Evaluation of electromagnetic interference of GSM mobile phones with pacemakers featuring remote monitoring functions.

UNLABELLED: The aim of this study was to evaluate whether global system for mobile communication (GSM) cellular phones can affect the home monitoring (HM) function implemented in last generation pacemakers (PM). METHODS: We performed in vitro and in vivo tests on the BA03 PM (Biotronik GmbH, Berlin, Germany). In vitro we evaluated whether an improper HM procedure or an altered patient-activated HM function occurred. We used two cellular phone models, with a fixed external or internal antenna, positioned close to both the PM and the mobile phone-like device, during handover, ringing, and talking. All the tests were done with the PM in air, at 900 and 1,800 MHz GSM bands, under worst case conditions. A subset of these tests was repeated in 17 patients: the mobile phones were moved both around the PM implant site and the mobile cell phone-like device, during talking. RESULTS: In vitro, neither the HM procedure nor PM functioning were corrupted by the GSM communications: all the transmissions were correctly received, with a maximum transmission delay of about 110 seconds. In vivo, the rate of successful transmissions was 93%. CONCLUSION: Our data show that HM function does not call for specific restrictions on the use of GSM cellular phones.

Efficacy of a dual chamber defibrillator with atrial antitachycardia functions in treating spontaneous atrial tachyarrhythmias in patients with life-threatening ventricular tachyarrhythmias.

BACKGROUND: Atrial fibrillation has a high incidence in patients wearing an implantable cardioverter defibrillator for ventricular tachyarrhythmias and may lead to palpitations, heart failure, angina, stroke and inappropriate defibrillator discharge. The aim of the study was to evaluate the efficacy of a dual chamber defibrillator with atrial antitachycardia functions in treating spontaneous atrial tachyarrhythmias. METHODS: One hundred and twelve patients, 88 male, mean age 64+/-11 years, were enrolled. Seventy-six had ischaemic heart disease, 21 idiopathic dilated cardiomyopathy, nine other heart diseases, six no structural heart disease. The mean left ventricular ejection fraction was 40+/-11%. Sixty-two had prior atrial tachyarrhythmias. RESULTS: Follow-up lasted 11+/-9 months (range 1-42). Among 933 ventricular tachyarrhythmia episodes, 100% of ventricular fibrillation and 92% of ventricular tachycardia were successfully cardioverted. Among 414 detected sustained atrial tachyarrhythmias, 195 were classified as atrial tachycardia (47.1%), 192 as atrial fibrillation (46.4%) and 27 (6.5%) as sinus rhythm. The detection-positive predictive value was 93.5%. Therapy success rates: antitachy pacing on atrial tachycardia = 71.3% (crude estimate); 66.1% (adjusted estimate); 50 Hertz on atrial fibrillation=36.2% (crude estimate); 13.5% (adjusted estimate); atrial shock on atrial fibrillation = 62.5% (mean energy 7.8+/-14.1J). Shock efficacy was 32% when delivered energy was < or = 2 atrial defibrillation threshold at implant and 92% when >2. Duration of successfully treated atrial episodes was significantly lower than that of unsuccessfully treated (6+/-26 min vs 42+/-60). CONCLUSIONS: Atrial antitachy pacing and shock therapies demonstrated very high efficacy in treating atrial tachyarrhythmias in defibrillator patients.

Paroxysmal atrial fibrillation in patients paced for atrioventricular block. Comparison between DDD and VDD single-lead pacing system.

BACKGROUND: Paroxysmal atrial tachyarrhythmias have been frequently detected in patients paced for atrioventricular block. However, it is not yet clear which is the actual incidence of such arrhythmias and if they were preexisting but not recognized, or if they could be related to the device. METHODS: One hundred and forty-five patients with a diagnosis of second or third degree atrioventricular block were enrolled into the study. One hundred and twenty-four received a pacemaker Medtronic Thera DDD and 21 a Medtronic Thera VDD. High rate atrial episodes were evaluated for 3 months after enrollment. Atrial electrograms documenting paroxysmal atrial fibrillation (AF) were stored and programming of atrial sensitivity and pacemaker diagnostics was very strict in order to exclude short and false positive AF episodes. RESULTS: Thirty-six patients (35%) in the DDD group and 8 (42%) in the VDD group presented with AF (p = NS). The mean number o

Randomized crossover comparison of right atrial appendage pacing versus interatrial septum pacing for prevention of paroxysmal atrial fibrillation in patients with sinus bradycardia.

