Phase III Cardiac Rehabilitation: Ambulatory Heart Groups　― A Model From Germany ―

Abstract

Approximately 7,000 ambulatory (outpatient) heart groups (AHG) with 125,000 patients who are physically active on a regular basis have been established in Germany since the mid-1960s. Following phase II cardiac rehabilitation (CR), patients in an AHG aim to meet their set CR goals in groups of up to 20 participants under the instruction of a competent exercise therapist, and with regular attendance by a physician. Physical activity is the dominant aspect; psychosocial and educative elements are integrated to stabilize secondary cardiovascular prevention. Patients are legally entitled by German rehabilitation law to participate in AHGs. According to current studies, only 13–40% of all patients attend an AHG after phase II CR. In 2019, special AHGs for patients with high cardiovascular risk (chronic heart failure) were established. In the future, special emphasis needs to be placed on the recruitment of more patients into AHGs, particularly for the known under-represented groups (i.e., women, older patients, patients with low socioeconomic status). Furthermore, AHGs have to be established for patients with special needs (e.g., adults with congenital heart diseases). To date, the efficiency of AHG participation has still not been sufficiently investigated. A case-control study analyzing the long-term results of AHG participation reported an improvement in physical performance, as well as a reduction in cardiovascular morbidity (54%) and medical costs (approximately 47%). More superior investigations in this field are needed.

Physical activity, as a part of cardiac rehabilitation (CR), plays an essential role for patients with established (or at high risk for) cardiovascular and metabolic diseases. However, physical activity as an essential core component of secondary prevention (and rehabilitation) was not accepted in cardiac care until the second half of the past century.

After discharge from the acute hospital (phase I CR [World Health Organization; WHO]), phase II CR (WHO) is performed in special CR centers on an inpatient or outpatient basis.

Unfortunately, however, current health care studies show that the long-term adjustment of risk factors in cardiovascular patients is insufficient after cardiovascular events.^1,2 These risk factors are usually optimized by a short-term CR, but then prevention and aftercare in the home environment are increasingly forgotten, resulting in a deterioration of modifiable risk factors in the long term.³

Therefore, it seems particularly important to optimize phase III CR as long-term prevention and aftercare at the patient’s place of residence.

Current Situation in Germany

In Germany, phase III CR (WHO) is offered in special ‘ambulatory heart groups’ (AHG). The very first AHG was founded in Germany by a general practitioner in 1965.

The Federal Association for Rehabilitation (BAR), the national association of rehabilitation providers in Germany, has been promoting the participation of people with disabilities in the social benefit system since 1969. It coordinates and supports the cooperation of rehabilitation providers, imparts knowledge, and works on the further development of rehabilitation and participation. Members are pension, health and accident insurance fonds, the Federal Employment Agency, federal states, the federal working group of the integration offices and main welfare offices, the federal working group of the national social welfare and integration assistance agencies, the National Association of Physicians, and other social partners.

Indications for an AHG in Germany

The indications for joining an AHG in Germany are almost identical to phase II CR and are shown in Table 1.

Table 1.

Indications for an Ambulatory Heart Group (AHG) in Germany

Indication
After acute cardiac arrest/resuscitation
After acute coronary syndrome (acute myocardial infarction, unstable angina)
After coronary bypass surgery
In chronic coronary syndrome
After surgical or interventional heart valve replacement and correction
For patients with an implanted cardioverter defibrillator, resynchronization therapy and wearable defibrillator vest
After pulmonary vein isolation, catheter ablation or modification of atrial fibrillation, re-entry tachycardia, or ventricular tachycardia
In systolic or diastolic heart failure
For patients with ventricular assist devices
After heart transplantation
After surgery or intervention on the aorta (dissection, aneurysm)
After pulmonary artery embolism with or without deep vein thrombosis
In pulmonary hypertension of various causes
After myocarditis
For interventionally or surgically treated congenital heart defects

Definition of an AHG in Germany

The German Society for Prevention and Rehabilitation of Cardiovascular Diseases (DGPR) defines the AHG as ‘a group of a maximum of 20 cardiac patients under medical supervision and led by a qualified instructor, who meet at least once a week for movement training (rehabilitation sports) and which, taking into account its holistic use in rehabilitation, takes up therapeutic elements of stress management through relaxation techniques, a healthy diet also with the aim of weight loss (or stabilization), support in smoking cessation and regular disease-related information support as health-forming measures’.⁴

Since 1965, the number of AHGs in Germany has grown to approximately 6,000–9,000 groups, but the coronavirus disease 2019 (COVID-19) pandemic resulted in a significant but not officially calculated reduction. Patients included in the AHGs are those with coronary artery disease (CAD), those who have had a coronary artery bypass graft (CABG) and/or cardiac valve surgery including transcatheter aortic valve implantation (TAVI), and those with peripherial artery disease (PAD) and chronic heart failure (CHF), with severe metabolic syndrome and other conditions as shown in Table 1.

