Paroxysmal atrial fibrillation triggered by a monomorphic ventricular couplet in a patient with acute coronary syndrome.

Atrial fibrillation is a common arrhythmia in patients suffering from acute myocardial infarction, however its pathophysiological mechanisms are not fully understood. We describe the unusual case of a 76-year old woman admitted for non-ST-segment elevation myocardial infarction, who developed multiple episodes of paroxysmal atrial fibrillation triggered by monomorphic ventricular couplets. Beta-blocking and amiodarone therapy resulted efficacious in preventing arrhythmic recurrences. We then discuss the possible arrhythmogenic mechanisms, with special emphasis on the unique electrophysiological, hemodynamic, cellular and anatomical milieu created by acute myocardial ischemia.

Placement Of A Coronary Sinus Pacing Lead From A Sub-occluded Left Subclavian Vein Using A Collateral Vein To The Right Subclavian Vein.

Upgrading of a pacing system in the presence of a subclavian occlusion is technically challenging. We describe the case of a patient who underwent a successful upgrading procedure of an implantable cardioverter-defibrillator (ICD) to a biventricular defibrillator (ICD-CRT) in the presence of a suboccluded left subclavian vein, using a collateral vein that drained into the contralateral subclavian vein.

Atrioventricular Interval Extension Is Highly Efficient in Preventing Unnecessary Right Ventricular Pacing in Sinus Node Disease: A Randomized Cross-Over Study Versus Dual- to Atrial Single-Chamber Mode Switch.

OBJECTIVES: This study sought to compare the Intrinsic Rhythm Support (IRSplus) and Ventricular Pace Suppress (VpS) in terms of right ventricular pacing percentage (VP %), mean atrioventricular interval (MAVI), atrial fibrillation, and cardiac volumes. BACKGROUND: Modern pacemakers are provided with algorithms for reducing unnecessary ventricular pacing. These may be classified as: periodic search for intrinsic atrioventricular (AV) conduction prolonging the AV delay accordingly; or DDD-ADI mode switch. The IRSplus and VpS algorithms belong to the former and latter classes, respectively. METHODS: Patients with sick sinus dysfunction without evidence of II/III degree AV block were 1:1 randomized to 6-month periods of either IRSplus or VpS, and then crossed over. Subsequent follow-ups were at the 12th month after randomization for device data retrieving, and at the 18th month with the same device programming for echocardiographic assessment. RESULTS: A total of 230 patients (62% males, median age 75 years [interquartile range: 69 to 79 years]) were enrolled. At a linear mixed-model analysis with order of treatment and investigational sites as nested random effects, differences in VP% and MAVI reached statistical significance: VP% was 1% (0% to 11%) during IRSplus and 3% (0% to 26%) during VpS (p = 0.029); MAVI was 225 ms (198 to 253 ms) during IRSplus and 214 ms (188 to 240 ms) during VpS (p = 0.014). No differences were observed in atrial fibrillation burden and incidence, ejection fraction, and cardiac volumes. CONCLUSIONS: Both IRSplus and VpS algorithms ensured VP% ≤3% in most patients with sinus node dysfunction and preserved AV conduction. The IRSplus was slightly more efficient in reducing VP% at the expense of a small MAVI increase, with statistical but clinically insignificant differences. (Ventricular Pace Suppression Versus Intrinsic Rhythm Support Study; NCT01528657).

Cardiac resynchronization therapy as an 'alternative' approach to a non-operable severe aortic stenosis with left ventricular dysfunction.

Severe symptomatic aortic stenosis (AS) is an indication for surgical replacement of the aortic valve in adults. Patients are often affected by comorbidities, and the surgical indication is sometimes problematic. Non-surgical techniques have been developed during the past few years, though their roles have not yet been established. Cardiac resynchronization therapy has been shown to be effective in selected patients, but no data yet exist on the role of this therapy in AS patients. The case is presented of a patient with non-operable severe symptomatic AS and cardiac dissynchrony who showed significant improvement following the implantation of a biventricular pacemaker.

