Artificial intelligence: an attempt to automate remote device follow-up

Funding Acknowledgements

Type of funding sources: None.

Introduction

Artificial intelligence (AI) through machine learning (ML) refers to the simulation of human intelligence with the capacity for achieving goals within computers. In electrophysiology, ML has many applications in electrocardiography, intracardiac mapping and cardiac implantable electronic devices (CIEDs).

Remote monitoring (RM) of patients equipped with CIEDs associates the analysis of event reports and calendar-based remote follow-ups (FU). ML applications have allowed for risk stratification, improved arrhythmia localisation and streamlined remote monitoring which may significantly reduce the workload faced by electrophysiologists.

Aim

To develop a system that automates cardiac implantable electronic devices remote follow-up.

Methods and Results

We created a Java software application, that uses the latest optical character recognition techniques combined with artificial intelligence and natural language processing to extract information from PDF reports of RM of CIEDs from different manufacturers. The current version is HIPAA (Health Insurance Portability and Accountability Act) complaint and runs on local computers only.

Using the current system, we were able to run and extract data from 30 remote follow-up PDF reports of Cardiac Implantable Defibrillators (ICDs) and Cardiac Resynchronization Therapy with Defibrillator (CRT-Ds).

Time taken from data extraction to conversion of all 30 device PDFs was under 5 minutes.

Process and data extracted are presented in the figure below. (Figure 1)

Conclusion

This machine learning algorithm proved that it is possible to facilitate and automate remote follow-up of cardiac implantable electronic devices.

In a near future this will allow to us to efficiently increase productivity, by speeding and facilitating interpretation of remote device follow-ups, leading to improvements in patientcare and precision cardiovascular medicine.

Furthermore, in the current and future pandemics it may help prevent unnecessary in-person medical visits, avoiding additional, unnecessary strain on an already overburdened and overwhelmed healthcare system, and saving costs. Abstract Figure 1

Ventricular tachycardia induced by pacing algorithm designed to avoid atrial fibrillation

A patient with a dual chamber pacemaker was admitted to the emergency room after out-of-hospital cardioversion for syncopal sustained monomorphic ventricular tachycardia. Device interrogation revealed an abnormally timed ventricular spike after a ventricular premature beat at the beginning of the event, caused by a pacemaker algorithm designed to avoid atrial fibrillation, non-competitive atrial pacing. Despite the absence of significant coronary lesions, in the setting of a vulnerable substrate - a hypokinetic and hyperechogenic region of ventricular myocardium - an upgrade to a dual-chamber implantable cardioverter-defibrillator was performed, and substrate ablation was planned.

PDBe-KB: a community-driven resource for structural and functional annotations

The Protein Data Bank in Europe-Knowledge Base (PDBe-KB, https://pdbe-kb.org) is a community-driven, collaborative resource for literature-derived, manually curated and computationally predicted structural and functional annotations of macromolecular structure data, contained in the Protein Data Bank (PDB). The goal of PDBe-KB is two-fold: (i) to increase the visibility and reduce the fragmentation of annotations contributed by specialist data resources, and to make these data more findable, accessible, interoperable and reusable (FAIR) and (ii) to place macromolecular structure data in their biological context, thus facilitating their use by the broader scientific community in fundamental and applied research. Here, we describe the guidelines of this collaborative effort, the current status of contributed data, and the PDBe-KB infrastructure, which includes the data exchange format, the deposition system for added value annotations, the distributable database containing the assembled data, and programmatic access endpoints. We also describe a series of novel web-pages-the PDBe-KB aggregated views of structure data-which combine information on macromolecular structures from many PDB entries. We have recently released the first set of pages in this series, which provide an overview of available structural and functional information for a protein of interest, referenced by a UniProtKB accession.