These concepts can and must be optimized; however, since October 2003, financial support from health insurance companies has been limited to a total of 90 sessions, during which the patients learn to independently perform heart-healthy exercises as an essential part of a healthy lifestyle.

Participating insurance companies pay approximately €10 for each of the 90 therapeutic units at 60–90 min each. Thereafter, the patient should be encouraged to continue participation at his/her own cost. According to current studies, only 13–40% of all patients attend an AHG after phase II CR.

Cardiac Diseases Including CAD and Physical Activity

The development of the AHG is closely linked to the history of treatment possibilities for CAD. Physical rest was the common treatment regimen after a heart attack until the 1960s, and the length of hospital stay by that time was usually 4–6 weeks or more.⁵ This approach was justified by findings from pathology, according to which a myocardial infarction (MI) would only be completely ‘scarred’ after 6 weeks.⁶ Only from this point on – in some cases even months later – was the patient allowed physical exertion again.

As early as 1786, William Heberden in Great Britain described that, in addition to opiates, regular physical activity in the form of 30 min of wood-chopping also led to alleviation of the symptoms of angina pectoris (AP).⁷

In 1870, Max Joseph Oertel, from Germany, was the first physician to call for physical activity in patients with CAD. His studies on daily climbing loads (‘terrain treatment’) showed a reduction in heart rate and blood pressure after just a 4-week treatment.⁸

In contrast, prolonged immobilization leads to a decrease in muscle mass and physical performance, an increased risk of thrombosis with pulmonary artery embolism, impaired lung function and a tendency towards orthostasis. To reduce these complications, Samuel Levine and Bernhard Lown from the United States of America (USA) recommended the so-called ‘armchair treatment’ for MI patients in 1951.⁹

In 1966, a 7-member international ad hoc committee called on the WHO to review the correctness of immobilization after MI, and Dieter Jeschke from Germany based his 1972 demands for early mobilization on the WHO recommendations that emerged from this in 1968.^5,10 In 1978, physical activity was finally recommended by American Medical Associations on day 2 or 3 after an uncomplicated MI.¹¹

Further important impulses for calculated training for MI patients were also set by the work of Hugo Knipping and Wildor Hollmann at the Institute of Circulation Research and Sports Medicine at the German Sports University in Cologne, which was founded in 1958.¹² Inspired by their work, Viktor Gottheiner from Israel performed a structured exercise therapy of relatively high intensity with patients completing luggage marches on Mount Tabor to an altitude of 588 m.¹³

The first evidence that targeted physical activity actually does not cause increased mortality was demonstrated by Herman K. Hellerstein in the USA in the mid-1960s.¹⁴ In addition, further studies not only disproved a possible increased risk, but showed that physical activity has positive effects on cardiac and psychosocial situations.^15,16

Development of AHGs in Germany

The very first AHG was founded in 1965 in Schorndorf, Germany, by the general practitioner and internal specialist Karl-Otto Hartmann. He integrated ‘his’ heart patients into a pre-existing ‘sports group for the disabled’ that he personally supervised, and then carried out gymnastic exercises and swimming training with them.¹⁷

At the same time, an AHG was set up in Berlin at the Institute for Preventive and Rehabilitative Cardiology by Weidner and Mellerowicz.¹⁸ The Heidelberg model followed under the sponsorship of the ‘homo ludens club’ (Latin: ‘the playing human’). Here, general information about CAD was provided in talks for heart patients and was then extended to include a rather cautious exercise therapy.¹⁹

In the former German Democratic Republic (GDR), corresponding developments were also taken up at an early stage. In the early 1970s, phase I and II CR (WHO) were successfully practised in many places; interdisciplinary treatment close to home followed step by step as a phase III CR, with the same positive experiences as in the former West Germany.²⁰ Other European countries also adopted CR (Sweden in 1967, Finland in 1970, and Austria in 1972).^21,22

In Germany itself, the Association for Rehabilitation was founded in 1958. Then, in 1976, the German Association for Cardiology Prevention and Rehabilitation was founded and renamed in 1990 to the DGPR, with 16 independent federal organizations.

