A randomized study to compare ramp versus burst antitachycardia pacing therapies to treat fast ventricular tachyarrhythmias in patients with implantable cardioverter defibrillators: the PITAGORA ICD trial.

BACKGROUND: In patients with implantable cardioverter-defibrillators (ICDs), antitachycardia pacing (ATP) is highly effective in terminating fast ventricular tachycardias (FVTs) and lowers the use of high-energy shocks, without increasing the risk of arrhythmia acceleration or syncope. METHODS AND RESULTS: The aim of the PITAGORA ICD trial was to randomly compare 2 ATP strategies (88% coupling interval burst versus 91% coupling interval ramp, both 8 pulses) in terms of ATP efficacy, arrhythmia acceleration, and syncope. Two hundred six ICD patients (83% male, 67+/-11 years) were enrolled. FVT episodes with cycle lengths between 240 and 320 ms were treated by 1 ATP sequence and, in the event of failure, by shocks. Over a median follow-up of 36 months, 829 spontaneous ventricular tachyarrhythmia episodes were detected in 79 patients. Episode review identified 595 episodes as true ventricular arrhythmias in 72 patients; devices classified 111 (18.7%) episodes as VF, 216 (36.3%) as FVT, and 268 (45.0%) as VT. Fifty-six patients had 214 treated FVT episodes-2 FVTs self-terminated before ATP release; 44 (79%) of these had at least 1 effective ATP intervention, and 34 (61%) were spared ICD shocks. Burst terminated 100 of 133 (75.2%) FVT episodes, whereas ramp terminated 44 of 81 (54.3%; P=0.015). Acceleration occurred in 9 of 214 (4.2%) FVT episodes treated: 6 episodes in 3 ramp patients and 3 episodes in 3 burst patients. Two patients-1 in each group-suffered 1 syncopal event associated to a nonterminated FVT episode. CONCLUSIONS: Burst is significantly more efficacious than ramp in terminating FVT episodes. As the first therapy for FVT episodes, ATP carries a low risk of acceleration or syncopal events.

Randomized comparison between Ramp and Burst+ atrial antitachycardia pacing therapies in patients suffering from sinus node disease and atrial fibrillation and implanted with a DDDRP device.

AIMS: Atrial tachycardia and flutter frequently occur in association with atrial fibrillation and may be treated by overdrive pacing in patients who receive pacemakers with antitachycardia pacing (ATP) capabilities. The PITAGORA trial was a multi-centre, randomized, cross-over study aimed at comparing two different ATP modes for atrial tachyarrhythmia (AT) termination in patients suffering from sinus node disease (SND). METHODS AND RESULTS: One hundred and seventy-six patients (72 M, age 71+/-9 years) received a Medtronic AT500 pacemaker. All patients were on class IC or III antiarrhythmic drugs. After a 5-month observation period, 170 patients were randomized to either Ramp or Burst+ ATP therapy; 4 months later they crossed over. One hundred and fifty-seven patients completed the 13 months of follow-up; 114 (72.6%) suffered 6088 AT episodes. In 75 patients, 1904 AT episodes were treated and 934 (49.1%) successfully terminated. The median value of individual patients' ATP efficacy was 60%. Burst+ terminated 387 out of 873 AT episodes (44%) in 58 patients. Ramp terminated 547 out of 1031 AT episodes (53%, P<0.001) in 56 patients. Ramp efficacy was significantly (P<0.01) and directly correlated with AT cycle length (ATCL), whereas Burst+ efficacy was not. Ramp showed higher (P<0.001) termination efficacy than Burst+ for ATCL >240 ms. Quality of life, as measured by the EuroQoL questionnaire, and number of symptoms significantly improved in the overall population. This improvement was significantly higher in patients with ATP efficacy >60%. CONCLUSION: In patients suffering from SND and AT, Ramp therapy shows higher termination efficacy than Burst+ therapy in AT episodes with ATCL >240 ms. Further studies are required to show the impact of ATP on clinical outcomes.