Muscular counterpulsation: preliminary results of a non-invasive alternative to intra-aortic balloon pump

Acute Beneficial Effects of Muscular Counterpulsation in Patients with Coronary Heart Diseases

This prospective pilot study was designed to investigate the acute hemodynamic effects and clinical applicability of muscular counterpulsation (MCP), a one-shot procedure for biomechanical circulatory support. The study included 17 consecutive patients with coronary artery disease (CAD) and impaired ejection fraction (EF ≤45%) who underwent elective coronary artery bypass grafting (CABG). Patients were divided into control ( n  = 7) and treatment ( n  = 10) groups. MCP was applied through adhesive skin electrodes to the thighs and calves with a battery-powered, portable, ECG-triggered device for 15 minutes prior to general anesthesia. Standard ECG and invasive hemodynamic data were obtained from all patients. MCP was well tolerated in all patients, with no complications. Patients receiving MCP exhibited better cardiac function as indicated by reduced systemic vascular resistance and an augmented cardiac stroke index (+10%), which was maintained over time. After inducing general anesthesia via endotracheal intubation, the treatment group exhibited a reduced after-load (systemic vascular resistance index -28% and mean arterial pressure -10%) with increased left ventricular efficiency (stroke index/left ventricular stroke work index, +22%). Our findings indicate that MCP method was safe and easy to use in this patient population. In conclusion, a one-shot application of MCP prior to anesthesia was associated with an improvement in cardiac pump function and myocardial contractility.

Acute effects of muscular counterpulsation therapy on cardiac output and safety in patients with chronic heart failure

Our aim was to investigate acute effects of muscular counterpulsation (MCP) on hemodynamic parameters and to evaluate its safety in regard to myocardial integrity and interferences with implanted rhythm devices in patients with chronic heart failure (CHF). A total of 22 patients with CHF (16 male, 67.8 ± 9.5 years, New York Heart Association [NYHA] class II + III, left ventricular ejection fraction 29.6 ± 6.6%) were treated with MCP for 3 consecutive days for 45 min, while hemodynamic parameters were measured noninvasively by bioimpedance (Task Force Monitor). Laboratory control and a complete device testing were performed prior to the first and after the third treatment. In addition, continuous rhythm device interrogation was performed online during the first MCP application. During each application, a significant increase in cardiac output (CO; average change +2.08 ± 2.33 L/min, P < 0.05) was documented. This increase was due to a decrease of total peripheral resistance (-336 ± 530 dyn × s/cm(5) , P < 0.05), to an augmented stroke volume (+8.35 ±  20.86 mL, P = n.s.), and an increase in heart rate (+17.12 ± 21.12 bpm, P < 0.05). Cardiac markers and enzymes were within normal limits at all times and did not increase during treatment. MCP stimuli were monitored using surface electrocardiogram, and no abnormal sensing or pacing events occurred. MCP acutely improves CO in patients with stable CHF. No adverse influence on myocardial integrity was observed nor were any inappropriate sensing or pacing artifacts detected in patients with implanted rhythm devices.

The units of measurement of the ventricular stroke work: a review study

BACKGROUND

The ventricular stroke work refers to the work done by the left or right ventricle to eject the volume of blood during one cardiac cycle, called stroke volume. Sarnoff and Berglund were one of the first to calculate the stroke work from the pressure volume diagram in 1954. However, they published a wrong unit of measurement for the stroke work, namely gram meter.

METHODS AND RESULTS

The present work reviewed 779 scientific publications between May 1954 and January 2010 which used the left or right ventricular stroke work as a variable. Interestingly, the majority (87.2%) of scientific papers since 1954 have either copied this (or a similar) wrong unit of measurement or have invented another one. Only 12.8% of the publications gave a correct unit.

CONCLUSION

The present search in scientific literature demonstrates that the haemodynamic variable ventricular stroke work, which is used daily by thousands of medical doctors and scientists, was specified in an incorrect manner for 56 years in the majority of scientific papers. A correct unit of measurement, of course, is an imperative condition when comparing scientific papers. The aim of this publication is the elimination of incorrect units of measurement of the ventricular stroke work variable in all future scientific papers. Moreover, the present work facilitates the interpretation of at least some of the studies containing the ventricular stroke work variable published up to now.

Therapeutic value of muscular counterpulsation after coronary bypass grafting operation

OBJECTIVE

Coronary artery bypass grafting continues to be the operation of choice in patients with severe multiple coronary artery disease. However, there are several unresolved issues such as treatment of postoperative heart failure following bypass surgery. There is worldwide interest in evaluating new treatment methods for this condition. The objective is to determine the effect of a new external, bioassisted circulation-muscular counterpulsation (MCP) method in patients with ischemic heart disease (IHD) undergoing coronary artery bypass grafting (CABG).

METHODS

Fifty patients (age 54 +/- 8) undergoing CABG were included in the present analysis. Patients were randomized into two groups: A control group (n = 20) receiving standard postoperative treatment without counterpulsation and a treatment group (n = 30) undergoing MCP with a cardio-synchronized pulse generator using stimulation electrodes on the lower extremities. Treatment was 30 minutes daily for the eight initial postoperative days in addition to standard therapy. In all patients, a resting electrocardiogram (ECG), two-dimensional echocardiography, and impedance plethysmography of the forearm were carried out pre-CABG and on the eighth postoperative day.

RESULTS

Follow-up was completed in 94% of the patients. Two patients of the control and one of the treatment group refused follow-up examination. MCP treatment resulted in a 36% decrease of systemic vascular resistance (p < 0.001) compared to a 16% decrease (p = 0.011) in the control group. Postoperative complications occurred in one (3%) patient of the treatment group and in seven (39%) patients of the control group. Compared to the control group, patients in the treatment group had a 28% shorter postoperative hospital stay (12.0 +/- 4.6 days) than in the control group (16.8 +/- 4.4 days) (p < 0.001).

CONCLUSIONS

MCP represents a new, noninvasive, ECG-triggered circulation support system, which is effective for achieving hemodynamic improvement via afterload reduction. The use of MCP decreases postoperative complications and significantly shortens the hospital stay.

ECG-triggered skeletal muscle stimulation improves hemodynamics and physical performance of heart failure patients

BACKGROUND

Muscular counterpulsation (MCP) was developed for circulatory assistance by stimulation of peripheral skeletal muscles. We report on a clinical MCP study in patients with and without chronic heart failure (CHF).

METHODS AND RESULTS

MCP treatment was applied (30 patients treated, 25 controls, all under optimal therapy) for 30 minutes during eight days by an ECG-triggered, battery-powered, portable pulse generator with skin electrodes inducing light contractions of calf and thigh muscles, sequentially stimulated at early diastole. Hemodynamic parameters (ECG, blood pressure and echocardiography) were measured one day before and one day after the treatment period in two groups: Group 1 (9 MCP, 11 no MCP) with ejection fraction (EF) above 40% and Group 2 (21 MCP, 14 no MCP) below 40%. In Group 2 (all patients suffering from CHF) mean EF increased by 21% (p<0.001) and stroke volume by 13% (p<0.001), while end systolic volume decreased by 23% (p<0.001). In Group 1, the increase in EF (6%) and stroke volume (8%) was also significant (p<0.05) but less pronounced than in Group 2. Physical exercise duration and walking distance increased in Group 2 by 56% and 72%, respectively.

CONCLUSIONS

Noninvasive MCP treatment for eight days substantially improves cardiac function and physical performance in patients with CHF.