Safety and feasibility of intravenous sotalol loading for the prevention of ventricular arrhythmias

Abstract

Background

The use of intravenous (IV) sotalol loading following recent U.S. Food and Drug Administration (FDA) approval of a 1-day loading protocol has reduced the obligatory 3-day hospital stay for sotalol initiation when given orally. Several studies have recently demonstrated the safety and feasibility of IV loading for patients with atrial arrhythmias. However, there is a paucity of data on the feasibility and safety of IV sotalol loading for patients with ventricular arrhythmias. This study aims to assess the safety, feasibility, and length of stay (LOS) outcomes of IV sotalol loading for the prevention of ventricular arrhythmias.

Methods

A retrospective analysis was performed of all patients undergoing IV sotalol loading and oral sotalol initiation for ventricular arrhythmias, or IV sotalol loading for atrial arrhythmias between August 2021 and December 2023 at Northwestern University. Baseline characteristics, success of sotalol initiation/loading, changes in heart rate (HR) and QT/QTc, safety, and LOS were compared between patients undergoing sotalol loading/initiation for ventricular arrhythmias (IV vs. PO) and between patients undergoing IV sotalol loading for ventricular arrhythmias vs. for atrial arrhythmias.

Results

A total of 28 patients underwent sotalol loading/initiation for ventricular arrhythmias (N = 15 IV and N = 13 PO) and 41 patients underwent IV sotalol loading for atrial arrhythmias. Baseline characteristics of congestive heart failure history and left ventricular ejection fraction were worse in the ventricular arrhythmias group. There was no significant difference in the successful completion of IV sotalol loading for ventricular arrhythmias compared to oral sotalol initiation for ventricular arrhythmias or IV sotalol loading for atrial arrhythmias (86.7% vs. 92.3% vs. 90.2%, p = 0.88). There was a significant increase in ΔQTc following IV sotalol infusion for ventricular arrhythmias compared to following PO sotalol initiation for ventricular arrhythmias (46.4 ± 29.2 ms vs. 8.9 ± 32.6 ms, p = 0.004) and following IV sotalol infusion for atrial arrhythmias (46.4 ± 29.2 ms vs. 24.0 ± 25.1 ms, p = 0.018). ΔHR following IV sotalol infusion for ventricular arrhythmias was similar to ΔHR following PO sotalol initiation for ventricular arrhythmias and ΔHR following IV sotalol infusion for atrial arrhythmias (− 7.5 ± 8.7 bpm vs. − 8.5 ± 13.9 bpm vs. − 8.3 ± 13.2 bpm, p = 0.87). There were no significant differences in discontinuation for QTc prolongation (6.7% vs. 1.7% vs. 2.4%, p = 0.64) and bradycardia (13.3% vs. 7.7% vs. 9.8%, p = 0.88) between IV sotalol loading for ventricular arrhythmias, PO sotalol initiation for ventricular arrhythmias, and IV sotalol loading for atrial arrhythmias. There were no instances of hypotension, life-threatening ventricular arrhythmias, heart failure, or death. Length of stay was significantly shorter for IV sotalol loading compared to PO sotalol initiation for ventricular arrhythmias (1.1 ± 0.36 days vs. 4.2 ± 1.0 days, p < 0.0001).

Conclusion

IV sotalol loading appears feasible and safe for use in ventricular arrhythmias and results in a decreased length of stay. Despite increased comorbidities and greater increase in QTc interval following IV sotalol infusion in the ventricular arrhythmias group, there were no significant differences in successful completion of loading or adverse outcomes when compared to PO sotalol initiation for ventricular arrhythmias and IV loading for atrial arrhythmias.

Graphical Abstract

1. Introduction

Sotalol is a class III antiarrhythmic drug commonly used for maintenance of sinus rhythm and suppression of dysrhythmias in patients with atrial and ventricular arrhythmias. It carries the risk of QTc prolongation and subsequent life-threatening ventricular arrythmias [1]. Accordingly, initiation or re-initiation of sotalol requires hospitalization for continuous electrocardiographic monitoring and proximity to cardiac resuscitation equipment, if needed [2]. Oral (PO) sotalol initiation typically involves a mandatory inpatient stay of at least 3 days (5 doses) for steady-state drug levels to be reached, leading to increased utilization of healthcare resources and a burden on patients [2].