Also, since 1976, the German Sports Confederation (DSB) and the German Disabled Sports Association (DBSB) have been providing training courses as ‘exercise and rehabilitation’ for AHG trainers. In 1979, the German Society for Sports Medicine and Prevention (DGSP) also started participation in and medical care for AHGs (as common curricula in the training of heart group physicians).

Meanwhile, many studies on secondary cardiovascular prevention show a possible positive direct influence of physical activity on CAD. Of particular interest are current studies on the influence of exercise on endothelial function.²³ In 2000, Hambrecht and co-workers in Germany showed an improvement in endothelial function in CAD patients with a 29% increase in coronary blood flow reserve after only 4 weeks of training.²⁴

A Cochrane meta-analysis from 2016 included 63 studies and 14,486 participants; exercise-based CR was associated with a reduction in cardiovascular mortality (risk ratio [RR] 0.74; 95% confidence interval [CI] 0.64–0.86) and a reduction in hospital admissions (RR 0.82; 95% CI 0.70–0.96).²⁵

Meta-analyses of the Cardiac Rehabilitation Outcome Studies (CROS, and CROS-HF) clearly proved that cardiovascular patients benefit from training-based CR.^26,27

Still, direct effects from an AHG have never been sufficiently investigated. There are no randomized controlled trials (RCT) on the effectiveness of an AHG. Reasons for this are that patients could not be randomized to ‘usual care’ for legal and ethical reasons, the voluntary renunciation of AHG participation creates selection and thus a scientific bias, and also unfortunately that funding for larger controlled trials in this area has so far never existed, although up to 9,000 already existing AHGs receive regular financing from the above-named insurance companies.²⁸

Only 1 investigation in the form of a case-control study looked at the long-term effects of an AHG back in 2002.²⁹ The control group (n=75) was selected by match-pairing from a group of 12,560 inpatients who matched essential medical criteria of the AHG participants (n=75) after an MI and/or CABG. The average observation duration was 7.5 years. The results showed that physical performance increased by an average of 50 W through AHG participation, with no changes in the control group (P<0.01). AHG participants reported fewer cardiac symptoms (P<0.01) and less exercise-induced AP (P<0.01). AHG participants had to take significantly fewer cardiac drugs at the time of follow up (AHG=3.06 vs. Control=3.81; P<0.01). In the AHG, fewer re-MIs were observed (AHG=3 vs. Control=19; P<0.01) and fewer interventions (such as percutaneous coronary intervention) had to be performed (AHG=6 vs. Control=19; P<0.05). In summary, cardiac morbidity in AHG was reduced by 54%, and therefore treatment costs were reduced by approximately 47%.

Table 2 shows the potential cardioprotective effects of regular physical activity.³⁰

Table 2.

Potential Cardioprotective Effects of Regular Physical Activity³⁰

Antiatherosclerotic	Psychological	Antithrombotic	Anti-ischemic	Antiarrhythmic
Improved lipids	Depression ↓	Thrombocyte adhesion ↓	Myocardial O2 demand ↓	Vagal tone ↑
Blood pressure ↓	Distress ↓	Fibrinolysis ↑	Coronary flow ↑	Adrenergic activity ↓
Obesity ↓	Social support ↑	Fibrinogen ↓	Endothelial function ↑	Heart rate variability ↑
Insulin sensitivity ↑		Blood viscosity ↓
Inflammation ↓

The main focus of AHG is exercise therapy (‘exercise-based’ CR). In the sense of so-called ‘comprehensive cardiac care’, elements in the areas of relaxation, smoking cessation, nutrition and psychosocial support, as well as disease-specific education, are also offered and regularly included.³¹ The aims of the AHG work are divided into somatic, functional, educational and psychosocial factors (Table 3).

Table 3.

