Half a century of continuous pacing: a living witness to the evolution of a technology.

To chart the development of pacing technology and its pitfalls we present the experience of a patient who has benefitted from it but also suffered as a result of it from its earliest days. A 53-year-old physician was referred to us with obstruction of the superior and inferior vena cava on a background of more than 50 years of continuous ventricular pacing and 24 previous pacemaker-related interventions. In a single surgical procedure, his existing pacing system and redundant leads were extracted, the superior vena cava was reconstructed, and a new biventricular pacing system with epicardial leads was implanted. Pacemakers can maintain life and preserve the quality of life for many decades. The quality of this therapy has improved due to advances in the technology and in techniques. Maintaining safe pacing in the very long term requires labour, patience, and ingenuity.

Permanent His Bundle Pacing: The Past, Present, and Future.

Long-term right ventricular (RV) apical pacing has been associated with an increased risk of death, heart failure, and atrial fibrillation (AF). Alternative sites for RV pacing have not proven to be superior to RV apical pacing. Cardiac resynchronization therapy (CRT) using a biventricular (BiV) lead system is indicated for patients with a low left ventricular ejection fraction and QRS prolongation, but there remains about a 25-30% nonresponse rate. CRT has been less effective for nonleft bundle branch block conduction delay and with normal/low normal left ventricular function. Over the past decade, there have been more data on the feasibility and advantages of pacing at the His Bundle (HB) region. We review the anatomy and physiology of the HB, the available data on permanent HB pacing, its current and potential future applications.

Cardiac resynchronization therapy. Indications and contraindications.

Progress in medical therapy wouldn't be possible without the contribution of the scientific community. Several randomized controlled trials have led to our current guidelines. Specifically, COMPANION and CARE-HF trials involved a turning point for cardiac resynchronization therapy, which became well recognized for the treatment of heart failure patients with QRS≥120ms, ejection fraction≤35%, and sinus rhythm to reduce hospitalizations and all-cause mortality. New indications were then established for atrial fibrillation, pacemaker-dependent, and mildly symptomatic patients, but new challenges should be addressed, namely reducing complication and nonresponder rates. To achieve this, further studies and new implant techniques are under investigation.

Past, present and future of cardiac resynchronization.

The growing interest in dyssynchrony and cardiac resynchronization therapy has opened the field of cardiac stimulation to new haemodynamic indications. French investigators have played a key role in the formulation of new concepts, all arising from clinical observations, and the development (in collaboration with industry) and clinical evaluation of resynchronization devices. This review summarizes recent knowledge and perspectives pertaining to atrial, atrioventricular and ventricular dyssynchrony and resynchronization. Some of these concepts have been validated by robust clinical evidence, on the basis of which scientific recommendations have been formulated. Other concepts have been less successful but probably merit further attention.

Past, present, and future of CRT.

Cardiac resynchronization therapy is a key non-pharmacological treatment strategy for drug-refractory moderate-to-severe symptomatic heart failure in the presence of compromised left ventricular function and ventricular conduction delay. Because not all patients with conventional criteria benefit from CRT, continuous efforts have been directed toward improving patient selection; in particular, emerging echocardiographic criteria such as regional and global myocardial strains are being investigated to better predict CRT response. In the meantime, growing evidence from large randomized controlled trials (RCTs, REVERSE, and MADIT-CRT) has demonstrated that even mildly symptomatic patients may benefit from CRT. The role of CRT in heart failure patients with narrow QRS, however, remains to be defined in the scheme of larger RCTs (such as EchoCRT) as the ones carried out thus far (RethinQ and ESTEEM-CRT). Important experimental data derived from animal heart failure models are gradually elucidating the complex pathophysiological basis of cardiac dyssynchrony, which involves diffuse alterations from genome to structure. At the same time, technological breakthroughs, such as wireless endocardial cardiac pacing, will render the prospect of delivering CRT more precisely and more effectively, a reality in the near future.

[On the history of heart failure]. / Zur Geschichte der Herzinsuffizienz.

The heart is by far the organ that is best known and has been identified for a long time. Myogenic weakness of the heart muscle pump with left-ventricular dysfunction remains the cardiac disease with the poorest prognosis while increasing in prevalence and incidence. Aside from all sorts of mystic treatment attempts and dubious herbal medicine, bloodletting was established early on as a superior remedy, which was applied in response to almost all cardiac illnesses. The first and perhaps most important cardiac drug was digitalis, the glycoside of the red and even more so of the white foxglove, described in 1552 by Leonhart Fuchs. In the 1980s, vasodilators and inotropic drugs supplemented the classical medications digitalis and diuretics. ACE inhibitors and beta-receptor blockers were added in the 1990s; at the turn of the millennium, the cardiac resynchronization therapy (CRT) and left-heart assist systems were developed; lately, there have been cellular and genetic approaches as well as xenotransplants. Preliminary results with stem cell technology are encouraging; however, it will be years until a clinical application-if it will happen at all.