Stroke incidence in patients with cardiac implantable electronic devices remotely controlled with automatic alerts of atrial fibrillation. A sub-analysis of the HomeGuide study.

BACKGROUND: Remote Monitoring (RM) of cardiac implantable electronic devices (CIEDs) is recommended in management of Atrial Fibrillation (AF), which is a recognized risk factor for thromboembolism. We tried to elucidate whether stroke incidence observed in a large, remotely monitored population was consistent with the CHA2DS2VASc risk profile. METHODS: Data from 1650 patients [76% male, age 72 (63-68), CHA2DS2VASc score 3.0 (2.0-4.0)] enrolled during the HomeGuide study and monitored with a daily-transmission RM system providing automatic alerts for AF, were analysed. Of those, 25% had a pacemaker and 75% an implantable cardioverter defibrillator with or without cardiac resynchronization. Estimations of the expected thromboembolic events were based on the population CHA2DS2VASc score profile used in a computer-simulated Markov model. RESULTS: Eight thromboembolic events were observed with a 4-year cumulative stroke rate of 0.8% (confidence interval, 0.4%-1.5%). Simulations returned from 18.7 to 17.1 expected events, depending on the AF duration assumed to trigger anticoagulation (one-sample log-rank p<0.03). During the study period, 681 (84%) AF episodes and 129 (16%) atrial tachycardias were detected in 291 patients (18%): 93% of episodes were detected remotely in 269 patients, 66% of whom had no history of AF. Medical interventions were necessary in 305 episodes, 85% of which were detected remotely. Reaction time was 1 (0-6) days for remotely-detected episodes and 33 (14-121) days for episodes detected in clinic (p<0.0001). CONCLUSIONS: In a large CIED population followed remotely for up to 4years, the incidence of thromboembolic events was less than half the estimations based on the CHA2DS2VASc risk profile.

A reliable witness: dual-chamber pacemaker prolonged intracardiac recordings of a resuscitated cardiac arrest episode.

We report the case of a patient with a previously implanted pacemaker, who suffered cardiac arrest due to ventricular fibrillation requiring cardiopulmonary resuscitation (CPR) manoeuvres and electrical cardioversion to restore sinus rhythm. Analysis of the pacemaker's stored electrograms showed the arrhythmia progression from monomorphic ventricular tachycardia to ventricular fibrillation and the electrophysiological effects of CPR manoeuvres and epinephrine administration before successful cardioversion.

Assessing access to MRI of patients with magnetic resonance-conditional pacemaker and implantable cardioverter defibrillator systems: the Really ProMRI study design.

BACKGROUND: Despite the fact that magnetic resonance (MR)-conditional pacemaker and lead systems have been introduced more than 5 years ago, it is still not clear whether they have actually facilitated the access of pacemaker patients to this important diagnostic tool. Factors limiting MR scans in daily practice in patients with MR-conditional cardiac implantable electronic device (CIED) systems may be related to organizational, cultural and sometimes legal aspects. The Really ProMRI registry is an ongoing survey designed to assess the annual rate of MR examinations in patients with MR-conditional implants, with either pacemakers or implantable cardioverter defibrillators, and to detect the main factors limiting MRI. METHODS: The primary endpoint of the Really ProMRI registry is to assess the current access to MRI of patients with MR-conditional pacemaker or implantable cardioverter defibrillator systems during normal practice. Data in the literature reported a 17% annual incidence of medical conditions requiring MRI in CIED patients. The Really ProMRI registry has been designed to detect 4.5% absolute difference with an 80% statistical power, by recruiting 600 patients already implanted with MR-conditional CIED implant. Patients will be followed up for 1 year, during which they will be asked to refer any prescription, execution or denial of an MR examination by patient questionnaires and original source documents. CONCLUSION: The ongoing Really ProMRI registry will assess the actual rate of and factors limiting the access to MRI for patients with MR-conditional CIEDs.

Transesophageal electrical cardioversion of persistent atrial fibrillation: a new approach for an old technology.