Utility of Pacemaker With Sleep Apnea Monitor to Predict Left Ventricular Overload and Acute Decompensated Heart Failure

Pacemakers with sleep apnea monitor (SAM) provide an easy tool to assess obstructive sleep apnea over long periods of time. The link between respiratory disturbances at night and the incidence of acute decompensated heart failure (ADHF) is not well established. We aimed at (1) determining the ability of SAM pacemakers to evaluate the extent of left ventricular overload and (2) assess the impact of respiratory disturbances at night on the occurrence of ADHF over 1-year of follow-up. We conducted a single-center prospective study. Consecutive patients with SAM pacemakers were comprehensively assessed. SAM automatically computes a respiratory disturbance index (RDI, apneas/hypopneas per hour - AH/h) in the previous night and the percentage of nights with RDI >20 AH/h in the previous 6 months. Thirty-seven patients were included (79.3 ± 11.2 years, 46% males). A high RDI in the previous night and a higher %nights with increased RDI were associated with increased NT-proBNP values (p = 0.008 and p = 0.013, respectively) and were the sole predictors of increased noninvasive pulmonary capillary wedge pressures (PCWP) in the morning of assessment (p = 0.031 and p = 0.044, respectively). Receiver operating characteristic curve analysis revealed an area under the curve of 0.804 (95% confidence interval 0.656 to 0.953, p = 0.002) for %nights with RDI >20 AH/h in the prediction of high PCWP. Patients with >12.5% of nights with RDI >20AH/h tended to have more ADHF during follow-up (log-rank p = 0.067). In conclusion, a high burden of apneas/hypopneas at night is associated with elevated NT-proBNP and PCWP values and an increased risk of ADHF over 1 year. These patients might benefit from early tailored clinical management.

Implantation of a Dual-Chamber Pacemaker in a Patient with Situs Inversus and Dextrocardia using a Novel Ultrasound Technique

We report a case of a 43-year-old man with situs inversus and dextrocardia who was admitted with syncope in the setting of complete atrioventricular block. The complex anatomy poses a considerable challenge to transvenous permanent pacemaker implantation. We employed a novel technique using vascular ultrasound and agitated saline solution to assist with lead positioning. This technique could be useful in pediatric populations or younger patients, in whom the use of ionizing radiation is an important issue.

Crack Front Interaction with Self-Emitted Acoustic Waves

The interaction of a propagating crack in implanted silicon with self-emitted acoustic waves results in periodic patterns on fractured surfaces. Direct measurement of the acoustic emission ahead of the fracture front shows the emergence of dominant acoustic frequency related to the crack velocity. It is shown that the surface modifications are made of roughness modulations due to periodic deviations of the crack front. A physical mechanism explaining the pattern formation is proposed, well in agreement with the observed pattern wavelengths.

An inappropriate defibrillator shock during ventricular tachycardia

Ventricular oversensing in patients with defibrillators is an infrequent but deleterious condition. We report a patient with a cardiac resynchronization–defibrillation device that presented with hyperkalemia and syncope. Device interrogation revealed ventricular double-counting within the QRS of a slow ventricular tachycardia, resulting detection of the slow ventricular tachycardia in the ventricular fibrillation zone, and delivery of an effective therapy, below device programmed detection rate. This case of defibrillator inappropriate detection emphasizes the relevance of device electrogram interrogation in order to minimize inappropriate therapies.

RIVER: Portuguese registry to monitor unnecessary right ventricular pacing

The aim of this prospective registry is to evaluate a new algorithm designed to reduce the percentage of unnecessary ventricular pacing (%VP) in patients implanted with a dual-chamber pacemaker, through a dedicated pacing mode (called AAISafeR2) operating in AAI mode with back-up ventricular pacing in DDD mode, and to describe the incidence and distribution of atrioventricular (AV) block in this population. Investigators were free to assign patients to AAISafeR2 mode or to standard DDD (if AAISafeR was contraindicated, mainly due to permanent high-degree AV block). Patients underwent routine follow-up visits at 3, 6, 12, 18 and 24 months after implantation. At each follow-up visit, data were retrieved from pacemaker memories and analyzed to extract %VP and incidence of AV block. Up to December 2006, 158 patients (94 men, mean age 69 +/- 14 years) from nine Portuguese centers had been consecutively included. We also determined the distribution of AV block (according to the criteria used by the pacemaker to classify AV block and switch to DDD mode). AAISafeR was shown to be effective in reducing unnecessary VP in our patient population. The analysis also reveals a high incidence of paroxysmal AV block, often unknown at the time of implantation. There were no complications associated with AAISafeR programming.

