Pacemaker Weight: How Much Does It Weigh?


Pacemaker Weight: How Much Does It Weigh?

Fashionable cardiac pacemakers, the small digital units implanted to assist regulate coronary heart rhythms, usually weigh between 20 and 50 grams. This light-weight design minimizes discomfort for the affected person and permits for simpler implantation and integration throughout the physique.

The minimal weight of those units represents a major development in medical know-how. Earlier pacemakers had been considerably bigger and heavier, which offered quite a few challenges. The decreased dimension and weight contribute to improved affected person consolation, decreased restoration occasions, and a decrease threat of issues. This miniaturization has additionally expanded the vary of sufferers who can profit from pacemakers, enhancing high quality of life for a lot of people with coronary heart situations. The continuing pursuit of smaller and lighter designs continues to boost affected person outcomes and increase remedy prospects.

This dialogue of system weight serves as a place to begin to understanding the broader context of pacemaker know-how. Subjects akin to energy sources, lifespan, performance, and the implantation process itself are essential to an entire understanding of this life-sustaining know-how.

1. Miniaturization

Miniaturization performs an important position in figuring out the load of a contemporary pacemaker. The drive to scale back the general dimension of those units immediately impacts affected person consolation and surgical procedures. Smaller, lighter pacemakers are much less noticeable and trigger much less discomfort, resulting in improved affected person acceptance and high quality of life. In addition they simplify the implantation course of, doubtlessly lowering surgical dangers and restoration occasions. This concentrate on miniaturization requires superior engineering and materials science, impacting every thing from the dimensions of the battery to the circuitry and casing.

Contemplate the evolution of pacemaker know-how. Early pacemakers had been cumbersome and heavy, requiring extra invasive surgical procedures and sometimes leading to noticeable protrusions below the pores and skin. Technological developments, notably in microelectronics and battery know-how, have enabled dramatic reductions in dimension and weight. Fashionable pacemakers are considerably smaller and lighter than their predecessors, usually weighing lower than a couple of cash. This miniaturization is a direct results of ongoing analysis and improvement efforts targeted on enhancing affected person outcomes.

The continuing pursuit of miniaturization continues to drive innovation in pacemaker know-how. Smaller units might doubtlessly result in much less invasive implantation methods, akin to transcatheter supply, additional minimizing surgical dangers and restoration occasions. Moreover, miniaturization can allow the combination of extra options and functionalities with out considerably rising the system’s general dimension or weight. This fixed drive for smaller and lighter pacemakers underscores the significance of miniaturization in enhancing affected person care and enhancing the effectiveness of this life-saving know-how.

2. Titanium Casing

Titanium’s outstanding position in pacemaker development stems immediately from its distinctive properties. Its distinctive biocompatibility minimizes adversarial reactions throughout the physique, a important issue for implanted units. Moreover, titanium’s excessive strength-to-weight ratio permits for the creation of sturdy but light-weight casings. This attribute immediately contributes to the general low weight of recent pacemakers, enhancing affected person consolation and minimizing surgical invasiveness. The fabric’s inherent resistance to corrosion ensures the system’s longevity and dependable efficiency throughout the physique’s difficult physiological atmosphere.

Contemplate the sensible implications of utilizing a heavier, much less biocompatible materials. Elevated weight might result in better discomfort and doubtlessly dislodgement of the system. A much less biocompatible materials would possibly set off adversarial reactions, necessitating removing or alternative. Titanium’s properties immediately deal with these challenges, contributing to the long-term success and reliability of implanted pacemakers. The selection of titanium, subsequently, is a important consider reaching the optimum steadiness between sturdiness, biocompatibility, and minimal weight.

Using titanium casings represents a major development in pacemaker know-how. This materials choice, pushed by the necessity for light-weight, biocompatible, and sturdy enclosures, has immediately contributed to the improved affected person outcomes noticed with fashionable pacemakers. Persevering with analysis into superior supplies and fabrication methods could additional optimize casing design and efficiency, resulting in even smaller, lighter, and extra biocompatible units sooner or later.

