“…When a patient develops VF the chances of successful electric shock treatment depend mainly upon whether or not left ventricular failure co-exists, as shown in Table 1, and as has been noted by others [11,14,17,20,22,23,26,27,32]. Episodes of VF unaccompanied by left ventricular failure are termed "primary" events, to distinguish them from episodes associated with left ventricular failure to which the term "complicating" has been applied [27].…”