Aims of the Ambulatory Heart Group (AHG) in Phase III Cardiac Rehabilitation (CR)³¹

Somatic / physical aims	Functional aims	Educational aims	Psychosocial aims
Improving movement restrictions caused by illness	Stabilization of physical and mental resilience for professional and everyday life	Improving knowledge about cardiovascular diseases and risk factors	Support of coping with the cardiovascular disease
Instructions for independently carrying out functional forms of exercise and training	Promote illness-adapted everyday activities and leisure activities	Development of a health-oriented competence	Entwicklung von Stressbewältigungsstrategien
Improvement or stabilization of cardiopulmonary resilience		Adaptation of eating, nutrition and enjoyment of food behavior	Developing appropriate stress management strategies
Positive influence on somatic risk and protection factors		Acquisition of practical skills for self-control and appropriate reactions to illness	Improvement of general well-being
Building up and improving body awareness		Motivation for a health-oriented behavior change
		Developing a comprehensive therapy adherence (compliance)
		Kowledge and control of emergency situations

Following CR after an acute event, patients aim to meet the set rehabilitation goals in groups of approximately 15–20 patients, who are instructed by a competent exercise therapist and attended by a physician. Whereas physical activity is the dominant aspect, psychosocial and educative elements are also integrated to stabilize secondary prevention. In their nearly 60-year history of existence, a close network of the current approximately 7,000 heart groups after COVID-19 has been established in Germany, treating well over 125,000 patients.

Elements of physical activity in an AHG include endurance (walking, cycling, outdoor activities) and resistance training, water therapy including swimming if feasible, coordination training, stretching and gymnastics. Local preferences by the participants and the availability of the given infrastructure of the AHG, either using the facilities of a hospital or phase II CR center, or a school or community sports hall, determine the precise framework. The average duration is 60–90 min, or sometimes 120 min per session. Participants are regulary asked about their current health status or new medical reports. Blood pressure, heart rates and perceived exertion scales, such as the Borg scale, are mandatorily checked at each exercise session.

Risk Stratification and (the Need for the) Development of New/Differentiated AHGs

Due to overall decreasing event rates during physical training/exercise of cardiovascular patients, it no longer seems necessary to have each AHG accompanied by a physician; however, before joining an AHG, an invididual risk stratification should be carried out. This was taken into account by the recent position paper of the German Cardiac Society in cooperation with the DGPR in 2021, and also strongly influenced by massive alterations in exercise and preventional medicine during and after the COVID-19 pandemic.³² Several AHGs did not reunite and continue their regular program after the end of the pandemic, leading to a significant decrease in the availability of AHGs in Germany, although no clear statistics have been published yet.

The Figure shows the proposed process of risk stratification for development of new/differentiated AHGs. It needs to be re-evaluated in these patients once per year.³²

Figure.

Model for risk stratification and care of ambulatory heart groups (AHG): risk stratification and development of new/differentiated AHGs.³² CCS, chronic coronary syndrome.

As a result, there will be 3 different AHGs: (1) Standard Group, only supervised by an AHG trainer (exercise therapist, with continuing education); (2) Group with ‘increased needs’, supervised by an AHG trainer (exercise therapist) and a physician (both with continuing education); (3) (High-risk or commonly called) Heart Failure Group, supervised by an AHG trainer (exercise therapist) and a physician (both with continuing education).

Indications for assignment to the Heart Failure Group include: severe heart failure (New York Heart Association [NYHA] III) in patients with moderate to severe reduced ejection fraction (HFrEF/left ventricular ejection fraction [LVEF] <40%; International Classification of Diseases [ICD] I50); severe right heart failure (e.g., chronic thromboembolic pulmonary hypertension [CTEPH] or primary pulmonary arterial hypertension [PAH]; ICD I50.0 and I27.28); patients with recurrent ventricular arrhythmias/SCD survivors with an implantable cardioverter defibrillator for 1 year (ICD I47.2 and I46.0); hypertrophic (obstructive) cardiomyopathy (HOCM/HCM) with/without an implantable cardioverter defibrillator (ICD I42/I42.1); moderate symptomatic valvular heart disease (ICD I34, I35, I36); or severe heart failure and intractable AP in ischemia or dyspnea when exercising below 6 METs (ICD I50 and I20).

A Standard Group has no requirement for the presence of a physician and includes the majority of stable and resilient patients, in particular, those with an LVEF≥50%. This group is led by a non-physician/AHG trainer (exercise specialist).

In addition, an automatic external defibrillator (AED) must always be on site, and the availability of an immediate call to the emergency services must be constantly ensured. The number of AHG participants should not exceed 20.

