underwent Holter recording for at least 24 h. Episodes of atrial fibrillation (AF) during Holter recording were compared with episodes of AT detected by the pacemaker. Only episodes of AF lasting for at least 1 min during Holter recording were registered. AT detected by the pacemaker telemetry was defined as: an atrial high rate episode with a rate of > or = 220 bpm for > or = 5 min, atrial sensing with a rate of > or = 170 bpm in > or = 5% of total counted beats, mode-switching in > or = 5% of total time recorded or a mode-switching episode of > or = 5 min. Twenty-eight Holter recordings (mean duration 31.5 h, range 20-72 h) were used for evaluation. Ten patients had one or more episodes of AF lasting at least 1 min on their Holter recordings. Nine of these patients had AT detected by their pacemaker telemetry according to our criteria. None of the patients had AT detected by the pacemaker telemetry and not by the Holter recording. The specificity and sensitivity for detection of AT recorded by the pacemaker telemetry in this study was 100% and 90%, respectively. The false-positive rate was 0%. CONCLUSION: Pacemaker telemetry was found to be a reliable tool for detecting AT in patients with SSS.     

Management of far-field R wave sensing for the avoidance of inappropriate mode switch in dual chamber pacemakers: results of the FFS-test study

Background and Objective: Far-field R wave sensing (FFS) in the atrial channel of dual chamber pacemakers is a relevant source for inappropriate mode switch from the DDD mode to the DDI or VDI mode. Inappropriate loss of atrioventricular synchrony due to false positive mode switch is hemodynamically disadvantageous, may induce atrial tachyarrhythmias, can lead to pacemaker syndrome, and impairs the reliability of pacemaker Holter data. The aim of the study was to determine whether individual adjustment of the postventricular atrial blanking period (PVAB) based on an additional test is effective in avoiding inappropriate mode switch due to FFS when compared with standard programming of the PVAB.
Methods: A total of 207 patients were supplied with a St. Jude Medical Identity DR® or Identity ADx DR® dual chamber pacemaker for sinus nodal disease (n = 84), atrioventricular block (n = 79), binodal disease (n = 35), or other indications (n = 9). At hospital discharge, they were randomized to an individually optimized PVAB (n = 100) or to a control group with the PVAB left at the nominal of 100 msec (n = 107). Primary endpoint was the occurrence of inappropriate mode switch due to FFS within 3 months after pacemaker implantation assessed by stored electrograms of the pacemaker.
Results: At the 3-month follow-up, 28/107 (26%) patients with the standard programming of the PVAB showed at least one episode of inappropriate mode switch due to FFS versus 10/100 (10%) patients with optimized PVAB (P < 0.01). The optimized PVAB was shorter than the nominal PVAB in about one-third of patients and longer in about two-third of patients. Different atrial lead localizations were not associated with the occurrence of inappropriate mode switch.
Conclusions: Individual adjustment of the PVAB significantly reduces the incidence of inappropriate mode switch due to FFS.     

Ventricular arrhythmias in patients recovering from myocardial infarction: Do residual myocardial ischemia and anti-ischemic medical intervention influence the one-month prevalence?

The relationship between myocardial ischemia revealed by exercise testing and ventricular arrhythmias on Holter monitoring, and the effect of anti-ischemic intervention on the incidence of ventricular arrhythmias in patients with residual ischemia were studied in 125 patients recovering from myocardial infarction. Prior to discharge exercise testing and 24-h Holter monitoring were carried out In patients with ST-segment depression (n = 34), ventricular arrhythmias on Holter monitoring were seen in 7 (21%) compared with 20 (22%) patients without ST-segment depression (NS). Patients were hereafter double-blindly randomized to intervention with verapamil (n = 63) or placebo (n = 62). One month after discharge, 24-h Holter monitoring was repeated. In the verapamil group ventricular arrhythmias increased from 25 to 33% (NS). In the placebo group the figures were 18 and 27%, respectively (NS). In patients with ST-segment depression and verapamil treatment, the prevalence increased from 25 to 38% (NS). In the placebo group the figures were 17 and 22%, respectively (NS). The differences between the groups were not significant. A significantly increased prevalence of ventricular arrhythmias was found in patients with either heart failure or non-Q-wave infarct. In these patients myocardial ischemia during exercise did not correlate with ventricular arrhythmias either. ST-segment depression during predischarge exercise testing correlated with neither the prevalence nor the incidence of ventricular arrhythmias, and anti-ischemic intervention with verapamil did not influence the incidence of ventricular arrhythmias in both patients with and without myocardial ischemia.     

