Evidence for partial sympathetic cardiac reinnervation following cardiac transplantation

Syncopal high-degree AV block treated with catheter RF ablation without pacemaker implantation

A 23-year-old-female patient had undergone a very successful gastric banding surgery to treat obesity. Six months later she began to present recurrent syncope due to very frequent, intermittent high-degree AV block referred to as pacemaker implantation. The electrophysiological study showed impaired AV nodal conduction but the His-Purkinje conduction was preserved. Partial catheter radiofrequency ablation of the cardiac autonomic nervous system guided by spectral endocardial mapping (cardioneuroablation) was performed. The electrophysiological parameters were normalized. Holter recordings were normal and the patient was asymptomatic with normal life without pacemaker implantation in a follow-up 21 months later.

"Cardioneuroablation"--new treatment for neurocardiogenic syncope, functional AV block and sinus dysfunction using catheter RF-ablation

Cardiac neuroablation is a new technique for management of patients with dominantly adverse parasympathetic autonomic influence. The technique is based on radiofrequency (RF) ablation of autonomic connections in the three main ganglia around the heart. Their connections are identified by Fast-Fourier Transforms (FFTs) of endocardial signals: sites of autonomic nervous connections show fractionated signals with FFTs shifted to the right. In contrast, normal myocardium without these connections does not show these features. RF-ablation is thought to inflict permanent damage on the parasympathetic autonomic influence because its cells are adjacent to the heart whereas sympathetic cells are remote. Twenty-one patients with a mean age of 48 years, neurally mediated reflex syncope in six, functional high grade atrioventricular block in seven and sinus node dysfunction in 13 (there is overlap between the second and third groups) were treated. Follow-up for a mean of 9.2 months demonstrated success in all cases with relief of symptoms. No complications occurred.

Acute cardiovascular responses to leg-press resistance exercise in heart transplant recipients

BACKGROUND

Reduced skeletal muscle strength is characteristic of individuals following heart transplantation. Weight lifting exercise has been demonstrated as an effective means by which to increase muscular strength in other cardiac patients but the appropriateness of this form of exercise in heart transplant patients has not been investigated. The purpose of this study was to describe the cardiovascular responses of heart transplant patients to a single, prolonged bout of weight lifting training.

METHODS

Twenty-three heart transplant recipients were stratified into early (Early; 3 months; n=6), intermediate (Intermediate; 1-3 years; n=7) and late (Late; 5-14 years; n=10) post transplant groups and studied in four experimental conditions: supine rest, upright rest, single leg-press exercise (28 repetitions over 2 min 20 s at 50% 1 repetition maximum) and recovery. Swan-Ganz catheterization allowed measurement of right heart pressures and cardiac output by thermodilution. Systemic arterial pressures and heart rate were measured continuously using a non-invasive finger cuff.

RESULTS

Cardiac output increased by 30, 40 and 54% during exercise in Early, Intermediate and Late, respectively. Heart rate increased by 4.5% in Early compared to 11 and 16% increases in Intermediate and Late. At peak exercise, systolic blood pressures reached average values of 179+/-9, 180+/-14 and 176+/-8 mmHg in Early, Intermediate and Late, respectively. Average mean pulmonary artery pressure did not exceed 30 mmHg and average pulmonary wedge pressure did not exceed 15 mmHg in any group during the exercise.

CONCLUSIONS

These observations indicate that a lengthened set of single leg-press exercise at a moderate lifting intensity can be performed within safe and acceptable physiological limits in patients following heart transplantation. To better address the specific rehabilitation needs of heart transplant recipients, future research should focus on developing training programs which include weight lifting exercise.