3. Battery Expertise

Battery know-how performs an important position in figuring out the general weight and lifespan of a pacemaker. Advances in battery chemistry and design have led to vital reductions in battery dimension and weight with out compromising efficiency. Larger power density batteries, for instance, retailer extra power in a smaller quantity, immediately contributing to the miniaturization and weight discount of pacemakers. This discount in weight enhances affected person consolation and facilitates much less invasive implantation procedures. Moreover, enhancements in battery longevity cut back the frequency of alternative surgical procedures, minimizing affected person threat and healthcare prices.

Contemplate the influence of older, much less environment friendly battery applied sciences. These batteries had been usually bigger and heavier, contributing considerably to the general dimension and weight of the pacemaker. The restricted lifespan of those older batteries additionally necessitated extra frequent alternative procedures, exposing sufferers to repeated surgical dangers and disruptions to their lives. The event of lithium-iodine batteries, adopted by extra superior chemistries, marked a turning level. These newer batteries provide greater power density and longer lifespans, considerably lowering the load and increasing the useful lifetime of pacemakers. This progress has immediately translated into improved affected person outcomes and decreased healthcare burdens.

The continuing evolution of battery know-how continues to form the way forward for pacemakers. Analysis into new battery chemistries, akin to solid-state batteries, guarantees even greater power densities and longer lifespans. This might additional cut back the dimensions and weight of pacemakers whereas extending the time between replacements. Moreover, developments in power harvesting applied sciences, which seize power from the physique’s personal actions or warmth, might doubtlessly remove the necessity for battery replacements altogether. These ongoing developments underscore the important hyperlink between battery know-how and the continued development of pacemaker design and performance.

4. Inside Parts

The inner parts of a pacemaker considerably contribute to its general weight. Understanding these parts and their respective contributions is essential for appreciating the engineering challenges concerned in minimizing system weight whereas sustaining performance. Every element, from the circuitry to the sensors, performs an important position within the system’s operation, and their miniaturization is immediately tied to the general weight discount efforts.

  • Circuitry

    The digital circuitry, accountable for controlling the pacing pulses delivered to the guts, is a key element. Miniaturization of those circuits, utilizing superior microchip know-how, has dramatically decreased their dimension and weight contribution. Fashionable pacemakers make use of extremely built-in circuits, consolidating a number of capabilities onto a single chip. This integration reduces the variety of particular person parts required, additional minimizing the system’s general dimension and weight.

  • Capacitors and Resistors

    These passive digital parts, important for regulating {the electrical} movement throughout the pacemaker, additionally contribute to the general weight. Whereas individually small, their mixed weight turns into an element. Advances in supplies and manufacturing methods have allowed for the manufacturing of smaller and lighter capacitors and resistors, additional contributing to the miniaturization efforts.

  • Sensors

    Fashionable pacemakers usually incorporate sensors to observe physiological parameters like coronary heart fee and exercise ranges. These sensors contribute to the system’s weight. Nonetheless, ongoing miniaturization efforts goal these parts as effectively, aiming to scale back their dimension and weight with out compromising their sensitivity and accuracy. Smaller, extra environment friendly sensors allow extra subtle pacing algorithms and enhance affected person outcomes.

  • Microprocessor

    The microprocessor is the “mind” of the pacemaker, accountable for processing information from the sensors and controlling the pacing output. Miniaturizing this advanced element is a important problem. Superior microfabrication methods and using low-power designs have considerably decreased the dimensions and weight of pacemaker microprocessors, enabling better performance inside a smaller footprint.

The continuing miniaturization of those inner parts is immediately linked to the discount within the general weight of American pacemakers. Every element represents an space the place developments in supplies science, microelectronics, and manufacturing processes contribute to creating smaller, lighter, and extra environment friendly units. This steady drive for miniaturization underscores the dedication to enhancing affected person consolation and increasing the therapeutic potential of pacemakers.

5. 20-50 grams

The load vary of 20-50 grams is central to understanding fashionable pacemaker know-how. This comparatively slender vary represents a major achievement in engineering and supplies science, immediately impacting affected person consolation and the feasibility of minimally invasive implantation procedures. Exploring the varied components contributing to and influenced by this weight vary gives essential insights into the developments and ongoing improvement of those life-saving units.

  • Affected person Consolation

    A pacemaker’s weight considerably impacts affected person consolation. A heavier system can result in discomfort, particularly throughout bodily exercise or sleep. The 20-50 gram vary represents a weight that’s typically well-tolerated by most sufferers, minimizing discomfort and selling a better high quality of life. This weight permits the system to stay comparatively unobtrusive, lowering the probability of it interfering with each day actions.