ICD defibrillation failure solved in an unusual fashion

An implantable cardioverter defibrillator (ICD) is designed to sense life-threatening ventricular arrhythmias and terminate them, either by rapid pacing or by delivering an electrical shock. Nowadays it is a proven therapy for both primary and secondary prevention of sudden cardiac death. The typical configuration of an ICD consists of a right ventricular sensing/defibrillator lead with two coils (one distal, located in the right ventricle, and one proximal, located at the superior vena cava-right atrium junction) and an active can, the so-called "ventricular triad". Although effective in the vast majority of patients, it could be argued that this is not the most rational arrangement in electrical terms, since the main shock vector is anteriorly displaced in relation to the greater portion of the left ventricular mass. We describe a case of an ICD defibrillation failure that was solved by placing an additional defibrillator lead in a tributary of the coronary sinus.

Blood lactate removal during recovery at various intensities below the individual anaerobic threshold in triathletes

AIM

Optimal lactate removal was reported to occur at work-rate between 30% and 70% VO2max. However, it has been recently recommended to quantify exercise intensity not in percentage of VO2max but in relation to validated metabolic reference points such as the individual anaerobic threshold (IAT) and the individual ventilatory threshold (IVT). The purpose of this study was to examine the effect on lactate removal of different recovery work-rates below the IAT defined calculating the difference (DT) between IAT and IVT, then choosing the IVT+50%DT, the IVT and the IVT-50%DT work-rates.

METHODS

Eight male triathletes (VO2max 69.7+/-4.7, VO2IAT 52.9+/-4, VO2IVT 41.1+/-4.7 mL x kg(-1) x min(-1)), after a 6-min treadmill run at 75% of difference between IAT and VO2max, performed in a random order the following 30-min recovery treatments: 1) run at IVT(plus;50%DT), 2) at IVT, 3) at IVT(-50%DT), 4) passive. Blood lactate was measured at 1, 3, 6, 9, 12, 15, 20, 25, 30 minutes of recovery.

RESULTS

All active recovery work-rates (from 50+/-5% to 67+/-4% VO2max) were within the range previously reported for optimal lactate removal, and significantly more efficient than passive recovery on lactate removal curve (% of accumulated lactate above rest value). However, significant differences (P<0.01) were found among active recovery intensities: the IVT(-50%DT) was the most efficient work-rate from the 9th minute to 30th minute.

CONCLUSIONS

In triathletes, the IVT(-50%DT) was the optimal work-rate for lactate removal; moreover none of the studied active work-rate showed further lactate decrease after the 20th minute of recovery.

Lactate removal during active recovery related to the individual anaerobic and ventilatory thresholds in soccer players

The aim of this study was to compare the lactate (La) removal during active recovery at three different work rates below the individual anaerobic threshold (IAT). Recently, it has been recommended that exercise intensity should be determined in relation to the IAT instead of the percentage of maximal oxygen uptake ( V(.)O(2max)), especially for training and research purposes. Therefore, we defined the recovery work rates by calculating 50% of the threshold difference (Delta T) between the IAT and the individual ventilatory threshold (IVT) work rates, then choosing the IVT(+50%DeltaT), the IVT and the IVT(-50%DeltaT). All these work rates fell within the range (30-70% V(.)O(2max)) previously reported for optimal La removal. After a 6-min treadmill run at 90% V(.)O(2max), soccer players [ n=12 male, age 22 (1) years] performed, in a random order, four 30-min recovery treatments: (1) run at IVT(+50%DeltaT), (2) at IVT, (3) at IVT(-50%DeltaT), (4) passive recovery. La was obtained at 1, 3, 6, 9, 12, 15, 20, 25 and 30 min of recovery. The La removal curve was significantly affected by treatments ( P<0.01) and recovery timing ( P<0.01), with a significant interaction between them ( P<0.01). Although they were more efficient than passive recovery, the studied work rates [between 39 (7) and 60 (4)% V(.)O(2max)) produced different lactate removal curves. IVT and IVT(-50%DeltaT) were significantly more efficient than IVT(+50%DeltaT), while no difference was found between IVT and IVT(-50%DeltaT) for any time point. In conclusion, both IVT(-50%DeltaT) and IVT were efficient individual work rates for La removal, and no further La decrease occurred after 20 min.