In the Group with increased needs, a permanent medical presence is required. This group is for patients for whom there are cardiovascular risk criteria based on the current S3 guidelines for CR and position papers of the European Society of Cardiology (ESC). Typical patients in this group are those with a reduced LVEF (<50%) and fewer symptoms (NYHA ≤II), or those with limited resilience who do not meet the criteria for the Heart Failure Group. The number of AHG participants should not exceed 20.

Last, in the Heart Failure AHG, patients who are considered high risk are permanently monitored by specially trained AHG trainers (exercise specialists) and physicians. Typical patients are those with clearly symptomatic heart failure (NYHA III) and severly reduced LVEF (<40%). The number of AHG participants should not exceed 12 (reduced number).^32,33

Role of AHG Trainers (Exercise Specialists)

Each AHG is led by a trained non-medical AHG trainer (exercise specialist with a mandatory personal continuity towards the AHG).

The various qualification requirements are controlled by the Federal Working Group for Rehabilitation (BAR). Qualifications that entitle a trainer to lead an AHG are ‘Heart Group Leader of the DGPR’, ‘Heart Group Leader DGPR – Internal Medicine’, or ‘Exercise Instructor B – Sport in Rehabilitation – Sport in Heart Groups and Internal Medicine’. All of these qualifications are officially recognized by medical institutions such as the DGPR.

AHG trainers must be trained in emergency care for cardiovascular patients. In addition, they have to know and explain contraindications for physical training in cardiovascular diseases according to the current guidelines (e.g., acute infections, cardiac decompensation) and educate the participants in this regard.

They also teach preventive medical aspects beyond physical training (e.g., education on healthy nutrition or smoking cessation). Physicians are not absolutely mandatory for this in the long term. Prevention programs primarily carried out by non-physician employees have been proven to be very effective. In the Intensive Prevention Program study, having non-physician ‘prevention assistants’ as the primary contacts in the context of a long-term prevention program after MI showed a highly significant improvement in the control of cardiovascular risk factors.²

Further Challenges

In the future, special emphasis has to be placed on the recruitment of more patients into AHGs, especially those in known under-represented groups (e.g., women, older patients, patients with low socioeconomic status). Furthermore, more AHGs have to be established for patients with special needs (e.g., younger patients with congenital heart diseases).

Further current challenges for phase III CR including AHGs also include remuneration and financing due to significantly increased energy and personnel costs, especially since 2022, and personnel/staff acquisition (exercise therapists/physicians).^2,32

Continuous advertising for participation in AHGs is now necessary (especially after the COVID-19 pandemic), as AHGs are no longer a sure-fire success like they were in recent decades.

In 2019, special AHGs for patients with high cardiovascular risk (CHF) were established.³³

To date, the efficiency of AHG participation has still not been sufficiently investigated after almost 60 years of existence. Funding for larger controlled trials is essential.

Acknowledgments

The author thanks Professor Haruki Itoh, MD, PhD, FACC, FESC, FJCC, FJSC, Consulting Cardiologist, Nagareyama Morinomachi Clinic, Keyakizakaue Medical and Dental Clinic for the invitation to speak at the Japanese Association of Cardiac Rehabilitation (JACR) 2024 Annual Meeting/AsiaPRevent (Asian International Session), July 13–14, in Kobe. The author also thanks the Japan Heart Club, Shibuya-ku, Tokyo, for its assistance during the JACR 2024 Annual Meeting, and Professor Masataka Sata, MD, PhD, Tokushima University, Institute of Biomedical Sciences, Department of Cardiovascular Medicine as the Chair of the JACR 2024 Annual Meeting/AsiaPRevent (Asian International Session) in Kobe. The author extends his sincere thanks to Professor Birna Bjarnason-Wehrens, German Sports University, Cologne, Germany, for support in preparing and supervising the original presentation. The author also extends his gratitude to Philipp Heinzel, ergoline academy Bitz, Germany, for his support in continuing education activities about physical exercise in prevention and rehabilitation in cardiac patients. During the preparation of this manuscript, the author is especially grateful to Sarah L. Kirkby, Loehne, Germany, for proofreading the article.

Disclosures

The author declares that he has no conflicts of interest to disclose.

IRB Information

As this is a ‘Statement / Opinion’ paper, there was no need to involve an ethics committee.

Data Availability

This manuscript reports on the results of other clinical trials. Therefore, the individual deidentified participant data (including data dictionaries) cannot be shared. No participant data were used.

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