  • Surgical Implications

    The light-weight nature of recent pacemakers facilitates much less invasive surgical methods. Smaller incisions and shorter process occasions are doable as a result of decreased dimension and weight of the system. This interprets to quicker restoration occasions, decreased threat of issues, and decrease general healthcare prices. The 20-50 gram vary is a key consider enabling these developments in surgical procedures.

  • Technological Developments

    Reaching this weight vary is a direct results of developments in supplies science, battery know-how, and microelectronics. Using light-weight, biocompatible supplies like titanium, mixed with high-energy-density batteries and miniaturized circuitry, has enabled the event of smaller and lighter pacemakers. The 20-50 gram vary displays the end result of those technological developments.

  • Future Developments

    Whereas the present weight vary represents a major achievement, ongoing analysis goals to additional cut back pacemaker dimension and weight. This might result in even much less invasive implantation procedures and doubtlessly new functionalities. Additional reductions in weight, whereas sustaining efficiency and longevity, stay a key goal within the ongoing improvement of pacemaker know-how. This pursuit of miniaturization means that the 20-50 gram vary could evolve additional as know-how progresses.

The 20-50 gram weight vary of up to date pacemakers is greater than only a numerical worth; it represents a important intersection of affected person well-being, surgical developments, and ongoing technological innovation. This weight vary immediately displays the success of miniaturization efforts and underscores the continuing dedication to enhancing affected person outcomes and increasing the probabilities of pacemaker remedy.

6. Affected person Consolation

Affected person consolation is paramount in pacemaker remedy, immediately influencing remedy acceptance and general high quality of life. A pacemaker’s weight performs an important position on this consolation stage, impacting each day actions, sleep, and psychological well-being. Understanding the connection between system weight and affected person consolation is important for optimizing remedy outcomes and selling long-term affected person satisfaction.

  • Weight and Bodily Sensation

    The load of a pacemaker can affect bodily sensations throughout the chest. A heavier system could create a sense of strain, fullness, and even delicate discomfort, notably throughout motion or sure postures. Conversely, a lighter system minimizes these sensations, permitting for better freedom of motion and lowering the probability of the system turning into a continuing bodily reminder of its presence. This discount in bodily consciousness contributes considerably to improved affected person consolation and acceptance of the implanted system.

  • Affect on Day by day Actions

    Pacemaker weight can influence a affected person’s skill to interact in each day actions. Heavier units could limit motion or trigger discomfort throughout train, work, and even easy duties like lifting or reaching. The lighter weight of recent pacemakers minimizes these limitations, permitting sufferers to take care of a extra energetic life-style. This skill to take part in common actions with out device-related restrictions is important for preserving independence and general high quality of life.

  • Sleep High quality

    Sleep consolation is one other essential side of affected person well-being. A heavier pacemaker could cause discomfort when mendacity down, doubtlessly disrupting sleep patterns and resulting in fatigue. The lighter weight of up to date pacemakers minimizes this disruption, selling higher sleep high quality. Improved sleep contributes to general well being and well-being, additional enhancing the optimistic influence of a light-weight pacemaker.

  • Psychological Affect

    Past the purely bodily points, pacemaker weight also can have a psychological influence. A much less noticeable, lighter system can cut back self-consciousness and promote a extra optimistic physique picture. This improved psychological acceptance of the system can contribute to better confidence and a extra optimistic outlook, fostering a way of normalcy and lowering anxiousness associated to the implanted system. This optimistic psychological influence underscores the significance of minimizing system weight for general affected person well-being.

The load of an American pacemaker immediately influences quite a few points of affected person consolation, from bodily sensations and exercise ranges to sleep high quality and psychological well-being. The continuing pursuit of smaller, lighter units demonstrates a dedication to prioritizing affected person consolation and maximizing the advantages of pacemaker remedy. By minimizing the bodily and psychological burden of the implanted system, developments in pacemaker know-how contribute to a extra seamless integration of the system into the affected person’s life, in the end selling higher remedy outcomes and a better general high quality of life.