Special program to reduce cardiology consultation waiting lists: report on an innovatory experience

The problem of waiting lists has been widely debated in the Portuguese society. In this paper, the authors report the first results of a prioritization approach, started in March 2000. In this program cardiologists and general practitioners work in close proximity, coordinating efforts in order to improve the establishment of clinical priorities, and consequently optimize hospital referral. Working as cardiology consultants, the authors were able to reduce the number of first consultation requests by 77.9% (December 2002). For the first time it was possible to match the number of requests with the available consultation times, halting the growth of the waiting list.

Evaluation of aortic stenosis severity: role of contrast echocardiography in comparison with conventional echocardiography and cardiac catheterization

OBJECTIVES

To evaluate the role of contrast Doppler echocardiography in the assessment of aortic stenosis severity, in comparison with the conventional method and using the catheterization study as the gold standard.

STUDY DESIGN

Prospective comparative study.

SETTING

Echocardiography Laboratory of Cardiology Department.

POPULATION

We included 36 consecutive patients, 20 male, aged 67 +/- 11 years, referred for catheterization study to evaluate aortic stenosis severity.

METHODS

All patients underwent conventional and contrast Doppler echocardiography and catheterization study. For contrast Doppler, we used Levovist (300 mg/ml infusion). We analyzed the following echocardiographic parameters: a) left ventricle dimensions, wall thickness and function; b) aortic valve morphology; c) post-stenotic aortic valve flow--peak velocity, velocity-time integral, peak gradient, mean gradient; d) left ventricle outflow tract flow--peak velocity, velocity-time integral; e) aortic valve functional area; f) acquisition time and Doppler signal intensity for post-stenotic aortic valve flow. Catheterization parameters analyzed: a) peak aortic valve gradient; b) mean aortic valve gradient.

RESULTS

Contrast Doppler yielded higher peak gradients than conventional Doppler (85.6 +/- 30.2 vs 72.6 +/- 26.1 mmHg, p < 0.001), as well as higher mean gradients (51.4 +/- 19.0 vs 44.2 +/- 15.9 mmHg, p < 0.001). Peak gradients obtained with contrast Doppler correlated with those obtained invasively (r = 0.88, p < 0.001), although the values were higher (85.6 +/- 30.2 vs 73.6 +/- 32.0 mmHg, p < 0.001). There was no difference between mean contrast Doppler gradients and mean catheterization gradients, which showed a high correlation (r = 0.89, p < 0.001). There was no difference between peak and mean gradients obtained by conventional Doppler and invasively, which yielded correlations of 0.73 and 0.75, respectively (p < 0.001). The sensitivity of contrast Doppler for detection of severe aortic stenosis was 100% for peak gradient and 84% for mean gradient, while for conventional Doppler it was 68% and 58%. The specificity of contrast Doppler was 65% for peak gradient and 88% for mean gradient, while for conventional Doppler it was, respectively, 58% and 88%. Acquisition time for aortic flow visualization was lower (p < 0.001) and flow intensity higher for contrast Doppler, in comparison with conventional Doppler.

CONCLUSIONS

In this study, contrast Doppler yielded high correlations with invasive data and higher sensitivity and specificity for detection of severe aortic stenosis than conventional Doppler. It is a useful method for evaluation of aortic stenosis severity.

Pulmonary transvalvular and venous flows in the estimation of left ventricular diastolic pressures. A comparative Doppler-catheterization study

OBJECTIVES

To evaluate the association between patterns of pulmonary transvalvular and venous flows in patients with ischemic heart disease, assessed by Doppler echocardiography, and invasive measurements of left ventricular (LV) diastolic pressures.

POPULATION

Thirty-seven patients with clinical diagnosis or suspicion of coronary heart disease and referred for coronary angiography; all were in sinus rhythm, and had no known valvular heart or chronic pulmonary disease.

