#include <amxmod>
 
#define VOL_NULL   0.0
#define VOL_MID    0.5
#define FLAG_NONE  0
#define PITCH_NONE 0
#define CHAN_HEART CHAN_VOICE
 
new const g_heartbeat[] = "player/heartbeat1.wav"
 
new g_pcvarLowHp
 
public plugin_precache() {
  precache_sound(g_heartbeat)
}
 
public plugin_init() {
  register_plugin("Low Hp Heart Beat", "0.1", "DokTor")
 
  g_pcvarLowHp = register_cvar("heartbeat_hp", "25")
 
  register_event("Damage", "e_Damage", "be", "2>0")
  register_event("DeathMsg", "e_DeathMsg", "a")
}
 
public e_Damage(id) {
  if( get_user_health(id) > get_cvarptr_num(g_pcvarLowHp) )
    return
 
  emit_sound(id, CHAN_HEART, g_heartbeat, VOL_NULL, ATTN_NONE, SND_STOP, PITCH_NONE)
  emit_sound(id, CHAN_HEART, g_heartbeat, VOL_MID, ATTN_NORM, FLAG_NONE, PITCH_NORM)
}
 
public e_DeathMsg() {
  emit_sound(read_data(2), CHAN_HEART, g_heartbeat, VOL_NULL, ATTN_NONE, SND_STOP, PITCH_NONE)
}