Studies have shown that magnetic resonance imaging (MRI) does not have clinically important effects on the device parameters of non-MRI-conditional implantable cardioverter-defibrillators (ICDs). ...However, data on non-MRI-conditional ICD detection and treatment of arrhythmias after MRI are limited.
To examine if non-MRI-conditional ICDs have preserved shock function of arrhythmias after MRI.
Prospective cohort study. (ClinicalTrials.gov: NCT01130896).
1 center in the United States.
629 patients with non-MRI-conditional ICDs enrolled consecutively between February 2003 and January 2015.
813 total MRI examinations at a magnetic field strength of 1.5 Tesla using a prespecified safety protocol.
Implantable cardioverter-defibrillator interrogations were collected after MRI. Clinical outcomes included arrhythmia detection and treatment, generator or lead exchanges, adverse events, and death.
During a median follow-up of 2.2 years from MRI to latest available ICD interrogation before generator or lead exchange in 536 patients, 4177 arrhythmia episodes were detected, and 97 patients received ICD shocks. Sixty-one patients (10% of total) had 130 spontaneous ventricular tachycardia or fibrillation events terminated by ICD shocks. A total of 210 patients (33% of total) are known to have died (median, 1.7 years from MRI to death); 3 had cardiac arrhythmia deaths where shocks were indicated without direct evidence of device dysfunction.
Data were acquired at a single center and may not be generalizable to other clinical settings and MRI facilities. Implantable cardioverter-defibrillator interrogations were not available for a subset of patients; adjudication of cause of death relied solely on death certificate data in a subset.
Non-MRI-conditional ICDs appropriately treated detected tachyarrhythmias after MRI. No serious adverse effects on device function were reported after MRI.
Johns Hopkins University and National Institutes of Health.
Recent advancements in smart, wearable technologies have allowed the detection of various medical conditions. In particular, continuous collection and real-time analysis of electrocardiogram data ...have enabled the early identification of pathologic cardiac rhythms. Various algorithms to assess cardiac rhythms have been developed, but these utilize excessive computational power. Therefore, adoption to mobile platforms requires more computationally efficient algorithms that do not sacrifice correctness. This study presents a modified QRS detection algorithm, the AccYouRate Modified Pan-Tompkins (AMPT), which is a simplified version of the well-established Pan-Tompkins algorithm. Using archived ECG data from a variety of publicly available datasets, relative to the Pan-Tompkins, the AMPT algorithm demonstrated improved computational efficiency by 5-20×, while also universally enhancing correctness, both of which favor translation to a mobile platform for continuous, real-time QRS detection.
Worldwide, population aging and unhealthy lifestyles have increased the incidence of high-risk health conditions such as cardiovascular diseases, sleep apnea, and other conditions. Recently, to ...facilitate early identification and diagnosis, efforts have been made in the research and development of new wearable devices to make them smaller, more comfortable, more accurate, and increasingly compatible with artificial intelligence technologies. These efforts can pave the way to the longer and continuous health monitoring of different biosignals, including the real-time detection of diseases, thus providing more timely and accurate predictions of health events that can drastically improve the healthcare management of patients. Most recent reviews focus on a specific category of disease, the use of artificial intelligence in 12-lead electrocardiograms, or on wearable technology. However, we present recent advances in the use of electrocardiogram signals acquired with wearable devices or from publicly available databases and the analysis of such signals with artificial intelligence methods to detect and predict diseases. As expected, most of the available research focuses on heart diseases, sleep apnea, and other emerging areas, such as mental stress. From a methodological point of view, although traditional statistical methods and machine learning are still widely used, we observe an increasing use of more advanced deep learning methods, specifically architectures that can handle the complexity of biosignal data. These deep learning methods typically include convolutional and recurrent neural networks. Moreover, when proposing new artificial intelligence methods, we observe that the prevalent choice is to use publicly available databases rather than collecting new data.
Out-of-hospital cardiac arrest is a leading cause of death in the US, with a mortality rate over 90%. Preclinical studies demonstrate that cooling during cardiopulmonary resuscitation (CPR) is highly ...beneficial, but can be challenging to implement clinically. No medications exist for improving long-term cardiac arrest survival. We have developed a 20-amino acid peptide, TAT-PHLPP9c, that mimics cooling protection by enhancing AKT activation via PH domain leucine-rich repeat phosphatase 1 (PHLPP1) inhibition. Complementary studies were conducted in mouse and swine. C57BL/6 mice were randomized into blinded saline control and peptide-treatment groups. Following a 12-minute asystolic arrest, TAT-PHLPP9c was administered intravenously during CPR and significantly improved the return of spontaneous circulation, mean arterial blood pressure and cerebral blood flow, cardiac and neurological function, and survival (4 hour and 5 day). It inhibited PHLPP-NHERF1 binding, enhanced AKT but not PKC phosphorylation, decreased pyruvate dehydrogenase phosphorylation and sorbitol production, and increased ATP generation in heart and brain. TAT-PHLPP9c treatment also reduced plasma taurine and glutamate concentrations after resuscitation. The protective benefit of TAT-PHLPP9c was validated in a swine cardiac arrest model of ventricular fibrillation. In conclusion, TAT-PHLPP9c may improve neurologically intact cardiac arrest survival without the need for physical cooling.