METHODS

The following were recorded during transthoracic Doppler echocardiography: acceleration time (AT) and total ejection time (ET) of right ventricular outflow; duration of the flow at atrial contraction (a duration) and duration of the "A" wave of mitral inflow (A duration). These data were correlated with the values of LV filling pressures previously obtained by cardiac catheterization.

RESULTS

We found a significant correlation of LV end-diastolic pressures with the difference a-A duration (r = 0.75; p < 0.001) and also with the ratio AT/ET (r = -0.73;.

[Prognosis of postoperative aortic dissection. Assessment with magnetic resonance]

OBJECTIVE

To evaluate operated type A aortic dissection by Magnetic Resonance Imaging (MRI), in order to detect long-term complications and identify prognostic indexes of evolution.

DESIGN

Prospective study with a three-year period of follow-up. Prognosis evaluation.

SETTINGS

Outpatient Clinic at Hospital de Santa Maria and Magnetic Resonance Imaging Center at Hospital da Cruz Vermelha.

PATIENTS

A sample of 37 patients submitted to type A aortic dissection surgery, included sequentially, after exclusion of those with contraindication to MRI.

METHODS

Initial evaluation (clinical and MRI study) at 3 to 4 months and at 1, 2 and 3 years after surgery. The mean follow-up time was 39.3 +/- 2.9 months. We evaluated the following complications over the aorta (aortic graft and five segments of residual aorta) and the aortic valve: aneurysm, pseudoaneurysm, rupture, re-dissection, progressive aortic valve regurgitation, reoperation and death. The prognostic indexes analysed were: presence of residual flap; false lumen patency; presence of re-entry points; false lumen to aorta dimension ratio; initial aortic dimension; increase of aortic dimension.

RESULTS

All patients, with the exception of three that died, remained asymptomatic.

COMPLICATIONS

Aneurysm was detected in 45.9% of patients, located in one or more segments; rupture occurred in three patients, preceded by aneurysm and pseudoaneurysm development; moderate or severe aortic regurgitation was detected in 47.8% of patients. Prognostic indexes: 1. Aneurysm development in each segment yeilded a significant association with: presence of residual flap in the same and other segments; higher initial dimension of the same and other segments, with the exception of the abdominal segment; higher increase in dimension of the same and other segments, with the exception of the abdominal segment; 2. Moderate or severe aortic regurgitation development showed a tendency to association with higher increase in dimension of proximal ascending aorta. 3. No association was found between aneurysm and aortic regurgitation development.

CONCLUSIONS

Patients operated for type A aortic dissection had a high incidence of late complications which lead to reoperation and in some cases death. The presence of a residual flap, increased aortic dimensions and higher increase rate of aortic dimensions were associated with a complicated evolution. MRI was a very useful technique for long-term monitoring and to identify prognostic indexes of evolution.

[The implantation of VDD pacemakers with a single electrode--a comparative study. The experience of the last 5 years]

OBJECTIVE

To compare the epidemiological characteristics and immediate results of all first single lead VDD pacemaker (PM) implantations with those of an equal number of dual chamber DDD PM, implanted during a 5-year period in a tertiary-care hospital.

POPULATION AND METHODS

A total of 41 patients (pts) (25 males, mean age of 69.0 +/- 11.8 years) underwent a VDD PM implantation, from 30-11-92 to 15-9-97. This group was compared with an equal number of patients (28 males, mean age of 69.9 +/- 7.31 years) with a DDD PM implanted in the same period, selected by a criterion of immediate temporal proximity of procedure. For each patient we collected the clinical and electrocardiographic (ECG) indications for PM implantation, parameters of atrial (AS) and ventricular (VS) sensing and ventricular pacing (VP), X-ray exposure time (XRT) and complications.