BACKGROUND: New atrial pacing techniques and overdrive pacing algorithms have been introduced to prevent atrial fibrillation. This study was designed to test the hypotheses that (1) interatrial septum pacing (IASP) at the triangle of Koch would be more effective than right atrial appendage pacing (RAAP) in preventing paroxysmal atrial fibrillation (PAF) in patients with sinus bradycardia and (2) an algorithm (CAP) designed to achieve constant atrial capture would increase the efficacy of rate-responsive atrial pacing. METHODS: We studied 46 patients with PAF and sinus bradycardia implanted with a DDD(R) (Medtronic Thera) pacemaker. Twenty-four patients (6.0 +/- 10.1 PAF episodes/month within 3 months before study) were randomized to RAAP and 22 patients (5.4 +/- 7.1, not significant) to IASP. Within each arm 2 randomized crossover periods of CAP-OFF and CAP-ON function were programed. RESULTS: The PAF episodes per month significantly decreased in the RAAP (CAP-OFF: 2.1 +/- 4.2, P <.05; CAP-ON: 1.9 +/- 3.8, P <.05) and in the IASP group (CAP-OFF: 0.2 +/- 0.5, P <.05; CAP-ON: 0.2 +/- 0.5, P <.05). Values were significantly lower in the IASP group than in the RAAP group in both CAP-OFF (0.2 +/- 0.5 vs 2.1 +/- 4.2, P <.05) and CAP-ON (0.2 +/- 0.5 vs 1.9 +/- 3.8, P <.05) conditions. PAF burden was significantly lower in the IASP than in the RAAP group in CAP-OFF (47 +/- 84 min/d vs 140 +/- 217, P <.05) and in CAP-ON (41 +/- 72 vs 193 +/- 266, P <.05) conditions. No differences were observed within each arm in PAF burden between the 2 crossover CAP programing periods. CONCLUSIONS: Rate-adaptive IASP at the triangle of Koch is more effective than RAAP in preventing PAF in patients with sinus bradycardia. In our sample of patients no additional clinical benefit is furnished by the CAP algorithm.

Immediate and long-term atrial sensing stability in single-lead VDD pacing depends on right atrial dimensions.

AIMS: Single-pass VDD is a physiological stimulation mode which requires a single-lead with a floating dipole to detect the atrial signal. We investigated the impact of right heart dimensions on immediate and long-term atrial sensing stability in VDD systems to draw guidelines for optimal atrial sensitivity programming. METHODS: Forty-one patients (23 males, mean age 73 +/- 11 years) with II or III degree AV block and normal sinus node function received a Thera VDD Medtronic 8948 pulse generator with Medtronic 5032 lead. Atrial sensing was evaluated at pre-discharge and during 12-months follow-up in the supine and upright positions, during normal and forced breathing. Atrial sensing variability, quantified by a D value (mV), which represents the difference between the maximum and the minimum atrial electrogram amplitude obtained during the various activities, was analyzed and related to right heart dimensions measured at echocardiography. RESULTS: Long-term appropriate atrial sensing was obtained in 40/41 patients. P wave mean amplitude at pre-discharge, during every specific activity, was predictive of 12-month values. No atrial oversensing was observed. According to the right atrial dimension (RAD), patients with RAD > 38 mm had a sensing variability significantly higher than those with RAD < or = 34 mm (D=1 + 1 Vs D=0.4+/-0.5; P<0.05). A linear relationship between D and RAD dimensions was observed (r=0.47; P<0.005). According to the distance from the roof of the right atrium to the right ventricular apex (RAVD), patients with RAVD < 93 mm had D=1.1 +/- 1, while patients with RAVD > 93 mm had D=0.5 +/- 0.4; P<0.05); a inverse correlation between RAVD and D was highlighted (r=-0.43; P<0.01). Using a cluster analysis, the combination of RAD and RAVD identified a subgroup (RAD > 30 mm and RAVD < 80 mm) at high risk of loss of AV synchrony with 67% sensitivity and 80% specificity. Nevertheless, apart from heart dimensions, no patient showed an atrial signal amplitude lower than 0.3 mV. CONCLUSIONS: According to our data, in VDD single-lead systems the amplitude of the atrial signal is stable over time in every physical activity. High RAD and low RAVD values may select patients with poor atrial sensing stability. Anyway, taking into account that no atrial oversensing was observed, atrial sensitivity setting at the highest value should be recommended.

