Patent Description:
Heart failure is a leading pandemic that is associated with poor quality of life, high morbidity and mortality. There are various treatments for heart failure: various drugs, resynchronization of the myocardial contraction by pacing the heart at different sites (CRT, cardiac resynchronization therapy), cardiac contractility modulation, neurohumoral stimulation, mechanical assist devices, attempts to use stem-cell therapy for myocardial regeneration and utilization of various materials for tissue rejuvenation. Despite the significant advances in all the suggested technologies and therapies the mortality and morbidity are still high and quality of life is very poor. Moreover, the prevalence of heart failure is expected to grow in the near future with the aging of the population.

The main problem of all known solutions for the treatment of heart failure is that their effectiveness is very limited. The current solutions have only limited success in altering the course of the disease, although they may ameliorate of rate of heart failure progression. Few thousands of assist devices are implanted every year in patients with end-stage heart-failure. Although this technology significantly prolongs their survival, these patients are only a small fraction of the population that suffer from severe heart-failure, few thousands out of a population of more than <NUM> million patients with stage III-IV heart failure, in the USA alone. Moreover, the assist device technology is associated with high rate of complications as gastrointestinal bleeding, stroke, and right-heart failure. In addition, it is a very expensive technology.

Cardiac Resynchronization Therapy (CRT) is another advanced technology, but it is effective in only a small fraction of the patients with severe systolic heart failure (patients with ejection fraction below <NUM>% and markedly prolonged QRS). Interestingly, more than half of the heart failure patients suffer from diastolic heart-failure, a problem in the filling of the left ventricle. The mechanisms underlying this type of heart failure are not well-understood and there is no effective remedy to this type of heart failure. This group of diastolic heart failure (or heart failure with preserved ejection fraction) is steadily growing with the aging of the population. Therefore, there is a crucial unmet need to develop novel technologies for the treatment of heart failure.

Three main paradigms have been suggested to explain the development of heart failure: (<NUM>) cardio-renal and volume overload, (<NUM>) cardio-circulation and coupling the cardiac function with the peripheral impedance, (<NUM>) neuro-humoral and the activation of the sympathetic system. The current available drug therapies and the various technologies relate to these three paradigms.

<CIT>discloses a medical system for controlling cardiac pacing of a patient, the system having a controller for adjusting the cardiac pacing rate in coordination with respiration cycles, wherein the controller modulates the cardiac pacing rate above and below the base rate.

The present invention provides an apparatus for treatment of cardiac problems according to claim <NUM>. The present disclosure provides novel methods and devices for treatment of heart-failure and pulmonary congestion and also for prevention of atrial fibrillation; without limitation, the invention may be used for treatment of cardiac decompensation, amelioration of dyspnea and prevention of deterioration to pulmonary congestion and pulmonary edema.

The invention can be used to treat the deterioration of heart failure, denoted as the "cardiopulmonary vicious cycle". The most cardinal complaint of severe heart failure and the main cause for rehospitalization is severe dyspnea. The inventor has found that the respiratory effort and the associated sensation of dyspnea are not only hallmarks of cardiac decompensation but the respiratory effort plays a pivotal role in the 'cardiopulmonary vicious cycle" that can lead to progressive deterioration.

The novel treatment is a breakthrough in the management of heart failure for the following main reasons:.

Advantages of the invention include, without limitation:.

The present disclosure provides a non-claimed method for treatment of cardiac problems, including performing modulation of a cardiac rhythm of a patient by increasing a number of heart beats during time segments with high pleural pressure relative to a number of heart beats in other time segments with relatively lower pleural pressure, wherein an amplitude of the modulation of the cardiac rhythm is determined by severity of a respiratory effort and lung congestion of the patient. The high pleural pressure is closer to zero than the relatively lower pleural pressure.

The method may further use the modulation of the cardiac pacing to remove fluids from a lung of the patient, to reduce pressures within pulmonary vessels of the patient and thereby reducing the respiratory effort and the sensation of dyspnea.

The method may further use the modulation of the cardiac pacing to reduce resistance to blood flow within pulmonary circulation of the patient and reducing the respiratory effort and thereby alleviating both right and left ventricle workloads.

The modulation of the cardiac pacing may further include sensors within a pleural space or/and intrathoracic vessels and/or heart chamber or/and a surface of a thorax and an epigastrium of the patient, that record and measure respiratory waves, and wherein severity of the respiratory effort is defined as peak to peak amplitude of the respiratory wave.

The modulation of the cardiac pacing may further include using a long-term central control system, with memory and communication units, that records past history of heart rate, respiratory dynamics and hemodynamic indices.