BACKGROUND: Low energy intracardiac cardioversion may be considered the elective, alternative method for the acute restoration of sinus rhythm when direct current cardioversion fails or is contraindicated. Transesophageal cardioversion is a further alternative method for the recovery of sinus rhythm and obviates the potential complications of the low energy intracardiac cardioversion venous approach. METHODS: The present prospective study including 30 patients (21 males, 9 females, mean age 65.1 years, range 52-76 years), with persistent atrial fibrillation (mean duration 4.3 months), was undertaken in order to further evaluate, with regard to transesophageal cardioversion: 1) the acute efficacy, 2) the patient acceptance of the procedure, 3) the preferable choice among direct current cardioversion, low energy intracardiac cardioversion and transesophageal cardioversion, 4) the time required to perform the procedure, 5) the incidence of complications, and 6) the persistence of sinus rhythm after 1 month. RESULTS: Sinus rhythm was acutely restored in 29 patients (96.7%). Discomfort induced by the electrical shock was minimal or mild in most patients (75.8%). Transesophageal cardioversion was usually preferred by patients who had been previously submitted to direct current cardioversion or low energy intracardiac cardioversion. The mean total time required to perform the procedure was 107.9 min. No complications related to the procedure occurred. In spite of adequate pharmacological prophylaxis of atrial fibrillation only 41.4% of patients were in sinus rhythm 1 month after successful transesophageal cardioversion. CONCLUSIONS: Transesophageal cardioversion may be considered a very effective, well accepted and non-time consuming procedure for the short-term restoration of sinus rhythm. The incidence of complications is low.

Management of patients with low-risk chest pain at the time of admission: a prospective study on a non-selected population from the Emergency Department.

BACKGROUND: The management of patients with acute chest pain is a common and difficult challenge from the epidemiological, clinical, organizational and malpractice points of view. Our purpose was to test and implement a simple clinical protocol for the management of patients with acute chest pain and at low-risk for an acute coronary syndrome (ACS) at the time of admission to the Emergency Department (ED). METHODS: During a 5-month study period, 570 consecutive patients were admitted to the ED with acute chest pain: 224 patients were excluded owing to the presence of a clear diagnosis of an ACS or of high-risk factors. The remaining 346 were considered, at the time of admission, as being at low risk for an ACS and constituted the study group (208 males, 138 females, mean age 65 years). These 346 patients were evaluated in the ED area by means of multiple ECGs and multiple blood sampling for the creatine kinase-MB mass and troponin I serum levels at the time of admission and 6 and 12 hours later. In selected cases a treadmill stress test was requested in order to further clarify the diagnosis. RESULTS: The ECG at the time of admission was normal or nearly normal in 79% of the patients. Stress testing was performed in 79 patients (25%). Sixty-six/346 low-risk patients (19%) were admitted to the coronary care unit during ED observation: 38 patients because of positive markers, 10 because of a positive ECG, 13 because of positive markers and ECG, and 5 because of a positive stress test. Two hundred and eighty low-risk patients without evidence of acute ischemia were definitively discharged and classified as having non-ischemic chest pain. At 1 month of follow-up, 1 patient underwent coronary artery bypass grafting, 1 patient was again admitted to the ED for acute pulmonary edema, and 2 patients had acute extracardiac events. Within 1 year of follow-up 4 deaths occurred: 2 were cancer-related and 2 were sudden deaths. CONCLUSIONS: The tested strategy, based on integrated clinical, ECG and multimarker data, and on a short "test of time" period of low-risk patient observation, can allow the identification of patients having an ACS on the one hand and of those for whom a safe, rapid and early discharge is possible on the other, in a low-cost environment.

[Safety and effectiveness of dual chamber pacing in patients over 80 years of age with previous episodes of paroxysmal atrial fibrillation]. / Utilità ed appropriatezza della stimolazione bicamerale nell'ultraottantenne con storia di fibrillazione atriale parossistica.