Intravenous (IV) sotalol gained US Food and Drug Administration (FDA) approval in 2009 for the maintenance of normal sinus rhythm in patients with atrial and ventricular arrhythmias who cannot tolerate oral medications. It was not until 2019 that the first use of IV sotalol for loading to accelerate initiation of PO sotalol for atrial arrhythmias was reported [3]. Subsequently, a model-informed drug development (MIDD) study led to the development of a IV sotalol loading protocol, involving 1-h IV infusion followed by 2 oral doses with serial monitoring for QTc prolongation and bradyarrhythmia prior to discharge within 1 day, and FDA approval for IV sotalol loading for atrial fibrillation was granted in 2020 [3, 4]. Subsequent studies have supported its feasibility and safety for atrial arrhythmias; however, there is limited data regarding IV sotalol loading for ventricular arrhythmias [4, 5].

This study aims to (1) compare feasibility and safety of IV sotalol loading for ventricular arrhythmias to PO sotalol initiation for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias; (2) describe QTc and heart rate (HR) trends with IV sotalol loading for ventricular arrythmia; (3) assess change in hospital length of stay with IV sotalol loading compared to PO sotalol initiation for ventricular arrythmia.

2. Methods

2.1. Patient selection and protocol description

Patients who underwent traditional PO sotalol initiation for ventricular arrhythmias (ventricular tachycardia and premature ventricular contraction) or IV sotalol loading for ventricular or atrial arrhythmias between August 2021 and December 2023 were retrospectively included. The decision to initiate PO sotalol or IV sotalol load for ventricular arrhythmias was at the discretion of the treating electrophysiologist.

In patients who underwent IV sotalol loading between August 2021 and March 2023, the FDA-approved IV sotalol loading protocol (1-h IV infusion followed by 2 oral doses prior to discharge) was followed. From March 2023 to December 2023, an expedited IV sotalol loading protocol (1-h IV infusion followed by only 1 oral dose prior to discharge) was followed in some patients. Details of the 1-h IV sotalol infusion protocol, including inclusion and exclusion criteria, can be found in the appendix of the previously published study by Liu et al. [5]. In patients who underwent PO sotalol initiation, the standard FDA-approved PO sotalol 5-dose regimen prior to discharge was followed [6]. While there was no lower limit for left ventricular ejection fraction or blood pressure, patients with decompensated heart failure or cardiogenic shock were excluded from this study.

Sotalol was stopped or dose-reduced in patients who developed significant bradycardia (HR < 50 beats per minute, bpm) or QTc prolongation (> 500 ms or > 550 ms with bundle branch block or paced rhythm). This study was approved by the Northwestern University Institutional Review Board.

2.2. Demographics and baseline characteristics

Patient demographics, baseline clinical characteristics and medical therapy, and indication for PO sotalol initiation or IV sotalol loading data were collected.

2.3. ECG characteristics

HR and QT/QTc intervals by ECG were obtained at baseline and every 15 min during 1-h IV sotalol infusion and 2 h after each PO sotalol dose. QT interval was used when HR was below 60 bpm.

2.4. Safety endpoints and outcome measures

Outcomes measures of completion of sotalol initiation/load, changes in HR and QTc interval, LOS, and continuation of PO sotalol on follow-up were evaluated. Safety endpoints of severe QTc prolongation (> 500 ms or > 550 ms with bundle branch block or paced rhythm) requiring discontinuation, severe bradycardia (< 50 bpm) requiring discontinuation, hypotension, life-threatening ventricular arrhythmias, heart failure exacerbation, and mortality were assessed.

2.5. Statistical analysis

Descriptive characteristics were reported as mean ± standard deviation or proportion, as appropriate. Continuous variables were assessed for normal distribution with the Shapiro–Wilk test. Differences in baseline demographics and characteristics, ECG characteristics, sotalol load/initiation completion, safety endpoints, and length of stay outcomes were compared using parametric tests (ANOVA, unpaired t-test, paired t-test); non-parametric tests (Mann–Whitney test, Kruskal–Wallis test, Wilcoxon signed-rank test); or categorical data tests (chi-square, Fisher’s exact test), as appropriate. JMP PRO 17 software and Microsoft Excel were used for statistical analysis.