Long-term cardiac remodeling and arrhythmias in nonelite marathon runners

Long-term endurance sports are associated with atrial remodeling and atrial arrhythmias. More importantly, high-level endurance training may promote right ventricular (RV) dysfunction and complex ventricular arrhythmias. We investigated the long-term consequences of marathon running on cardiac remodeling as a potential substrate for arrhythmias with a focus on the right heart. We invited runners of the 2010 Grand Prix of Bern, a 10-mile race. Of 873 marathon and nonmarathon runners who applied, 122 (61 women) entered the final analysis. Subjects were stratified according to former marathon participations: control group (nonmarathon runners, n = 34), group 1 (1 marathon to 5 marathons, mean 2.7, n = 46), and group 2 (≥6 marathons, mean 12.8, n = 42). Mean age was 42 ± 7 years. Results were adjusted for gender, age, and lifetime training hours. Right and left atrial sizes increased with marathon participations. In group 2, right and left atrial enlargements were present in 60% and 74% of athletes, respectively. RV and left ventricular (LV) dimensions showed no differences among groups, and RV or LV dilatation was present in only 2.4% or 4.3% of marathon runners, respectively. In multiple linear regression analysis, marathon participation was an independent predictor of right and left atrial sizes but had no effect on RV and LV dimensions and function. Atrial and ventricular ectopic complexes during 24-hour Holter monitoring were low and equally distributed among groups. In conclusion, in nonelite athletes, marathon running was not associated with RV enlargement, dysfunction, or ventricular ectopy. Marathon running promoted biatrial remodeling.     

Arrhythmia disorders after repair of ventricular septal defects. Comparison of atrial and ventricular approaches

Post-operative disorders of conduction and of ventricular and supraventricular excitability were studied in 50 patients operated upon for ventricular septal defect (VSD). The VSD was approached by right ventriculotomy in 29 patients aged 4.4 +/- 3.1 years at surgery and 15.1 +/- 6.5 years at evaluation. The VSD was closed by the atrial route in 21 patients aged 6.6 +/- 3.9 years at surgery and 12.1 +/- 6.8 years at evaluation. Complete right bundle branch block (CRBB) was significantly more frequent in patients who underwent ventriculotomy (62 p. 100 vs 33 p. 100, p less than 0.05), but 2 late complete atrioventricular blocks were observed in patients in whom the atrial route was used. 34 p. 100 of the patients with ventriculotomy and 26.5 p. 100 of those without ventriculotomy had significant ventricular arrhythmias on Holter recordings (greater than or equal to Lown's grade 2, p = NS). The occurrence of ventricular arrhythmias in the patient population as a whole increased significantly with age at surgery and age at evaluation (p less than 0.05); this increase was also noted in each group (p = 0.06). Pre-operative right ventricular systolic pressure, severity of intraventricular disorders of conduction or duration of extracorporeal circulation and aortic clamping had no influence on the occurrence of ventricular arrhythmias. Disorders of supraventricular excitability were found in 1 patient who had ventriculotomy and in 2 patients whose VSD was corrected by the atrial route. No sinus dysfunction was observed. It is concluded that the ventricular approach of VSD significantly increases the occurrence of post-operative CRBB.(ABSTRACT TRUNCATED AT 250 WORDS)     

Value of electrophysiologic studies in hypertrophic cardiomyopathy treated with amiodarone

