Questionable dysfunction of a dual-Chamber pacemaker in a 17-year-old female: differential diagnoses of missing ventricular beats.

The case of a 17-year-old female who had been implanted a dual-chamber DDD pacemaker because of third-degree atrioventricular block is reported. There is a history of continued dizziness and even occasional syncopes. At heart rates of 111/min to 124/min, 24-h Holter electrocardiography revealed isolated missing ventricular beats in an otherwise continuous atrially sensed and triggered, ventricularly paced rhythm. Differential diagnoses of a putative pacemaker dysfunction are presented, comprising 2:1-block at maximum programmed heart rate, intermittent lead fracture, anti-pacemaker-mediated tachycardia algorithm, ventricular oversensing, P wave signal undersensing, and atrial oversensing.

Do airport metal detectors interfere with implantable pacemakers or cardioverter-defibrillators?

OBJECTIVES: The aim of this study was to determine whether airport metal detector gates (AMDGs) interfere with pacemakers (PMs) or implantable cardioverter-defibrillators (ICDs). BACKGROUND: It is currently unknown whether AMDGs interfere with implanted PMs or ICDs. METHODS: A total of 348 consecutive patients (200 PM and 148 ICD recipients) have been tested for the occurrence of electromagnetic interference (EMI) within the electromagnetic field of a worldwide-used airport metal detector. RESULTS: No interference, such as pacing or sensing abnormalities, was observed in any of the 200 PM and 148 ICD patients; also no reprogramming occurred. CONCLUSIONS: In vivo testing of PM and ICD systems showed no EMI with a standard AMDG. Clinically relevant interactions with implanted PMs or ICDs seem unlikely.

Electrocardiographic algorithm for assignment of occluded vessel in acute myocardial infarction.

BACKGROUND: This study was performed to elaborate an electrocardiographic (ECG) algorithm enabling assignment of an occluded coronary artery in acute myocardial infarction (AMI). PATIENTS AND INTERVENTIONS: In 109 patients (age, 59+/-12 years) with AMI (pain onset, 3.6+/-1.7 h), coronary angiography with PTCA/stenting of the culprit lesion was performed. The diagnosis of AMI was confirmed by emergency coronary angiography and laboratory analyses. Admission ECG parameters (amplitude of R-wave, ST-segment deviation, presence of Q-wave, deflection of T-wave) in standard 12-lead ECG plus extended (V(3)R to V(6)R and V(7-9)) leads were subjected to classification and regression tree (CART) analysis. RESULTS: Continuous CART analysis assessed ST-segment deviations in V(2) and V(5)R. AMI of the left anterior descending (LAD), right coronary artery (RCA) and left circumflex coronary artery (CX) were correctly classified in 94, 64, and 91% of cases, respectively. Dichotomised CART analysis assessed ST-segment deviations in V(2), V(5)R, and aVF. True classification rates for LAD, RCA, and CX amounted to 84, 74, and 71%, respectively. CONCLUSIONS: Dichotomised CART analysis is a simple means of differentiation of CX from RCA occlusion during AMI.

Absence of an impact of emotional distress on the perception of intracardiac shock discharges.

The pain of transvenous cardioversion shocks in awake patients is an important clinical problem. It is unknown whether psychological factors modulate any observed variation in pain perception. Thirty-seven patients with chronic atrial fibrillation (AF; mean age 61.9 years, 29 men, 8 women) were consecutively included in the study. Pain perception of a low energy test shock (60V, 0.1J) during internal cardioversion was assessed immediately following the stimulus. Before treatment anxiety, depression, somatization were evaluated. The intracardiac shock was perceived as hypalgesic in 15 (41%) patients, as normalgesic in 10 (27%), and as hyperalgesic in 10 (32%) patients. Pain threshold was significantly lower in patients in which AF was accidentally diagnosed (p < 0.029). Age, sex, and the level of education were equally distributed over the three pain groups. The hyperalgesic pain threshold was not associated with anxiety, depression, or the patients' tendency to amplify benign bodily sensations. This study discloses a wide range of perceived pain intensity caused by a homogenous intracardiac stimulation. Anxiety and depression do not amplify perception of intracardiac shocks. Sensory gating mechanisms may play a more important role in the level of intracardiac shock perception than distressing affective factors.

Treatment satisfaction of internal versus external cardioversion in patients with chronic atrial fibrillation--a randomized, prospective, 28-day follow-up study.

BACKGROUND AND HYPOTHESIS: The use of internal cardioversion (IC) in chronic atrial fibrillation (AF) may be limited by procedure-related distress. This procedure may be efficacious but is not necessarily perceived as satisfactory by the patient because of the frequent procedure-related distress. METHODS: We compared treatment satisfaction in 55 patients with chronic AF referred for cardioversion (CV). Satisfaction with conventional external cardioversion (EC, n = 27) and low-energy IC (n = 28) was compared immediately after the approach and at 28-day follow-up. RESULTS: Four hours after CV, satisfaction scores (ranging from 0 to 7) were higher with EC (mean 6.1 standard deviation [SD] +/- 1.4) versus IC (m = 5.4 SD +/- 1.8) (p = 0.09). At 28 days, treatment satisfaction decreased in EC (m = 5.5 SD +/- 2.1) and increased in the IC group (5.7 SD +/- 1.8) because of a decrease in the trustful attitude subscale (p = 0.026) followed by tolerance for distressing factors (p = 0.059). The analysis of variance for repeated measures revealed a significant time by method interaction effect (p = 0.04). Patients prone to developing low treatment satisfaction (LTS) at follow-up were more anxious (p = 0.007) before treatment. They suffered more from sleeping disorders (p = 0.009) and considered their disease condition to be worse than that in their counterparts (p = 0.027). Low treatment satisfaction at 28 days was associated with anxiety (p = 0.017), depression (p = 0.01), and the perception of heart-related symptoms (p = 0.001). Multivariate analysis revealed the failure to maintain sinus rhythm (p = 0.001) as the most powerful contributor to LTS. CONCLUSIONS: The novel IC approach causes acute procedure-related distress but has no enduring negative psychological side effects. Despite a greater patient perception of distressing procedure-related factors during IC compared with EC, the IC approach provides a greater 28-day benefit in terms of tolerability and acceptance on the part of the patients. Failure to maintain sinus rhythm rather than the method applied contributes most to LTS.

Atrial mechanical performance after internal and external cardioversion of atrial fibrillation: an echocardiographic study.

OBJECTIVES: To compare the time course of resumption of mechanical performance of the left and right atrium after the novel method of internal low-energy cardioversion (CV) and conventional external CV of atrial fibrillation (AF). BACKGROUND: Right atrial performance has been shown to normalize before the left atrium after external CV. However, no data on atrial function after internal CV are available. PATIENTS AND INTERVENTIONS: Sixty-three patients with chronic AF were randomized to participate in either external or internal CV. MEASUREMENTS: Echocardiographic examinations were carried out before as well as immediately after CV (day 0), and at days 1, 7, and 28 thereafter for the determination of cardiac dimensions, volumes, and transvalvular flow patterns. RESULTS: After randomized internal CV or external CV, stable sinus rhythm was restored in 59 patients. Irrespective of the mode of CV, the right atrium resumed its mechanical function immediately after CV, whereas the left atrium was stunned beyond day 7. The mode of CV, internal or external, had no influence on the recovery of atrial mechanical function. CONCLUSIONS: The right atrium resumes its normal function immediately after internal as well as external CV, whereas left atrium function is delayed. In contrast to the assumption that low-energy internal CV would impact less on atrial mechanical recovery, the type of method of CV used has no effect on such recovery.