Epidemiological impact of microvolt T-wave alternans in sudden cardiac death primary prevention.
Explore the source record for details and available documents.
Death, Sudden, Cardiac↗
Biomedical subjects
Christian Machado
Publications and source records attributed to Christian Machado.
The association of the heart failure score with mortality and heart failure hospitalizations in elderly patients: insights from the Mode Selection Trial (MOST).
BACKGROUND: Patient and physician preferences as well as cost favor an increasingly higher threshold for hospital admission for heart failure (HF) treatment. This trend risks masking the severity and prevalence of HF as hospitalization for HF may decrease. METHODS: Heart Failure Score (HFS) has 4 ordinal subscales assessing (1) HF symptoms, physical signs of left (2) and (3) right HF, and (4) therapy changes for HF. Heart Failure Score was calculated for 1257 of 2010 (63%) patients enrolled in the MOST trial in sinus node dysfunction, who survived and had complete first-year HFS data at 4 postpacemaker implant visits (1, 3, 6, and 12 months). Heart Failure Score was summed and ranged from 0 to 14, with lower scores representing less HF. RESULTS: There were 1257 patients (median age 74 years [interquartile range 68-79], 47% were women, 61% had hypertension, 20%, diabetes mellitus, and 23%, prior myocardial infarction). The median HFS accumulated during 1 year was 4 (interquartile range 1-8). Of patients with a benign first year, those with a higher HFS were more likely to die during subsequent follow-up compared with patients with lower HFS (hazard ratio 1.07, 95% CI 1.04-1.10 for each 1-point increase, P < .001). CONCLUSIONS: Increasing HFS is associated with an increased risk of mortality in mostly elderly patients without pre-existing HF. Heart Failure Score may be a useful surrogate HF end point for clinical trials.
Aged↗
Large vegetation associated with implantable cardioverter-defibrillator lead.
Explore the source record for details and available documents.
Aged↗
Safe scanning, but frequent artifacts mimicking bradycardia and tachycardia during magnetic resonance imaging (MRI) in patients with an implantable loop recorder (ILR).
BACKGROUND: Patients with implantable devices are generally not permitted to undergo magnetic resonance imaging (MRI) because of potentially deleterious interactions. Little has been reported regarding the safety and effects of MRI scanning of patients with implantable loop recorders (ILRs). We evaluated the safety of scanning patients with ILRs and the output of the ILR after undergoing MRI. METHODS: Ten patients underwent 11 MRI scanning events. All patients had Reveal Plus (Medtronic, Minneapolis, MN) ILRs. Seven cranial, two lumbar-spine, one shoulder, and one knee MRI were performed. All of the MRIs were performed with the understanding that the patient had an ILR. In each patient, the ILR was cleared moments before the scan and the integrity of the signal and time date stamp were verified. The devices were reinterrogated immediately after MRI in 10 patients and two days post MR scanning in one patient. Each patient was questioned post MRI regarding any symptoms experienced during the scan. RESULTS: Both tachy and bradyarrhythmias appeared as artifacts as a result of ILR exposure to MRI. Post MRI, none of the ILRs showed diminished signal integrity, altered programmed parameters, diminished battery status, inability to communicate or be reprogrammed. No sensations of tugging or warmth at the implant site were noted. CONCLUSION: MRI was performed in ILR patients without harm to the patient or permanent damage to the ILR. MRI scanning of the Reveal appears safe. Artifact mimicking an arrhythmia was common, however, and must be excluded in any ILR patient undergoing MRI to avoid mistakenly attributing a syncopal episode, or palpitations to the artifacts produced from MRI exposure.
Artifacts↗
Expanding cardiac resynchronization for systolic heart failure to patients with mechanical dyssynchrony and atrial fibrillation.