BACKGROUND: Dual chamber pacing (DDD) in the elderly is still a controversial issue because of its short life expectancy and the risk of atrial fibrillation. The aim of the study was 1) to evaluate the cumulative survival and the events capable of modifying it, 2) to evaluate the stability of sinus rhythm, and 3) to try to identify patients who are at a higher risk of developing permanent atrial fibrillation after DDD implantation. We evaluated clinical, electrophysiological and pacing parameters at the time of implantation. METHODS: We examined retrospectively a group of 135 consecutive patients who were > 80 years old and who were treated with DDD in the last decade. RESULTS: At the time of evaluation (mean 33.51 +/- 27.10 months, range 4-148 months) after DDD implantation, 72% of patients were still alive. Sinus rhythm was documented in 96 (71%) patients (group A). Thirty-nine (29%) patients (group B) developed atrial fibrillation after a mean period of 28.56 +/- 30.9 months (range 1-125 months). The right atrial endocavitary signal amplitude was lower in group B compared to that observed in group A (2.6 +/- 1.16 vs 3.27 +/- 1.91 mV). The pacing and sensing atrioventricular delay were not statistically different in both groups. The minimum heart rate was higher in patients who developed atrial fibrillation (64.53 +/- 7.7 vs 67.7 +/- 5.72 b/min respectively in group A and in group B, p = 0.02). Group B patients had a higher rate of atrial fibrillation pre-implantation episodes. The incidences of sick sinus disease and of atrioventricular nodal disease were similar in both groups. CONCLUSIONS: In elderly patients the benefits of DDD are maintained for a long period of time before the development of atrial fibrillation. Episodes of atrial fibrillation prior to DDD, apart from sinus dysfunction alone, are predictive of the development of a permanent atrial fibrillation. Permanent atrial fibrillation does not seem to reduce life expectancy. A higher minimum heart rate does not seem to prevent atrial fibrillation. The capability of recording a right atrial signal amplitude > 3 mV seems to identify those patients with a lower risk of developing atrial fibrillation.

[Proarrhythmic effects of propafenone in a woman with hepatopathy: is it always a simple drug in clinical practice?]. / Effetto proaritmico del propafenone in donna con epatopatia: è sempre un farmaco di semplice utilizzo nella pratica clinica?

A 65-year-old woman with a history of alcoholic liver disease and presenting with fever and vomiting was admitted to an internal medicine unit. In view of recent atrial fibrillation with inadequate heart rate control, digoxin and propafenone were included in the therapeutic regimen. After a few days sinus rhythm was restored but suddenly ventricular arrhythmias with the characteristics of a non-responsive electrical storm arose shortly following the appearance of clinical symptoms of drug intoxication.

[Long QT and torsade de pointes in a patient with acquired human immunodeficiency virus infection in multitherapy with drugs affecting cytochrome P450]. / Allungamento del QT e torsione di punta in un paziente con immunodeficienza virale acquisita in multiterapia con farmaci utilizzatori del citocromo P450.

In acquired human immunodeficiency virus (HIV) infection, a long depolarization period at ECG may be the consequence of cardiac complications due to viral myocarditis or cardiomyopathy or indirectly due to autonomic neuropathy, or sometimes resulting from pharmacological treatments. Several drugs administered for direct treatment of HIV disease or its complications, such as antiretrovirus, fluconazole, and antibiotics, may induce ventricular arrhythmias due to long QT prolonged depolarization period. Also methadone, frequently associated with HIV therapy to treat patients with opiate addiction, is described in the literature to have cardiac inotropic effects. It has also the potential to increase the QT period and to develop ventricular torsade de pointes, primarily through interference with the rapid component of the delayed rectifier potassium ion current. Moreover, the use of methadone associated with other inhibitors of cytochrome P450 might increase plasma concentrations and contribute to methadone cardiac toxicity. We report the case of an HIV patient receiving antiretroviral treatment, fluconazole and high-dose methadone, who suddenly complained of vertigo, dizziness, pre-syncope and syncope due to severe ventricular arrhythmias that disappeared after discontinuation of all treatments.