RESULTS

In the VDD group, 46.3% of the patients had syncope, 51.2% had complete AV block on the ECG, and 14.6% were PM-dependent. Analyzed procedure-related parameters were as follows: P-wave amplitude: 2.1 +/- 0.6 V; AS threshold: 1.2 +/- 0.7 V; R-wave amplitude: 9.1 +/- 3.3 V; VS threshold: 7.0 +/- 2.0 V; VP thresholds: 0.68 +/- 0.24 mA, 0.43 +/- 0.12 V (for a spike duration of 0.5 ms); ventricular impedance: 644.9 +/- 132.0 ohm; XRT; 7' 43" +/- 8' 23". There were two minor complications, for an incidence of 4.9% (one local hematoma and a vagal reaction). In the DDD group the clinical and ECG characteristics were similar, but there was a 22.0% prevalence of sinus-node dysfunction, VS 0% in the VDD group). The P-wave amplitude and AS threshold were significantly (p < 0.005) better (2.8 +/- 0.9 V and 2.8 +/- 0.9 V respectively). The other parameters were similar to those of the VDD group.

CONCLUSIONS

The immediate results of VDD PM implantation are good and comparable with those of DDD PM, although with worse acute AS parameters.

Trypanosoma cruzi in the opossum Didelphis marsupialis: a study of the correlations and kinetics of the systemic and scent gland infections in naturally and experimentally infected animals

The genus Didelphis (Marsupialia, Didelphidae) has the unique capacity of supporting both multiplication cycles of Trypanosoma cruzi simultaneously; besides the intracellular forms, the epimastigotes can be found multiplying and differentiating abundantly in the lumen of the scent glands. The biological significance of the life cycle of T. cruzi within the scent glands of Didelphis marsupialis, as well as its contribution to the epidemiology of the disease, is presently unclear. In order to clarify the mechanisms involved in the colonization of this singular habitat by T. cruzi, as well as to understand its biological role, we have carried out a serological and parasitological follow-up of both natural and experimental infections of young and adult opossums. Although all natural infections were stable and long lasting, no infected scent glands were found, indicating that the stability of the systemic infections does not depend on the presence of flagellates in the scent gland. In 84% of the experimentally infected animals the colonization of the scent glands was preceded by a period of patent parasitemia. Parasitism of the scent glands was essentially permanent and bilateral, and its maintenance was independent of circulating parasites. Moreover, the course of the infection differed depending on the source (scent glands versus axenic culture-derived) of the metacyclic forms. Our results suggest that parasitism of the SG of D. marsupialis is most likely a secondary acquisition, a step toward independence from the insect vector, similarly to what is accepted for Trypanosoma equiperdum.

[Demographic discontinuities in Brazil and the state of Sao Paulo]

"Given the importance of information on the population age structure when planning short, medium and long-term needs within the different social strata, this paper is a proposal to deepen...the study of changes in the population pyramids.... Based on the most recent methodologies a study of age discontinuities is carried out and a method of follow-up by cohorts is suggested, taking the 15-19 and 20-24 age groups as an example. The purpose is to show that, as a...cohort ascends in the age pyramid, new and different necessities arise and also different responses are demanded on the part of the social system." Data are for Brazil as a whole and for the state of Sao Paulo. (SUMMARY IN ENG)

Preliminary study of the relationship between plasma and erythrocyte magnesium variations and some circulating pro-oxidant and antioxidant indices in a standardized physical effort

The aim of this preliminary study was to determine the relationship between exercise, magnesium (Mg) status, oxidative stress, and antioxidant defence systems. Some corresponding indices have been evaluated: plasma Mg, ascorbate, uric acid, adrenaline, creatine kinase (CK), thiobarbiturate reactive substances, adrenochrome; and in erythrocytes (RBC): reduced and oxidized glutathione (GSH and GSSG) and Mg. Venous blood samples were withdrawn before and 3 min after completion of a 40 min run. Only two significant changes were observed after effort: plasma Mg decreased (P < 0.009) and plasma adrenaline increased (P < 0.005). There was a non-significant tendency for indices of oxidative stress and antioxidant capacity to increase. The significant correlations between plasma Mg and CK (r = -0.88) and between RBC Mg and plasma ascorbate (r = -0.76) disappeared after the effort. Further research is necessary, with a larger number of subjects and variables, to obtain a better understanding of these interactions.