3. Results

Between August 2021 and December 2023, a total of 28 patients underwent sotalol loading/initiation for ventricular arrhythmias (N = 15 IV and N = 13 PO), and 41 patients underwent IV sotalol loading for atrial arrhythmias. Among the IV sotalol loading for the ventricular arrhythmias group, the FDA protocol (1-h IV infusion followed by 2 oral doses prior to discharge) was followed in 10 patients, and the expedited protocol (1-h IV infusion followed by only 1 oral dose prior to discharge) was followed in 5 patients. Among the IV sotalol loading for the atrial arrhythmias group, the FDA protocol (1-h IV infusion followed by 2 oral doses prior to discharge) was followed in 32 patients, and the expedited protocol (1-h IV infusion followed by only 1 oral dose prior to discharge) was followed in 9 patients.

3.1. Demographics and baseline clinical characteristics

Patient demographics, baseline clinical characteristics and medical therapy, and indication for PO sotalol initiation or IV sotalol loading are reported in Table 1. There were no significant baseline differences between IV sotalol loading for ventricular arrhythmias and PO sotalol initiation for ventricular arrhythmias. The IV sotalol ventricular arrhythmias group had significantly greater proportion of patients with history of congestive heart failure (CHF) (75.0% vs. 36.6%, p = 0.006) and lower average left ventricular ejection fraction (LVEF) (44.5 ± 10.5% vs. 55.3 ± 11.2%, p = 0.002) compared to the IV sotalol loading for atrial arrhythmias group. Creatinine clearance (CrCl) was lower for the IV sotalol loading for ventricular arrythmia arm compared to PO sotalol initiation arm and IV sotalol loading for atrial arrhythmias arm but did not meet statistical significance (80.6 ± 24.1 mL/min vs. 87.8 ± 28.7 mL/min vs. 97.9 ± 24.0 mL/min, p = 0.06). IV sotalol load doses did not differ significantly between the atrial arrhythmias and ventricular arrhythmias arms.

Table 1.

Baseline characteristics for PO sotalol initiation and IV sotalol loading for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias

		PO sotalol initiation for ventricular arrhythmias (N = 13)	IV sotalol loading for ventricular arrhythmias (N = 15)	IV sotalol loading for atrial arrhythmias (N = 41)	P-value	P-value PO vs. IV sotalol for ventricular arrhythmias	P-value IV sotalol for ventricular vs. atrial arrhythmias
Age (mean)		63.8 ± 13.2	65.3 ± 10.5	64.5 ± 10.0	0.93	-	-
Male (%)		9 (69.2)	10 (66.7)	29 (70.7)	0.96	-	-
BMI (mean)		27.6 ± 4.5	27.2 ± 6.2	30.9 ± 6.1	0.02	0.82	0.04
HTN (%)		11 (84.6)	7 (46.7)	29 (70.7)	0.09	-	-
HLD (%)		8 (61.5)	6 (40.0)	23 (56.1)	0.46	-	-
DM (%)		4 (30.8)	3 (20.0)	5 (12.2)	0.29	-	-
CAD (%)		7 (53.9)	5 (33.3)	14 (34.2)	0.41	-	-
CrCl (mean)		87.8 ± 28.7	80.6 ± 24.1	97.9 ± 24.0	0.06	-	-
CHF (%)		9 (69.2)	12 (80.0)	15 (36.6)	0.006	0.67	0.006
LVEF (mean)		44.3 ± 15.3	44.5 ± 10.5	55.3 ± 11.2	0.003	0.96	0.002
OSA (%)		6 (46.2)	3 (20.0)	12 (29.3)	0.34	-	-
CRT (%)		1 (7.7)	2 (13.3)	2 (4.9)	0.56	-	-
BB use (%)		6 (46.2)	6 (40.0)	26 (56.1)	0.23	-	-
Non-dihydropyridine CCB use (%)		0 (0)	0 (0)	2 (4.9)	0.49	-	-
Digoxin use (%)		0 (0)	0 (0)	2 (4.9)	0.49	-	-
Wide QRS (LBBB, RBBB, IVCD, ventricular paced rhythm) (%)		7 (53.9)	5 (33.3)	13 (31.7)	0.34	-	-
Type of ventricular arrhythmia	PVC	5 (38.5)	4 (26.7)	-	-	0.69	-
	VT	8 (61.5)	11 (73.3)
PO sotalol dose in mg (%)	80	2 (15.4)	-	-	-	-	-
	120	11 (84.6)
IV sotalol dose in mg (%)	60	-	1 (6.7)	8 (19.5)		-	0.06
	75		2 (13.3)	1 (2.4)
	82.5		1 (6.7)	9 (22.0)
	90		4 (26.7)	17 (41.5)	-
	112.5		3 (20.0)	2 (4.9)
	125		4 (26.7)	4 (9.6)