The relation of electrophysiologic effects of amiodarone to long-term outcome was studied in 35 patients with hypertrophic cardiomyopathy (HC). Indications for electrophysiologic studies were: cardiac arrest (n = 3), syncope/presyncope (n = 27) and asymptomatic ventricular tachycardia (VT) (n = 5). Twenty-eight patients (80%) had VT, 3 (9%) atrial tachycardia and 3 (9%) paroxysmal atrial fibrillation during 24-hour Holter monitoring. The studies were repeated after a total amiodarone dose of 58 +/- 122 g and during a maintenance median daily dose of 400 mg. Amiodarone abolished paroxysmal atrial arrhythmias in all 6 patients. However, it caused marked atrioventricular nodal conduction abnormality in 3 patients and heart block or marked HV interval prolongation (to greater than or equal to 100 ms) in 4 patients. Sustained VT was induced in 26 patients (74%) at baseline study and in 23 patients (66%) taking amiodarone therapy. With amiodarone, VT was no longer inducible or was more difficult to induce in 11 patients (31%), and the drug abolished VT during Holter monitoring in all patients. However, VT was easier to induce with amiodarone or was induced only with amiodarone in 18 (51%) patients. Amiodarone significantly slowed the rate of induced VT (from 248 +/- 29 to 214 +/- 37 beats/min, p less than 0.001). This was associated with a change in its morphology from polymorphic to monomorphic VT in 7 patients. During a follow up of 18 +/- 14 months (range 2 to 56), amiodarone was discontinued because of adverse effects in 8 patients (23%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Autoantibodies: new upstream targets of paroxysmal atrial fibrillation in patients with congestive heart failure

OBJECTIVES: The clinical implications of autoantibodies (Abs) were investigated as upstream indicators of paroxysmal atrial fibrillation in patients with congestive heart failure. METHODS: Circulating Abs against myosin (M-Abs) detected by immunofluorescence, Abs against beta 1-adrenergic receptors (Beta 1-Abs) detected by enzyme-linked immunosorbent assay (ELISA), and Abs against NA-K-ATPase (NKA-Abs) detected by ELISA were screened in 95 congestive heart failure patients with < or = 45% left ventricular ejection fraction (coronary artery disease, n = 48; dilated cardiomyopathy, n = 47) and 48 age-matched control patients with hypertension. No patient received antiarrhythmic therapy. All patients were enrolled with angiotensin converting enzyme inhibitors in the chronic stable state. Relationship of the presence of paroxysmal atrial fibrillation to other clinical variables were assessed by 48-hour Holter monitoring. RESULTS: No control patient had Abs. However, M-Abs, Beta 1-Abs, and NKA-Abs were detected in 22%, 26% and 16% of patients with congestive heart failure (coronary artery disease; 8%, 10%, and 4%, dilated cardiomyopathy; 36%, 43%, and 28%, respectively). Paroxysmal atrial fibrillation was more frequent in patients with dilated cardiomyopathy than in those with coronary artery disease (47% vs 15%, p < 0.01). Multivariate analysis suggested that NKA-Abs was an independent risk factor for the occurrence of paroxysmal atrial fibrillation (p < 0.01), although there were no differences in other clinical factors: age, sex, New York Heart Association functional class, concomitant medication, left ventricular ejection fraction, left atrial diameter, severity of mitral regurgitation, serum potassium, plasma norepinephrine, and atrial natriuretic peptide concentration. CONCLUSIONS: Autoantibodies against sarcolemmal Na-K-ATPase were closely related to the occurrence of paroxysmal atrial fibrillation in patients with congestive heart failure, so an autoimmune process may be an upstream factor in atrial fibrillation.     

Usefulness of 24-h Holter monitoring in patients with unexplained syncope and a high likelihood of arrhythmias