Background Common carotid intima medial thickness (IMT) increases with aging. However, the longitudinal association between IMT and other age-associated hemodynamic alterations in men and in women ...are not fully explored. Methods and Results We analyzed repeated measures of IMT, blood pressure, and carotid-femoral pulse wave velocity over a 20-year period in 1067 men and women of the Baltimore Longitudinal Study on Aging; participants were ages 20 to 92 years at entry and free of overt cardiovascular disease. Linear mixed-effects models were used to calculate the individual rates of change (
) of IMT, pulse pressure, mean arterial pressure, and pulse wave velocity, among other covariates. Multivariate regression analysis was used to examine the association of IMT
with baseline and rates of change of hemodynamic parameters and cardiovascular risk factors. IMT increased at accelerating rates from 0.02 mm/decade at age 50 years to 0.05 mm/decade at age 80 years greater rates in men than in women. IMT
was positively associated with baseline low-density lipoprotein, low-density lipoprotein
, and baseline systolic blood pressure and systolic blood pressure
, but inversely with baseline diastolic blood pressure and diastolic blood pressure
. When blood pressure was expressed as pulse pressure and MAP, IMT
was positively associated with baseline pulse pressure and pulse pressure
and inversely with baseline mean arterial pressure and mean arterial pressure
. In sex-specific analysis, these associations were observed in women, but not in men. Conclusions In summary, our analyses showed that IMT increases at accelerating rates with aging. Age-associated changes in IMT were modulated by concurrent changes of low-density lipoprotein in both sexes, and of pulsatile and mean blood pressure in women but not men.
Background Lower ankle-brachial index (ABI) values within the 0.90 to 1.40 range are associated with poorer mitochondrial oxidative capacity of thigh muscles in cross-sectional analyses. Whether ABI ...decline is associated with greater declines in thigh muscle oxidative capacity with aging is unknown. Method and Results We analyzed data from 228 participants (100 men) of the BLSA (Baltimore Longitudinal Study of Aging), aged 39 to 97 years, with an ABI between 0.9 and 1.40 at baseline and at follow-up (mean follow-up period of 2.8 years). We examined mitochondrial oxidative capacity of the left thigh muscle, by measuring the postexercise phosphocreatine recovery rate constant (
PCr) from phosphorus-31 magnetic resonance spectroscopy. Greater
PCr indicated higher mitochondrial oxidative capacity. Although
PCr was available on the left leg only, ABI was measured in both legs. Longitudinal rates of change (
) of left and right ABI and
PCr of the left thigh muscle were estimated using linear mixed effects models, and their association was analyzed by standardized multiple linear regressions. In multivariate analysis including sex, age, baseline
PCr, both left and right baseline ABI, and ABI change in both legs, (
PCr)
was directly associated with ipsilateral (left) (ABI)
(standardized STD-β=0.14;
=0.0168) but not with contralateral (right) (ABI)
(
=0.22). Adjusting for traditional cardiovascular risk factors, this association remained significant (STD-β=0.18;
=0.0051). (
PCr)
was steeper in White race participants (STD-β=0.16;
=0.0122) and body mass index (STD-β=0.13;
=0.0479). There was no significant association with current smoking status (
=0.63), fasting glucose (
=0.28), heart rate (
=0.67), mean blood pressure (
=0.78), and low-density lipoprotein (
=0.75), high-density lipoprotein (
=0.82), or triglycerides (
=0.15). Conclusions In people without peripheral arterial disease, greater decline in ABI over time, but not baseline ABI, was associated with faster decline in thigh mitochondrial oxidative capacity in the ipsilateral leg. Further studies are needed to examine whether early interventions that improve lower extremity muscle perfusion can improve and prevent the decline of muscle energetics.