Abbreviations: BMI body mass index, HTN hypertension, HLD hyperlipidemia, DM diabetes mellitus, CAD coronary artery disease, CrCl creatinine clearance, CHF congestive heart failure, LVEF left ventricular ejection fraction, OSA obstructive sleep apnea, CRT cardiac resynchronization therapy, BB beta blocker, CCB calcium channel blocker, LBBB left bundle branch block, RBBB right bundle branch block, IVCD interventricular conduction delay, PVC premature ventricular contraction, VT ventricular tachycardia, PO by mouth, IV intravenous

3.2. ECG characteristics

ECG characteristics (QTc and HR) during PO sotalol initiation for ventricular arrhythmias, IV sotalol loading for ventricular arrhythmias, and IV sotalol loading for atrial arrhythmias are noted in Tables 2 and 3 as well as Figs. 1 and 2. A significantly greater increase in ΔQTc was observed following IV sotalol infusion for ventricular arrhythmias compared to following PO sotalol initiation for ventricular arrhythmias (46.4 ± 29.2 ms vs. 8.9 ± 32.6 ms, p = 0.004) and IV sotalol infusion for atrial arrhythmias (46.4 ± 29.2 ms vs. 24.0 ± 25.1 ms, p = 0.018). ΔHR following IV sotalol infusion for ventricular arrhythmias was similar to ΔHR following PO sotalol initiation for ventricular arrhythmias and ΔHR following IV sotalol infusion for atrial arrhythmias (− 7.5 ± 8.7 bpm vs. − 8.5 ± 13.9 bpm vs. − 8.3 ± 13.2 bpm, p = 0.87). The peak in mean QTc was noted to occur following IV sotalol infusion for both ventricular arrhythmias and atrial arrhythmias.

Table 2.

ECG characteristics during different times of PO sotalol initiation and IV sotalol loading for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias

	PO sotalol initiation for ventricular arrhythmia (N = 13)		IV sotalol loading for ventricular arrhythmia (N = 15)		IV sotalol loading for atrial arrhythmia (N = 41)		P-value		P-value PO vs. IV sotalol for ventricular arrhythmia		P-value IV sotalol for ventricular vs. atrial arrhythmia
	HR (mean)	QTc (mean)	HR (mean)	QTc (mean)	HR (mean)	QTc (mean)	HR	QTc	HR	QTc	HR	QTc
Baseline	76.2 ± 11.6	464.1 ± 33.2	69.8 ± 8.4	452.9 ± 27.5	72.6 ± 11.4	455.3 ± 34.3	0.37	0.63	-	-	-	-
Completion of IV load	-	-	62.8 ± 2.8	501.4 ± 40.0	63.7 ± 11.1	478.2 ± 30.3	-	-	-	-	0.79	0.03
After the final PO dose	67.7 ± 14.5	473.0 ± 28.4	63.8 ± 11.5	480.2 ± 35.1	61.5 ± 8.0	473.7 ± 31.0	0.34	0.77	-	-	-	-

Abbreviations: PO by mouth, IV intravenous, HR heart rate

Table 3.

Comparison of ΔHR and ΔQTC following PO sotalol initiation for ventricular arrhythmias, IV sotalol loading for ventricular arrhythmias, and IV sotalol loading for atrial arrhythmias arms (amongst patients who successfully completed sotalol initiation/loading)

	PO sotalol initiation for ventricular arrhythmia (N = 12)		IV sotalol loading for ventricular arrhythmia (N = 13)		IV sotalol loading for atrial arrhythmia (N = 37)		P-value		P-value PO vs. IV sotalol for ventricular arrhythmia		P-value IV sotalol for ventricular vs. atrial arrhythmia
	ΔHR (mean)	ΔQTc (mean)	ΔHR (mean)	ΔQTc (mean)	ΔHR (mean)	ΔQTc (mean)	ΔHR	ΔQTc	ΔHR	ΔQTc	ΔHR	ΔQTc
Completion of load	−8.5 ± 13.9	8.9 ± 32.6	−7.5 ± 8.7	46.4 ± 29.2	−8.3 ± 13.2	24.0 ± 25.1	0.87	0.003	-	0.004	-	0.018

Abbreviations: PO by mouth, IV intravenous, HR heart rate

Fig. 1.