The modulation of the cardiac pacing may further include using a long-term central control system, with a central processing unit that analyzes the changes in hemodynamic congestion or hemodynamic pressure, respiratory effort and/or heart rates.

The modulation of the cardiac pacing may further include using a long-term central control system that sets a threshold level for segmentation of the respiratory cycles into intervals with relatively high pleural pressure and relatively low pleural pressure.

The modulation of the cardiac pacing may further include suppressing normal sinus node pacing.

The modulation of the cardiac pacing may further include an intentional increase in the number of heart beats during time intervals with high pleural pressure that suppresses sinus node pacing during the relatively low pressure time intervals by an autonomic nerve system of the patient, in response to a transient increase in cardiac output during the time interval with high pleural pressure.

The modulation of the cardiac pacing may further include an algorithm of adaptive control of the modulation, within a long-term control system, using feedback from sensors that assess respiratory effort level, to control the modulation of the cardiac pacing, wherein the control of the moculation includes determining a number of pacing beats that should be added per minutes (NpM), that are added during the high pleural pressure intervals, and wherein a depth of the modulation (NpM) increases with severity of the monitored respiratory effort.

The method may further include using a long-term central control system that determines a respiratory rate (RR) interval of elicited pacing, based on past history of electrocardiogram (ECG) recordings.

The method may further include using a real time control unit that accepts a threshold for segmentation of the respiratory wave, the required number of additional pacing (NpM) and the RR interval of the elicited pacing, and identifies in real time the beginning of each high pleural pressure interval and computes the pacing time based on identifying the last heartbeat, the number of pacing provided recently and the required NpM.

The method may further include using a real time control unit and an output power unit that executes the real time additional pacing.

The modulation of the cardiac pacing may be carried out by pacing electrodes placed within at least one of the cardiac chambers.

The invention provides a novel apparatus for providing cardiopulmonary reverse cycling therapy for treating what is called herein the "cardiopulmonary vicious cycle", described herein. No prior art has related to the crucial role of the respiratory effort in the development of cardiac decompensation.

The novel "cardiopulmonary reverse cycling" (CPRC) aims to: <NUM>. break all the cardiopulmonary vicious feedback loops that lead to cardiac decompensation, <NUM>. prevent the development of hemodynamic and pulmonary congestions by utilizing the large changes in the intrathoracic pressure (the work of the respiratory pump/machine) to pull blood and fluid out of the lung back into the peripheral circulation, <NUM>. decrease the transmural pressure across the pulmonary capillaries and the left atrium, and thereby to improve lung compliance. ameliorate the problem of dyspnea, and <NUM>. Decrease the workloads of both the right and left ventricles. The "cardiopulmonary vicious cycle" leads to progressive increase in the pulmonary capillary pressure and lung congestion and increase the workloads of the two heart ventricles. The device provides cardiopulmonary reverse cycling by reversing these ominous effects of the vicious cycle.

The device utilizes the works that are generated by the respiratory system (the "respiratory pump") and cardiac contractions in order to remove fluids from the lung, to reduce the pressures within the pulmonary vessels and to reduce the resistance to blood flow within the pulmonary circulation. These effects alleviate the hemodynamic and lung congestions. The pressures in the pulmonary circulation (hemodynamic congestion) and the amount of blood and fluids with the lung (lung congestion) are mainly determined by the inflow of blood into the lung through the right ventricle and the outflow of blood out from the lung back into the peripheral circulation through the left ventricle. However, these inflow and outflow, through the right and left ventricle, are modulated by the intrathoracic pressure. In the presence of a deep negative intrathoracic pressure the inflow into the lung is larger than the outflow from the lung. The opposite occurs in the presence of close to zero and positive intrathoracic pressure. Therefore, the inflow and outflow are modulated by the respiratory pump. The device utilized the pressures that are generated by the respiratory pump to shift blood out of the lung and to reduce the pressures in the pulmonary circulation. It is done by pacing the heart and increasing the number of heart beats when the intrathoracic pressure is close to zero relative to the number during deep negative intrathoracic pressure.

The anticipated pacing rate is very low, about a single paced beat every <NUM> normal heart beats. The mean cardiac stroke volume of an adult is about <NUM>. Let assume that each pacing during the appropriate time interval (close to zero intrathoracic pressure) shift only <NUM> of blood out of the lung (<NUM>% of the stroke volume), i.e. the stroke volumes of the right and left ventricles are <NUM> and <NUM>, respectively. Thus, to shift a relative large amount of <NUM> of blood out of the lung we have to add <NUM> heat beats at the appropriate time window. However, in a single day we have on average about <NUM>,<NUM> breath cycle and <NUM>,<NUM> heart beats. Thus, only a modest pacing of once every <NUM> breath cycle or <NUM> heart beats is needed. Moreover, it was well established the cardiac decompensation of chronic heart failure patient develops and progress slowly over a period of <NUM> to <NUM> weeks. Thus there is reverse cycling can be extended over couple of days.