7. Surgical Implications

Pacemaker weight considerably influences surgical procedures, impacting every thing from incision dimension to restoration time. A lighter system permits for smaller incisions, minimizing tissue trauma and lowering the chance of an infection. This additionally interprets to shorter process occasions, lessening anesthesia publicity and general surgical threat. Contemplate the distinction between implanting a cumbersome, older-generation pacemaker and a contemporary, light-weight system. The previous would necessitate a bigger incision and extra in depth tissue dissection, rising the potential for issues. The latter, as a result of its smaller dimension and weight, can usually be implanted via a minimally invasive strategy, leading to a faster, much less traumatic process.

This discount in surgical invasiveness facilitated by lighter pacemakers has profound implications for affected person restoration. Smaller incisions heal quicker, lowering post-operative ache and scarring. Shorter process occasions contribute to quicker restoration and earlier ambulation, minimizing the chance of issues like deep vein thrombosis. Moreover, much less invasive procedures usually translate to shorter hospital stays, lowering healthcare prices and permitting sufferers to return to their regular actions sooner. For instance, minimally invasive pacemaker implantation could permit a affected person to return to work inside per week, in comparison with a number of weeks for extra conventional procedures involving bigger incisions and heavier units.

The connection between pacemaker weight and surgical implications underscores the significance of ongoing miniaturization efforts. As know-how advances, additional reductions in system dimension and weight might result in even much less invasive implantation methods, doubtlessly increasing the pool of eligible candidates for pacemaker remedy. Minimally invasive procedures not solely enhance affected person consolation and restoration but in addition contribute to useful resource optimization throughout the healthcare system. The continued pursuit of lighter, smaller pacemakers demonstrates a dedication to refining surgical methods and enhancing affected person care via technological innovation.

8. Technological Developments

Technological developments are intrinsically linked to the load of American pacemakers. The relentless pursuit of smaller, lighter, and extra environment friendly units has pushed innovation throughout numerous disciplines, from supplies science to microelectronics. Understanding these developments gives essential context for appreciating the present state of pacemaker know-how and its potential future trajectory. The load of a pacemaker shouldn’t be merely a static attribute however somewhat a dynamic indicator of progress, reflecting steady enhancements in design, supplies, and manufacturing processes.

  • Miniaturization of Electronics

    Advances in microelectronics have enabled dramatic reductions within the dimension and weight of pacemaker circuitry. Built-in circuits, combining a number of capabilities onto a single chip, have drastically decreased the general footprint of digital parts. This miniaturization, pushed by Moore’s Regulation and developments in semiconductor know-how, has been instrumental in reaching the light-weight profile of recent pacemakers. For example, early pacemakers relied on discrete transistors and different cumbersome parts, whereas modern units make the most of extremely built-in microchips, considerably lowering dimension and weight.

  • Battery Expertise Evolution

    Battery know-how has undergone vital evolution, immediately impacting pacemaker weight and longevity. The event of lithium-iodine batteries, adopted by different superior chemistries, has resulted in greater power densities and longer lifespans. This implies extra energy will be saved in a smaller and lighter package deal, lowering the general weight of the system and increasing the time between alternative procedures. The transition from mercury-zinc batteries to lithium-iodine batteries exemplified a major leap in power density, dramatically lowering battery dimension and increasing operational life.

  • Superior Supplies and Manufacturing

    Using superior supplies, akin to titanium, has been essential in lowering pacemaker weight. Titanium’s excessive strength-to-weight ratio permits for strong but light-weight casings. Moreover, developments in manufacturing methods, akin to laser welding and micromachining, allow the creation of intricate parts with excessive precision, contributing to the general miniaturization and weight discount. The shift from stainless-steel to titanium casings exemplifies the influence of fabric science on pacemaker design and weight.

  • Lead Design and Expertise

    The leads connecting the pacemaker to the guts have additionally undergone vital developments. Smaller, thinner leads cut back the general weight and profile of the system whereas enhancing affected person consolation. Developments in lead supplies and insulation know-how have additional enhanced their biocompatibility and longevity. For instance, the introduction of silicone-based insulation supplies improved lead flexibility and decreased their diameter, contributing to better affected person consolation and lowering the chance of lead-related issues.

These intertwined technological developments have collectively contributed to the numerous weight discount noticed in American pacemakers over time. This steady drive for miniaturization and improved efficiency underscores the essential position of know-how in enhancing affected person outcomes and increasing the probabilities of pacemaker remedy. The present weight of a pacemaker displays not solely the end result of previous improvements but in addition serves as a benchmark for future developments, driving ongoing analysis and improvement efforts in the direction of even smaller, lighter, and extra subtle units.