Impact of consistent atrial pacing algorithm on premature atrial complexe number and paroxysmal atrial fibrillation recurrences in brady-tachy syndrome: a randomized prospective cross over study.

AIM OF THE STUDY: The Consistent Atrial Pacing (CAP) algorithm has been designed to achieve a high percentage of atrial pacing to suppress paroxysmal atrial fibrillation. The aim of our study was to compare the impact of DDDR+CAP versus DDDR pacing on paroxysmal atrial fibrillation recurrences and triggers in patients with Brady-Tachy Syndrome. METHODS: 61 patients, 23 M and 38 F, mean age 75+/-9 y, affected by Brady-Tachy Syndrome, implanted with a DDDR pacemaker, were randomized to DDDR or DDDR+CAP pacing with cross over of pacing modality after 1 month. RESULTS: 78 % of patients in DDDR pacing and 73 % in DDDR + CAP pacing (p=n.s.) were free from symptomatic paroxysmal atrial fibrillation recurrences. During DDDR+CAP pacing, the atrial pacing percentage increased from 77+/-29 % to 96+/-7 % (p<0.0001). Automatic mode switch episodes/day were 0.73+/-1.09 in DDDR and 0.79+/-1.14 (p=n.s.) in DDDR+CAP. In patients with less than 50 % of atrial pacing during DDDR, automaticmode switch episodes/day decreased during DDDR+CAP from 1.13+/-1.59 to 0.23+/-0.32 (p<0.05) and in patients with less than 90 % from 1.23+/-1.27 to 0.75+/-1.10 (p<0.001). The number of premature atrial complexes per day decreased during DDDR + CAP from 2665+/-4468 to 556+/-704 (p<0.02). CONCLUSION: CAP algorithm allowed continuous overdrive atrial pacing without major side effects. Triggers of paroxysmal atrial fibrillation induction, such as premature atrial complexes, were critically decreased. Paroxysmal atrial fibrillation episodes were reduced in patients with atrial pacing percentage lower than 90 % during DDDR pacing.

Electrotherapeutic management of patients with heart failure.

Heart failure is associated with poor long term survival due to progressive refractory heart dysfunction and sudden cardiac death. Cardiac resynchronization through atrio-biventricular pacing has been introduced to treat patients affected by drug-refractory heart failure with desynchronized ventricular activation, as for complete left bundle branch block. The technique is aimed to overcome interventricular and intraventricular conduction delays leading to ventricular dysynchrony, paradoxical septal wall motion, presystolic mitral regurgitation and reduced diastolic filling times. Short term studies demonstrated that biventricular pacing (and perhaps left ventricular pacing alone) may improve both systolic and diastolic function. Initial studies in patients receiving long term pacing consistently showed significant QRS shortening associated with improvement in symptoms, left ventricular ejection fraction, exercise tolerance, quality of life and New York Heart Association functional class. As far as sudden cardiac death prevention in heart failure is concerned, implantable cardioverter defibrillator (ICD) implantation has been demonstrated to be the most effective therapy in patients with prior cardiac arrest due to ventricular fibrillation or poorly tolerated ventricular tachycardia. Low left ventricular ejection fraction, unsustained ventricular tachycardia and inducibility at electrophysiological study also may identify high risk patients requiring ICD implantation. Further studies are needed to evaluate the effect of cardiac resynchronization on hard end-points, such as survival and long term clinical outcome, and to upgrade risk stratification criteria to be used in selection of candidates for ICD implantation.

Role of different determinants of psychological distress in acute coronary syndromes.

OBJECTIVES: The aim of this study was to examine the prevalence of psychological distress and of its major determinants in acute coronary patients and in a control group. BACKGROUND: The prevalence and major determinants of psychological distress in acute coronary patients are not clear. METHODS: One hundred and thirty cardiac patients (110 men, age 56+/-9; 85 with acute myocardial infarction and 45 with unstable angina) and 102 controls hospitalized for acute trauma (70 men, age 55+/-9 years) were studied and the level of psychological distress estimated by a Modified Maastricht Questionnaire, self-ratings and ratings by a close relative. Major determinants of psychological distress were assessed by the Life Events Assessment, the Social Support Questionnaire and the Ways of Coping Checklist. RESULTS: The average level of psychological distress was significantly higher (p < 0.001) in coronary patients than in controls in all tests (self-evaluation=7.1+/-2.3 vs 4.3+/-2.4; relative-evaluation = 7.4+/-2.4 vs 4.2+/- 2.5; Modified Maastricht Questionnaire=91+/-32 vs 59+/-30). Cardiac patients reported significantly higher (p < 0.05) levels of social isolation (28.9+/-11.1 vs 23.4+/-8.8), self-blame (7.2+/-1.9 vs 5.8+/- 1.6) and avoidance (21.1+/-3.5 vs 18.9+/-3) and more painful life events (3.9+/-3.8 vs 2.6+/-2.2), than controls. However, not all patients had evidence of distress; indeed, cluster analysis identified a subgroup that comprised 75% of controls and 25% of cardiac patients with no determinants eliciting distress, while the other four subgroups, with one or more determinants of distress, comprised about 75% of patients and only 25% of controls. CONCLUSIONS: These results show that a high level of psychological distress is detectable in about 75% of patients with acute myocardial infarction or unstable angina and is related to one or more major determinants.