It is important to note that the device has insignificant effect on the heart rate (less than <NUM>%), in contrast to other patents that aim to change the heart rate according the breathing rate or phases.

It is important to note that the device does not directly change the breathing rate, as was suggested by various other patents (<CIT>, <CIT>, <CIT>), on the contrary, it utilizes the respiratory pump to shift blood out of the lung. Moreover, in contract to these patents that suggest to pace the heart only when the patient is asleep, this device aims to work around the clock and also to alleviate the respiratory effort during physical activities.

Moreover, in contract to other patents, the pacing is not aligned to a simple segmentation of breathing cycle to inspiration and expiration phase, but based on the intrathoracic pressure levels, as depicted in <FIG>. Inspiration is defined the time interval of inhalation, when the intrathoracic pressure drop from a pressure close to zero to the lowest negative intrathoracic pressure. Thus pacing during the inspiratory phase as suggested by other patents <CIT>, <CIT>) will not provide the anticipated cardiopulmonary reverse cycling, since pacing at low negative intrathoracic pressure only accentuates the vicious cycle and lung congestion. Similarly, pacing during the expiratory phase is ineffective, since the intrathoracic pressure is very low at the beginning of the expiration phase. The appropriate pacing window cross the inspiration and expiration phases, and start before the end expiration and end after the beginning of inspiration. This segmentation of the respiratory cycle is unique to this embodiment, in comparison the all the other suggested pacing of the heart (<CIT>, <CIT>).

The invention surprisingly achieves this by using a counterintuitive mode of pacing the heart, which is opposite to the physiological autonomic modulation of the cardiac pacing by the respiration, which is denoted as "respiratory sinus arrhythmia". While in the physiological respiratory sinus arrhythmia the heart rate increases during inspiration, when the intrathoracic pressure drop down to the deepest negative pressure, the CPRC performs the opposite mode of pacing and increases the heart rate when the intrathoracic pressure is close to zero, as depicted in <FIG> and <FIG>.

Moreover, the amplitude of the modulation of the cardiac pacing is determined by the severity of the respiratory effort and lung congestion.

The novel CPRC may include the following elements:.

There are two physiological advantages for having the heart within the chest cage: The chest cage protects the heart and the main vessels from external trust and the "respiratory pump" increases the cardiac output by increasing the venous return. The normal physiological control of the heart rate aims to increase the cardiac output during exercises, and it is done efficiently in healthy subjects. An increase in the respiratory work by the "respiratory pump" (the diaphragm and all the respiratory and accessory muscles), decreases the intrathoracic pressure during inspiration and facilitates venous return to the right atrium. The cardiac output of the left ventricle is equal to the venous return, at steady state, and is limited by the venous return. Under normal physiological conditions, an increase in the venous return and the ensuing dilatation of the right atrium expedites the pacing rate of the sinus node. There is an increase in the heart rate especially during inspiration, since the venous return increases during inspiration. This phenomenon denoted is denoted as the "respiratory sinus arrhythmia" and is depicted in <FIG>. The increase in the cardiac output during exercise is due to an increase in the venous return to the heart and an increase in the heart rate.

However, except for this positive effect of the "respiratory pump" on the cardiac output under normal physiological condition, an increase in the respiratory effort has <NUM> severe detrimental effects on the pulmonary circulation and the cardiac workloads. The increase in the respiratory effort increases the: (<NUM>) intrapulmonary capillary pressure (PCWP). (<NUM>) pulmonary vascular resistance (PVR), pulmonary artery pressure (PAP) and right-ventricle afterload, (<NUM>) lung congestion by shifting blood into the lung, (<NUM>) LV afterload, and (<NUM>) metabolic demand due to the increase in the work of the respiratory muscles. All these mechanisms are described in more detailed in the attached supplement. These five adverse effects of an increase in the respiratory effort lead to accelerated decompensation in the presence of heart or lung diseases.

It is important to note that intrathoracic (pleural) pressure has significant effects on the pulmonary hemodynamics and lung congestion. Negative pleural pressure increases the lung blood pool and increases in the pulmonary bed pressure since it:.

All these effects are reversed when the pleural pressure is close to zero or above zero. During this phase there is:.