Despite progress in the management of heart failure (HF) using pharmacotherapy, the mortality and morbidity associated with this condition remain unacceptably high. Cardiac resynchronization therapy (CRT), a left-sided pacing therapy for drug-refractory and highly symptomatic HF patients with ventricular conduction delay, has been shown to improve left ventricular (LV) systolic function, myocardial oxygen consumption, and New York Heart Association functional class and to inhibit or reverse LV chamber dilation and remodeling. Atrial fibrillation is common in patients with HF and is associated with significant worsening of HF and myocardial function. Only recently have trials been designed to specifically study CRT in patients with HF and chronic atrial fibrillation. These studies have shown that CRT with biventricular or univentricular LV pacing in patients with atrial fibrillation corrects mechanical dyssynchrony and results in significant and sustained improvement in functional capacity, LV ejection fraction, quality of life, and QRS duration.
Atrial Fibrillation↗
Prospective randomized multicenter trial of empirical antitachycardia pacing versus shocks for spontaneous rapid ventricular tachycardia in patients with implantable cardioverter-defibrillators: Pacing Fast Ventricular Tachycardia Reduces Shock Therapies (PainFREE Rx II) trial results.
BACKGROUND: Successful antitachycardia pacing (ATP) terminates ventricular tachycardia (VT) up to 250 bpm without the need for painful shocks in implantable cardioverter-defibrillator (ICD) patients. Fast VT (FVT) >200 bpm is often treated by shock because of safety concerns, however. This prospective, randomized, multicenter trial compares the safety and utility of empirical ATP with shocks for FVT in a broad ICD population. METHODS AND RESULTS: We randomized 634 ICD patients to 2 arms-standardized empirical ATP (n=313) or shock (n=321)-for initial therapy of spontaneous FVT. ICDs were programmed to detect FVT when 18 of 24 intervals were 188 to 250 bpm and 0 of the last 8 intervals were >250 bpm. Initial FVT therapy was ATP (8 pulses, 88% of FVT cycle length) or shock at 10 J above the defibrillation threshold. Syncope and arrhythmic symptoms were collected through patient diaries and interviews. In 11+/-3 months of follow-up, 431 episodes of FVT occurred in 98 patients, representing 32% of ventricular tachyarrhythmias and 76% of those that would be detected as ventricular fibrillation and shocked with traditional ICD programming. ATP was effective in 229 of 284 episodes in the ATP arm (81%, 72% adjusted). Acceleration, episode duration, syncope, and sudden death were similar between arms. Quality of life, measured with the SF-36, improved in patients with FVT in both arms but more so in the ATP arm. CONCLUSIONS: Compared with shocks, empirical ATP for FVT is highly effective, is equally safe, and improves quality of life. ATP may be the preferred FVT therapy in most ICD patients.
Aged↗
Bachmann's bundle versus right atrial appendage capture.
The tissue in the high intraatrial septum in the region of Bachmann's Bundle (BB) exhibits electrophysiological properties that differ from the right atrial appendage (RAA). As BB pacing emerges as an alternative to RAA pacing, the feasibility of using automatic capture recognition technology in this location should be examined. At implant, active-fixation leads were consecutively placed in the RAA, then the BB in 18 patients (55.5% men, mean age 77.1 +/- 9.1). There was no significant difference between BB and RAA in the average capture threshold (1.12 vs 1.77 V, P = 0.09), sensing threshold (3.85 vs 3.69 mV, P = 0.84), impedance (508 vs 529 Ohms, P = 0.64), evoked response (1.78 vs 1.67 mV, P = 0.83), and polarization (0.41 vs 0.46 mV, P = 0.84) between. The difference in tissue characteristics was not associated with a different evoked response measured by the ventricular capture recognition algorithm. Based on the analogous evoked response and polarization values, capture recognition technology designed for the atrium will most likely be applicable at both pacing sites.
Aged↗
Radiofrequency catheter ablation of fast pathway via unconventional right subclavian venous access for atrioventricular nodal reentrant tachycardia.
We report the case of a patient with atrioventricular nodal reentry tachycardia (AVNRT), who was found to have obstruction of the inferior vena cava (IVC) by a calcified mass during an electrophysiologic study (EPS). Subsequently, complete EPS was performed via a combined right internal jugular and subclavian venous access. Successful radiofrequency catheter ablation of the fast pathway was performed via the unconventional right subclavian venous route.
Aged↗