9. Future Developments

The way forward for pacemaker know-how is inextricably linked to the continuing pursuit of miniaturization and weight discount. Additional developments in supplies, battery know-how, and system design maintain the potential to create even smaller and lighter pacemakers, resulting in much less invasive procedures, improved affected person consolation, and expanded therapeutic prospects. Exploring these potential developments gives helpful insights into the path of pacemaker innovation and its potential influence on affected person care.

  • Leadless Pacemakers

    Leadless pacemakers, fully self-contained throughout the coronary heart, characterize a major departure from conventional units. Eliminating leads reduces the chance of issues akin to an infection and lead dislodgement. These units are considerably smaller and lighter than conventional pacemakers, minimizing the invasiveness of implantation procedures. Present leadless pacemakers are primarily designed for single-chamber pacing, however future developments could increase their capabilities to dual-chamber pacing and different superior functionalities.

  • Biodegradable Pacemakers

    Analysis into biodegradable pacemakers goals to create units that dissolve throughout the physique after serving their supposed goal. This eliminates the necessity for extraction procedures, additional lowering affected person burden and healthcare prices. Biodegradable supplies current distinctive challenges by way of sustaining system integrity and performance for the required period. Profitable improvement of such units might revolutionize pacemaker remedy by eliminating the long-term presence of international supplies throughout the physique.

  • Vitality Harvesting

    Vitality harvesting applied sciences discover the potential to energy pacemakers utilizing power sources throughout the physique, akin to kinetic power from heartbeats or physique warmth. This might remove the necessity for battery replacements, considerably extending the lifespan of the system and lowering the frequency of surgical interventions. Sensible implementation of power harvesting faces challenges by way of effectivity and reliability, however profitable improvement might dramatically alter the panorama of pacemaker know-how.

  • Distant Monitoring and Diagnostics

    Integration of superior sensors and wi-fi communication capabilities allows distant monitoring of pacemaker efficiency and affected person physiological information. This permits for early detection of potential points and facilitates customized changes to remedy. Whereas indirectly impacting the system’s weight, distant monitoring contributes to improved affected person outcomes and reduces the necessity for in-person follow-up visits. Future developments could concentrate on integrating extra subtle diagnostic capabilities and increasing the vary of remotely monitored parameters.

These future developments underscore the continuing dedication to enhancing pacemaker know-how and affected person care. Whereas the load of a pacemaker stays a important consideration, future improvements could transfer past merely lowering weight to embody completely new paradigms in system design, performance, and affected person interplay. The pursuit of leadless, biodegradable, and self-powered pacemakers, together with developments in distant monitoring, guarantees to remodel the way forward for cardiac rhythm administration, additional minimizing affected person burden and maximizing therapeutic efficacy.

Ceaselessly Requested Questions

This part addresses frequent inquiries relating to the load of up to date pacemakers and its implications for sufferers.

Query 1: Does the load of a pacemaker trigger noticeable discomfort?

Fashionable pacemakers, usually weighing 20-50 grams, are designed to reduce discomfort. Whereas some sufferers could initially expertise delicate strain or consciousness of the system, this sensation often diminishes over time. Important discomfort associated to system weight is rare with modern fashions.

Query 2: How does pacemaker weight have an effect on bodily exercise?

The light-weight design of recent pacemakers typically doesn’t limit bodily exercise. Sufferers can usually resume their traditional actions, together with train, with out experiencing limitations as a result of system weight. Nonetheless, consulting a doctor relating to particular exercise suggestions is all the time advisable.

Query 3: Does the load of the pacemaker affect the implantation process?

Sure, lighter pacemakers facilitate minimally invasive implantation methods, utilizing smaller incisions. This leads to shorter process occasions, quicker restoration, and decreased threat of issues.

Query 4: Does a heavier pacemaker last more than a lighter one?

No, the lifespan of a pacemaker is primarily decided by battery know-how, not weight. Developments in battery know-how have enabled longer lifespans in smaller and lighter units.

Query 5: Are there completely different weight issues for several types of pacemakers (single-chamber, dual-chamber, biventricular)?

Whereas minor weight variations could exist between several types of pacemakers as a result of element variations, the general weight vary stays comparatively constant. The first components influencing weight are battery dimension and casing materials.