Under steady state condition, the cardiac stroke volume is about <NUM> on average and about <NUM> of blood enters into the lung through the right-ventricle and the same amount of <NUM> is propelled out through the left ventricle, as schematically described in <FIG>. However, when the pleural pressure dropped down the inflow though the right-ventricle increases, from <NUM> to <NUM> in the example in <FIG>. At the same time, the outflow from the lung through the left ventricle decreases from <NUM> to <NUM>. When the pleural pressure is close to zero the picture is reversed, as shown the <FIG>, and the amount of blood in the lung reaches a steady state. <FIG> also presents the physiological "respiratory sinus arrhythmia" where there is an increase in the heart rate during inspiration. The main strategy behind the present innovation is to utilize the "respiratory pump" (part of the inspiratory and expiratory works) and cardiac contractions in order to pump blood out of the lung and to alleviate the hemodynamic congestion. It is done by modulating cardiac pacing according to the changes in the pleural pressure, but counterintuitively, it works against the normal physiology and increases the heart rate during end expiration and early inspiration. During end inspiration and early expiration, when the pleural pressure is negative and the "respiratory pump" increases the right-ventricle preload and the left-ventricle afterload, the novel device decreases the pacing rate to reduce the net inflow into the lung. During late expiration and early inspiration, when the "respiratory pump" decreases the right-ventricle preload and increases the left-ventricle preload, the device increases the pacing rate to facilitate the removal of blood from the lung.

In the example presented in <FIG> the mean heart rate is <NUM> bpm during normal condition with respiratory sinus arrhythmia and cardiopulmonary reverse cycling therapy (CPRC). However, the device imposes higher pacing rate during late expiration and early inspiration phases, in contrast to the normal pacing. Consequently, during the two seconds of inspiration there are only two beats, while during the <NUM> seconds of expiration there are <NUM> beats. If there is an increase of <NUM> (+<NUM>% of the stroke volume) in the inflow to the lung and a decrease of <NUM> (-<NUM>%) in the outflow through the left-ventricle, for each heart beat during the negative pleural pressure intervals, each beat during this interval increases the lung blood volume by <NUM> of blood. In total, the decrease in the heart rate to two beats during the negative pressure interval decreases the shift of blood to only <NUM> (instead of <NUM>) during this time interval. During the high pleural pressure intervals the picture is reversed, as described in <FIG>. There is a decrease of <NUM> (-<NUM>% of the stroke volume) in the inflow to the lung and an increase of <NUM> (+<NUM>%) in the outflow through the left-ventricle, for each heartbeat. The CPRC increases the heart rate to four beats during the high pleural pressure interval (instead of three) and increases the shift of blood out of the lung to <NUM> (instead of <NUM>). Thus, the CPRC produces a net shift of <NUM> out of the lung during a single breathing-cycle (within <NUM> sec). Although the effect within a single breathing-cycle is small, it is accumulative, and within one minute it produces a net outflow of <NUM> out of the lung, when the respiratory rate is <NUM> bpm as in <FIG>, or <NUM> within only <NUM> minutes. It is important to note that under normal condition there are only about <NUM> of blood within the lung, and accumulated effect within <NUM> is huge (theoretically can decrease the lung blood volume by <NUM>%). The effect of CPRC may diminish with time as the lung blood pool may decrease. However, lung congestion, an increase in the respiratory effort and a deeper modulation of the CPRC (larger difference between the inspiratory and expiratory heart rate) intensify the effects of the CPRC in a cooperative mode, and cooperatively assist in alleviating the hemodynamic and lung congestions.

Applications of the invention include, without limitation, treatment of heart failure patients, including all heart failure types. The invention aims to decrease the probability of gradual development of hemodynamic or lung congestion. The invention may provide precise diagnosis of the severity of the decompensation, based on the assessment of the severity of respiratory effort and the hemodynamic congestion. Moreover, it provides the immediate and the proportional appropriate treatment for the prevention of further deterioration and the return toward normal condition. Dyspnea is the most cardinal symptom of heart failure, and the technology directly targets this symptom.

Claim 1:
An apparatus for treatment of cardiac problems, comprising:
a cardiopulmonary reverse cycling therapy (CPRC) device for cardiac pacing (<NUM>);
a heart rate sensor;
an intrathoracic pressure sensor (<NUM>); and
a control unit in communication with said CPRC device, said heart rate sensor and said intrathoracic pressure sensor, said control unit configured to modulate a cardiac rhythm of a patient by causing said CPRC device to increase a number of heart beats during time segments with high pleural pressure relative to a number of heart beats in other time segments with relatively lower pleural pressure, said high and low pleural pressures being sensed by said intrathoracic pressure sensor, wherein an amplitude of modulation of the cardiac rhythm is determined by severity of a respiratory effort and a lung congestion of the patient.