Table 2.
Time course and verapamil dosing for participants developing AV block.
| Case 1: 11-year-old, 31 kg at randomization | ||||||
|---|---|---|---|---|---|---|
| Weeks since verapamil started | Baseline | 6 | 24* | 27 | ||
| Verapamil (mg) [mg/kg] | 0 | 120 [3.4] | 240 [6.2] | 0 | ||
| PR interval on ECG (ms) | 136 | 124 | 340 | 130 | ||
| ECG report | Normal | Normal | 1st degree heart block | Normal | ||
| Blood Pressure (mmHG) Systolic/Diastolic** | 99/54 | 116/57 | 107/59 | 107/59 | ||
| Heart Rate (bpm)** | 99 | 102 | 79 | 79 | ||
| Case 2: 17-year-old, 96 kg at randomization | ||||||
| Weeks since verapamil started | Baseline | 5 | 22 | 22 + 1 day | 26 | 49 |
| Verapamil (mg) [mg/kg] | 0 | 240 [2.5] | 360 [3.9] | 0 | 0 | 360 [3.6] |
| PR interval on ECG | 155 | 151 | N/A | 154 | 150 | 269 |
| ECG report | Normal | Normal | 2nd degree AV block, type 1 (Wenckebach) | Normal | Normal | Prolonged PR |
| Blood Pressure (mmHG) Systolic/Diastolic** | 108/58 | 108/58 | 106/59 | 106/59 | 106/59 | 107/57 |
| Heart Rate (bpm)** | 64 | 64 | 78 | 78 | 78 | 64 |
| Case 3: 13-year-old, 46 kg at randomization | ||||||
| Weeks since verapamil started | Baseline | 6† | 10 | 22 | ||
| Verapamil (mg) [mg/kg] | 0 | 180 [3.5] | 120 [2.3] | 120 [2.2] | ||
| PR Interval | 178 | 220 | 156 | 164 | ||
| ALT (10–35) | 43 | 75 | 53 | 20 | ||
| AST (<44) | 37 | 39 | 45 | 24 | ||
| ECG report | Normal | 1st degree AV block | Normal | Normal | ||
| Blood Pressure (mmHG) Systolic/Diastolic** | 95/52 | 119/58 | 109/69 | 99/50 | ||
| Heart Rate (bpm)** | 69 | 68 | 79 | 77 | ||
| Case 4: 18-year-old, 63 kg, started verapamil in extension study after receiving placebo in RCT with verapamil overdose and acute cardiotoxicity | ||||||
| Timeline | Baseline at study enrollment | 6 weeks post max dose | 12 h post admit | 36 hrs post admit | 72 hrs post admit | |
| Verapamil (mg) [mg/kg] | 0 | 360[5.8]*** | 0 | 0 | 0 | |
| PR interval | 145 | 0 | 147 | 131 | 125 | |
| ECG report | L anterior fascicular block. Axis deviation suggestive of endocardial cushion defect | Junctional rhythm RBBB and LPFB nonspecific st and t wave changes | Sinus bradycardia left axis deviation nonspecific t wave changes | Sinus rhythm left anterior fascicular block nonspecific t wave changes | Sinus rhythm early transition nonspecific t wave changes | |
| Blood Pressure (mmHG) Systolic/Diastolic** | 121/74 | 70/30 | 110/51 | 120/66 | 133/76 | |
| Heart Rate | 89 | 43 | 47 | 55 | 86 | |
| Treatment | Atropine Norepinephrine Dopamine | Dopamine | Dopamine | |||
*Decision made by investigator to stop verapamil (masked decision).
†ALT elevated and PR prolonged, so dose decreased to 120 mg for duration of study.
**Most recent measurement shown.
***This dose was unintentionally doubled on day of admission