AIMS: To analyze the diagnostic yield of 24-h electrocardiographic monitoring (Holter) as a function of cardiac disease and electrocardiography (ECG) status in patients with unexplained syncope. METHODS: Patients were considered as having unexplained syncope when a careful clinical history, physical and neurological examination, 12-lead ECG and testing for orthostatic hypotension were negative. All patients underwent 24-h Holter. According to the type of arrhythmias that occurred during monitoring, Holter was classified as: (1) normal, in the absence of significant arrhythmias; (2) abnormal, in the presence of significant (e.g. atrial fibrillation) but non-diagnostic arrhythmias; or (3) diagnostic, in the presence of serious arrhythmia (e.g. complete AV block) with simultaneous symptoms. Clinical features, ECG and echocardiography were used to stratify patients and identify those in whom electrophysiological studies (EPS) were indicated. RESULTS: 140 consecutive patients with unexplained syncope underwent 24-h Holter and 44 of them (31%) had non-diagnostic arrhythmias. These occurred more frequently in patients with a positive cardiac history or an abnormal ECG (31/73, 42%), compared to patients without these features (13/67, 19%, p<0.05). Nine of the 140 patients (6%) had serious arrhythmias during Holter considered as diagnostic because of the presence of simultaneous symptoms. These occurred exclusively in patients with a positive cardiac history or an abnormal ECG (9/67, 12%). All diagnostic arrhythmias recorded during Holter occurred in patients in whom EPS was beforehand deemed indicated based on the presence of structural heart disease and/or an abnormal ECG. CONCLUSIONS: When restricted to high-risk patients, 24-h Holter remained a useful initial step in the evaluation of unexplained syncope with a symptoms and arrhythmias correlation occurring in 12% of patients. When performed first, this procedure might avoid doing EPS.     

Sleep-related breathing disorders are associated with ventricular arrhythmias in patients with an implantable cardioverter-defibrillator

STUDY OBJECTIVES: The aim of this study was to examine the influence of sleep-related breathing disorders (SBDs) on the occurrence of ventricular arrhythmias in patients with reduced left ventricular ejection fraction (LVEF), and life-threatening ventricular tachyarrhythmias treated with an implantable cardioverter-defibrillator. PATIENTS: Thirty-eight patients with LVEF of 36 +/- 13% (mean +/- SD) underwent a sleep study. When an apnea-hypopnea index (AHI) > 10/h occurred, SBD was diagnosed. MEASUREMENTS AND RESULTS: In patients with SBDs, ventricular arrhythmias (couplets, triplets, short runs) were recorded simultaneously by Holter ECG and differentiated in episodes with and without disordered breathing. An apnea-associated arrhythmia index (AI) was defined as the number of ventricular arrhythmias occurring simultaneous to disordered breathing. Accordingly, a nonapnea-associated arrhythmia index (NAI) was calculated as the number of ventricular arrhythmias during normal breathing. SBDs were diagnosed in 14 patients: Cheyne-Stokes respiration (CSR) [n = 8; AHI, 32.1 +/- 25.0/h], and obstructive sleep apnea (OSA) [n = 6; AHI, 34.1 +/- 14.6/h]. Four patients in the OSA group and four patients in the CSR group had ventricular arrhythmias during sleep, revealed by Holter ECG. In these eight patients, the AI was significantly higher than the NAI (20.9 +/- 18.8/h vs 4.9 +/- 3.3/h, respectively). CONCLUSIONS: These data show that ventricular arrhythmias occurred significantly more often in association with disordered breathing in patients at high risk for arrhythmias and reduced LVEF.     

Cardiac arrhythmias and left ventricular hypertrophy in dipper and nondipper patients with essential hypertension

To evaluate the behavior of cardiac arrhythmias in dipper and nondipper hypertensive patients, 48-h ambulatory blood pressure monitoring, 24-h Holter electrocardiogram recording and echocardiographic studies were performed in 56 untreated outpatients with essential hypertension. These patients were divided into 2 groups according to the presence (dipper, n=33) or absence (nondipper, n=23) of reduction of both systolic and diastolic blood pressure during nighttime by an average of more than 10% of daytime blood pressure. Mean 48-h systolic and diastolic blood pressures did not differ between the 2 groups. Nondipper patients had a significantly larger left atrial dimension (31.9+/-3.8 vs 35.6+/-3.7 mm; p<0.01), left ventricular mass index (114+/-26 vs 136+/-36 g/m2; p<0.05), as well as a larger number of total supraventricular (16+/-19 vs 89+/-197 beats; p<0.05) and ventricular ectopic beats (7+/-14 vs 47+/-96 beats; p<0.05) during daytime as compared with dippers. In conclusion, nondipper hypertensive patients are likely to experience supraventricular and ventricular arrhythmias more frequently than dippers. A blunted nocturnal blood pressure fall may be involved in the appearance of cardiac arrhythmias in patients with essential hypertension.