ΔQTc following PO sotalol initiation and IV sotalol loading for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias.

Abbreviations: PO by mouth, IV intravenous

Fig. 2.

ΔHR following PO sotalol initiation and IV sotalol loading for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias.

Abbreviations: HR heart rate, PO by mouth, IV intravenous

3.3. Outcome measures and safety endpoints

Table 4 contains outcome and safety data for PO sotalol initiation and IV sotalol loading for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias. Rates of successful completion of IV sotalol loading for ventricular arrhythmias compared to oral sotalol initiation for ventricular arrhythmias or IV sotalol loading for atrial arrhythmias were similar (86.7% vs. 92.3% vs. 90.2%, p = 0.88). There were no significant differences between IV sotalol loading for ventricular arrhythmias, PO sotalol initiation for ventricular arrhythmias, and IV sotalol loading for atrial arrhythmias in discontinuation for QTc prolongation (6.7% vs. 1.7% vs. 2.4%, p = 0.64) or bradycardia (13.3% vs. 7.7% vs. 9.8%, p = 0.88). There were no instances of hypotension, life-threatening ventricular arrhythmias, heart failure, or death in any group. Length of stay (LOS) was significantly shorter for IV sotalol loading compared to PO sotalol initiation for ventricular arrhythmias (1.1 ± 0.36 days vs. 4.2 ± 1.0 days, p < 0.0001) and similar to IV sotalol loading for atrial arrhythmias (1.1 ± 0.36 days vs. 1.0 ± 0.2 days, p = 0.29). Rates of continuation of PO sotalol on outpatient follow up amongst patients with follow up data available were similar across groups (p = 0.22).

Table 4.

Outcome data for PO sotalol initiation and IV sotalol loading for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias

		PO sotalol initiation for ventricular arrhythmia (N = 13)	IV sotalol loading for ventricular arrhythmia (N = 15)	IV sotalol loading for atrial arrhythmia (N = 41)	P-value	P-value PO vs. IV sotalol for ventricular arrhythmia	P-value IV sotalol for ventricular vs. atrial arrhythmia
Completion of sotalol load (%)		12 (92.3)	13 (86.7)	37 (90.2)	0.88	-	-
Reason for dis-continuation	QTc prolongation (%)	1 (7.7)	1 (6.7)	1 (2.4)	0.64	-	-
	Bradycardia (%)	1 (7.7)	2 (13.3)	4 (9.8)	0.88	-	-
	Hypotension (%)	0 (0.0)	0 (0.0)	0 (0.0)	-	-	-
	Life threatening ventricular arrhythmia (%)	0 (0.0)	0 (0.0)	0 (0.0)	-	-	-
	Heart failure exacerbation (%)	0 (0.0)	0 (0.0)	0 (0.0)	-	-	-
	Mortality (%)	0 (0.0)	0 (0.0)	0 (0.0)	-	-	-
Length of hospital admission in days (mean)		4.2 ± 1.0	1.1 ± 0.36	1.0 ± 0.2	< 0.0001	< 0.0001	0.29
Discharge on PO sotalol amongst patients who completed IV sotalol loading (%)		-	12 (92.3)	34 (91.9)	-	-	1.00
Outpatient continuation of PO sotalol amongst those with follow-up data available (%)		9 (100.0)	9 (75.0)	28 (90.3)	0.22	-	-
Follow up duration in weeks (mean)		9.3 ± 9.1	7.1 ± 3.0	6.4 ± 2.8	0.80	-	-