Background Aging is associated with a modest decline in ankle-brachial index (ABI); however, the underpinnings of this decline are not fully understood. The greater systolic ankle than brachial blood ...pressure, a normal ABI implies, is partially attributed to lower central than peripheral arterial stiffness. Hence, we examined the hypothesis that the age-associated decline in ABI is associated with central arterial stiffening with aging, assessed by pulse wave velocity. Methods and Results We analyzed longitudinal data from 974 participants aged 27 to 95 years from the Baltimore Longitudinal Study of Aging who were free of clinically significant cardiovascular disease. Participants had an average of 4 visits with a 6.8-year average follow-up time. Linear mixed-effects models showed that the average ABI decline beyond the age of 70 years was 0.03 per decade. In multiple regression analysis, the ABI rate of change was inversely associated with initial age (standardized β=-0.0711, P=0.0282), independent of peripheral disease factors and baseline ABI. After adjustment, the pulse wave velocity rate of change was inversely associated with ABI rate of change (standardized β=-0.0993, P=0.0040), rendering the association of the latter with initial age nonsignificant (standardized β=-0.0265, P=0.5418). Conclusions A modest longitudinal decline in ABI beyond the age of 70 years was shown to be independent of traditional risk factors for peripheral arterial disease but was accounted for by an increase in pulse wave velocity. A modest decline in ABI with aging might be a manifestation of changes in central hemodynamics and not necessarily attributable to peripheral flow-limiting factors.
External defibrillators are used for arrhythmia cardioversion and for defibrillating during cardiac arrest. During defibrillation, short-duration biphasic pulses cause intense motion due to rapid ...chest-wall muscle contraction. A reduced motion external defibrillator (RMD) was constructed by integrating a commercial defibrillator with a Tetanizing-waveform generator. A long-duration, low-amplitude, tetanizing waveform slowly stimulated the chest musculature before the biphasic pulse, reducing muscle contraction during the shock.
The purpose of this study was to evaluate RMD defibrillation in swine for subject motion during defibrillation pulses and for defibrillation effectiveness. RMD defibrillation can reduce the duration of arrhythmia ablation therapy or simplify cardioversion procedures.
The tetanizing unit delivered a triangular 1-kHz pulse of 0.25- to 2.0-second duration and 10- to 100-V peak amplitude, subsequently triggering the conventional defibrillator to output standard 1- to 200-J energy biphasic pulses at the next R wave. Forward limb motion was evaluated by measuring peak acceleration and limb work during RMD (tetanizing + biphasic) or biphasic pulse-only waveforms at 10
-second sampling rate. Seven swine were arrested electrically and subsequently defibrillated. Biphasic pulse-only and RMD defibrillations were repeated 25-35 times per swine, varying tetanizing parameters and biphasic pulse energy. Defibrillation thresholds (DFTs) were established by measuring the minimum energy required to restore sinus rhythm with biphasic pulse-only or RMD defibrillations.
Two forward-limb acceleration peaks occurred during both the tetanizing waveform and biphasic pulse, indicating rapid and slower nociceptic (pain sensation) nerve fiber activation. Optimal RMD tetanizing parameters (25-35 V, 0.25- to 0.75-second duration), relative to biphasic pulse-only defibrillations, resulted in 74% ± 10% smaller peak accelerations and 85% ± 10% reduced limb work. DFT energies were identical when comparing RMD to biphasic pulse-only defibrillations.
Relative to conventional defibrillations, RMD defibrillations maintain rhythm restoration efficiency with drastically reduced subject motion.
Wearable electronics are increasingly common and useful as health monitoring devices, many of which feature the ability to record a single-lead electrocardiogram (ECG). However, recording the ECG ...commonly requires the user to touch the device to complete the lead circuit, which prevents continuous data acquisition. An alternative approach to enable continuous monitoring without user initiation is to embed the leads in a garment. This study assessed ECG data obtained from the YouCare device (a novel sensorized garment) via comparison with a conventional Holter monitor. A cohort of thirty patients (age range: 20–82 years; 16 females and 14 males) were enrolled and monitored for twenty-four hours with both the YouCare device and a Holter monitor. ECG data from both devices were qualitatively assessed by a panel of three expert cardiologists and quantitatively analyzed using specialized software. Patients also responded to a survey about the comfort of the YouCare device as compared to the Holter monitor. The YouCare device was assessed to have 70% of its ECG signals as “Good”, 12% as “Acceptable”, and 18% as “Not Readable”. The R-wave, independently recorded by the YouCare device and Holter monitor, were synchronized within measurement error during 99.4% of cardiac cycles. In addition, patients found the YouCare device more comfortable than the Holter monitor (comfortable 22 vs. 5 and uncomfortable 1 vs. 18, respectively). Therefore, the quality of ECG data collected from the garment-based device was comparable to a Holter monitor when the signal was sufficiently acquired, and the garment was also comfortable.
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