Abstract

The authors have carried out a retrospective analysis on 18.588 athletes who came to the Sports Medicine Centre of Casalecchio di Reno for granting athletic sports ability in the last twenty years, in order to find left bundle branch block cases. Prevalence of left bundle branch block has appeared to be very low, corresponding to 3,76 cases every ten thousand people analysed. They were 7 athletes, 2 with incomplete left bundle branch block, with a mean follow-up of 7,3 years. The study has been limited to the 5 athletes with complete left bundle branch block, aged 37-61 years at the time of diagnosis, who undergone myocardial perfusion study with MRI. In no any athlete was diagnosed an organic disease referable to left bundle branch block; ischemic cardiopathy was not documented neither at the time of left bundle branch block diagnosis nor during follow-up, as well as in no any case has been registered an evolution of left bundle branch block towards complete atrio-ventricular block. The only athlete with precordial pain and exertional dyspnea showed a correlation between left bundle branch block appearance and symptoms. The study has shown an evolution of frequency-dependent left bundle branch block in two of four cases: one towards complete left bundle branch block at rest, in the other case towards a reduction of cardiac frequency to which left bundle branch block manifest itself. On the other hand, in one athlete left bundle branch block threshold has not changed: besides he's the athlete with the shorter follow-up (2 years), while in the oldest athlete, frequency-dependent left bundle branch block did not recurred in the following two MET performed during 11 years. Myocardial perfusion study with MRI showed high sensitivity, allowing identification of a functional and anatomic pattern of left bundle branch block in four of five cases and giving precious informations of segmentary and global cardiac contractile function. The authors consider these aspects very interesting and they therefore hope that myocardial perfusion study with MRI will be performed not only at rest, but also after pharmacologic stress to arise the possibility of ischemic alterations identification with first-pass technique. As concerns MRI specificity, the authors underline the need of a better knowledge of the method itself and testing it with a larger number of left bundle branch block cases. Anyway the authors consider myocardial perfusion study with MRI to be included in the diagnostic protocol of complete left bundle branch block as an alternative to EES, because it is less invasive, or at least performing it before the EES, owing to his high sensitivity. As regards incidence of complete left bundle branch block in the sportive population of our series (18.588), an extremely low number of cases is confirmed, even if frequency-dependent left bundle branch block could not be identified because of non-routinary use of MET in the athletic ability protocol of ministerial law by decree 18.02.82. As regards the meaning of complete left bundle branch block, in addition to ischemic cardiopathy and fibrotic diseases of interventricular septum, the cause could also be related to microvascular alterations and interstitial alterations atthe level of interventricular septum; nevertheless it seems we could exclude a worsening of clinical status due to sports practice, even agonistic. We therefore consider that, in the absence of symptoms and arrythmic and macroscopic alterations of the heart, it could be issued athletic ability, even to athletes that practice medium-high cardiovascular effort sports, recommanding semestral clinical controls.