Abbreviations: PO by mouth, IV intravenous, HR heart rate

4. Discussion

Much of the current data supporting the safety and feasibility of IV sotalol loading is limited to its use in atrial arrhythmias. The PEAKS study was a prospective, multicenter observational registry of patients undergoing elective IV sotalol load for atrial arrhythmias. Of 167 patients enrolled, only 2 patients required discontinuation of sotalol infusion. The study also noted a peak in QTc prolongation and nadir in heart rate to occur during IV sotalol infusion. The mean length of stay was 1.1 days. Overall, the authors suggested IV sotalol loading to be safe in atrial arrhythmias with low rates of discontinuation due to adverse effects and a considerable reduction in duration of hospital stay [7]. The DASH AF trial was a multicenter study that evaluated the feasibility and safety of a further expedited IV sotalol load protocol (IV infusion followed by 1 PO dose before discharge) compared to traditional PO sotalol loading in 120 patients with atrial arrhythmias. There were statistically similar rates of load completion, QTc prolongation, and incidences of ventricular arrhythmias and bradyarrhythmia between the IV sotalol load group and PO sotalol initiation group [8]. The study further extrapolated potential cost savings of $3500.68 per admission with IV sotalol loading compared to traditional PO sotalol loading [8].

Our study is the first to assess the feasibility and safety of IV sotalol loading for patients with ventricular arrhythmias, to our knowledge. These single-center retrospective data suggest that IV sotalol loading for ventricular arrhythmias may have similar rates of successful load completion and safety outcomes as traditional PO sotalol initiation for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias. Notably, ΔQTc was noted to be greater following IV sotalol infusion for ventricular arrhythmias compared to PO sotalol initiation for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias. Hospital length of stay was significantly reduced with IV sotalol loading compared to traditional PO sotalol initiation for ventricular arrhythmias.

The significant increase in QTc prolongation following IV sotalol infusion for ventricular arrhythmias as compared to PO sotalol initiation is consistent with pharmacokinetic computer modeling of IV sotalol in the MIDD study [9]. Furthermore, the peak in mean QTc duration was observed to occur following IV sotalol infusion for ventricular arrhythmias in our study, similar to prior published findings of peak QTc prolongation occurring during sotalol infusion with subsequent attenuation on transition to PO formulation for atrial arrhythmias [7, 8]. Given these findings, the switch to an expedited IV loading protocol (IV infusion followed by a single oral dose) in some patients during the study period is not thought to have affected the overall results when comparing IV sotalol loading to oral sotalol initiation. However, further study comparing the safety of the FDA-approved IV sotalol loading protocol (IV infusion followed by 2 PO doses before discharge) to the expedited IV loading protocol (IV infusion followed by 1 PO dose before discharge) for ventricular arrhythmias should be considered in a larger patient population [8]. The poorer baseline cardiac substrate (greater prevalence of congestive heart failure and lower average LVEF) as well as the trend towards poorer CrCl of the ventricular arrhythmias group may contribute to the significant difference in ΔQTc following IV sotalol infusion between the ventricular arrhythmias group and the atrial arrhythmias group. Indeed, risk factors for QTc prolongation in patients receiving sotalol include congestive heart failure, reduced LVEF, and reduced creatinine clearance [10, 11]. However, despite the sicker patient population, the frequency of IV sotalol load discontinuation due to QTc prolongation was not significantly different as compared to the atrial arrhythmias group. Significant bradycardia limiting sotalol loading was also infrequent across sotalol load formulations and indications, and there were no incidences of serious adverse outcomes, supporting the safety and feasibility of IV sotalol loading for ventricular arrhythmias.

There was a significantly shorter average LOS with IV sotalol loading compared to PO sotalol initiation for ventricular arrhythmias by approximately 3.1 days. These results mirror the average length of stay reduction in previously published data on IV sotalol loading for atrial arrhythmias [8].

4.1. Study limitations

The retrospective, observational nature of the study limits control of confounding variables and biases that may have impacted key outcomes. Furthermore, the cohort sizes were relatively small, limiting the power of our study and allowing for outcomes (particularly QTc duration) to be more influenced by patient-to-patient variability. While this study yielded favorable results supporting safety and feasibility of IV sotalol loading to expedite PO sotalol initiation for ventricular arrhythmias, larger, prospective data are needed to validate our findings.

4.2. Conclusion

IV sotalol loading for ventricular arrhythmias was well-tolerated with similar load completion rates and safety as PO sotalol initiation for ventricular arrhythmias and IV sotalol loading for atrial arrhythmias, despite a greater degree of QTc prolongation following IV infusion for ventricular arrhythmias. In addition, the use of IV sotalol loading to expedite initiation of PO sotalol for ventricular arrhythmias significantly reduced the average length of hospital admission by approximately 3 days compared to traditional PO sotalol initiation. Larger, prospective data are needed to validate these findings.

Data Availability

Data is available upon reasonable request to the corresponding author.