Israel Medical Association Journal

Background: The predictive value of electrophysiologic studies depends on the aggressiveness of the programmed ventricular stimulation protocol.

Objectives: To assess if non-inducibility with an "aggressive" protocol of PVS[1] identifies post-infarction patients with low ejection fraction (EF[2] ≤ 30%) who may safely be treated without implantable cardioverter defibrillator.

Methods: We studied 154 patients during a 9 year period. Our aggressive PVS protocol included: a) stimulus current five times the diastolic threshold (≤ 3 mA) and b) repetition of double and triple extrastimulation at the shortest coupling intervals that capture the ventricle.

Results: Sustained ventricular tachyarrhythmias were induced in 116 patients (75.4%) and 112 (97%) of them received an ICD[3] (EPS[4]+/ICD+ group). Of the 38 non-inducible patients, 34 (89.5%) did not receive an ICD (EPS-/ICD- group). In comparison to the EPS+/ICD+ group, EPS-/ICD- group patients were older (69 ± 10 vs. 65 ± 10 years, P < 0.05), had a lower EF (23 ± 5% vs. 25 ± 5%,  P < 0.05) and a higher prevalence of left bundle branch block (45.5% vs. 20.2%, P < 0.005). Follow-up was longer for EPS+/ICD+ patients (40 ± 26 months) than for EPS-/ICD- patients (27 ± 22 months) (P = 0.011). Twelve EPS+/ICD+ patients (10.7%) and 5 EPS-/ICD- patients (14.7%) died during follow-up (P = 0.525). Kaplan-Meier survival curves did not show a significant difference between the two groups (P = 0.18).
Conclusions: The mortality rate in patients without inducible VTAs[5] using an aggressive PVS protocol and who did not undergo subsequent ICD implantation is not different from that of patients with inducible arrhythmias who received an ICD. Using this protocol, as many as one-fourth of primary prevention ICD implants could be spared without compromising patient prognosis

Background: Radiofrequency ablation has been suggested as first-line therapy in the management of accessory pathways. There are limited data on the results of ablation over years of experience.

Objectives: To assess the results and complications following RFA[1] of APs[2] performed in our institution over a 14 year period.

Methods: RFA was performed using deflectable electrode catheters positioned at the mitral or tricuspid annulus. The site of the AP was localized by electrophysiological study and radiofrequency energy was applied via the tip of the catheter

Results: The study cohort comprised 508 consecutive patients (64.2% males, mean age 33.6 ± 15.1 years) who underwent 572 RFA procedures for ablating 534 APs. A single AP was found in 485 (95.5%) patients while multiple APs were noted in 23 patients (4.5%). The APs were manifest, concealed or intermittent in 46.8%, 44.4% and 8.8% of cases, respectively. AP distribution was as follows: left free wall (56.6%), posteroseptal (23%), right anteroseptal (7.9%), right free wall (6.2%), midseptal (3.4%) and right atriofascicular (3.0%). Acute successful rates for a first or multiple ablation attempts were 93.1% and 95.3%, respectively. At a first ablation attempt, acute success and failure rates were the highest for midseptal (100%) and right atriofascicular (12.5%) APs respectively. Right anteroseptal APs were associated with the highest rate (23.9%) of discontinued or non-attempted procedures. Recurrent conduction in an AP after an initial successful ablation was observed in 9.9% of cases; it was the highest (24.2%) for right free wall APs and the lowest (5.0%) for left free wall APs. During follow-up (85 ± 43 months), definite cure of the AP was achieved in 94.9% of cases following a single or multiple procedures: midseptal (100%), left free wall (98%), right free wall (97%), posteroseptal (92.7%), right atriofascicular (87.5%) and right anteroseptal (78.5%). A non-fatal complication occurred in 18 patients (3.5%), more frequently in females (6.6%) than in males (1.8%) (P < 0.01). The two major complications (pericardial effusion and myocardial ischemic events) mainly occurred during RFA of a left free wall AP using a retrograde aortic approach. Catheter-induced mechanical trauma to APs was observed in 56 cases (10.5%). Mechanical trauma mainly involved right atriofascicular (43.8%) and right anteroseptal (38.1%) APs and contributed to the low success rate of RFA at these AP locations. During the 14 year period, our learning curve was achieved quickly in terms of success rate, although the most significant complications were observed at the beginning of our experience.

Conclusions: The results of this study confirm the efficacy and safety of RFA and suggest that it is a reasonable first-line therapy for the management of APs at any location.

Objectives: To report a 14 year experience of RFA[2] of the slow pathway in patients with AVNRT treated in our laboratory.

Methods: A total of 901 consecutive patients (aged 9–92, mean 50.8 ± 18.2 years) underwent RFA of the slow pathway. All patients had sustained AVNRT induced with or without intravenous administration of isoproterenol. A standard electrophysiologic method with three diagnostic and one ablation catheter was used in 317 patients (35.2%); in the remaining 584 patients (64.8%), only two electrode catheters (one diagnostic, one ablation) were used ("two-catheter approach").

Results: Catheter ablation of the slow pathway abolished AVNRT induction in 877 patients (97.3%). In 14 patients (1.6%) the procedure was discontinued while in 10 (1.1%) the procedure failed. In 864 patients (95.9%) there were no complications. Transient or permanent AV block occurred during the procedure in 31 patients (3.4%), of whom 8 (0.9%) eventually required pacemaker insertion (n=7) or upgrade of a previously implanted VVI pacemaker (n=1) during the month following the procedure. The number of catheters used did not significantly affect the rate of results or complications of the ablation procedure. The success and complication rates remained stable over the years, although a significant trend for increased age and associated heart disease was observed during the study period.

Conclusions: The results of this single-center large study, which included patients with a wide age range, showed results similar to those of previous studies. The use of a "two-catheter approach" (one diagnostic and one ablation) was as effective and safe as a multi-catheter approach.

Background: Chlorpromazine is a dopamine-receptor antagonist antipsychotic agent. Because of its strong alpha-blocking and sedative actions, it has also been used as emergency therapy for extreme arterial hypertension. Published reports to date have included very small numbers of patients (i.e., 5–30).

Objectives: To analyze data on almost 500 patients who received intravenous chlorpromazine for the emergency treatment of uncontrolled symptomatic hypertension in the pre-hospital setting.

Methods: We reviewed data from 496 consecutive patients who received intravenous chlorpromazine as emergency therapy for uncontrolled symptomatic hypertension. Chlorpromazine was injected intravenously. The dose was 1 mg every 2–5 minutes until the systolic pressure was -<140 mmHg and the diastolic pressure -<100 mmHg with alleviation of symptoms.

Results: The mean dose of chlorpromazine administered was 4.5 +- 5 mg (range 1–50 mg). Only 33 patients (7%) required >10 mg. Chlorpromazine reduced the systolic blood pressure from 222.82 +- 26.31 to 164.93 +- 22.66 mmHg (P < 0.001) and the diastolic blood pressure from 113.5 +- 16.63 to 85.83 +- 11.61 mmHg (P < 0.001). The sinus rate decreased from 97.9 +- 23.5 to 92.2 +- 19.7 beats per minute (P < 0.001). These results were achieved within the first 37 +- 11 minutes.

Conclusions: Intravenous chlorpromazine is safe and effective when used as emergency treatment for uncontrolled symptomatic hypertension.