Query 6: Will future pacemakers be even lighter?

Ongoing analysis and improvement efforts concentrate on additional miniaturization, together with the event of leadless pacemakers, that are considerably smaller and lighter than conventional fashions. Future developments could result in even lighter and fewer invasive pacing options.

Understanding the components influencing pacemaker weight empowers sufferers to make knowledgeable selections relating to their remedy. Consulting with a healthcare skilled gives customized steering based mostly on particular person wants and circumstances.

The following part will focus on the everyday lifespan of a contemporary pacemaker and components influencing its longevity.

Understanding Pacemaker Weight

The load of a pacemaker, whereas usually missed, performs an important position in affected person consolation and therapeutic success. The next suggestions provide helpful insights for sufferers and healthcare professionals relating to the implications of system weight.

Tip 1: Prioritize Affected person Consolation:
When discussing pacemaker choices, contemplate the affected person’s particular person circumstances and preferences relating to system dimension and weight. Open communication ensures the chosen system aligns with the affected person’s life-style and luxury expectations. A lighter system could enhance general satisfaction and cut back the psychological influence of dwelling with an implanted system.

Tip 2: Perceive Surgical Implications:
Acknowledge the connection between pacemaker weight and surgical strategy. Lighter units facilitate much less invasive procedures, minimizing restoration time and potential issues. Talk about the surgical implications of varied pacemaker fashions with the affected person to make sure knowledgeable decision-making.

Tip 3: Acknowledge Technological Developments:
Keep knowledgeable about developments in pacemaker know-how, notably relating to miniaturization and weight discount. Newer units usually provide improved consolation and efficiency traits as a result of developments in supplies and design. Remaining present on technological developments ensures sufferers profit from the most recent improvements.

Tip 4: Contemplate Lengthy-Time period Implications:
Consider the long-term implications of pacemaker weight, together with potential influence on bodily exercise, sleep, and physique picture. A lighter, much less obtrusive system could contribute to raised long-term affected person outcomes and high quality of life. Discussing these long-term issues may also help sufferers make knowledgeable selections.

Tip 5: Have interaction in Open Communication:
Foster open communication between sufferers and healthcare suppliers relating to pacemaker choice. Encourage sufferers to precise any considerations or preferences relating to system weight and luxury. This open dialogue facilitates shared decision-making and promotes patient-centered care.

Tip 6: Emphasize Individualized Care:
Acknowledge that every affected person’s wants and preferences are distinctive. Keep away from a one-size-fits-all strategy to pacemaker choice. Tailoring system suggestions to particular person affected person traits, together with life-style and anatomical issues, optimizes therapeutic outcomes and affected person satisfaction.

By contemplating the following pointers, healthcare professionals can information sufferers in the direction of making knowledgeable selections about pacemaker choice, guaranteeing the chosen system aligns with particular person wants and preferences whereas maximizing each consolation and therapeutic efficacy. This concentrate on patient-centered care contributes to improved outcomes and enhanced high quality of life.

This exploration of pacemaker weight issues now transitions to the concluding remarks of this text.

Conclusion

The exploration of pacemaker weight reveals its essential position in affected person well-being and the continuing evolution of cardiac rhythm administration. From influencing affected person consolation and surgical procedures to driving technological innovation, system weight serves as a important benchmark of progress. The standard 20-50 gram vary represents a major achievement in miniaturization, enabling much less invasive procedures and enhancing high quality of life for numerous people. Understanding the components contributing to this weight vary, together with developments in battery know-how, supplies science, and microelectronics, gives helpful context for appreciating the complexity and class of recent pacemakers.

The continuing pursuit of lighter, smaller, and extra environment friendly units guarantees to additional rework the panorama of pacemaker remedy. Analysis into leadless pacemakers, biodegradable supplies, and power harvesting applied sciences holds the potential to revolutionize cardiac rhythm administration, minimizing affected person burden and maximizing therapeutic effectiveness. As know-how continues to advance, the load of a pacemaker will doubtless change into an much more important issue, driving additional innovation and shaping the way forward for this life-saving know-how. Continued concentrate on miniaturization and patient-centric design will stay important for optimizing outcomes and guaranteeing that pacemakers proceed to enhance the lives of people affected by coronary heart rhythm issues.