Reliability of a new algorithm for automatic mode switching from DDDR to DDIR pacing mode in sinus node disease patients with chronotropic incompetence and recurrent paroxysmal atrial fibrillation.

To evaluate the safety and efficacy of a new algorithm for automatic mode switching (AMS) from DDD-DDDR to DDIR, 26 patients, 16 females and 10 males, mean age 73 +/- 6 years of age, affected by sinus node disease, chronotropic incompetence, and recurrent paroxysmal atrial fibrillation (PAF) received the Medtronic Thera DR pacemaker. The device continuously calculates, in ms, the running average of the intrinsic atrial rate (MAR) and compares the current atrial interval (CAI) with the stored MAR. When the CAI is greater than the MAR it increases by 8 ms, and when the CAI is less than the MAR, it decreases by 23 ms. When MAR < or = 330 ms (182 beats/min), tachycardia is detected and AMS is activated. All patients had clinical evaluation, 12-lead ECG, Holter monitoring, and exercise testing after implantation and every 3 months for 1 year. The results were compared with the data stored in the pacemaker memory: AMS episodes number; the histogram of the last 14 episodes; and atrial electrogram recording. Twenty-two Holter recordings in 13 patients showed PAF and in all of them AMS occurred simultaneously. AMS lasted between 10 seconds and 20 hours, and MAR ranged from 195-400 beats/min. No episode of PAF and no AMS were recorded in 39 Holter recordings in 22 patients. Appropriate AMS was confirmed in five patients by stored atrial electrogram and in nine by 12-lead ECG and pacemaker event markers. Mean atrial sensing was 2.13 +/- 1.04 mV during PAF and 3.18 +/- 1.46 mV during sinus rhythm. No PAF episode and no AMS were recorded during exercise testing. In conclusion, this new algorithm was very reliable, sensitive, and specific.

[Psychological stress as precipitating factor of the acute manifestations of ischemic cardiopathy]. / Lo stress psicologico come fattore scatenante nelle manifestazioni acute della cardiopatia ischemica.

Psychological stress may play an important role as a risk factor for coronary heart disease (CHD). Psychological stress consists of different components whose diverse role in the onset of the acute manifestations of CHD is still not clear. We studied 80 patients with acute CHD (56 with unheralded myocardial infarction, 24 with unstable angina, mean age 55 +/- 9 years, 55 men) vs 80 controls (mean age 50 +/- 9 years, 52 men) admitted for an acute traumatic event. We proposed to both groups these questionnaires: a retrospective self and etero-evaluation of the degree of psychological stress; the modified Maastricht questionnaire (MMQ) that evaluates psychic and physical manifestations of psychological stress in the period preceding admission; the social support questionnaire (SSQ); the life event assessment that evaluates frequency and importance of life events in the year preceding admission. Psychological stress index was greater in patients (self-evaluation = 7.1 +/- 2.4; etero-evaluation = 7.4 +/- 2.3; MMQ = 91 +/- 30.8) than controls (self-evaluation = 4.3 +/- 2.3; etero-evaluation = 4.3 +/- 2.4; MMQ = 58.6 +/- 32.5; p < 0.001 for all questionnaires). The perception of strong social isolation was greater in patients (SSQ = 29.8 +/- 11.8) than controls (SSQ = 23.8 +/- 9.6; p < 0.001). Painful life events were more numerous in patients (10.7 +/- 2.3) than controls (8.2 +/- 3.4; p < 0.05) and perceived in a more negative way (patients = 12.7 +/- 4.1 vs controls = 10.2 +/- 3.8; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)