Clinical outcomes in patients with implantable cardioverter defibrillators and Sprint Fidelis leads.

OBJECTIVE: The performances of implantable cardioverter defibrillators and leads are important issues for healthcare providers and patients. In 2007 Sprint Fidelis leads were found to be associated with an increased failure rate and so the purpose of the study was to evaluate long-term mortality and clinical outcomes in patients implanted with Sprint Fidelis leads compared with Sprint Quattro leads. DESIGN, SETTING, PATIENTS: 508 patients with Sprint Fidelis leads and 468 with Sprint Quattro leads were prospectively followed in 12 Italian cardiology centres. MAIN OUTCOME MEASURES: Information on hospitalisations and other clinical events were collected during scheduled and unscheduled hospital visits. Deaths were identified from medical records or via phone contacts with patients' family members or through the National Office of Vital Statistics. RESULTS: Over a mean follow-up of 27±18 months 141 deaths occurred in the overall population. No death was observed in patients with diagnosed failing lead. Kaplan-Meier patient survival differed between the two lead groups (80±2% in Fidelis leads vs 70±4% in the Sprint Quattro leads at 4 years, p=0.002). Multivariate analyses showed that mortality was neither associated with lead type nor with diagnosed failed lead. The annual rate of lead failure was 1.8% patient-year for Fidelis leads and 0.2% for the Sprint Quattro leads. CONCLUSIONS: In our multicentre research, the clinical outcomes of patients with Fidelis leads differed from those of patients with Sprint Quattro leads. Nevertheless, neither mortality nor the combined endpoint of mortality and heart failure hospitalisations was associated with the lead type. http://clinicaltrials.gov/ct2/show/NCT01007474.

Indication to cardioverter-defibrillator therapy and outcome in real world primary prevention. Data from the IRIDE [Italian registry of prophylactic implantation of defibrillators] study.

AIMS: Several trials demonstrated the life saving role of implantable cardioverter-defibrillators (ICD) in primary prevention of sudden cardiac death (SCD). The aim was to evaluate the clinical characteristics and 4-year outcome of consecutive patients treated in clinical practice by prophylactic ICD implantation on the basis of class I recommendations and up-to-date ICD programming. METHODS AND RESULTS: IRIDE multi-center, prospective and observational study enrolled 604 consecutive patients (mean age: 66 ± 10 years) treated by ICD between 01/01/2006 and 30/06/2010. Main characteristics were similarly distributed among the inclusion criteria of MADIT II (24%), SCD-HeFT (24%), COMPANION (26%) and MADIT-CRT (18%) trials, while a small number of patients met the MUSTT and MADIT (7%) inclusion criteria. Single-chamber ICDs were implanted in 168 (28%) patients, dual-chamber in 167 (28%) and biventricular in 269 (43%) patients. ATP programming was activated in 546 (90%) patients. Overall survival and rate of appropriate ICD intervention by ATP and/or shock at 12-24-36-48 months of follow-up were 94%, 89%, 80%, 75% and 16%, 28%, 37% and 50%, respectively. No difference in mortality rate between the groups who received or did not receive appropriate ICD interventions was demonstrated (p=ns). CONCLUSIONS: The IRIDE study confirms the effectiveness in real world practice of ICD implantation in patients at risk of SCD. The life saving role of ICD therapy increases as the duration of follow-up is prolonged and the survival benefit is similar in patients who received or did not receive appropriate device treatment, thus suggesting a beneficial effect of up-to-date device programming.

Severe ventricular dysrhythmias and silent ischemia during infusion of the antimetabolite 5-fluorouracil and cis-platin.

The antimetabolite 5-fluorouracil is frequently used in the therapy of various malignancies. Cardiotoxicity has frequently been described during treatment, but there is no common agreement on the need to perform cardiovascular monitoring of patients during 5-fluorouracil administration. We report the case of a young patient with an head-neck cancer on whom a continuous electrocardiogram recording was performed, documenting serious ventricular dysrhythmias in the presence of myocardial ischemia during 5-fluorouracil and cis-platin infusion.